DK154824B - POLYCRYSTALLIC DIAMOND BODIES AND PROCEDURES FOR PREPARING IT - Google Patents
POLYCRYSTALLIC DIAMOND BODIES AND PROCEDURES FOR PREPARING IT Download PDFInfo
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Description
DK 154824 BDK 154824 B
Opfindelsen angår et polykrystallinsk diamantlegeme/ især i form af en skive, stav eller hul cylinder, med en masse af diamantkrystaller.The invention relates to a polycrystalline diamond body / especially in the form of a disc, rod or hollow cylinder, with a mass of diamond crystals.
Fra US 2.391.589 kendes et polykrystallinsk diamantlegeme, 5 hvori bindemidlet er en blanding af siliciumcarbid, borcarbid og aluminiumoxid, og fra US 4.042.347 kendes der et polykrystallinsk diamantlegeme, hvori bindemidlet er en metal- og polymermatrix, men en teknisk hindring for opnåelse af et diamantkompositmateriale med høj tæthed (stort volumenindhold af diamant) og fremstillet under 10 diamantstabilitetstrykområdet har hidtil været en manglende udvikling af et egnet bindemiddel, som var i stand til at trænge ind i eller infiltrere kapillarhulrummene i et tætpakket diamantpulver af fin partikelstørrelse. Bindemidlet skal endvidere danne en termisk stabil, stærk binding med diamant og må ikke omdanne diamanten til grafit 15 eller reagere for vidtgående med diamanten.From US 2,391,589 there is known a polycrystalline diamond body, wherein the binder is a mixture of silicon carbide, boron carbide and alumina, and from US 4,042,347 a polycrystalline diamond body is known in which the binder is a metal and polymer matrix, but a technical barrier to obtaining of a high density diamond composite material (high volume diamond volume) and manufactured below the diamond stability pressure range has heretofore been a failure to develop a suitable binder capable of penetrating or infiltrating the capillary cavities in a densely packed fine particle size diamond powder. The binder must also form a thermally stable, strong bond with the diamond and must not transform the diamond into graphite 15 or react too far with the diamond.
Det polykrystallinske diamantlegeme er ifølge opfindelsen ejendommeligt ved, at diamantkrystallerne er bundet til hinanden med et siliciumatomholdigt bindemiddel, som udgøres af siliciumcarbid og frit silicium, at diamantkrystallerne har en størrelse på fra 1 til 1000 pm, 20 at diamantkrystaltætheden i legemet ligger i området fra 65 til højst 80 volumenprocent af legemet, at andelen af siliciumatomholdigt bindemiddel udgør op til 35 volumenprocent af legemet, at bindemidlet er fordelt i alt væsentligt ligeligt i legemet, at den andel af bindemidlet, som er i kontakt med diamantoverflader i alt væsentligt 25 består af siliciumcarbid, og at diamantlegemet i alt væsentligt er porefrit.According to the invention, the polycrystalline diamond body is characterized in that the diamond crystals are bonded to each other with a silicon atom-containing binder constituted by silicon carbide and free silicon, that the diamond crystals have a size of from 1 to 1000 µm, that the diamond crystal density in the body ranges from 65 to a maximum of 80% by volume of the body, that the proportion of silicon-containing binder constitutes up to 35% by volume of the body, that the binder is distributed substantially evenly within the body, that the proportion of the binder which contacts diamond surfaces is substantially composed of silicon carbide and that the diamond body is essentially pore-free.
Det polykrystallinske legeme ifølge opfindelsen er anvendeligt som slibemateriale, skæreværktøj, dyse eller anden slidbestandig komponent.The polycrystalline body of the invention is useful as abrasive material, cutting tool, nozzle or other abrasion resistant component.
30 Opfindelsen angår også en fremgangsmåde til fremstilling af det polykrystallinske diamantiegeme ifølge opfindelsen under anvendelse af et varmepresningstrin, hvilken fremgangsmåde er ejendommelig ved det i krav 5's kendetegnende del angivne.The invention also relates to a process for producing the polycrystalline diamond body of the invention using a heat pressing step which is characterized by the characterizing part of claim 5.
Ved fremgangsmåden ifølge opfindelsen anvendes der tryk, som 35 er væsentligt lavere end dem, der er påkrævet i diamantstabilitetsområdet.In the method of the invention, pressures which are substantially lower than those required in the diamond stability range are used.
Opfindelsen vil i det følgende blive nærmere forklaret i forbindelse med tegningen, hvor: figur 1 viser et tværsnit af et apparat til frembringelse af 2The invention will be further explained in the following with reference to the drawing, in which: Figure 1 shows a cross-section of an apparatus for producing 2
DK 15 4 8 2 4 BDK 15 4 8 2 4 B
en hulhed i et tryktransmitterende pulvermedium; figur 2 viser et tværsnit af et apparat til udøvelse af et i alt væsentligt isostatisk tryk på cellen, dvs. hulheden og Indholdet, ved hjælp af et tryktransmitterende 5 pulvermedium til dimensionsmæssig stabilisering af cellen under frembringelse af et i alt væsentligt iso-statisk sytem; figur 3 viser et tværsnit af en grafitform til samtidig afgivelse af varme og tryk til det i alt væsentligt iso-10 statiske system, og hvor cellen ses indeholdt deri, og figur 4 viser et fotografi (forstørret 690X) af et poleret tværsnit af et diamantlegeme, som er frembragt ved fremgangsmåden ifølge, opfindelsen, hvorhos diamantindholdet udgjorde 72 volumenprocent af legemet. Den 15 lyse, gråhvide fase i figur 4 er bindemediet, og den grå fase er diamantkrystal. De mørke pletter er urenheder.a cavity in a pressure transmitting powder medium; Figure 2 shows a cross-section of an apparatus for exerting a substantially isostatic pressure on the cell, i.e. the cavity and contents, by means of a pressure transmitting powder medium for dimensional stabilization of the cell to produce a substantially isostatic system; Figure 3 shows a cross-section of a graphite form for simultaneously delivering heat and pressure to the substantially iso-static system and where the cell is seen contained therein, and Figure 4 shows a photograph (enlarged 690X) of a polished cross-section of a diamond body produced by the method of the invention wherein the diamond content was 72% by volume of the body. The 15 light gray-white phase in Figure 4 is the binder and the gray phase is diamond crystal. The dark spots are impurities.
Ved udøvelse af fremgangsmåden ifølge opfindelsen underkastes en masse bestående af diamantkrystaller i kontakt med en silicium-20 masse et koldpresningstrin ved omgivelsestemperaturen eller stuetemperatur til i alt væsentlig fuldstændig stabilisering af deres dimensioner i alt væsentligt ensartet og derpå et varmpresningstrin, hvorved siliciumet siver ind gennem massen af sammenpressede diamantkrystaller.In practicing the method of the invention, a mass of diamond crystals in contact with a silicon mass is subjected to a cold pressing step at ambient or room temperature to substantially complete stabilization of their dimensions substantially uniformly and then a hot pressing step, whereby the silicon seeps through the mass. of compressed diamond crystals.
25 Diamantkrystalmassen og siliciummassen kan have mange for skellige former. F.eks. kan hver masse have form af et lag med det ene lag overlejret det andet. Alternativt kan siliciumet have form af et rør eller en cylinder med et gennemgående hulrum, .og diamantkrystallerne kan være pakket i siliciumcylinderens hulrum. I en 20 anden udførelsesform kan siliciumet have form af en stang, som kan være anbragt centralt i en hulhed og det omsluttende rum mellem siliciumstangen og den indre væg af hulheden være pakket med diamantkrystaller.25 The diamond crystal mass and the silicon mass can have many different shapes. Eg. each mass may take the form of one layer with one layer superimposed on the other. Alternatively, the silicon may be in the form of a tube or cylinder with a through cavity, and the diamond crystals may be packed in the silicon cylinder cavity. In another embodiment, the silicon may be in the form of a rod which may be centrally located in a cavity and the enclosing space between the silicon rod and the inner wall of the cavity may be packed with diamond crystals.
Diamantkrystallerne, der anvendes ved den foreliggende frem-35 gangsmåde, kan være naturlige eller syntetiske, dvs. menneskeskabte. De varierer i størrelse med hensyn til største dimension fra ca. 1 pm og til ca. 1000 pm, og den bestemte størrelse, eller de bestemte størrelser, der anvendes, afhænger i stor udstrækning af den særlige pakning eller tæthed af diamantkrystaller, der ønskes,The diamond crystals used in the present method may be natural or synthetic, i.e. manmade. They vary in size with respect to largest dimension from approx. 1 pm to approx. 1000 µm, and the specific size or sizes used depend to a large extent on the particular packing or density of diamond crystals desired,
DK 154824 BDK 154824 B
3 og også af den særlige anvendelse af det tilvejebragte legeme. Imidlertid må krystaller med størrelse mindre end 5 pm tilbiandes krystaller større end 10 pm, og krystaller, der er mindre end 5 pm med hensyn til størrelse, bør fortrinsvis ikke udgøre mere end 50 5 volumenprocent af diamantblandingen for at muliggøre tilfredsstillende indsivning af siliciumet. Til de fleste slibemiddelanvendelser foretrækkes diamentkrystaller, der ikke er større end ca. 60 pm. Krystallerne skal fortrinsvis, for at gøre pakningen af diamantkrystaller maksimal, sorteres efter størrelse for at komme til at 10 indeholde en række størrelser, dvs. krystaller af lille, medium og stor størrelse. Fortrinsvis skal de størrelsessorterede krystaller ligge mellem ca. 1 pm og ca. 60 pm, og inden for dette størrelsesområde stammer fortrinsvis ca. 60 volumenprocent til ca. 80 volumenprocent af den totale masse af krystaller fra den størrelsesmæssigt 15 større del af området, ca. 5-10 volumenprocent er af medium størrelse, og resten udgøres af størrelsesmæssigt små krystaller eller partikler.3 and also of the particular use of the body provided. However, crystals of size less than 5 microns should be offered crystals larger than 10 microns, and crystals of less than 5 microns in size should preferably not constitute more than 50% by volume of the diamond blend to allow satisfactory silicon sieving. For most abrasive applications, diamonds crystals not greater than about 10 cm are preferred. 60 pm. Preferably, in order to maximize the diamond crystal packing, the crystals must be sorted by size to contain a variety of sizes, i.e. crystals of small, medium and large size. Preferably, the size-sorted crystals should be between ca. 1 pm and approx. 60 µm, and within this size range, preferably about 60% by volume to approx. 80% by volume of the total mass of crystals from the larger portion of the region, approx. 5-10% by volume is of medium size and the rest is made up of relatively small crystals or particles.
Klassificeringen af diamentkrystallerne lettes ved behandling af de større diamentkrystaller i en strålemølle. Diamantkrystallerne er 20 fortrinsvis kemisk rensede for at fjerne eventuelle oxider eller andre urenheder fra deres overflader inden anvendelsen i den foreliggende fremgangsmåde. Dette kan udføres ved at opvarme diamantkrystallerne i hydrogen ved ca. 900°C i ca. 1 time.The classification of the diamond crystals is facilitated by the treatment of the larger diamond crystals in a jet mill. The diamond crystals are preferably chemically purified to remove any oxides or other impurities from their surfaces prior to use in the present process. This can be done by heating the diamond crystals in hydrogen at approx. 900 ° C for approx. 1 hour.
Ifølge den foreliggende opfindelse anvendes silicium til at 25 infundere eller sive ind i porerne eller mellemrummene mellem diamantkrystallerne. Siliciumet, som f.eks. kan foreligge i. form af et fast legeme eller pulver, anvendes i en mængde, der er tilstrækkelig til at fylde porerne eller mellemrummene i diamantkrystalmassen, der har en krystaltæthed på mere end 65 volumenprocent af det rumfang, 30 som krystallerne optager. Almindeligvis kan siliciumet anvendes i en mængde på mellem ca. 25 volumenprocent og ca. 80 volumenprocent, men til opnåelse af de bedste resultater fortrinsvis på fra ca. 30 til ca. 60 volumenprocent af rumfanget af diamantkrystaller med en krystaltæthed på mere end 65 volumenprocent.According to the present invention, silicon is used to infuse or seep into the pores or gaps between the diamond crystals. The silicon, e.g. may be in the form of a solid body or powder, used in an amount sufficient to fill the pores or gaps in the diamond crystal mass having a crystal density greater than 65% by volume of the volume occupied by the crystals. In general, the silicon can be used in an amount of between about 25% by volume and approx. 80% by volume, but to obtain the best results preferably from approx. 30 to approx. 60% by volume of the volume of diamond crystals with a crystal density greater than 65% by volume.
35 Det foreliggende varmpresningstrin udføres i en atmosfære, som ikke har nogen signifikant, skadelig effekt på diamantkrystallernes egenskaber eller det indsivende silicium. Specielt kan varmpresningstrinnet udføres i praktisk talt vakuum eller i en inert gas som f.eks. argon eller helium, eller det kan udføres i nitrogen ellerThe present hot pressing step is carried out in an atmosphere which has no significant detrimental effect on the properties of the diamond crystals or the silicon ingested. In particular, the hot pressing step may be carried out in practically a vacuum or in an inert gas such as e.g. argon or helium, or it can be carried out in nitrogen or
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4 hydrogen. Den foreliggende varmpresning udføres tilstrækkeligt hurtigt, således at der ikke finder nogen signifikant reaktion sted mellem det flydende silicium og nitrogen eller hydrogen. Det foreliggende varmpresningstrin kan ikke udføres i atmosfærisk luft, da 5 diamant i atmosfærisk luft ved mere end 800°C hurtigt omdannes til grafit, og det flydende silicium ville blive oxideret under dannelse af fast kiselsyreanhydrid, inden en signifikant infusion af flydende silicium i diamantmassen ville have fundet sted.4 hydrogen. The present hot pressing is carried out sufficiently quickly so that no significant reaction occurs between the liquid silicon and nitrogen or hydrogen. The present hot pressing step cannot be carried out in atmospheric air since 5 diamonds in atmospheric air at more than 800 ° C are rapidly converted to graphite and the liquid silicon would be oxidized to form solid silicic anhydride before a significant infusion of liquid silicon into the diamond mass would have occurred.
Den nævnte varmpresning udføres ved mellem den temperatur, 10 ved hvilken silicium bliver flydende, og ca. 1600°C, under et tryk, som kun behøver at være tilstrækkeligt ved varmpresningstemperaturen til at nedbryde modstandsdygtige grænsefladelag (eng: interfacial refractory layers) i diamantmassen, som forhindrer penetrering med flydende silicium gennem porerne deri, og sædvan-15 ligvis kræver dette et minimumstryk på ca. 34,5 bar overtryk (500 psi). Specielt kan varmpresningstrykket variere fra ca. 34,5 bar overtryk (500 psi) til ca. 1380 bar overtryk (20.000 psi), men almindeligvis ligger det mellem ca. 69 bar overtryk (1.000 psi) og ca. 690 bar overtryk (10.000 psi). Varmpresningstryk større end ca.Said hot pressing is carried out at between the temperature at which silicon becomes liquid and approx. At a pressure which need only be sufficient at the hot pressing temperature to break down interfacial refractory layers in the diamond mass which prevent liquid silicon penetration through the pores therein and usually this requires a minimum pressure of approx. 34.5 bar overpressure (500 psi). Specifically, the hot pressing pressure may vary from approx. 34.5 bar overpressure (500 psi) to approx. 1380 bar overpressure (20,000 psi), but it usually ranges between approx. 69 bar overpressure (1,000 psi) and approx. 690 bar overpressure (10,000 psi). Hot pressing pressure greater than approx.
20 690 bar overtryk (10.000 psi) tilvejebringer ingen signifikante fordele. Ligeledes tilvejebringer temperaturer højere end 1600°C ingen signifikante fordele og kan føre til omdannelse af diamanterne til grafit i øget grad.20,690 bar overpressure (10,000 psi) provides no significant benefits. Likewise, temperatures higher than 1600 ° C provide no significant benefits and may lead to the conversion of the diamonds to graphite to a greater extent.
Ved en temperatur, ved hvilken silicium bliver flydende, forstås 25 her en temperuatur, ved hvilken siliciumet er i stand til let at flyde.Here, a temperature at which silicon becomes liquid is understood to mean a temperature at which the silicon is able to flow easily.
Når silicium er ved dets smeltetemperatur, som i litteraturen er angivet til at gå fra ca. 1412°C til ca. 1430°C, har det en høj viskositet, men efterhånden som dets temperatur hæves, bliver det mindre viskøst, og ved en temperatur på ca. 10° over dets smelte-30 punkt bliver det flydende. Temperaturen, ved hvilken siliciumet er flydende, er den temperatur, ved hvilken det vil infundere eller sive ind gennem de kapillarstore passager, mellemrum eller porer i den foreliggende komprimerede diamantkrystalmasse, der har en krystal-tæthed større end 65 volumenprocent. Med endnu yderligere øgning 35 af temperaturen stiger flydeevnen for det flydende silicium, hvilket resulterer i en hurtigere penetrationshastighed gennem diamant-krystalmassen, og ved maksimumvarmpresningstemperaturen på ca.When silicon is at its melting temperature, which in the literature is stated to go from ca. 1412 ° C to approx. 1430 ° C, it has a high viscosity, but as its temperature is raised it becomes less viscous and at a temperature of approx. 10 ° above its melting point it becomes liquid. The temperature at which the silicon is liquid is the temperature at which it will infuse or seep through the capillary-sized passages, gaps, or pores of the present compacted diamond crystal mass, having a crystal density greater than 65% by volume. With even further increase of 35, the flowability of the liquid silicon increases, resulting in a faster penetration rate through the diamond-crystal mass, and at the maximum heat-pressing temperature of approx.
1600°C har det flydende silicium sin største flydeevne og den hurtigste penetrationshastighed gennem krystalmassen.At 1600 ° C, the liquid silicon has its greatest flowability and the fastest penetration rate through the crystal mass.
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Med det i figur 1 viste apparat udpresses en hulhed af forud fastlagt størrelse i et tryktransmitterende pulvermedium 19a ved hjælp af en form 9. På dette punkt behøver man kun at afgive tilstrækkelig tryk, almindeligvis ca. 690 bar overtryk (10.000 psi) til 5 ca. 3450 bar overtryk (50.000 psi), med stemplet 23a til at gøre pulveret 19a i det mindste i alt væsentligt formstabilt, således at når trykket fjernes, dvs. når stemplet 23a trækkes tilbage, kan formen 9 fjernes og efterlade hulheden 11, som formen har trykket i pulveret.With the apparatus shown in Figure 1, a cavity of predetermined size is extruded in a pressure transmitting powder medium 19a by means of a mold 9. At this point only sufficient pressure, usually approx. 690 bar overpressure (10,000 psi) to approx. 3450 bar overpressure (50,000 psi), with the plunger 23a for making the powder 19a at least substantially stable, so that when the pressure is removed, i.e. when the plunger 23a is withdrawn, the mold 9 can be removed leaving the cavity 11 which the mold has pressed into the powder.
Formen 9 kan bestå af et hvilket som helst materiale med glat 10 overflade, som f.eks. rustfrit stål eller hirdtmetal, der kan modstå det afgivne tryk, og som kan fjernes fra det sammenpressede pulver og lade hulheden 11, som formen har trykket deri, tilbage.The mold 9 may consist of any smooth surface 10 material, e.g. stainless steel or hard metal which can withstand the pressure released and which can be removed from the compressed powder and leave the cavity 11 as the mold has pressed therein.
Når formen 9 i figur 1 er trukket tilbage og har efterladt hulheden 11, anbringes i hulheden en skive 12 af silicium og en 15 diamantkrystalmasse i kontakt med siliciumet. For at sikre at diamantkrystalmassen har en tykkelse, der er som ønsket for det resulterende polykrystailinske legeme, skal hulheden være af sådan en størrelse, at der intet frit rum er til overs deri, hvilket ville muliggøre en omplacering eller større bevægelse af diamantpartiklerne 20 under en senere koldpresning, som tjener til stabilisering af systemet med hensyn til dimensioner, som vist i figur 2. En yderligere mængde tryktransmitterende pulver placeres derpå over hulheden og dens indhold, således at der tilvejebringes en pulver-indesluttet celle 10, dvs. hulhed og indhold, som vist i figur 2.When the mold 9 in Figure 1 is withdrawn leaving the cavity 11, a disc 12 of silicon and a diamond crystal mass are placed in contact with the silicon. To ensure that the diamond crystal mass has a thickness as desired for the resulting polycrystalline body, the cavity must be of such a size that there is no free space left therein, which would allow for the displacement or greater movement of the diamond particles 20 during later cold pressing which serves to stabilize the system in terms of dimensions, as shown in Figure 2. An additional amount of pressure transmitting powder is then placed over the cavity and its contents so as to provide a powder-enclosed cell 10, i. holiness and content, as shown in Figure 2.
25 Som vist i figur 2 underkastes cellen 10 derpå et koldpres ningstrin, som udføres ved stue- eller omgivelsestemperatur, hvortil der kun kræves påført tilstrækkeligt tryk til at tilvejebringe et med hensyn til dimensioner stabiliseret, praktisk talt isostatisk system. I figur 2 er cellen 10 i den cylindriske kerne af trykformen 20 omgivet 30 af en masse 19, som består af tryktransmitterende pulvermedium.As shown in Figure 2, cell 10 is then subjected to a cold pressing step performed at room or ambient temperature to which only sufficient pressure is required to provide a dimensionally stabilized, practically isostatic system. In Figure 2, the cell 10 in the cylindrical core of the printing mold 20 is surrounded 30 by a mass 19 which consists of pressure transmitting powder medium.
Det foreliggende tryktransmitterende pulvermedium indeholder meget små partikler, fortrinsvis sigte 0,037 mm (-400 mesh) partikler, af et tryktransmitterende pulvermedium, som bevares praktisk talt usintret under de tryk- og temperaturbetingelser, der anvendes 35 ved den foreliggende fremgangsmåde, og som er praktisk talt inert over for flydende silicium. Typiske eksempler på et sådant pulver er hexagonalt bornitrid og siliciumnitrid. Denne tryktransmitterende partikelmasse eller dette tryktransmitterende pulvermedium bevirker udøvelse af tilnærmelsesvis eller praktisk talt isostatisk tryk på 6The present pressure transmitting powder medium contains very small particles, preferably sieve 0.037 mm (-400 mesh) particles, of a pressure transmitting powder medium which is kept practically unsintered under the pressure and temperature conditions used in the present process and which is practically inert to liquid silicon. Typical examples of such a powder are hexagonal boron nitride and silicon nitride. This pressure transmitting particle mass or this pressure transmitting powder medium causes the application of approximately or practically isostatic pressure of 6
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cellen 10, hvorved cellen 10 og dens indhold bliver stabiliseret med hensyn til dimensioner, dvs. densificeret, praktisk talt ensartet, hvorved der tilvejebringes et formet, i alt væsentligt isostatisk system bestående af den puiverindesluttede celle, i hvilken tætheden 5 af det resulterende, komprimerede lag af krystaller er større end 65 volumenprocent af de komprimerede krystallers rumfang. Trykformen 20 (ring 22 og stemplerne 23, 23a) kan fremstilles af værktøjsstål, og hvis det ønskes, kan ringen 22 som vist være forsynet med en bøsning . 22a af sintret hårdtmetal for at muliggøre anvendelsen af 10 tryk så høje som 13.800 bar overtryk (200.000 psi) ved det i figur 2 viste koldpresningstrin. .Tryk højere end 13.800 bar overtryk (200.000 psi) tilvejebringer ingen signifikant fordel. Inden for rammerne af stemplet 23, bøsningen 22a og stemplet 23a, som vist i figur 2 for koldpresningstrinnet, udøves der fortrinsvis tryk i 15 området fra ca. 1380 bar overtryk (20.000 psi) til ca. 6900 bar overtryk (100.000 psi) og almindeligvis op til 3450 bar overtryk (50.000 psi) på det tryktransmitterende pulvermedium ved hjælp af stemplerne, der drives på konventionel mide, indtil det pålagte tryk stabiliseres, således, som det gøres ved konventionel pulverpak-20 ningsteknologi.cell 10, whereby cell 10 and its contents are stabilized with respect to dimensions, i.e. densified, substantially uniform, providing a shaped, substantially isostatic system consisting of the powder-enclosed cell, in which the density 5 of the resulting compressed layer of crystals is greater than 65% by volume of the volume of the compressed crystals. The pressure mold 20 (ring 22 and pistons 23, 23a) can be made of tool steel, and if desired, the ring 22 may as shown be provided with a bushing. 22a of sintered cemented carbide to enable the application of 10 pressures as high as 13,800 bar overpressure (200,000 psi) at the cold pressing step shown in Figure 2. Pressures higher than 13,800 bar overpressure (200,000 psi) provide no significant benefit. Within the framework of the plunger 23, the bushing 22a and the plunger 23a, as shown in Figure 2 for the cold pressing step, pressure is preferably exerted in the range of from approx. 1380 bar overpressure (20,000 psi) to approx. 6900 bar overpressure (100,000 psi) and generally up to 3450 bar overpressure (50,000 psi) on the pressure transmitting powder medium by means of the pistons operated on conventional medium until the applied pressure is stabilized, as is done with conventional powder packing technology .
Det kan bemærkes, at det særlige koldpresningstryk, der skal anvendes, kan fastlægges empirisk, og tryk højere end det tryk, som tilvejebringer et med hensyn til dimensioner stabiliseret, praktisk talt isostatisk system, giver ikke nogen signifikant, 25 yderligere densifikation eller stabilisering med hensyn til dimensioner af cellen 10 og dens indhold.It should be noted that the particular cold pressing pressure to be used can be determined empirically, and pressures higher than the pressure which provides a dimensionally stabilized, practically isostatic system do not provide any significant additional densification or stabilization with respect to to dimensions of cell 10 and its contents.
Det foreliggende, tryktransmitterende pulvermedium, som f.eks. hexagonalt bornitrid og siliciumnitrid, er af en sådan natur, at det, som følge af det uniaksialt påførte tryk, tilvejebringer en tilnær-30 melsesvis hydrostatisk påvirkning og derved udøver et praktisk talt isostatisk tryk på hele cellen 10. Det antages, at det påførte tryk transmitteres praktisk talt uformindsket til cellen 10. Koldpresnings-trinet mindsker størrelsen af porerne og gør derved forekomsten af tilstedeværende porer med kapillarstørrelse i krystalmassen maksimal, 35 hvilket er hensigtsmæssigt ved tilvejebringelse af den krævede diamant krysta Itæthed på over 65 volumenprocent af diamantmassen.The present pressure transmitting powder medium, e.g. hexagonal boron nitride and silicon nitride are of such a nature that, due to the uniaxially applied pressure, it provides an approximately hydrostatic effect, thereby exerting a practically isostatic pressure on the entire cell 10. It is assumed that the applied pressure practically unabated transmits to cell 10. The cold pressing step reduces the size of the pores, thereby maximizing the presence of capillary-sized pores in the crystal mass, which is convenient by providing the required diamond crystal density of over 65% by volume of the diamond mass.
Denne reduktion i porevolumen nedsætter også det endelige indhold af ikke-diamantmateriale i diamantmassen og tilvejebringer flere, for effektiv binding til hinanden passende placerede, side om side stil-This reduction in pore volume also decreases the final content of non-diamond material in the diamond mass and provides several, side-by-side, effective bonding to each other appropriately placed.
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7 lede krystal-mod-krystal områder.7 lead crystal-to-crystal areas.
Efter afslutning af dette koldpresningstrin skulle tætheden af de komprimerede diamantkrystaller i cellen 10 være over 65 volumenprocent af rumfanget af krystaller. Ofte kan diamanttætheden af de 5 komprimerede diamantkrystaller ligge mellem ca. 66 volumenprocent og højst ca. 85 volumenprocent af de komprimerede diamantkrystaller. Jo højere tætheden af krystaller er, desto mindre vil mængden af tilstedeværende ikke-diamantmateriale mellem krystallerne være, hvilket resulterer i et forholdsvis hårdere slibeiegeme.Upon completion of this cold pressing step, the density of the compressed diamond crystals in cell 10 should be over 65% by volume of the volume of crystals. Often, the diamond density of the 5 compressed diamond crystals can be between approx. 66% by volume and no more than approx. 85% by volume of the compressed diamond crystals. The higher the density of crystals, the less the amount of non-diamond material present between the crystals will be, resulting in a relatively harder abrasive body.
10 Det praktisk talt isostatiske system 21, der består af den pulverindesluttede celle, som er tilvejebragt ved koldpresningstrinet, underkastes derpå et varmpresningstrin, hvorunder det underkastes varmpresningstemperatur og tryk samtidigt.The practically isostatic system 21, which consists of the powder-enclosed cell provided by the cold-pressing step, is then subjected to a hot-pressing step, under which it is subjected to hot-pressing temperature and pressure simultaneously.
Det bemærkes, at når koldpresningstrinet er tilendebragt, 15 trækkes et af stemplerne 23, 23a tilbage, og det frembragte, til en hird masse praktisk talt isostatiske, formede system 21 tvinges ud af et foringsrør 22a og ind i et hul med identisk diameter i en grafitform 30, således at det overførte system 21 nu indesluttes af væggene i et hul 31 mellem grafitstemplerne 32, 32a. Grafitformen 30 er 20 forsynet med termoelement 33, således at der tilvejebringes en indikation af den temperatur, der påføres det med hensyn til dimensioner stabiliserede, praktisk talt isostatiske system 21. Formen 30, med det således indesluttede, ialt væsentligt isostatiske system 21, anbringes i en konventionel ikke vist varmpresningsovn. Ovnkamme-25 ret evakueres eller evakueres i hvert fald næsten fuldstændigt, hvilket medfører evakuering af systemet 21 inklusive cellen 10, og derved tilvejebringes i systemet 21 og cellen 10 et næsten fuldstændigt vakuum, i hvilket varmpresningstrinet kan udføres. På dette sted kan der imidlertid om ønsket ledes nitrogen eller hydrogen 30 eller en inert luftart som argon ind i ovnkammeret for derved at tilvejebringe en passende varmpresningsatmosfære i kammeret såvel som i systemet 21 inklusive det indre af cellen 10. Medens stemplerne 32, 32a påfører systemet 21 et uniaksialt tryk, dvs. varmpresningstrykket, hæves dets temperatur til en temperatur, ved hvilken 35 siliciumskiven 12 er flydende.It is noted that when the cold pressing step is completed, one of the pistons 23, 23a is retracted, and, to a hard mass of practically isostatic shaped system 21, is forced out of a casing 22a and into a hole of identical diameter in a graphite form 30 so that the transferred system 21 is now enclosed by the walls of a hole 31 between the graphite pistons 32, 32a. The graphite mold 30 is provided with thermocouple 33 so as to provide an indication of the temperature applied to the dimensionally stabilized, practically isostatic system 21. The mold 30, with the thus substantially substantially isostatic system 21, is placed in a conventional hot pressing furnace not shown. The furnace chamber 25 is evacuated or evacuated almost completely, at least causing the evacuation of the system 21 including the cell 10, thereby providing in the system 21 and the cell 10 an almost complete vacuum in which the hot pressing step can be performed. However, at this point, nitrogen or hydrogen 30 or an inert gas species, such as argon, may be introduced into the furnace chamber to provide a suitable hot-pressing atmosphere in the chamber as well as in system 21 including the interior of cell 10. While pistons 32, 32a apply to the system 21 a uniaxial pressure, i.e. at the hot pressing pressure, its temperature is raised to a temperature at which the silicon wafer 12 is liquid.
Under varmpresningstrinet skal varmpresningstemperaturen nås hurtigt og holdes almindeligvis i mindst 1 minut på en sådan temperatur under varmpresningstrykket for at sikre tilfresstillende indtrængning gennem diamantkrystalmassen. Almindeligvis er en varm-During the hot pressing step, the hot pressing temperature must be reached quickly and usually maintained for at least 1 minute at such temperature below the hot pressing pressure to ensure satisfactory penetration through the diamond crystal mass. Generally, a
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8 presningstid pi fra ca. 1 minut til ca. 5 minutter hensigtsmæssig. Eftersom omdannelse af diamant til en elementær ikke-diamant carbonfase i det store og hele afhænger af tid og temperatur, dvs. jo højere temperetur og jo længere tid ved en sidan temperatur, jo 5 mere sandsynlig er omdannelsen til elementært, ikke-diamant carbon, mi varmpresningstrinet være udført inden 5 volumenprocent af diamanten er omdannet til ikke-diamant rent carbon, og dette kan bestemmes empirisk. Omdannelse af 5 volumenprocent eller mere diamant til elementært, ikke-diamant carbon er tilbøjelig til at resul-10 tere i, at en ren ikke-diamant carbonfase resterer I det endelige produkt, hvilket vil have en signifikant, skadelig effekt pi dets mekaniske egenskaber.8 pressing time pi from approx. 1 minute to approx. 5 minutes appropriate. Since the conversion of diamond into an elemental non-diamond carbon phase depends largely on time and temperature, ie. the higher the temperature and the longer the time at a side temperature, the more likely the conversion to elemental, non-diamond carbon, in the hot pressing step, is to be completed before 5% by volume of the diamond is converted to non-diamond pure carbon, and this can be determined empirically. Conversion of 5% by volume or more diamond to elemental, non-diamond carbon tends to result in a pure non-diamond carbon phase remaining in the final product, which will have a significant detrimental effect on its mechanical properties.
Under varmpresningstrinet sprænges det modstandsdygtige grænsefladeiag eller grænsefladeslagge, som hovedsagelig bestir af 15 oxid eller carbid, der sædvanligvis er til stede eller som dannes mellem det flydende silicium og diamantoverfladerne, pi grund af varmpresningstrykkets overføring til det flydende silicium, og herved udsættes kapillarporesystemet for siliciumet, hvorefter infusion ved hirrørsvirkning finder sted. Forsøg har vist, at 20 infusion af siliciumet i diamantmassen ikke vil finde sted, med mindre der piføres og opretholdes et tryk, som er tilstrækkeligt til at opbryde slaggen, pi systemet 21 under varmpresningen, medens siliciumet er flydende.During the hot pressing step, the resilient interface layer or interface slag, which is mainly composed of oxide or carbide usually present or formed between the liquid silicon and diamond surfaces, due to the transfer of the hot pressing pressure into the liquid silicon, is expelled, after which infusion by hiring action takes place. Tests have shown that 20 infusion of the silicon into the diamond mass will not occur unless a pressure sufficient to break the slag is maintained and maintained in the system 21 during hot pressing while the silicon is liquid.
Endvidere vil under den foreliggende fremgangsmåde, nlr 25 siliciumet bliver flydende, enhver slagge eller ethvert oxid, som dannes eller er til stede deri, flyde deri og blive ladt tilbage, når det flydende silicium trænger gennem den komprimerede diamant-masse. Som følge heraf er det foreliggende diamantkompakt uden indhold af nogen glasagtig fase, som ville hindre en stærk binding i 30 at dannes mellem diamanten og det siliciumatomholdige bindemedium.Further, in the present process, when the silicon becomes liquid, any slag or oxide formed or present therein will flow therein and be left as the liquid silicon penetrates the compacted diamond mass. As a result, the present diamond compact is devoid of any vitreous phase which would prevent a strong bond to form between the diamond and the silicon atom-containing binder.
Når det flydende silicium under varmpresningen siver og strømmer gennem diamantmassen, indkapsler det overfladerne af de komprimerede diamantkrystaller og reagerer med diamantoverfladerne eller med den eventuelle fase af elementært, ikke-diamant carbon, 35 som eventuelt dannes, og derved tilvejebringes siliciumcarbid ved diamantkrystallernes overflader, hvilket resulterer i et integreret, stærkt bundet diamantlegeme.As the liquid silicon, during hot pressing, seeps and flows through the diamond mass, it encapsulates the surfaces of the compressed diamond crystals and reacts with the diamond surfaces or with any phase of elemental, non-diamond carbon, optionally formed, thereby providing silicon carbide at the diamond crystals' surfaces. results in an integrated, highly bonded diamond body.
Det er under dette varmpresningstrin, at det er særligt vigtigt, at praktisk talt isostatiske betingelser opretholdes, således at nårIt is during this hot pressing step that it is particularly important to maintain practically isostatic conditions so that when
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Siliciumet er omdannet til det flydende stadium, vil denne væske ikke være i stand til at passere mellem massen 13 og hulheden 11 og undslippe i signifikant grad men vil blive tvunget til at bevæge sig gennem massen 13 af diamantkrystaller. Den del af det tryktrans-5 mitterende pulver, der er i tæt forbindelse med indholdet i hulheden, dvs. den del af det tryktransmitterende pulver, der strækker sig fra indervæggen af hulheden eller cellen til fortrinsvis ca. 25 mm derfra, bør, for at forhindre for vidtgående udslip af flydende silicium under varmpresningen, ikke indeholde indbyrdes forbundne 10 porer større end ca. 5 pm.The silicon is converted to the liquid stage, this liquid will not be able to pass between the mass 13 and the cavity 11 and escape to a significant extent but will be forced to move through the mass 13 of diamond crystals. The part of the pressure transmitting powder which is closely related to the contents of the cavity, ie. the portion of the pressure transmitting powder extending from the inner wall of the cavity or cell to preferably ca. 25 mm away, to prevent excessive leakage of liquid silicon during hot pressing, it should not contain interconnected 10 pores larger than approx. 5 pm.
Nir varmpresningstrinnet er tilendebragt, skal der i det mindste opretholdes et tilstrækkeligt tryk under afkølingen af det varmpressede system 21, således at den varmpressede celle 10, der under afkølingen holdes i systemet 21, udsættes for et i alt væsent-15 ligt isostatisk tryk, der er tilstrækkeligt højt til at bevare dens stabilitet med hensyn til dimensioner. Det varmpressede system får fortrinsvis lejlighed til at køle ned til stuetemperatur, og det resulterende, foreliggende diamantlegeme tages ud. Eventuelt udpresset overskudssilicium pi de ydre overflader af det 20 polykrystallinske diamantlegeme kan fjernes ved konventionelle metoder, som f.eks. ved slibning.After the hot pressing step is completed, at least a sufficient pressure must be maintained during the cooling of the hot pressed system 21, so that the hot pressed cell 10, which is kept in the system 21 during cooling, is subjected to a substantially isostatic pressure which is sufficiently high to maintain its stability in terms of dimensions. Preferably, the hot pressed system is allowed to cool to room temperature and the resulting present diamond body is removed. Optionally, excess silicon extruded on the outer surfaces of the polycrystalline diamond body can be removed by conventional methods such as e.g. by grinding.
Det foreliggende polykrystallinske diamantlegeme omfatter en masse af diamantkrystaller, der er fast bundne til hinanden ved hjælp af et siliciumatomholdigt bindemedium, som i hovedsagen består 25 af siliciumcarbid og rent silicium, og i hvilket diamantkrystallerne har størrelser på fra ca. 1 pm til ca. 1000 pm, hvorhos tætheden af diamantkrystaller varierer fra ca. 65 volumenprocent til højst ca. 80 volumenprocent af legemet og ofte udgør ca. 78 volumenprocent af legemet, og hvor det siliciumatomholdige bindemedium indgår i en 30 mængde på indtil ca. 35 volumenprocent af legemet, hvilket bindemedium er fordelt i hvert fald praktisk talt ensartet igennem det polykrystallinske diamantlegeme, hvori den del eller overflade af bindemediet, der er i kontakt med overfladerne af de bundne krystaller, udgøres i hvert fald i væsentligt omfang af silicium-35 carbid, dvs. at mindst 85 volumenprocent og fortrinsvis 100 volumenprocent af den del eller overflade af bindemediet, der er i direkte kontakt med overfladerne af diamantkrystallerne, er siliciumcarbid. Det foreliggende diamantlegeme er porefrit eller i hvert fald praktisk talt porefrit.The present polycrystalline diamond body comprises a mass of diamond crystals which are firmly bonded to each other by means of a silicon atom-containing binder consisting essentially of silicon carbide and pure silicon, and in which the diamond crystals have sizes of from about. 1 pm to approx. 1000 pm, where the density of diamond crystals varies from approx. 65% by volume to a maximum of approx. 80% by volume of the body and often constitutes approx. 78% by volume of the body, and wherein the silicon atom-containing binder is contained in a quantity of up to approx. 35% by volume of the body, which binder is distributed at least substantially uniformly throughout the polycrystalline diamond body, wherein the portion or surface of the binder which contacts the surfaces of the bound crystals is at least substantially silicon-35. carbide, ie at least 85% by volume and preferably 100% by volume of the portion or surface of the binder in direct contact with the surfaces of the diamond crystals is silicon carbide. The present diamond body is pore-free or at least practically pore-free.
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10 Mængden af siliciumcarbid og silicium i det foreliggende diamantlegemes bindemedium kan variere afhængig af graden af reaktion mellem diamantkrystallernes overflader og det indsivende silicium og af reaktionen mellem fasen af elementært, ikke-diamant 5 carbon og indsivende silicium. Alt andet lige afhænger den konkrete mængde af siliciumcarbid i bindemediet stort set af den bestemte varmpresningstemperatur, der er anvendt, og af den tid, i hvilken denne temperatur er opretholdt. Specielt stiger indholdet af siliciumcarbid, når tiden og/eller temperaturen øges. Fremgangsmåden til 10 fresmtilling af det foreliggende legeme af sammenbundne diamant krystaller med et bestemt ønsket indhold af siliciumcarbid med f.eks. det formål at opnå bestemte, ønskelige egenskaber kan bestemmes empirisk. Specielt kan bindemediet variere med hensyn til sammensætning fra en detekterbar mængde siliciumcarbid til en detekterbar 15 mængde rent silicium, hvor der her ved en detekterbar mængde siliciumcarbid eller rent silicium menes en mængde, der er detekterbar ved selektiv overfladediffraktionsanalyse (eng.: selective area diffraction analysis) ved transmissionselektronmikroskopi af et tyndt snit af det foreliggende legeme. Almindeligvis udgøres det 20 foreliggende bindemedium imidlertid i hovedsagen af siliciumcarbid i mængder, der varierer fra ca. 2 volumenprocent til ca. 30 volumenprocent af det foreliggende polykrystallinske diamantlegeme og af rent silicium i mængder, der varierer fra ca. 33 volumenprocent til ca. 5 volumenprocent af legemet. Desuden ligger diamantindholdet i 25 det foreliggende legeme mellem ca. 65 volumenprocent og højst ca. 80 volumenprocent af legemets volumen.The amount of silicon carbide and silicon in the binder medium of the present diamond body may vary depending upon the degree of reaction between the surfaces of the diamond crystals and the inset silicon, and on the reaction between the elemental, non-diamond carbon and inset silicon phase. All else being equal, the actual amount of silicon carbide in the binder depends largely on the particular hot pressing temperature used and on the time during which this temperature is maintained. In particular, the content of silicon carbide increases as time and / or temperature increase. The method of milling the present body of bonded diamond crystals with a certain desired content of silicon carbide with e.g. the purpose of obtaining certain desirable properties can be determined empirically. Specifically, the binder may vary in composition from a detectable amount of silicon carbide to a detectable amount of pure silicon, where by a detectable amount of silicon carbide or pure silicon is meant an amount detectable by selective surface diffraction analysis. ) by transmission electron microscopy of a thin section of the present body. Generally, however, the present binder is essentially silicon carbide in amounts ranging from about 2% by volume to approx. 30% by volume of the present polycrystalline diamond body and of pure silicon in amounts ranging from approx. 33% by volume to approx. 5% by volume of the body. In addition, the diamond content of the present body is between ca. 65% by volume and no more than approx. 80% by volume of the body volume.
Selektiv overfladediffraktionsanalyse ved transmissionselektronmikroskopi af et tyndt snit af det polykrystallinske diamantlegeme vil ligeledes vise, at den del af bindemediet, der er i kontakt med 30 overfladerne af de bundne diamanter,, består i hvert fald i væsentlig mængde af siliciumcarbid.Selective surface diffraction analysis by transmission electron microscopy of a thin section of the polycrystalline diamond body will also show that at least a significant amount of silicon carbide in contact with the 30 diamonds bonded surfaces.
Det foreliggende legeme af bundne diamantkrystaller er uden hulrum eller porer eller i hvert fald praktisk talt porefrit, dvs. det kan indeholde hulrum eller porer i en mængde på mindre· end 1 35 volumenprocent af legemet, forudsat at sådanne hulrum eller porer er små, dvs. mindre end 0,5 pm, og tilstrækkeligt jævnt fordelt i hele legemet, således at de ikke har nogen signifikant, forringende effekt på dets mekaniske egenskaber. Indholdet af hulrum eller porer i det foreliggende legeme kan bestemmes ved metal log raf isk standardtek-The present body of bound diamond crystals is devoid of voids or pores or at least practically pore-free, i.e. it may contain voids or pores in an amount of less than 1 35% by volume of the body, provided that such voids or pores are small; less than 0.5 µm, and sufficiently evenly distributed throughout the body, so that they have no significant deteriorating effect on its mechanical properties. The content of voids or pores in the present body can be determined by standard metal log
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11 nik, som f.eks. optisk undersøgelse af et poleret tværsnit af legemet.11 nicks, such as optical examination of a polished cross section of the body.
Det foreliggende diamantlegeme er ligeledes uden indhold af en fase af elementært, ikke-diamant carbon, idet det ikke indeholder 5 nogen fase af ikke-diamant carbongrundstof i mængder, der er detekterbare ved røntgendiffraktionsanalyse.The present diamond body is also devoid of a phase of elemental, non-diamond carbon in that it contains no phase of non-diamond carbon in amounts detectable by X-ray diffraction analysis.
Når den foreliggende fremgangsmåde gennemføres med siliciumet og dlamantkrystalmassen foreliggende som lag, der er overlejret hinanden, kan det resulterende produkt have mindst én flad over-10 flade og kan foreligge i et antal forskellige former, som f.eks. en skive, terning eller rektangel, stav eller stang.When the present process is carried out with the silicon and dlamant crystal mass present as layers superimposed on each other, the resulting product may have at least one surface surface and may be available in a number of different forms, e.g. a slice, cube or rectangle, rod or rod.
Når den foreliggende fremgangsmåde gennemføres med siliciumet foreliggende som et rør eller en cylinder med en kerne eller et gennemgående hul og med diamantparti kierne pakket i kernen, siver 15 siliciumet under varmpresningen ind gennem kernen af komprimerede diamantkrystaller og tilvejebringer det foreliggende diamantlegeme med form som en stang med cirkulært tværsnit.When the present process is carried out with the silicon present as a tube or cylinder with a core or through hole and with the diamond portions of the cores packed into the core, the silicon seeps in during hot pressing through the core of compressed diamond crystals and provides the present diamond body with the shape of a rod. with circular cross section.
Når den foreligggende fremgangsmåde gennemføres med en siliciumstang placeret centralt i hulheden, og rummet mellem silicium-20 stangen og hulhedens væg er pakket med diamantkrystaller, siver siliciumet ind gennem den omgivende masse af diamantkrystaller og tilvejebringer det foreligggende diamantlegeme med form som et rør eller en hul cylinder.When the present process is carried out with a silicon rod located centrally in the cavity and the space between the silicon rod and the cavity wall is packed with diamond crystals, the silicon seeps in through the surrounding mass of diamond crystals and provides the present diamond body with the shape of a tube or hole. cylinder.
Et særligt fordelagtigt træk ved den foreliggende opfindelse er, 25 at det foreliggende polykrystallinske diamantlegeme kan tilvejebringes i mange forskellige størrelser og former. F.eks. kan det foreliggende legeme være si bredt eller så langt som 25 mm eller mere. Polykrystallinske diamantlegemer pi 25 mm eller mere i længden og med den foreliggende diamanttæthed kan, på grund af begrænsningerne i 30 den indretning, der er nødvendig til at modstå de høje tryk-tempe-raturkrav i den påkrævede tid, dvs. indretningen er så kompleks og massiv, at dens kapacitet er begrænset, i praksis ikke fremstilles eller lader sig overhovedet ikke fremstille ved fremgangsmåder, der benytter de for diamantstabilitetsomridet ultrahøje tryk og tempe-35 raturer. På den anden side kan det foreliggende polykrystallinske diamantlegeme fremstilles så lille eller så tyndt som ønsket, men det vil altid være på mere end ét monolag af diamantkrystaller.A particularly advantageous feature of the present invention is that the present polycrystalline diamond body can be provided in many different sizes and shapes. Eg. For example, the present body may be as wide or as long as 25 mm or more. Polycrystalline diamond bodies of 25 mm or more in length and with the present diamond density can, due to the limitations of the device necessary to withstand the high pressure temperature requirements for the required time, ie. the device is so complex and massive that its capacity is limited, in practice it is not produced or cannot be produced at all by methods utilizing the ultra high pressure and temperature for the diamond stability range. On the other hand, the present polycrystalline diamond body can be made as small or as thin as desired, but it will always be on more than one monolayer of diamond crystals.
En del af det foreliggende diamantlegeme kan loddes, slagloddes eller på anden måde fastgøres til et passende bæremateriale, som 12Part of the present diamond body may be soldered, brazed or otherwise secured to a suitable support material which
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f.eks. sintret eller varmtpresset siliciumcarbid, sintret eiler varm-presset siiiciumnitrid eller hårdtmetal eller et metal, som f.eks. molybdæn, der udgør en værktøjsindsats, som f.eks. kan fastholdes af et værktøjsskaft, der er egnet til fastholdelse i en værktøjs-5 maskine, og derved kan den blottede overflade af diamantlegemet anvendes til direkte spåntagende bearbejdning. Alternativt kan det foreliggende diamantkrystallegeme fastspændes mekanisk til et drejestål, således at der kan opnås direkte spåntagende bearbejdning med den blottede overflade af diamantlegemet.eg. sintered or hot pressed silicon carbide, sintered or hot pressed silicon nitride or cemented carbide or a metal such as e.g. molybdenum, which constitutes a tool insert such as e.g. can be held by a tool shank suitable for holding in a machine tool, and thereby the exposed surface of the diamond body can be used for direct machining. Alternatively, the present diamond crystal body may be mechanically clamped to a swivel steel so that direct machining can be achieved with the exposed surface of the diamond body.
10 Opfindelsen vil blive yderligere beskrevet ved hjælp af følgende eksempel.The invention will be further described by the following example.
EksempelExample
Det apparat, der anvendtes i dette eksempel, var i alt væsent-15 ligt magen til det, der er vist i figur 1, 2 og 3.The apparatus used in this example was substantially similar to that shown in Figures 1, 2 and 3.
Hexagonalt bornitrid med en størrelse pi fra ca. 2 pm til ca. 20 pm, blev pakket i en matrice, og en cylinder, der anvendtes som form, blev presset ind i pulveret som vist i figur 1 ved 19a og 9.Hexagonal boron nitride having a size p from approx. 2 pm to approx. 20 µm was packed in a die and a cylinder used as a mold was pressed into the powder as shown in Figure 1 at 19a and 9.
Cylinderen var fremstillet af sintret metalcarbid (eng.: cement-20 ed metal carbide) og var ca. 8,89 mm i diameter og 6,35 mm tyk. Cylinderens akse flugtede tilnærmelsesvis med matricens centralakse.The cylinder was made of sintered metal carbide (cement: 20-oct metal carbide) and was approx. 8.89 mm in diameter and 6.35 mm thick. The axis of the cylinder aligned with the central axis of the matrix.
I denne udførelsesform blev der til forskel fra figur 1, efter at cylinderen var indsat i pulveret, anbragt en yderligere mængde hexagonalt bornitridpulver i matricen, således at cylinderen dække-25 des fuldstændigt, og den tilvejebragte pulverindesluttede cylinder blev ved stuetemperatur presset under et tryk på 3450 bar overtryk (50.000 psi). Stemplet 23a blev derefter trukket tilbage, og stemplet 23 blev anvendt til at skubbe den tilvejebragte, pressede, pulverindesluttede cylinder delvis ud af matricen. Den blottede del af det 30 pressede pulver blev fjernet, således at cylinderen blev delvis blottet. Cylinderen blev derpå fjernet og efterlod hulheden 11, som den havde trykket deri.In this embodiment, unlike Figure 1, after the cylinder was inserted into the powder, an additional amount of hexagonal boron nitride powder was placed in the matrix so that the cylinder was completely covered and the provided powder enclosed cylinder was pressurized at room temperature at 3450 bar overpressure (50,000 psi). The piston 23a was then retracted and the piston 23 was used to push the provided, pressed, powder-enclosed cylinder partially out of the die. The exposed portion of the pressed powder was removed so that the cylinder was partially exposed. The cylinder was then removed leaving the cavity 11 as it had pressed therein.
En skive af silicium vejende 140 mg og med samme diameter som hulhedens indre diameter blev anbragt i bunden af hulheden. Ca.A slice of silicon weighing 140 mg and of the same diameter as the inner diameter of the cavity was placed at the bottom of the cavity. Ca.
35 250 mg størrelsesklassificeret diamantpulver med diamantstørrelser på fra ca. 1 pm til ca. 60 pm og deraf ca. 40 vægtprocent mindre end 10 pm pakkedes ovenpå siliciumskiven.35 250 mg size graded diamond powder with diamond sizes of approx. 1 pm to approx. 60 pm and thereof approx. 40 weight percent less than 10 µm was packed on top of the silicon wafer.
En skive varmpresset, hexagonalt bornitridpulver med samme diameter som hulhedens indre diameter anbragtes i hulheden oven påA disc of hot pressed hexagonal boron nitride powder of the same diameter as the inner diameter of the cavity is placed in the cavity on top of
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13 diamantpul veret, for derved at sikre at overfladen af det resulterende polykrystallinske diamantlegeme ville blive plan.13 diamond powder, thereby ensuring that the surface of the resulting polycrystalline diamond body would be flat.
Hele massen blev derpå skubbet ind i matricens center ved hjælp af stemplet 23a, som derpå blev trukket tilbage. En yderligere 5 mængde hexagonalt bornitridpulver anbragtes i matricen for at dække den varmpressede skive af hexagonalt bornitrid, siledes at hulheden og dens indhold blev indesluttet i hexagonalt bornitrid, som det er vist ved 19 i figur 2. Den tilvejebragte charge blev derefter presset ved stuetemperatur, dvs. koldpresset, i stålmatricen under et tryk 10 pi 5520 bar overtryk (80.000 psi), som det er vist i figur 2, idet hulheden og dens indhold blev påført et praktisk talt isostatisk tryk, indtil trykket stabiliseredes, og derved dannedes et med hensyn til dimensioner stabiliseret, formet, praktisk talt isostatisk system af pulverindesluttet hulhed samt indhold. Fra tidligere forsøg 15 var det kendt, at diamantkrystaltætheden i den tilvejebragte, pressede samling af elementer, dvs. i det tilvejebragte, formede, praktisk talt isostatiske system af pulverindesluttet hulhed samt indhold, var diamantkrystaltætheden større end 75 volumenprocent af den komprimerede diamantmasse. Den tilstedeværende mængde af 20 silicium udgjorde ca. 40 volumenprocent af den komprimerede diamantmasse.The entire mass was then pushed into the center of the die by means of the plunger 23a, which was then withdrawn. An additional 5 amounts of hexagonal boron nitride powder were placed in the matrix to cover the hot pressed disc of hexagonal boron nitride, so that the cavity and its contents were enclosed in hexagonal boron nitride, as shown at 19 in Figure 2. The charge obtained was then pressed at room temperature. i.e. cold press, in the steel matrix under a pressure of 10 µl 5520 bar overpressure (80,000 psi), as shown in Figure 2, with the cavity and its contents being applied at practically isostatic pressure until the pressure stabilized, thereby forming one with respect to dimensions stabilized, shaped, practically isostatic system of powder-contained cavity as well as content. From previous Experiment 15, it was known that the diamond crystal density in the provided pressed assembly of elements, i.e. in the formed, practically isostatic system of powder-encapsulated hollowness and content, the diamond crystal density was greater than 75% by volume of the compacted diamond mass. The amount of silicon present was approx. 40% by volume of the compacted diamond mass.
Den tilvejebragte, pressede samling af elementer 21 bestående af den pulverindesluttede hulhed samt indhold blev derpå varmpresset, dvs. den blev trykket ind i en grafitform med samme diameter-25 størrelse som stålmatricen, som det er vist i figur 3, og anbragt i en induktionsvarmeovn. Hulhedens indre blev evakueret, og en nitrogenatmosfære blev ledt derind, idet varmeovnen blev evakueret til ca. 1330 Pa (10 torr), inden den blev fyldt igen med en strøm af tør nitrogen. Et tryk på ca. 345 bar overtryk (5.000 psi) blev påført 30 den pressede samling af elementer 21 og opretholdt ved hjælp af grafitmatricen, som derpå opvarmedes af induktionsvarmeovnen til en temperatur på 1500°C i 7 minutter. Ved denne opvarmning nåede trykket op på ca. 690 bar overtryk (10.000 psi) på grund af hele systemets ekspansion.The provided pressed assembly of elements 21 consisting of the powder enclosed cavity and contents was then hot pressed, i.e. it was pressed into a graphite form of the same diameter size as the steel matrix as shown in Figure 3 and placed in an induction heater. The interior of the cavity was evacuated and a nitrogen atmosphere was passed in, evacuating the heater to approx. 1330 Pa (10 torr) before being refilled with a stream of dry nitrogen. A pressure of approx. 345 bar overpressure (5,000 psi) was applied to the pressed assembly of elements 21 and maintained by the graphite matrix, which was then heated by the induction heater to a temperature of 1500 ° C for 7 minutes. At this heating, the pressure reached approx. 690 bar overpressure (10,000 psi) due to the entire system expansion.
35 Ved 1500°C sank stemplet 23a, og trykket faldt til ca. 345 bar overtryk (5.000 psi), hvilket viste, at siliciumet var smeltet og blevet flydende og var sivet ind i diamantmassen. Trykket blev hævet til det igen var 690 bar overtryk (10.000 psi) og blev, for at sikre at siliciumet var sivet fuldstændigt ind i diamantmassen, holdtAt 1500 ° C the plunger 23a sank and the pressure dropped to approx. 345 bar overpressure (5,000 psi), indicating that the silicon had melted and become liquid and seeped into the diamond mass. The pressure was raised until it was again 690 bar overpressure (10,000 psi) and, to ensure that the silicon was completely seeped into the diamond mass, was kept
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14 pi denne værdi i 1 minut ved 1500°C. Energiforsyningen blev derpå afbrudt, men der blev ikke pålagt yderligere tryk. Dette tilvejebragte et fast tryk ved høj temperatur men nedsat tryk ved lavere temperatur, og derved tilvejebragtes fyldestgørende, geometrisk 5 stabilitet. Ved stuetemperatur blev det frembragte poiy krystal linske diamantlegeme afdækket.14 p in this value for 1 minute at 1500 ° C. The energy supply was then interrupted, but no further pressure was imposed. This provided a fixed pressure at high temperature but lower pressure at lower temperature, thereby providing adequate geometric stability. At room temperature, the generated crystal crystal lined diamond body was uncovered.
Efter fjernelse af overfladeskaller bestående af hexagonalt bornitridpulver havde det tilvejebragte, integrale, polykrystallinske diamantlegeme skiveform med en diameter på 8,89 mm og en tykkelse 10 p| 1,27 mm.After removal of surface shells of hexagonal boron nitride powder, the integral polycrystalline diamond body disc provided had a diameter of 8.89 mm and a thickness of 10 µm | 1.27 mm.
Den polykrystallinske skive havde praktisk talt glatte, plane overflader og var tilsyneladende blevet velgennemtrængt af bindemedium. Optisk undersøgelse af skiven forstørret 100X i et mikroskop viste, at den var porefri.The polycrystalline slice had practically smooth, flat surfaces and had apparently been well penetrated by binder. Optical examination of the disc magnified 100X in a microscope showed that it was pore-free.
15 Under anvendelse af en hammer og en kile blev skiven fraktu- reret så at sige midt over. Undersøgelse af skivens frakturerede tværsnitsoverflader viste, at frakturen eller bruddet var trans-granulær snarere end intergranulær, dvs. den var fraktureret gennem diamantkornene snarere end langs korngrænserne. Dette 20 viser, at bindemediet var stærkt vedhængende, og at det var lige så stærkt som selve diamantkornene eller diamantkrystal lerne. Ligeledes var de frakturerede overflader porefri, og bindemediet var jævnt fordelt igennem legemet.15 Using a hammer and a wedge, the disc was fractured, so to speak, in the middle. Examination of the fractured cross-sectional surfaces of the disc revealed that the fracture or fracture was trans-granular rather than intergranular, ie. it was fractured through the diamond grains rather than along the grain boundaries. This 20 shows that the binder was strongly adherent and that it was as strong as the diamond grains themselves or the diamond crystal clays. Likewise, the fractured surfaces were pore-free and the binder was evenly distributed throughout the body.
En brudflade vinkelret på skiven blev poleret på et støbejerns-25 diamantpoleringsapparat. Undersøgelse af den polerede flade viste ingen rækker af huller dannet ved udtrækning af diamantfragmenter, hvilket viser den stærke binding deri og dets anvendelighed som slibemiddel. Det polerede tværsnit ses i figur 4.A fracture surface perpendicular to the disc was polished on a cast-iron diamond polishing apparatus. Examination of the polished surface showed no rows of holes formed by extraction of diamond fragments, showing the strong bonding therein and its utility as abrasive. The polished cross section is shown in Figure 4.
Diamanttætheden blev bestemt til ca. 72 volumenprocent af 30 skiven. Diamanttætheden blev bestemt ved standardpunkttælleteknik ved anvendelse af et mi krofotografi af den polerede brudflade forstørret 690X, og det overfladeareal, der undersøgtes, var tilstrækkeligt stort til at repræsentere hele legemets mikrostruktur.The diamond density was determined to be approx. 72% by volume of the 30 slice. The diamond density was determined by standard point counting technique using a micrograph of the polished fracture surface enlarged 690X, and the surface area examined was large enough to represent the entire body microstructure.
Røntgendiffraktionsanalyse af det knuste legeme viste, at det 35 omfattede diamant, siliciumcarbid og rent silicium, og at silicium-carbidet og det rene silicium udgjorde mindst 2 volumenprocent af legemet. Røntgendiffraktionsanalysen af det knuste legeme detekterede imidlertid ikke nogen fase af frit, ikke-diamant carbon.X-ray diffraction analysis of the crushed body revealed that it comprised diamond, silicon carbide and pure silicon, and that the silicon carbide and pure silicon constituted at least 2% by volume of the body. However, the X-ray diffraction analysis of the crushed body did not detect any phase of free, non-diamond carbon.
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AU (1) | AU526018B2 (en) |
BE (1) | BE871433A (en) |
BR (1) | BR7806952A (en) |
CA (1) | CA1105948A (en) |
CH (1) | CH644090A5 (en) |
DE (1) | DE2845755A1 (en) |
DK (1) | DK154824C (en) |
ES (1) | ES474328A1 (en) |
FR (1) | FR2414031B1 (en) |
GB (1) | GB2006732B (en) |
IE (1) | IE47959B1 (en) |
IL (1) | IL55718A0 (en) |
IN (1) | IN150647B (en) |
IT (1) | IT1101661B (en) |
MX (1) | MX151724A (en) |
NL (1) | NL186380C (en) |
SE (1) | SE451378B (en) |
ZA (1) | ZA785931B (en) |
Families Citing this family (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4220455A (en) * | 1978-10-24 | 1980-09-02 | General Electric Company | Polycrystalline diamond and/or cubic boron nitride body and process for making said body |
AU7919682A (en) * | 1981-01-21 | 1982-07-29 | General Electric Company | Silicon carbide-diamond/boron nitride composite |
AT386558B (en) * | 1984-03-30 | 1988-09-12 | De Beers Ind Diamond | USE OF A GRINDING TOOL |
US4874398A (en) * | 1984-08-24 | 1989-10-17 | Ringwood Alfred E | Diamond compacts and process for making same |
IE57439B1 (en) * | 1985-04-09 | 1992-09-09 | De Beers Ind Diamond | Wire drawing die |
ZA864402B (en) * | 1985-06-18 | 1987-02-25 | De Beers Ind Diamond | Abrasive tool |
WO1988007409A1 (en) * | 1987-03-23 | 1988-10-06 | The Australian National University | Diamond compacts |
WO1990001986A1 (en) * | 1988-08-17 | 1990-03-08 | The Australian National University | Diamond compact possessing low electrical resistivity |
CN110125390A (en) * | 2018-02-08 | 2019-08-16 | 罗天珍 | The padding and compacting sintering process of 3 D-printing metal powder bond blank |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2391589A (en) * | 1943-04-29 | 1945-12-25 | Hatim Attari | Abrasive tool |
US4042347A (en) * | 1974-04-15 | 1977-08-16 | Norton Company | Method of making a resin-metal composite grinding wheel |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
NL129734C (en) * | 1960-07-22 | |||
CA1070123A (en) * | 1969-04-17 | 1980-01-22 | Howard T. Hall | Diamond compacts |
US3913280A (en) * | 1971-01-29 | 1975-10-21 | Megadiamond Corp | Polycrystalline diamond composites |
US3912500A (en) * | 1972-12-27 | 1975-10-14 | Leonid Fedorovich Vereschagin | Process for producing diamond-metallic materials |
-
1978
- 1978-09-19 IN IN1027/CAL/78A patent/IN150647B/en unknown
- 1978-10-05 GB GB7839448A patent/GB2006732B/en not_active Expired
- 1978-10-05 CA CA312,780A patent/CA1105948A/en not_active Expired
- 1978-10-12 IL IL7855718A patent/IL55718A0/xx not_active IP Right Cessation
- 1978-10-18 ES ES474328A patent/ES474328A1/en not_active Expired
- 1978-10-19 IT IT28922/78A patent/IT1101661B/en active
- 1978-10-20 CH CH1089878A patent/CH644090A5/en not_active IP Right Cessation
- 1978-10-20 DE DE19782845755 patent/DE2845755A1/en active Granted
- 1978-10-20 DK DK468778A patent/DK154824C/en not_active IP Right Cessation
- 1978-10-20 IE IE2086/78A patent/IE47959B1/en not_active IP Right Cessation
- 1978-10-20 ZA ZA00785931A patent/ZA785931B/en unknown
- 1978-10-20 NL NLAANVRAGE7810522,A patent/NL186380C/en not_active IP Right Cessation
- 1978-10-20 BE BE191262A patent/BE871433A/en not_active IP Right Cessation
- 1978-10-20 SE SE7810970A patent/SE451378B/en not_active IP Right Cessation
- 1978-10-20 JP JP12993878A patent/JPS5485212A/en active Granted
- 1978-10-20 BR BR7806952A patent/BR7806952A/en unknown
- 1978-10-20 FR FR7829911A patent/FR2414031B1/en not_active Expired
- 1978-10-20 AT AT0754078A patent/AT371401B/en not_active IP Right Cessation
- 1978-10-23 MX MX175339A patent/MX151724A/en unknown
- 1978-10-30 AU AU41175/78A patent/AU526018B2/en not_active Expired
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2391589A (en) * | 1943-04-29 | 1945-12-25 | Hatim Attari | Abrasive tool |
US4042347A (en) * | 1974-04-15 | 1977-08-16 | Norton Company | Method of making a resin-metal composite grinding wheel |
Also Published As
Publication number | Publication date |
---|---|
GB2006732A (en) | 1979-05-10 |
ES474328A1 (en) | 1979-11-01 |
JPS5485212A (en) | 1979-07-06 |
IT1101661B (en) | 1985-10-07 |
IL55718A0 (en) | 1978-12-17 |
AU526018B2 (en) | 1982-12-16 |
IT7828922A0 (en) | 1978-10-19 |
DK468778A (en) | 1979-04-22 |
DE2845755A1 (en) | 1979-05-10 |
AU4117578A (en) | 1980-05-08 |
SE7810970L (en) | 1979-04-22 |
AT371401B (en) | 1983-06-27 |
IE47959B1 (en) | 1984-08-08 |
NL186380C (en) | 1990-11-16 |
IN150647B (en) | 1982-11-20 |
IE782086L (en) | 1979-04-21 |
FR2414031A1 (en) | 1979-08-03 |
FR2414031B1 (en) | 1985-11-08 |
BR7806952A (en) | 1979-05-08 |
SE451378B (en) | 1987-10-05 |
MX151724A (en) | 1985-02-18 |
JPS6213305B2 (en) | 1987-03-25 |
CH644090A5 (en) | 1984-07-13 |
GB2006732B (en) | 1982-10-20 |
DK154824C (en) | 1989-05-29 |
ATA754078A (en) | 1982-11-15 |
NL186380B (en) | 1990-06-18 |
ZA785931B (en) | 1979-09-26 |
CA1105948A (en) | 1981-07-28 |
DE2845755C2 (en) | 1989-09-14 |
NL7810522A (en) | 1979-04-24 |
BE871433A (en) | 1979-04-20 |
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PBP | Patent lapsed |