SI9700229A - Process for protection of aluminium nitride powder against hydrolysis - Google Patents
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- SI9700229A SI9700229A SI9700229A SI9700229A SI9700229A SI 9700229 A SI9700229 A SI 9700229A SI 9700229 A SI9700229 A SI 9700229A SI 9700229 A SI9700229 A SI 9700229A SI 9700229 A SI9700229 A SI 9700229A
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Abstract
Description
POSTOPEK ZAŠČITE PRAHU A1N PRED HIDROLIZOPROCEDURE FOR PROTECTING A1N DUST BEFORE HYDROLYSIS
Predmet izuma je postopek zaščite prahu aluminijevega nitrida A1N pred razkrajanjem, to je hidrolizo v vlažni atmosferi ali v vodnem mediju.The object of the invention is a method of protecting aluminum nitride A1N from decomposition, i.e. hydrolysis in a humid atmosphere or in an aqueous medium.
Tehnični problem, ki ga rešuje izum, je zaščita, to je pasivacija prahu A1N pred razkrajanjem oz. hidrolizo v vlažni atmosferi ali v vodnem mediju, pri čemer bo postopek zaščite enostavnejši, cenejši in ekoliško sprejemljivejši od dosedanjih postopkov, zaščiten, to je pasiviran prah pa odporen proti hidrolizi do višjih temperatur od večine do sedaj znanih pasiviranih prahov AlN ter občutno odpornejši proti hidrolizi med mokrim mletjem v vodnem mediju od do sedaj znanih pasiviranih praškov A1N.A technical problem solved by the invention is the protection, that is, the passivation of A1N dust from decomposition or decomposition. hydrolysis in a humid atmosphere or in an aqueous medium, making the protection process simpler, cheaper and more environmentally friendly than previous procedures, protected, that is, passive powder resistant to hydrolysis to higher temperatures than most of the known passive AlN powders and significantly more resistant to hydrolysis during wet milling in aqueous medium of the previously known passivated A1N powders.
Keramika iz aluminijevega nitrida je pomembna za industrijo zaradi nekaterih izjemnih fizikalnih lastnosti, kot so dobra toplotna prevodnost, nizek temperaturni razteznostni koeficient, odpornost proti obrabi, transparentnost itd. Poleg tega se prah A1N uporablja kot dodatek za izdelavo nekaterih vrst strukturne keramike, kot sta Si3N4 ali SiC. Največjo težavo pri izdelavi sintrane A1N keramike oziroma keramike, ki v izhodni mešanici vsebuje prah A1N, predstavlja neobstojnost prahu A1N v vlagi ali v vodnem mediju. Prah AlN namreč reagira z vodo (hidrolizira), pri čemer se tvorita amonijak in aluminijev hidroksid po reakcijski shemi:Aluminum nitride ceramics are important to the industry due to some outstanding physical properties such as good thermal conductivity, low temperature expansion coefficient, abrasion resistance, transparency, etc. In addition, A1N powder is used as an adjunct for the manufacture of certain types of structural ceramics, such as Si 3 N 4 or SiC. The biggest problem with the production of sintered A1N ceramics or ceramics containing A1N powder in the initial mixture is the absence of A1N powder in moisture or in aqueous medium. Namely, the AlN powder reacts with water (hydrolyzes) to form ammonia and aluminum hydroxide according to the reaction scheme:
-2Α1Ν + 2H2O - A100H + NH3 (1)-2Α1Ν + 2H 2 O - A100H + NH 3 (1)
NH3 + H2O - NH4 +OH~ (2)NH 3 + H 2 O - NH 4 + OH ~ (2)
A1OOH + H2O - Al(OH)3 (3)A1OOH + H 2 O - Al (OH) 3 (3)
Ker se med reakcijo sprošča amoniak, ki v vodi disociira po reakciji (2), je najenostavnejši način spremljanja hitrosti hidrolize oziroma preverjanja učinkovitosti zaščite prahu A1N pred hidrolizo, merjenje pH vrednosti razredčene vodne suspenzije prahu A1N.As ammonia is released during the reaction, dissociating in water after reaction (2), the simplest way to monitor the rate of hydrolysis or to check the effectiveness of protecting A1N dust from hydrolysis is to measure the pH of the diluted aqueous suspension of A1N powder.
Zaradi reaktivnosti je problematično že samo skladiščenje prahu A1N, začetne faze izdelave keramike kot so deaglomeracija prahu, homogenizacija z organskimi in anorganskimi dodatki, granuliranje in oblikovanje surovcev pa zahtevata delo v nevodnih medijih, kar je iz ekonomskih, varnostnih in ekoloških razlogov nezaželeno. Zaradi tega skušajo prah A1N zaščititi pred hidrolizo, s čimer se olajša skladiščenje in omogoči procesiranje in oblikovanje surovcev v vodnem mediju.Due to the reactivity, the storage of A1N dust is problematic, the initial stages of ceramics production, such as powder deagglomeration, homogenization with organic and inorganic additives, and the granulation and forming of the workpieces, require work in non-aqueous media, which is undesirable for economic, safety and environmental reasons. As a result, they try to protect A1N dust from hydrolysis, thus facilitating storage and allowing the processing and formation of the blanks in an aqueous medium.
Znanih je več postopkov zaščite prahu A1N pred hidrolizo v vlažni astmosferi oziroma v vodnem mediju. Zelo pogosto se uporablja postopek površinske zaščite delcev prahu A1N z organskimi molekulami z dolgimi verigami kot so npr. karboksilne kisline, zlasti stearinska kislina, poročajo pa tudi o uporabi cetil alkohola, n-dekanojske kisline, dodecilamina in drugih. Značilnost omenjenih organskih substanc je, da so hidrofobne, s čimer preprečujejo dostop vode do površine zaščitenih delcev. Hidrofobizacija keramičnih prahov je že dolgo znana in se tradicionalno uporablja npr. v barvilstvu, da pa se uporabiti tudi zaSeveral methods are known for protecting A1N dust from hydrolysis in a humid atmosphere or in an aqueous medium. Very often, the process of surface protection of A1N dust particles with long-chain organic molecules such as e.g. carboxylic acids, in particular stearic acid, and the use of cetyl alcohol, n-decanoic acid, dodecylamine and others have been reported. The organic matter mentioned is characterized by the fact that they are hydrophobic, thus preventing the access of water to the surface of the protected particles. Hydrophobization of ceramic powders has long been known and has been traditionally used e.g. in coloring, but also used for
-3zaščito prahu A1N pred hidrolizo. Stearinsko kislino ali katero drugo omenjeno organsko substanco raztopijo v nepolarnem organskem topilu, največkrat v cikloheksanu ali benzenu, v raztopini ob intenzivnem mešanju dispergirajo prah A1N, nastalo suspenzijo pa segrevajo nad temperaturo vrelišča organskega topila z refluksom. Da odstranijo odvečno karboksilno kislino, suspenzijo filtrirajo, pogačo pa spirajo z organskim topilom in jo posušijo na zraku. Pomanjkljivost tega postopka je, da uporablja zdravju škodljiva in vnetljiva organska topila, zaradi česar so pri takem postopku zaščite prahu A1N potrebni posebni varnostni ukrepi. Do neke mere je ta pomanjkljivost odpravljena s postopkom suhega mletja prahu A1N s stearinsko ali kakšno drugo karboksilno kislino v zaščitni atmosferi inertnega plina, kar je tehnološko precej zahtevno, poleg tega pa karboksilna kislina ni povsem homogeno porazdeljena po površini delcev prahu in je praviloma v prebitku. Nadalje je pomanjkljivost obeh postopkov zaščite prahu A1N s karboksilnimi kislinami v tem, da tako zaščitenega prahu, ki je hidrofoben (odbija vodo) ni mogoče dispergirati v vodi brez dodatkov organskih ali anorganskih omakal, ki praviloma povzročajo penjenje suspenzije. Zato je poleg omakal treba v suspenzijo dodati še tretji dodatek, ki omogoča pripravo suspenzije brez zračnih mehurčkov.-3 A1N dust protection against hydrolysis. Stearic acid or any other of the aforementioned organic substance is dissolved in a non-polar organic solvent, most preferably in cyclohexane or benzene, and the A1N powder is dispersed in the solution with vigorous stirring and the resulting suspension is heated above the boiling point of the organic solvent by reflux. To remove excess carboxylic acid, the suspension is filtered and the cake is washed with an organic solvent and air-dried. The disadvantage of this process is that it uses harmful and flammable organic solvents, which requires special precautionary measures in this A1N dust protection process. To some extent, this deficiency is eliminated by the process of dry grinding of A1N powder with stearic or other carboxylic acid in a protective atmosphere of an inert gas, which is technologically quite demanding, and the carboxylic acid is not completely homogeneously distributed over the surface of the dust particles and is usually in excess. . Furthermore, a disadvantage of both the A1N carboxylic acid powder protection processes is that such a protected hydrophobic (water repellant) powder cannot be dispersed in water without the addition of organic or inorganic dipping agents, which generally cause foaming of the suspension. Therefore, in addition to the sauces, a third additive should be added to the suspension, which allows the preparation of the suspension without air bubbles.
Drug znan postopek zaščite prahu A1N pred hidrolizo je adsorbcija fosforjeve kisline ali organskih ali anorganskih spojin fosforjeve kisline na površini prašnih delcev. V US Pat. 4,923,689 je opisan postopek zaščite prahu A1N s fosforjevo kislino, ortofosforjevo kislino, in vrsto organskih fosforjevih kislin ali njihovih spojin. Po temAnother known method of protecting A1N dust from hydrolysis is the adsorption of phosphoric acid or organic or inorganic phosphoric acid compounds on the surface of dust particles. In US Pat. No. 4,923,689 describes a process for protecting A1N dust with phosphoric acid, orthophosphoric acid, and a range of organic phosphoric acids or their compounds. After that
-4postopku prah A1N najprej dispergirajo v segretem organskem topilu, običajno etanolu, nakar tej suspenziji med mešanjem dodajo raztopino ene od omenjenih spojin. Po sušenju zaščiten prah še še segrejejo na tempearturo 150-550°C. Tako zaščiten A1N prah je pri sobni temperaturi obstojnejši proti hidrolizi v vodi od prahu, ki je zaščiten s karboksilnimi kislinami in je po navedbah v patentu odporen tudi pri temperaturah do 80°C. Pomanjkljivost postopka je v tem, da je suspenzija z anorganskimi fosforjevimi kislinami zaščitenega prahu A1N zelo kisla, kar je neugodno pri nadaljni tehnologiji izdelave keramike iz A1N, zlasti če se kot dodatek za sintranje uporablja Y2O3, ki se pri nizkih pH vrednostih vodne suspenzije raztaplja. Nadalje je pomankljivost postopka v tem, da se pri pripravi tako zaščitenega prahu uporabljajo organska topila, kar je neugodno iz ekonomskega in eološkega vidika.In the process, the A1N powders are first dispersed in a heated organic solvent, usually ethanol, and then a solution of one of these compounds is added to this suspension while stirring. After drying, the protected dust is still heated to a temperature of 150-550 ° C. The A1N powder thus protected is more resistant to hydrolysis in water at room temperature than the powder which is protected by carboxylic acids and, according to the patent, is also resistant to temperatures up to 80 ° C. The disadvantage of this process is that the suspension with inorganic phosphoric acids of the protected powder A1N is very acidic, which is disadvantageous for the further technology of making ceramics from A1N, especially when used as sintering additive Y 2 O 3 used at low pH values of aqueous the suspension dissolves. Furthermore, the disadvantage of the process is that organic solvents are used in the preparation of the dust thus protected, which is economically and eologically disadvantageous.
Pomanjkljivost vseh omenjenih zaščitenih praškov A1N je nadalje v tem, jih ne smejo izpostaviti intenzivnim strižnim silam, npr. pri mletju, ker sicer pride do hidrolize.The disadvantage of all the mentioned A1N shielding powders is that they should not be subjected to intense shear forces, e.g. when grinding because otherwise hydrolysis takes place.
Cilj izuma je torej učinkovita zaščita prahu A1N, tako da ta ne bo hidroliziral v vlažni atmosferi med daljšim skladiščenjem niti ne bo hidroliziral med mešanjem ali zmernim mletjem v vodnem mediju, zaščiten prah A1N ne bo imel slabih lastnosti, ko večina prahov zaščitenih po dosedaj znanih postopkih, sam postopek zaščite pa bo enstavnejši, cenejši in ekološko sprejemljivejši od dosedaj znanih postopkov.The object of the invention is therefore an effective protection of A1N dust so that it will not hydrolyze in a humid atmosphere during prolonged storage or hydrolyze during agitation or moderate grinding in aqueous medium, the protected A1N powder will not have poor properties, when most powders protected by the present known and the protection process itself will be simpler, less costly and more environmentally friendly than previously known procedures.
-5Po izumu je navedeni tehnični problem rešen s postopkom zaščite prahu AlN z adsorbcijo silicijeve kisline ali soli silicijeve kisline na površino delcev prahu AlN med mešanjem ali mletjem v vodi ali tekočini, ki vsebuje vodo, pri čemer je postopek zaščite po izumu značilen po tem, da se v vodi ali raztopini, ki vsebuje od ΙχΙΟ-3 do 5χ10_1 mol dm3 raztopljene silicijeve kisline ali ortosilicijeve kisline ali kakšne druge silicijeve kisline ali soli silicijeve kisline, ki je v vodi topna, dispergira do masnega deleža 1 do 60 % praha A1N, s povprečno velikostjo delcev od 0,1 ^m do 1 mm in da se med dispergiranjem suspenzije prahu A1N ne segreje nad temperaturo 90°C in da se v primeru dispergiranja z mletjem doda tej suspenziji, še od 0,01 do 0,1 ml na gram prahu A1N organskega ali anorganskega oksidanta, tipično H2O2 ter da se po dispergiranju suspenzijo prahu AlN posuši ali se prah A1N loči od tekočine s filtriranjem, centrifugiranjem ali dekantiranjem ter se posuši ali spere in posuši oziroma, da se po dispergiranju in homogenizaciji z organskimi in anorganskimi dodatki, ki so potrebni za izdelavo keramike AlN suspenzijo uporabi za oblikovanje keramičnih surovcev.According to the invention, said technical problem is solved by a method of protecting AlN dust by adsorbing silicic acid or a salt of silicic acid onto the surface of particles of AlN powder while stirring or grinding in water or a liquid containing water, the protection process of the invention being characterized, to dissolve in water or solution containing ΙχΙΟ -3 to 5χ10 _1 mol dm 3 dissolved silicic acid or orthosilicic acid or any other silicic acid or salt of water-soluble acid, up to 1 to 60% by weight of powder A1N, with an average particle size of 0.1 ^ m to 1 mm and not to be heated above 90 ° C during the dispersion of the powder suspension, and to be added to this suspension in the case of grinding dispersion, from 0.01 to 0, 1 ml per gram of A1N organic or inorganic oxidant powder, typically H 2 O 2, and after dispersion the AlN powder suspension is dried or the A1N powder is separated from the liquid by filtration, centrifugation or decantation. r is dried or washed and dried or used after dispersion and homogenization with the organic and inorganic additives required to make the AlN ceramics slurry to form ceramic blanks.
Postopek po izumu za zaščito prahu AlN pred hidrolizo v vlažni atmosferi ali vodnem mediju obsega naslednje korake:The process of the invention for protecting AlN dust from hydrolysis in a humid atmosphere or aqueous medium comprises the following steps:
Pripravi se raztopina silicijeve kisline, ortosilicijeve kisline ali vodotopne soli katere od silicijevih kislin npr. natrijevega silikata, v vodi in sicer z uvajanjem katerekoli komercialno dostopne ali v laboratoriju pripravljene silicijeve kisline ali soli silicijeve kisline ali snovi, ki pri reakciji z vodo tvori silicijevo kislino. Čistoča omenjenih snovi ni bistvenega pomena, saj nečistoče v mejah,A solution of silicic acid, orthosilicic acid or a water-soluble salt of any of the silicic acids, e.g. sodium silicate, in water, by the introduction of any commercially available or laboratory-grade silicic acid or silicic acid salt or substance which, when reacted with water, forms silicic acid. The purity of these substances is not essential, as the impurities within the boundaries,
-6~ ki so običajne za tehnične surovine ne vplivajo na sam postopek zaščite prahu A1N. Zaželeno pa je, da so omenjene snovi čim čistejše, ker nečistoče kvarno vplivajo na lastnost sintrane A1N keramike. Večji problem, kot je čistoča silicijeve kisline ali njenih spojin, predstavlja njihova topnost v vodi, ki je odvisna od vrste snovi, vrste topila in temperature. V vodo ali vodno raztopino, ki vsebuje od lxlO~3 do ΙχΙΟ-1 molov/liter silicijeve kisline in katere pH se običajno giblje med 3 in 10, odvisno od vrste in koncentracije silicijeve kisline ali vodotopne soli silicijeve kisline, se dispergira prah A1N z mešanjem v posodi ali mletjem. V kolikor dispergiranje poteka med mešanjem v posodi, dodatek vodotopnega oksidanta, npr. H2O2, ni potreben, v primeru dispergiranja z intenzivnejšim mletjem pa je potrebno pred začetkom mletja raztopini dodati še od 0,01 do 0,1 ml H2O2 na 1 gram prahu A1N, ali katerega drugega vodotopnega oksidanta, ki med mešanjem ali mletjem sprošča kisik. Med dispergiranjem prahu A1N v raztopini z mešanjem ali mletjem zaščitna atmosfera inertnega plina ni potrebna. Dispergiranje lahko poteka pri sobni ali povišani temperaturi, ki pa ne sme preseči 85°C. Dispergiranj e prahu A1N v raztopini ni časovno omejeno, običajno pa poteka eno uro, lahko pa tudi dalj časa, ne da bi se s tem zmanjšal učinek zaščite prahu A1N. Po mešanju ali mletju se lahko suspenzijo prahu A1N posuši ali pa se odstrani odvečna raztopina silicijeve kisline ali soli silicijeve kisline s filtriranjem, centrifugiranjem ali dekantiranjem. Vlažna pogača se lahko spere z destilirano ali deionizirano vodo, ali pa se nesprana posuši na zraku pri temperaturi, ki lahko presega 100°C. V kolikor zaščita prahu A1N ni potrebna zaradi skladiščenja, lahko poteka homogenizacija prahu A1N z-6 ~ which are common to technical raw materials do not affect the A1N dust protection process itself. However, it is desirable that the substances mentioned are as pure as possible because the impurities adversely affect the sintered A1N ceramic property. A major problem, such as the purity of silicic acid or its compounds, is their solubility in water, which depends on the type of substance, the type of solvent and the temperature. A1N is dispersed in water or aqueous solution containing from lxlO ~ 3 to ΙχΙΟ -1 moles / liter of silicic acid and whose pH typically ranges between 3 and 10, depending on the type and concentration of silicic acid or the water-soluble salt of silicic acid. stirring in a pan or grinding. To the extent that dispersion occurs during mixing in a container, the addition of a water-soluble oxidant, e.g. H 2 O 2 is not required, and in the case of intensive grinding dispersion, 0.01 to 0.1 ml of H 2 O 2 per 1 gram of A1N powder or any other water-soluble oxidant which, during mixing or grinding releases oxygen. During the dispersion of A1N powder in solution by stirring or grinding, an inert gas protective atmosphere is not required. Dispersion may be carried out at room or elevated temperature, but must not exceed 85 ° C. The dispersion of A1N powder in the solution is not limited in time, but usually lasts for one hour, but can be continued for a long time without reducing the effect of protecting the A1N dust. After mixing or grinding, the suspension of the A1N powder may be dried or the excess solution of silicic acid or silicic acid salt may be removed by filtration, centrifugation or decantation. The wet cake may be rinsed with distilled or deionized water or dried in air at a temperature in excess of 100 ° C. If A1N dust protection is not required for storage, the A1N dust homogenization with
-Ίanorganskimi dodatki za sintranje in organskimi dodatki za oblikovanje v raztopini silicijeve kisline, ortosilicijeve kisline ali vodotopne soli katere od silicijevih kislin, ki ji sledi mokro oblikovanje, sušenje in sintranje.- Organic sintering additives and organic additives for forming in solution of silicic acid, orthosilicic acid or the water-soluble salt of any of the silicic acids, followed by wet forming, drying and sintering.
Izum bo dodatno opisan na osnovi izvedbenih primerov.The invention will be further described based on embodiments.
Primer 1Example 1
Pripravi se 1000 ml raztopine silicijeve kisline s koncentracijo 5*10~3 mol dm-3 z raztapljanjem silicijeve kisline (proizvajalca Koch-Light Laboratories, chromatographic grade) v vreli deionizirani vodi. V to raztopino, ki se jo ohladi na sobno temperaturo in katere pH vrednost je 6, se med mešanjem z magnetnim mešalom dispergira 25 g prahu A1N (proizvajalca H.C. Starck, Grade C). Mešanje poteka na zraku pri sobni temperaturi. Po mešanju, ki traja 1 uro, se suspenzija odcentrifugira. Vlažno pogačo se 6 ur suši na zraku pri temperaturi 85°C, nato še 2 uri na tempearturi 110°C. Koncentracija SiO2 na zaščitenem prahu A1N je 0,09%. Posušen prah razen A1N ne vsebuje nobene druge kristalinične faze, ki bi jo zaznala rentgenska analiza. Preverjanje odpornosti tako zaščitenega prahu A1N je potekalo z redispergiranjem prahu v deionizirani vodi, v tem primeru 5g/100ml vode pri sobni tempearturi in pri temperaturi 70°C s spremljanjem spremembe pH s stekleno elektrodo in pH metrom v odvisnosti od časa v časovnem razdobju 24 ur. Za primeravo so bili pripravljeni še prahovi zaščiteni z dTug^mi anorganskimi kislinami. Rezultati so podani v Tabeli 1 jin Tabeli 2. Iz rezultatov je razvidno, da je postopek zaščitePrepare 1000 ml of a 5 * 10 ~ 3 mol dm -3 solution of silicic acid by dissolving silicic acid (manufactured by Koch-Light Laboratories, chromatographic grade) in boiling deionized water. 25 g of A1N powder (manufactured by HC Starck, Grade C) are dispersed in this solution, which is cooled to room temperature and whose pH is 6, while stirring with a magnetic stirrer. Stirring is carried out in air at room temperature. After stirring for 1 hour, the suspension was centrifuged. The moist cake is air-dried at 85 ° C for 6 hours, then at 110 ° C for 2 hours. The concentration of SiO 2 on the protected A1N powder is 0.09%. Dried powder other than A1N contains no other crystalline phase that can be detected by X-ray analysis. Checking the resistance of the A1N dust thus protected was performed by redispersing the powder in deionized water, in this case 5g / 100ml water at room temperature and at 70 ° C by monitoring the pH change with a glass electrode and pH meter as a function of time over a 24 hour period. . For comparison, powders protected with dTug ^ inorganic acids were prepared. The results are given in Table 1 and Table 2. The results show that the process of protection
-8prahu A1N uspešen tako pri sobni temperaturi, kot tudi pri povišani temperaturi, v tem primeru 70°C, za razliko od zaščite prahu s fosforjevo kislino, pri kateri je zaščita uspešna samo pri sobni temperaturi, pri povišani temperaturi pa ne, kar kaže porast pH vrednosti.-8A1N powder is effective both at room temperature and at elevated temperature, in this case 70 ° C, unlike dust protection with phosphoric acid, at which protection is only successful at room temperature but not at elevated temperature, indicating an increase pH values.
Tabela 1. Sprememba pH pri sobni temperaturiTable 1. pH change at room temperature
Primer 2Example 2
Postopek zaščite je enak kot v primeru 1, samo da se po raztapljanju silicijeve kisline v vreli vodi raztopina ohladi na 85°C, nakar se med mešanjem dispergira prah A1N. Dispergiranje poteka 10 min pri 85°C, nakar se suspenzija ohladi, filtrira in posuši. Po redispergiranju zaščitnegaThe protection procedure is the same as in Example 1, except that after dissolving the silicic acid in boiling water, the solution is cooled to 85 ° C and then the A1N powder is dispersed while stirring. The dispersion was carried out for 10 min at 85 ° C, after which the suspension was cooled, filtered and dried. After redispersing the protective
-9prahu v vodi, v tem primeru 5g/100 ml, je bila suspenzija segrevana s hitostjo 10°C/min do temperture 90°C. Med segrevanjem na to temperaturo se pH suspenzije ni spreminjal.-9 Powder in water, in this case 5g / 100 ml, the suspension was heated at a rate of 10 ° C / min to a temperature of 90 ° C. The pH of the suspension did not change during warming to this temperature.
Primer 3Example 3
Postopek zaščite prahu A1N je enak kot v primeru 1, samo da se namesto raztopine silicijeve kisline uporabi 10% raztopina natrijevega silikata s pH vrednostjo 10. Dispergiranje poteka pri sobni temperaturi in sicer se dispergira 100 g A1N v 250 ml raztopine. Preverjanje odpornosti tako zaščitenega prahu A1N je potekalo z redispergiranjem prahu v deionizirani vodi, v tem primeru 5g/100ml vode, pri sobni temperaturi in pri temperaturi 70°C s spremljanjem spremembe pH v odvisnosti od časa v časovnem razdobju 24 ur. pH se med preverjanjem ni spreminjal.The procedure for protecting the A1N powder is the same as in Example 1, except that a 10% solution of sodium silicate with a pH value of 10. is used instead of the silicic acid solution. The dispersion is carried out at room temperature, dispersing 100 g of A1N in 250 ml of solution. Checking the resistance of the A1N dust thus protected was carried out by redispersing the powder in deionized water, in this case 5g / 100ml water, at room temperature and at 70 ° C by monitoring the change in pH as a function of time over a 24 hour period. The pH did not change during verification.
Primer 4Example 4
V planetni mlin z volumnom 750ml in z 17Og aluminatnih krogel s premerom 20mm se zatehta 50g prahu A1N. Doda se 50ml raztopine silicijeve kisline s koncentracijo 5 mmol/1, pripravljene po postopku iz Primera 1, in še 5 ml vodikovega peroksida. Prah A1N se dispergira v raztopini silicijeve kisline in H2O2 z enournim mletjem pri lOOobr/min. pH suspenzije se med mletjem ne spreminja, niti se ne zazna značilnega vonja po amoniaku, ki pa se ga zazna v primeru mletja A1N prah v vodi ali pa raztopini silicijeve kisline brez dodatka H2O2 pod enakimi pogoji. Po mletju se odstrani mlevna telesa in se suspenzijo posuši na zraku. Med dispergiranjem z mletjem se je povprečna velikost delcevWeigh 50g of A1N powder into a planetary mill with a volume of 750ml and 17Og of 20mm aluminum balls. Add 50 ml of a 5 mmol / l solution of silicic acid prepared according to the procedure of Example 1 and 5 ml of hydrogen peroxide. The A1N powder was dispersed in a solution of silicic acid and H 2 O 2 with a one-hour grinding at 100 rpm. The pH of the suspension does not change during grinding, nor does it detect a characteristic odor of ammonia, which is detected in the case of grinding of A1N powder in water or in silicic acid solution without the addition of H 2 O 2 under the same conditions. After grinding, the grinding bodies are removed and the suspension is air-dried. During milling dispersion, the average particle size
-10prahu A1N zmanjšala od začetnih 1,5 μια na 1,3 μία, posušen prah je rentgensko A1N, in po redispergiranju v deionizirani vodi, v tem primeru 5g/100ml, po 24 urah pri sobni temperaturi ne hidrolizira. Zaradi prisotnosti H2O2 med dispergiranjem prahu A1N, se je vsebnost kisika v A1N od začetne vrednosti 2,6% povečala in sicer na 3,1%.-10 Dusts the A1N from the initial 1.5 μια to 1.3 μία, the dried powder is X-ray A1N, and after redispersion in deionized water, in this case 5g / 100ml, does not hydrolyze after 24 hours at room temperature. Due to the presence of H 2 O 2 during the dispersion of A1N powder, the oxygen content of A1N increased from 2.6% to 3.1% from the initial value.
Primer 5Example 5
V atritorskem mlinu v tem primeru z volumnom 750ml, v katerem je lOOOg ZrO2 kroglic premera 2mm se pripravi suspenzija lOOg prahu A1N v 43ml absolutnega etanola. Suspenzija se melje l/2h pri 800obr/min. Po polurnem mletju se doda še 57ml raztopine silicijeve kisline s koncentracijo 5mmol/l. Suspenzija se melje še 10 min nakar se odstrani mlevna telesa, suspenzija pa posuši na temperaturi 110°C. Povprečna velikost delcev prahu A1N se je med mletjem v atritorskem mlinu zmanjšala od začetnih 1,5 μιη na 1,0 μαχ, Tako pripravljen prah A1N, v tem primeru 5g se ponovno dispergira v lOOml deionizirane vode, da bi se ugotovilo, ali je prah uspešno zaščiten proti hidrolizi. Po 24-urnem mešanju pri sobni temperaturi se pH suspenzije ne spremeni.In the attritor mill, in this case, with a volume of 750ml, containing 100g of ZrO 2 2mm diameter beads, a suspension of 100g of A1N powder in 43ml of absolute ethanol is prepared. The suspension is ground l / 2h at 800rpm. After grinding for half an hour, a further 57ml of 5mmol / l silicic acid solution was added. The suspension is ground for a further 10 minutes, after which the grinding bodies are removed and the suspension is dried at 110 ° C. The average particle size of the A1N powder decreased during grinding in the atritor mill from the initial 1.5 μιη to 1.0 μαχ, the A1N powder thus prepared, in which case 5g was again dispersed in lOOml of deionized water to determine whether the powder was successfully protected against hydrolysis. After stirring at room temperature for 24 hours, the pH of the suspension does not change.
Primer 6Example 6
V planetarni mlin z volumnom 750ml in z 17Og aluminatnih krogel premera 20mm se zatehta 47g prahu A1N in 3g prahu Y2O3. Doda se 50ml raztopine silicijeve kisline s koncentracijo 5mmol/l, pripravljene po postopku iz primera 1 in 5ml H2O2. Po enournem mletju pri 100 obr/min, se suspenzija odstrani od mlevnih teles in vlije v gipsni model, kjer se posuši. MedWeigh 47g of A1N powder and 3g of Y 2 O 3 powder in a planetary mill with a volume of 750ml and 17Og of 20mm aluminum spheres. Add 50ml of silicic acid solution with a concentration of 5mmol / l prepared according to the procedure of Example 1 and 5ml of H 2 O 2 . After one hour of milling at 100 rpm, the suspension is removed from the milling bodies and poured into a plaster model where it is dried. Med
-11mletjem in homogenizacijo z Y2O3, se A1N ne hidrolizira in se lahko sintra do visoke gostote.By grinding and homogenization with Y 2 O 3 , A1N is not hydrolyzed and can be sintered to high density.
Z rešitvijo po izumu se doseže naslednje prednosti: z adsorbcijo silicijeve kisline ali ortosilicijeve kisline ali kakšne druge silicijeve kisline ali soli silicijeve kisline na površini delcev se doseže učinkovita zaščita prahu A1N pred hidrolizo v vlažni atmosferi ali v vodnem mediju do temperature 90°C, kar pri večini dosedaj znanih postopkov ni bil slučaj. Nadalje je po izumu zaščiten prah A1N dalj časa obstojen proti hidrolizi v vodnem mediju pri povišani pH vrednosti, kar pri nekaterih dosedaj znanih postopkih tudi ni slučaj. Posušen zaščiten prah A1N po izumu ni hidrofoben in se brez omakal dobro dispergira v vodi. Ob dodatku organskega ali anorganskega oksidanta je možno prah A1N tudi mleti v vodnem mediju oz. ga homogenizirati z dodatki za oblikovanje in sintranje z mokrim mletjem ali ultrazvočnim mešanjem pri temperaturah do 90°C. Postopek zaščite prahu A1N po izumu ni drag in tehnično zahteven, niti ne zahteva posebnih zaščitnih ukrepov, saj uporabljene substance niso vnetljive, delo z njimi pa ne ogroža zdravja ali okolja.The solution according to the invention achieves the following advantages: adsorption of silicic acid or orthosilicic acid or any other silicic acid or silicic acid salt on the particle surface results in effective protection of A1N dust from hydrolysis in a humid atmosphere or in aqueous medium to a temperature of 90 ° C, this has not been the case with most procedures known to date. Furthermore, according to the invention, the protected A1N powder is stable for a long time against hydrolysis in aqueous medium at an elevated pH, which is not the case in some of the methods known to date. The dried proprietary A1N powder of the invention is not hydrophobic and is well dispersed in water without water. With the addition of an organic or inorganic oxidant, the A1N powder may also be ground in aqueous medium or. homogenize it with molding and sintering additives by wet milling or ultrasonic mixing at temperatures up to 90 ° C. The A1N dust protection process of the invention is not expensive and technically demanding, nor does it require special protective measures, since the substances used are non-flammable and do not endanger health or the environment.
Claims (4)
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SI9700229A SI9700229A (en) | 1997-09-05 | 1997-09-05 | Process for protection of aluminium nitride powder against hydrolysis |
| AU88220/98A AU8822098A (en) | 1997-09-05 | 1998-08-26 | Process for the protection of aln powder against hydrolysis |
| PCT/SI1998/000018 WO1999012850A1 (en) | 1997-09-05 | 1998-08-26 | PROCESS FOR THE PROTECTION OF AlN POWDER AGAINST HYDROLYSIS |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SI9700229A SI9700229A (en) | 1997-09-05 | 1997-09-05 | Process for protection of aluminium nitride powder against hydrolysis |
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| SI9700229A true SI9700229A (en) | 1999-04-30 |
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|---|---|---|---|
| SI9700229A SI9700229A (en) | 1997-09-05 | 1997-09-05 | Process for protection of aluminium nitride powder against hydrolysis |
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| Country | Link |
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| AU (1) | AU8822098A (en) |
| SI (1) | SI9700229A (en) |
| WO (1) | WO1999012850A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108217688A (en) * | 2018-01-25 | 2018-06-29 | 中国科学院过程工程研究所 | A kind of depth hydrolysis method of aluminum nitride in aluminum ash |
| CN112897481A (en) * | 2020-12-30 | 2021-06-04 | 河北利福光电技术有限公司 | Aluminum nitride powder and preparation method thereof |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| TWI450855B (en) * | 2011-08-04 | 2014-09-01 | Method for making a pure aluminum nitride substrate | |
| US10005699B2 (en) | 2016-07-28 | 2018-06-26 | Battelle Memorial Institute | Nitride-based controlled-release fertilizers and process for making same |
| CN109354500A (en) * | 2018-11-30 | 2019-02-19 | 华南理工大学 | A kind of aluminium nitride powder of resistant to hydrolysis and preparation method thereof |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4923689A (en) * | 1988-08-01 | 1990-05-08 | Toyo Aluminium Kabushiki Kaisha | Aluminum nitride power having improved water-resistance |
| US5234712A (en) * | 1992-06-08 | 1993-08-10 | The Dow Chemical Company | Method of making moisture resistant aluminum nitride powder and powder produced thereby |
| JPH07235742A (en) * | 1993-12-27 | 1995-09-05 | Mitsubishi Materials Corp | Surface-treated aluminum nitride board for thin-film circuit |
| JPH07315813A (en) * | 1994-05-27 | 1995-12-05 | Shin Etsu Chem Co Ltd | Aluminum nitride powder |
-
1997
- 1997-09-05 SI SI9700229A patent/SI9700229A/en not_active IP Right Cessation
-
1998
- 1998-08-26 WO PCT/SI1998/000018 patent/WO1999012850A1/en active Application Filing
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108217688A (en) * | 2018-01-25 | 2018-06-29 | 中国科学院过程工程研究所 | A kind of depth hydrolysis method of aluminum nitride in aluminum ash |
| CN112897481A (en) * | 2020-12-30 | 2021-06-04 | 河北利福光电技术有限公司 | Aluminum nitride powder and preparation method thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| AU8822098A (en) | 1999-03-29 |
| WO1999012850A1 (en) | 1999-03-18 |
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