EP0043506A2 - Method of forming vanadium carbide layers on iron - Google Patents

Method of forming vanadium carbide layers on iron Download PDF

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Publication number
EP0043506A2
EP0043506A2 EP81104912A EP81104912A EP0043506A2 EP 0043506 A2 EP0043506 A2 EP 0043506A2 EP 81104912 A EP81104912 A EP 81104912A EP 81104912 A EP81104912 A EP 81104912A EP 0043506 A2 EP0043506 A2 EP 0043506A2
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Prior art keywords
vanadium
iron
salt
vanadium carbide
carbide layers
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EP81104912A
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German (de)
French (fr)
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EP0043506A3 (en
EP0043506B1 (en
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Ulrich Dr. Dipl.-Chem. Baudis
Peter Ing.Grad. Biberbach
Wolfgang Weber
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Evonik Operations GmbH
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Degussa GmbH
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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
    • C23C10/18—Solid state diffusion of only metal elements or silicon into metallic material surfaces using liquids, e.g. salt baths, liquid suspensions
    • C23C10/20—Solid state diffusion of only metal elements or silicon into metallic material surfaces using liquids, e.g. salt baths, liquid suspensions only one element being diffused
    • C23C10/24—Salt bath containing the element to be diffused

Definitions

  • the invention relates to a process for producing vanadium carbide layers on iron and iron alloys with a content of at least 0.1% by weight of carbon by treating the workpieces at 800 to 1100 ° C. in a salt bath which contains 1 to 30% by weight of vanadium or ferrovanadium powder .
  • Vanadium carbide layers are characterized by great hardness, wear resistance, good oxidation and corrosion resistance. It is therefore endeavored to apply such layers to workpieces made of iron and iron alloys, in particular to highly stressed tool and machine parts, such as e.g. Drawing and punching tools, cutting tools or nozzles.
  • DE-OS 20 53 063 describes a method for forming a carbide layer of an element of the fifth subgroup of the periodic system of the elements on the surface of metal objects.
  • a molten salt bath containing boric acid or a borate and a metal powder of an element of the fifth subgroup is used for this.
  • the layer-forming metal is partially dissolved in the very aggressive borate melt and transported to the material surface in this way.
  • DE-OS 32 22 159 describes a modification of this process, in which the metal forming the carbide layer. is anodically dissolved in the melt.
  • a process is further described in DE-OS 28 19 856 ! described, in which the metal forming the layer is produced by a reduction of the corresponding metal oxides by means of a boron-containing substance, such as ferroboron or boron carbide.
  • a boron-containing substance such as ferroboron or boron carbide.
  • a common feature of the known processes is the use of boron oxide or borates as an essential component of the melts.
  • borate or melts containing boron oxide are extremely aggressive at the high temperature of 800 - 1100 o C required for the treatment. This often leads to noticeable attacks on the crucible material or on the workpieces to be treated, which sometimes manifests itself in considerable surface roughness.
  • these melts are extremely viscous even at high temperatures. Because of the High viscosity of the boron-containing melts can lead to an uneven temperature distribution in the bath.
  • the known electrolytic processes involve a greater outlay on the process, such as, for example, precise bath control and keeping the current density constant, and cause additional costs.
  • it is e.g. necessary to maintain a very specific ratio of metal oxide to boron, since an excess of boron does not form a carbide layer, but a boride layer. If the boron deficit is too low, no carbide layer is formed either, since the reducing effect is insufficient.
  • the salt bath consists of alkaline earth and / or alkali halides.
  • vanadium carbide layers of excellent quality are obtained even when molten alkaline earth and / or alkali halides are used, especially without using boron or boron oxide-containing melts in the form of their chlorides and / or fluorides, for activating the solid vanading agent (ferrovanadin or vanadium powder).
  • the activating effect is that a direct solid-state reaction between the vanading agent and the material surface to be coated is made possible.
  • the vanadium coming into contact with the material surface reacts with the carbon of the substrate material to form a closed, uniform, firmly adhering vanadium carbide layer.
  • Barium chloride is preferably used as the molten salt, to which 1-50% by weight sodium chloride can advantageously be added.
  • sodium chloride can advantageously be added.
  • an annular nozzle which is provided with specially arranged gas outlet openings according to the size of the crucible and the amount of melt, a very uniform distribution of the vanading agent is achieved.
  • This preferred procedure has the further advantage that a protective gas curtain is formed on the bath surface, which reduces the access of atmospheric oxygen to the oxidation-sensitive vanading agent. This considerably increases the lifespan of the bath.
  • the melt according to the invention has a number of advantages over the known melts. It is thin even at low irradiation temperatures, which means that salt drag-out losses are low. The adhering salt residues can be easily removed by washing. Since corrosion attacks do not occur due to the neutral behavior of the salts, crucibles made of relatively cheap mild steel can be used to absorb the melts.
  • layer thicknesses of 2-16 ⁇ m can be achieved with the method according to the invention within 2-4 hours.
  • a mixture of 19 kg barium chloride, 1 kg sodium chloride and 1 kg ferrovanadium with a grain size smaller than 150 ⁇ m is melted in a mild steel crucible of 18 cm diameter and 30 cm depth and heated to a temperature of 950 ° C.
  • the ferrovanadium powder is homogeneously distributed in the melt with the aid of a stirrer.
  • a workpiece made of Ck 60 steel is treated in this bath for 4 hours and cooled in air.
  • the metallographic examination shows that an approximately 10 ⁇ m thick, homogeneous and smooth layer has formed on the surface. This can be identified radiographically as vanadium carbide (VC).
  • VC vanadium carbide
  • Example 2 In the same way as in Example 1, 20 kg of BaCl 2 are melted and 3 kg of ferrovahadine powder are added. The temperature is set at 1050 ° C. When a sample of X155CVMo12 is treated in this melt, an approximately 8 ⁇ m thick, uniform and homogeneous vanadium carbide layer is obtained on the surface after 2 hours.
  • Example 3 As in Example 3, a mixture of 10 kg BaCl 2 , 5 kg KF, 3.6 kg NaF and 2.4 kg ferrovanadium powder is melted and heated to 850 ° C. An argon flow of 60 liters / h is passed through the melt. Samples of 100 Cr 6 have vanadium carbide layers 4-5 ⁇ m thick after 6 hours of treatment.
  • Example 3 Using a procedure analogous to that in Example 3, using pure vanadium powder instead of ferrovanadin, a vanadium carbide layer of 4 ⁇ m thick is obtained on steel 34 CrMo4 after 4 hours of treatment, and a layer of 6 ⁇ m thick on steel C45.
  • the layers created are always dense, even and smooth. They show a high hardness (approx.3,000nV) and an extraordinarily good abrasion resistance.
  • Pure alkali halide melts can also be used for the process according to the invention, but are Baths are very thin and evaporate at high temperatures, so that use is only possible at relatively low temperatures.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Carbon And Carbon Compounds (AREA)
  • Chemical Treatment Of Metals (AREA)

Abstract

Zur Herstellung von Vanadincarbidschichten auf Werkstücken aus kohlenstoffhaltigem Eisen und Eisenlegierungen benützte man bisher bei 800 bis 1100° Salzbäder, die hauptsächlich Borate als Grundsubstanz enthielten. Dadurch wurden die Schmelzen sehr viskos, die Austragsverluste groß. Dies kann man vermeiden mit Salzbädern, die neben 1-30% Vanadium- oder Ferrovanadinpulver als Salz Erdalkali- und/oder alkalihalogenide enthalten. Besonders bewährt haben sich Bäder aus Bariumchlorid mit 1-50% Natriumchlorid.For the production of vanadium carbide layers on workpieces made of carbon-containing iron and iron alloys, salt baths containing mainly borates as the basic substance were used at 800 to 1100 °. As a result, the melts became very viscous and the discharge losses were large. This can be avoided with salt baths which contain, in addition to 1-30% vanadium or ferrovanadium powder, as the salt, alkaline earth and / or alkali halides. Baths of barium chloride with 1-50% sodium chloride have proven particularly useful.

Description

Die Erfindung betrifft ein Verfahren zur Herstellung von Vanadincarbidschichten auf Eisen und Eisenlegierungen mit einem Gehalt von mindestens 0,1 Gew-% Kohlenstoff durch Behandlung der Werkstücke bei 800 bis 1100°C in einem Salzbad, das 1 bis 30 Gew% Vanadium- oder Ferrovanadinpulver enthält.The invention relates to a process for producing vanadium carbide layers on iron and iron alloys with a content of at least 0.1% by weight of carbon by treating the workpieces at 800 to 1100 ° C. in a salt bath which contains 1 to 30% by weight of vanadium or ferrovanadium powder .

Vanadincarbidschichten zeichnen sich durch eine große Härte, Verschleißfestigkeit, gute Oxidations- und Korrosionsfestigkeit aus. Man ist daher bestrebt, solche Schichten auf Werkstücke aus Eisen und Eisenlegierungen aufzubringen, insbesondere auf hochbeanspruchte Werkzeug- und Maschinenteile, wie z.B. Zieh- und Stanzwerkzeuge, Schneidwerkzeuge oder Düsen.Vanadium carbide layers are characterized by great hardness, wear resistance, good oxidation and corrosion resistance. It is therefore endeavored to apply such layers to workpieces made of iron and iron alloys, in particular to highly stressed tool and machine parts, such as e.g. Drawing and punching tools, cutting tools or nozzles.

Es sind bereits zahlreiche Verfahren zur Erzeugung versuhleißfester Vanadincarbidschichten bekannt. So beschreibt z.B. die DE-OS 20 53 063 ein Verfahren zur Bildung einer Carbidschicht eines Elements der fünften Nebengruppe des periodischen Systems der Elemente auf der Oberfläche von Metallgegenständen. Dazu verwendet man ein geschmolzenes Salzbad, das Borsäure oder ein Borat und ein Metallpulver eines Elements der fünften Nebengruppe enthält. Das schichtbildende Metall wird hierbei teilweise in der sehr aggressiven Boratschmelze gelöst und auf diese Weise an die Werkstoffoberfläche transportiert.Numerous methods for producing wear-resistant vanadium carbide layers are already known. For example, DE-OS 20 53 063 describes a method for forming a carbide layer of an element of the fifth subgroup of the periodic system of the elements on the surface of metal objects. A molten salt bath containing boric acid or a borate and a metal powder of an element of the fifth subgroup is used for this. The layer-forming metal is partially dissolved in the very aggressive borate melt and transported to the material surface in this way.

Eine Abwandlung diesesVerfahrens beschreibt die DE-OS 32 22 159, wobei das die Carbidschicht bildende Metall. anodisch in der Schmelze gelöst wird.DE-OS 32 22 159 describes a modification of this process, in which the metal forming the carbide layer. is anodically dissolved in the melt.

In der DE-OS 23 22 157 wird zur Herstellung verschleißfester Carbidschichten das carbidbildende Metall aus einer Boratschmelze kathodisch am Werkstück abgeschieden.In DE-OS 23 22 157 the carbide-forming metal from a borate melt is deposited cathodically on the workpiece for the production of wear-resistant carbide layers.

Weiter wird in der DE-OS 28 19 856 ein Verfahren!beschrieben, bei dem das die Schicht bildende Metall durch eine Reduktion der entsprechenden Metalloxide mittels eines borhaltigen Stoffes, wie Ferrobor oder Borcarbid, erzeugt wird.A process is further described in DE-OS 28 19 856 ! described, in which the metal forming the layer is produced by a reduction of the corresponding metal oxides by means of a boron-containing substance, such as ferroboron or boron carbide.

Alle diese bekannten Verfahren weisen eine Reihe von Nachteilen auf. Ein gemeinsames Merkmal der bekannten Verfahren ist die Verwendung von Boroxid oder Boraten als wesentlicher Bestandteil der Schmelzen. Borat oder boroxidhaltige Schmelzen sind jedoch bei der zur Behandlung erforderlichen hohen Temperatur von 800 - 1100o C außerordentlich aggressiv. Dies führt häufig zu merklichen Angriffen auf das Tiegelmaterial oder auf die zu behandelnden Werkstücke, was sich bisweilen in beträchtlicher Oberflächenrauhigkeit äußert. Ferner sind diese Schmelzen auch bei hohen Temperaturen überaus zähflüssig. Wegen der hohen Viskosität der borhaltigen Schmelzen kann eine ungleiche Temperaturverteilung im Bad auftreten. Durch Zusatz von Alkalihalogeniden läßt sich die Viskosität dieser Schmelzen allerdings etwas erniedrigen, doch ist die dadurch erzielbare Viskosität immer noch sehr hoch. Dadurch wird auch eine beträchtliche Menge des Bades mit den behandelten Teilen ausgetragen, wobei hohe Salzverluste entstehen. Ferner läßt sich die den erkalteten Teilen anhaftende Schmelze aufgrund ihrer glasartigen Beschaffenheit nur äußerst schwer entfernen.All of these known methods have a number of disadvantages. A common feature of the known processes is the use of boron oxide or borates as an essential component of the melts. However, borate or melts containing boron oxide are extremely aggressive at the high temperature of 800 - 1100 o C required for the treatment. This often leads to noticeable attacks on the crucible material or on the workpieces to be treated, which sometimes manifests itself in considerable surface roughness. Furthermore, these melts are extremely viscous even at high temperatures. Because of the High viscosity of the boron-containing melts can lead to an uneven temperature distribution in the bath. However, the viscosity of these melts can be somewhat reduced by adding alkali halides, but the viscosity which can be achieved as a result is still very high. As a result, a considerable amount of the bath with the treated parts is discharged, with high salt losses. Furthermore, the melt adhering to the cooled parts is extremely difficult to remove due to its glassy nature.

Die bekannten elektrolytischen Verfahren bedingen einen größeren Verfahrensaufwand, wie z.B- genaue Badkontrolle und Konstanthaltung der Stromdichte, und verursachen zusätzliche Kosten. Beim Verfahren nach der DE-OS 28 19 856 ist es z.B. erforderlich, ein ganz bestimmtes Verhältnis von Metalloxid zu Bor einzuhalten, da bei einem Überschuß an Bor keine Carbid-, sondern eine Boridschicht gebildet wird. Bei einem Unterschuß an Bor wird ebenfalls keine Carbidschicht gebildet, da die Reduktionswirkung nicht ausreicht.The known electrolytic processes involve a greater outlay on the process, such as, for example, precise bath control and keeping the current density constant, and cause additional costs. In the process according to DE-OS 28 19 856 it is e.g. necessary to maintain a very specific ratio of metal oxide to boron, since an excess of boron does not form a carbide layer, but a boride layer. If the boron deficit is too low, no carbide layer is formed either, since the reducing effect is insufficient.

Es war daher Aufgabe der vorliegenden Erfindung, ein Verfahren zur Herstellung von Vanadiumcarbidschichten auf Eisen und Eisenlegierungen mit einem Gehalt von mindestens 0,1 Gew% Kohlenstoff zu finden, durch Behandlung der Werkstücke bei 800 bis 1100°C in einem Salzbad, das 1 -30 Gew% Vanadium- oder Ferrovanadinpulver enthält, ohne Anwendung, von Strom und mit einer niederviskosen, wenig aggressiven Salzschmelze.It was therefore an object of the present invention to find a process for producing vanadium carbide layers on iron and iron alloys with a content of at least 0.1% by weight of carbon, by treating the workpieces at 800 to 1100 ° C. in a salt bath, the 1-30 % By weight contains vanadium or ferrovanadium powder, without use, of electricity and with a low-viscosity, less aggressive Molten salt.

Diese Aufgabe wurde erfindungsgemäß dadurch gelöst, daß das Salzbad aus Erdalkali- und/oder Alkalihalogeniden besteht.. Überraschenderweise wurde festgestellt, daß man auch ohne Verwendung bor- bzw. boroxidhaltiger Schmelzen Vanadincarbidschichten ausgezeichneter Qualität erhält, wenn geschmolzene Erdalkali- und/oder Alkalihalogenide, insbesondere in Form ihrer Chloride und/oder Fluoride, zur Aktivierung des festen Vanadierungsmittels (Ferrovanadin- oder Vanadiumpulver) eingesetzt werden. Die aktivierende Wirkung besteht darin, daß eine direkte Festkörperreaktion zwischen dem Vanadierungsmittel und der zu beschichtenden Werkstoffoberfläche ermöglicht wird. Das mit der Werkstoffoberfläche in Kontakt tretende Vanadium reagiert mit dem Kohlenstoff des Substratmaterials unter Ausbildung einer geschlossenen, gleichmäßigen, festhaftenden Vanadincarbid-Schicht.This object has been achieved according to the invention in that the salt bath consists of alkaline earth and / or alkali halides. Surprisingly, it was found that vanadium carbide layers of excellent quality are obtained even when molten alkaline earth and / or alkali halides are used, especially without using boron or boron oxide-containing melts in the form of their chlorides and / or fluorides, for activating the solid vanading agent (ferrovanadin or vanadium powder). The activating effect is that a direct solid-state reaction between the vanading agent and the material surface to be coated is made possible. The vanadium coming into contact with the material surface reacts with the carbon of the substrate material to form a closed, uniform, firmly adhering vanadium carbide layer.

Vorzugsweise verwendet man als Salzschmelze Bariumchlorid, dem man vorteilhafterweise noch 1-50 Gew% Natriumchlorid zugeben kann. Zur Erzielung eines gleichmäßigen Vanadinangebotes hat es sich als vorteilhaft erwiesen, ein möglichst feinkörniges Ferrovanadinpulver zu verwenden und dieses möglichst homogen in der Schmelze zu verteilen. Dies kann z.B. auf mechanische Weise durch einen leistungsfähigen Rührer erreicht werden. Besonders vorteilhaft ist es jedoch, zur Verteilung einen Inertgasstrom durch die Schmelze zu leiten. Durch Verwendung einer Ringdüse, die entsprechend der Größe des Tiegels und der Menge an Schmelze mit speziell angeordneten Gasaustrittsöffnungen versehen ist, wird eine sehr gleichmäßige Verteilung des Vanadierungsmittels erzielt.Barium chloride is preferably used as the molten salt, to which 1-50% by weight sodium chloride can advantageously be added. In order to achieve an even supply of vanadium, it has proven to be advantageous to use the finest possible ferrovanadium powder and to distribute it as homogeneously as possible in the melt. This can be achieved, for example, mechanically using a powerful stirrer. However, it is particularly advantageous to distribute an inert gas stream to conduct through the melt. By using an annular nozzle, which is provided with specially arranged gas outlet openings according to the size of the crucible and the amount of melt, a very uniform distribution of the vanading agent is achieved.

Diese bevorzugte Verfahrensweise hat den weiteren Vorteil, daß an der Badoberfläche ein Schutzgasschleier entsteht, der den Zutritt von Luftsauerstoff zu dem oxidationsempfindlichen Vanadierungsmittel vermindert. Dadurch wird die Lebensdauer des Bades beträchtlich erhöht.This preferred procedure has the further advantage that a protective gas curtain is formed on the bath surface, which reduces the access of atmospheric oxygen to the oxidation-sensitive vanading agent. This considerably increases the lifespan of the bath.

Die erfindungsgemäße Schmelze weist gegenüber den bekannten Schmelzen eine Reihe von Vorteilen auf. Sie ist auch bei niedrigen Bestrahlungstemperaturen dünnflüssig, wodurch die Salzausschleppverluste gering sind. Die anhaftenden Salzreste lassen sich durch Abwaschen leicht entfernen. Da Korrosionsangriffe wegen des neutralen Verhaltens der Salze nicht auftreten , können zur Aufnahme der Schmelzen Tiegel aus relativ billigem Flußstahl verwendet werden.The melt according to the invention has a number of advantages over the known melts. It is thin even at low irradiation temperatures, which means that salt drag-out losses are low. The adhering salt residues can be easily removed by washing. Since corrosion attacks do not occur due to the neutral behavior of the salts, crucibles made of relatively cheap mild steel can be used to absorb the melts.

In der Praxis können mit dem erfindungsgemäßen Verfahren innerhalb von 2-4 Stunden je nach Temperatur und Kohlenstoffgehalt des Grundwerkstoffs Schichtdicken von 2-16 µm erzielt werden.In practice, depending on the temperature and carbon content of the base material, layer thicknesses of 2-16 μm can be achieved with the method according to the invention within 2-4 hours.

Folgende Beispiele sollen das erfindungsgemäße Verfahren näher erläutern:The following examples are intended to explain the process according to the invention in more detail:

Beispiel 1example 1

In einem Flußstahltiegel von 18 cm Durchmesser und 30 cm Tiefe wird ein Gemisch aus 19 kg Bariumchlorid, 1 kg Natriumchlorid und 1 kg Ferrovanadin mit einer Korngröße kleiner als 150 µm aufgeschmolzen und auf eine Temperatur von 950°C erwärmt. Das Ferrovanadinpulver wird mit Hilfe eines Rührers homogen in der Schmelze verteilt. Ein Werkstück aus Stahl Ck 60 wird in diesem Bad 4 Stunden behandelt und an Luft abgekühlt. Die metallographische Untersuchung zeigt, daß sich eine ca. 10 um dicke, homogene und glatte Schicht an der Oberfläche gebildet hat. Diese kann röntgenographisch als Vanadincarbid (VC) identifiziert werden.A mixture of 19 kg barium chloride, 1 kg sodium chloride and 1 kg ferrovanadium with a grain size smaller than 150 μm is melted in a mild steel crucible of 18 cm diameter and 30 cm depth and heated to a temperature of 950 ° C. The ferrovanadium powder is homogeneously distributed in the melt with the aid of a stirrer. A workpiece made of Ck 60 steel is treated in this bath for 4 hours and cooled in air. The metallographic examination shows that an approximately 10 μm thick, homogeneous and smooth layer has formed on the surface. This can be identified radiographically as vanadium carbide (VC).

Beispiel 2Example 2

In gleicher Weise wie in Beispiel 1 werden 20 kg BaCl2 aufgeschmolzen und mit 3 kg Ferrovahadinpulver versetzt. Die Temperatur wird auf 1050°C eingestellt. Bei Behandlung einer Probe aus X155CVMo12 in dieser Schmelze wird nach 2 Stunden an der Oberfläche eine ca. 8 µm dicke, gleichmäßige und homogene Vanadincarbidschicht erhalten.In the same way as in Example 1, 20 kg of BaCl 2 are melted and 3 kg of ferrovahadine powder are added. The temperature is set at 1050 ° C. When a sample of X155CVMo12 is treated in this melt, an approximately 8 µm thick, uniform and homogeneous vanadium carbide layer is obtained on the surface after 2 hours.

Beispiel 3Example 3

In einem Flußstahltiegel von 18 cm Durchmesser und 30 cm Tiefe wird ein Gemisch aus 18 kg BaCl2, 2 kg NaCl und 1,5 kg Ferrovanadin mit einer Korngräße unter 50 µm aufgeschmolzen und auf 930°C erwärmt. Durch die Schmelze wird ein Stickstoffstrom von 80 Ltr./h geleitet. Eine 3 Stunden lang darin behandelte Probe aus Ck 60 zeigt eine Vanadincarbidschicht von 6 µm Dicke.In a Flußstahltiegel of 18 cm diameter and 30 cm depth of a mixture of 18 kg BaCl 2, 2 kg of NaCl and 1, 5 kg ferrovanadium with a K o rngräße to below 50 microns melted and heated to 930 ° C. A nitrogen stream of 80 l / h is passed through the melt. A sample of Ck 60 treated therein for 3 hours shows a vanadium carbide layer 6 µm thick.

Beispiel 4Example 4

Wie in Beispiel 3 wird ein Gemisch aus 10 kg BaCl2, 5 kg KF, 3,6 kg NaF und 2,4 kg Ferrovanadinpulver aufgeschmolzen und auf 850°C erwärmt. Durch die Schmelze wird ein Argonstrom von 60 Ltr./h geleitet. Proben aus 100 Cr 6 weisen nach 6 Stunden Behandlungsdauer Vanadincarbidschichten von 4-5 um Dicke auf.As in Example 3, a mixture of 10 kg BaCl 2 , 5 kg KF, 3.6 kg NaF and 2.4 kg ferrovanadium powder is melted and heated to 850 ° C. An argon flow of 60 liters / h is passed through the melt. Samples of 100 Cr 6 have vanadium carbide layers 4-5 µm thick after 6 hours of treatment.

Beispiel 5Example 5

Bei analoger Arbeitsweise wie in Beispiel 3, wobei anstelle von Ferrovanadin reines Vanadinpulver verwendet wird, erzielt man auf Stahl 34 CrMo4 nach 4 Stunden Behandlungsdauer eine Vanadincarbidschicht von 4 µm Dicke, auf Stahl C45 eine Schicht von 6 µm Dicke.Using a procedure analogous to that in Example 3, using pure vanadium powder instead of ferrovanadin, a vanadium carbide layer of 4 μm thick is obtained on steel 34 CrMo4 after 4 hours of treatment, and a layer of 6 μm thick on steel C45.

Die erzeugten Schichten sind stets dicht, gleichmäßig und glatt. Sie zeigen eine hohe närte (ca.3000nV) und eine außerordentlich gute Abriebfestigkeit.The layers created are always dense, even and smooth. They show a high hardness (approx.3,000nV) and an extraordinarily good abrasion resistance.

Reine Alkalihalogenidschmelzen sind für das erfindungsgemäße Verfahren ebenfalls verwendbar, doch sind die Bäder sehr dünnflüssig und dampfen bei hohen Temperaturen ab, so daß ein Einsatz nur bei relativ niedrigen Temperaturen möglich ist.Pure alkali halide melts can also be used for the process according to the invention, but are Baths are very thin and evaporate at high temperatures, so that use is only possible at relatively low temperatures.

Claims (6)

1. Verfahren zur Herstellung von Vanadincarbidschichten auf Eisen und Eisenlegierungen mit einem Gehalt von mindestens 0,1 Gev% Kohlenstoff durch Behandlung der Werkstücke bei 800 bis 1100°C in einem Salzbad, das 1-30Gew% Vanadium- oder Ferrovanadinpulver enthält, dadurch gekennzeichnet, daß das Salzbad aus Erdalkali-und/oder Alkalihalogeniden besteht.1. A process for the production of vanadium carbide layers on iron and iron alloys with a content of at least 0.1% by weight carbon by treating the workpieces at 800 to 1100 ° C in a salt bath containing 1-30% by weight vanadium or ferrovanadium powder, characterized in that that the salt bath consists of alkaline earth and / or alkali halides. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß als Halogenide Chloride und/oder Fluoride verwendet werden.2. The method according to claim 1, characterized in that chlorides and / or fluorides are used as halides. 3. Verfahren nach Anspruch 1 und 2, dadurch gekennzeichnet, daß als Salzbad Bariumchlorid verwendet wird.3. The method according to claim 1 and 2, characterized in that barium chloride is used as the salt bath. 4. Verfahren nach Anspruch 1 bis 3, dadurch gekennzeichnet, daß dem Salzbad 1-50 Gew% Natriumchlorid zugesetzt werden.4. The method according to claim 1 to 3, characterized in that 1-50 wt% sodium chloride are added to the salt bath. 5. Verfahren nach Anspruch 1 bis 4, dadurch gekennzeichnet, daß das Vanadium- bzw. Ferrovanadinpulver homogen in der Salzschmelze verteilt wird.5. The method according to claim 1 to 4, characterized in that the vanadium or ferrovanadium powder is homogeneously distributed in the molten salt. 6. Verfahren nach Anspruch 1 bis 5, dadurch gekennzeichnet, daß ein Inertgasstrom in die Salzschmelze eingeleitet wird.6. The method according to claim 1 to 5, characterized in net that an inert gas stream is introduced into the molten salt.
EP81104912A 1980-07-02 1981-06-25 Method of forming vanadium carbide layers on iron Expired EP0043506B1 (en)

Applications Claiming Priority (2)

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DE3025033 1980-07-02
DE19803025033 DE3025033A1 (en) 1980-07-02 1980-07-02 METHOD FOR PRODUCING VANADINE CARBIDE LAYERS ON IRON

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US5141773A (en) * 1990-11-05 1992-08-25 Northeastern University Method of forming a carbide on a carbon substrate
US5238711A (en) * 1990-11-05 1993-08-24 The President And Fellows Of Harvard College Method of coating carbon fibers with a carbide
US5798002A (en) * 1996-12-02 1998-08-25 Gugel; Saveliy M. Method of and device for producing carbide and carbon solid solution containing surface layers
JP3747373B2 (en) * 2000-06-29 2006-02-22 ボーグワーナー・インコーポレーテッド Steel products coated with carbide and method for producing the same
JP3659963B2 (en) * 2003-10-28 2005-06-15 株式会社椿本チエイン Automotive engine timing chain

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GB442629A (en) * 1934-03-08 1936-02-12 Fritz Bergmann Improvements in the production of surface alloys by diffusion
DE765769C (en) * 1942-02-07 1954-10-25 Metall Diffusions Ges M B H Process for chroming objects made of iron or steel in a salt bath
US2732321A (en) * 1956-01-24 Plating processes and compositions
US3263325A (en) * 1963-05-07 1966-08-02 Du Pont Method of coating and bonding refractory-base-metal articles
DE2362284A1 (en) * 1972-12-28 1974-07-04 Nordstjernan Rederi Ab Formation of carbide layer on steel surfaces - using fused salt bath contg. metal halide and metal, at low temp
JPS5335637A (en) * 1976-09-16 1978-04-03 Kazuo Hosokawa Method of coating metals or alloys with vanadium carbide or niobium carbide
JPS54147140A (en) * 1978-05-11 1979-11-17 Toyoda Chuo Kenkyusho Kk Forming manganese carbide layer on iron alloy material surfaces

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US3719518A (en) * 1969-11-01 1973-03-06 Toyoda Chuo Kenkyusho Kk Process of forming a carbide layer of vanadium, niobium or tantalum upon a steel surface
JPS4938416B1 (en) * 1970-03-06 1974-10-17
GB1396455A (en) * 1972-05-04 1975-06-04 Toyoda Chuo Kenkyusho Kk Method of forming a carbide layer
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DE765769C (en) * 1942-02-07 1954-10-25 Metall Diffusions Ges M B H Process for chroming objects made of iron or steel in a salt bath
US3263325A (en) * 1963-05-07 1966-08-02 Du Pont Method of coating and bonding refractory-base-metal articles
DE2362284A1 (en) * 1972-12-28 1974-07-04 Nordstjernan Rederi Ab Formation of carbide layer on steel surfaces - using fused salt bath contg. metal halide and metal, at low temp
JPS5335637A (en) * 1976-09-16 1978-04-03 Kazuo Hosokawa Method of coating metals or alloys with vanadium carbide or niobium carbide
JPS54147140A (en) * 1978-05-11 1979-11-17 Toyoda Chuo Kenkyusho Kk Forming manganese carbide layer on iron alloy material surfaces

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EP0043506A3 (en) 1982-05-26
US4440581A (en) 1984-04-03
DE3025033A1 (en) 1982-01-21
EP0043506B1 (en) 1985-03-27
CA1128378A (en) 1982-07-27
DE3169526D1 (en) 1985-05-02

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