EP1026282A2 - Paste boriding agent - Google Patents
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- EP1026282A2 EP1026282A2 EP00100550A EP00100550A EP1026282A2 EP 1026282 A2 EP1026282 A2 EP 1026282A2 EP 00100550 A EP00100550 A EP 00100550A EP 00100550 A EP00100550 A EP 00100550A EP 1026282 A2 EP1026282 A2 EP 1026282A2
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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
- C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
- C23C8/60—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes
- C23C8/62—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using solids, e.g. powders, pastes only one element being applied
- C23C8/68—Boronising
- C23C8/70—Boronising of ferrous surfaces
Definitions
- the invention relates to a borating agent in the form of a paste for the production of boride layers on metallic Materials. This is used in particular for generation single-phase, hard and adhesive boride layers Iron materials to increase wear resistance and corresponding to improve the corrosion resistance Workpieces.
- Boronizing for wear protection of iron, steel and refractory metals has been a well-known process.
- By diffusing the element boron into the surface of the treated workpiece and reacting with the base material dense, uniform layers of the respective boride are formed, on iron, for example, the borides FeB, Fe 2 B.
- the borides have significantly changed properties compared to the pure metals, in particular they are Most borides are very hard, corrosion-resistant and therefore extremely wear-resistant. Due to their generation by diffusion and solid-state reaction, the boride layers are firmly connected to the base material. With regard to their wear resistance, borated steels, for example, are sometimes superior to steels treated by nitriding or carburizing.
- boroning is mainly done in solid Borating agents applied.
- the closed boxes are for annealed for a while, being in direct Solid state reaction or by transporting the boron over the Gas phase on the parts the desired boride layers be formed.
- Boronization is usually carried out at temperatures between 800 and 1100 ° C and especially between 850 and 950 ° C carried out.
- the achievable layer thicknesses of the Boride layers are usually in the range between 30 and 300 ⁇ m.
- boriding agents come as boron-releasing substances amorphous and crystalline boron, ferroboron, boron carbide and Borates like Borax in question.
- Chlorine- or fluoride-releasing compounds are suitable such as alkali and alkaline earth chlorides or fluorides.
- Fluoroborates such as are commonly used as activators especially potassium tetrafluoroborate.
- Typical extenders are aluminum oxide, silicon dioxide and silicon carbide. Borating agents of this type are described, for example, in DE-PS 17 96 216.
- a typical composition that extends up to proven today as a borating agent contains about 5% by weight Boron carbide, 5% by weight potassium tetrafluoroborate and 90% by weight Silicon carbide.
- the boron-rich FeB phase is much more brittle than the Fe 2 B phase, which has a negative effect on the wear resistance of the borated components.
- boride layers over 50 ⁇ m an FeB boundary layer is easily formed, which should be avoided as far as possible for the reason mentioned.
- boron pastes are among the usual Process conditions for single-phase layers only To achieve layer thicknesses below 50 microns.
- Boride layers have to be elaborately annealed in a vacuum or Salt bath can be used for subsequent diffusion or it is special borating agents (e.g. after the German Patent application 198 30 654.7) required.
- fluoride emissions in the exhaust gas determine. Both through the post-diffusion as well the fluoride emission becomes a porosity in the layer causes that adversely affect the layer properties effect.
- the well-known Borierpaste is used in many Materials a corrosion attack on the coated Workpiece effected during the drying phase. Thereby paste residues adhere so firmly to the skin after treatment Workpiece surface that a cleaning of the components with Water is insufficient and an additional Blasting process is required, and also the There is a risk that the boride layer produced in Is affected.
- the corrosion attack can do so be pronounced that the application of the So far, paste boriding has not been possible with certain steel types is possible because there are real gnawings.
- the known boron pastes have storage instabilities, in particular at elevated temperatures, which is caused by the dissociation of the activator KBF 4 with a lowering of the pH.
- the invention was therefore based on the object of developing a borating agent in the form of a paste with which, in particular on iron materials, practically exclusively single-phase, Fe 2 B-containing boride layers can be produced. Furthermore, the content of water-soluble fluorides in this paste-like borating agent should be reduced and, when used as intended, there should be a reduced fluoride emission. In particular, the porosity of the boride layer formed should also be reduced. Furthermore, the corrosion attacks should be prevented and the cleaning of the components should be made easier. In addition, the storage stability of the boron paste should be improved.
- the porosity of the boride layer can be significantly reduced. This results in a longer service life for the components.
- the hydrogen fluoride emissions are also reduced by binding fluorides, for example HF, as CaF 2 .
- the CaF 2 which may arise also has the positive effects described in German patent application 198 30 654.7.
- the borating paste according to the invention preferably contains based on the solids content, 0.1-5% by weight Compounds according to (a), 0.1-2% by weight of compounds according to (b) and 0.1-2% by weight of compounds according to (c).
- the boron paste contains, based on the Solids content, 1-3% by weight of compounds according to (a), 0.2-1 % By weight of compounds according to (b) and 0.2-1% by weight Compounds according to (c).
- Particularly suitable compounds according to (a) are Carbonates of sodium, potassium, calcium and magnesium in Question. Calcium carbonate is particularly preferred.
- Preferred compounds according to (b) are Alkali nitrites such as sodium and potassium nitrite in particular Question. Sodium nitrite is particularly preferred.
- alkali borates such as in particular sodium and Potassium borate in question.
- the borating paste according to the invention preferably contains as Boron-releasing substance Boron carbide, as an activating substance Potassium tetrafluoroborate and as an extender silicon carbide.
- the Borier paste as an activating substance a combination of Potassium tetrafluoroborate and calcium fluoride.
- a conventional borating agent to which calcium fluoride is added as a further activating substance in addition to the usual activator substances, can be used to specifically influence and control the type of boride formation in the workpiece surface.
- practically FeB-free, single-phase Fe 2 B layers can be produced without further ado.
- the borating paste according to the invention expediently contains as a activating substance a combination of 1 to 15 % By weight potassium tetrafluoroborate and 5 to 40% by weight Calcium fluoride, each based on the solids content.
- the pasty boroning agent according to the invention can contain the usual boron-releasing substances, such as amorphous or crystalline ferroboron and in particular boron carbide (B 4 C). It preferably contains 1 to 15% by weight of boron carbide, based on the solids content.
- the Borierpaste according to the invention also contains the rest the usual extenders, in particular silicon carbide (SiC), further water and optionally auxiliary substances.
- SiC silicon carbide
- the borating paste according to the invention preferably contains based on the solids content, 8 to 10% by weight boron carbide, 5 to 10% by weight potassium tetrafluoroborate, 10 to 30% by weight Calcium fluoride, 1-3% by weight calcium carbonate, 0.2-1% by weight Sodium nitrite, 0.2-1% by weight sodium tetraborate and the rest as an extender silicon carbide, water and optionally auxiliary substances.
- a typical composition consists of approximately 10% by weight Boron carbide, 7% by weight potassium tetrafluoroborate, 15% by weight Calcium fluoride, 1.5% by weight calcium carbonate, 0.5% by weight Sodium nitrite, 0.5% by weight sodium tetraborate and the rest Silicon carbide, based on the solids content.
- Borating agent can be added by adding water and if necessary, minor amounts of auxiliaries, such as e.g. commercially available binders and / or Thickener, from the corresponding powder mixture respectively.
- auxiliaries such as e.g. commercially available binders and / or Thickener
- the water content based on the total amount, 25 to 40 wt.%.
- the paste preferably contains 30 to 35% by weight and in particular about 30% by weight of water.
- Thickeners may be used as other auxiliary substances and binders as used in the formulation of pastes are common in question.
- a particularly suitable one Bentonite is a thickener. This will decrease Amount, typically about 1% by weight, based on the total amount used in the borier paste.
- the borating paste according to the invention can be very advantageous for Generation of boride layers on metallic workpieces be used.
- the addition of carbonate reduces the porosity of the boride layer and thus increases the durability of the components.
- the addition of nitrite eliminates the tendency of known boron pastes to cause corrosion attack on the component. This results in a very good surface appearance.
- the agent according to the invention is significantly less critical with regard to fluoride emissions, which in particular means the disposal of waste water after washing the borated components and of depleted borating agent concerns.
- a reduced KBF 4 content is also an advantage when the agent is used as intended, since correspondingly lower fluoride-containing gas emissions occur.
- By adding carbonate these emissions are further reduced, which leads to an increased environmental compatibility of the process.
- the problems of known borating pastes with regard to storage stability are eliminated by adding borate.
- the borate, together with the nitrite additive also makes the components much easier to clean than known boron pastes.
- a particular process advantage of the boron paste according to the invention is that single-phase, Fe 2 B-containing, low-pore boride layers can be easily and easily produced on workpieces made of ferrous materials. This is due to the preferred choice of a combination of 1 to 15% by weight of potassium tetrafluoroborate and 5 to 40% by weight of calcium fluoride, based on the amount of solids in the borating paste, as the activating substance.
- the surface of the workpieces is covered with the borating paste and this is then treated at temperatures between 800 and 1100 ° C. until a boride layer of the desired size Has formed thickness.
- the surface of the parts is coated with the borating agent paste. This is particularly advantageous when a partially borated surface is desired.
- the borating agent can also be applied by dipping the parts into the paste or by spraying on the paste.
- Boronation is preferably carried out at temperatures between 850 and 980 ° C. over a period of 20 minutes to 2 hours.
- single-phase Fe 2 B layers with a thickness of 30 to 150 ⁇ m can be obtained.
- the borating agent was left after the heat treatment remove easily and residue-free with water, the Components showed no corrosion attacks or stains on.
- the boride layer was FeB-free, low in pores and had one Thickness of approx. 50 ⁇ m.
- the paste also showed after a long time Storage at elevated temperature does not change the Processing properties.
- the pH was around 7.5.
- Example 2 (comparative example )
- the borating agent was acceptable after the heat treatment Do not remove water completely without residue, only after The components were sufficient for brushing or blasting cleaned. The components showed slight corrosion attacks and a strong spotting.
- the boride layer had a thickness of about 50 microns, but was two-phase; the FeB needles reached to a depth of 14 ⁇ m. It was opposite Example 1 recognizing stronger pore hem. After a long time Storage at elevated temperature was the viscosity of the Paste dropped and it had a stronger settling of the Solids occurred. The pH of the paste was approx. 4.
- the borating agent was left after the heat treatment remove easily and residue-free with water, the Components showed no corrosion attacks or stains on.
- the boride layer was FeB-free, low in pores and had one Thickness of approx. 70 ⁇ m.
- the borating agent was left after the heat treatment remove easily and residue-free with water Component showed no corrosion attacks or stains.
- the boride layer was FeB-free, low in pores and had one Thickness of approx. 140 ⁇ m.
- the borating agent was left after the heat treatment remove easily and residue-free with water, the Components showed no corrosion attacks or stains on.
- the boride layer was FeB-free, low in pores and had one Thickness of approx. 52 ⁇ m.
- the emissions of fluorine compounds were approximately 25% higher than those from Example 1.
- Example 6 (Comparative example )
- the borating agent was left after the heat treatment remove easily and residue-free with water, the Components showed no corrosion attacks or stains on.
- the approximately 50 ⁇ m thick boride layer was two-phase, the FeB needles reached a depth of 10 ⁇ m.
- the shift was more porous than in example 5.
- the emissions of fluorine compounds were approximately 40% higher than those from example 1.
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Abstract
Description
Die Erfindung betrifft ein Boriermittel in Form einer Paste zur Erzeugung von Boridschichten auf metallischen Werkstoffen. Dieses dient insbesondere zur Erzeugung einphasiger, harter und haftfester Boridschichten auf Eisenwerkstoffen zur Erhöhung der Verschleißfestigkeit und zur Verbesserung der Korrosionsbeständigkeit entsprechender Werkstücke.The invention relates to a borating agent in the form of a paste for the production of boride layers on metallic Materials. This is used in particular for generation single-phase, hard and adhesive boride layers Iron materials to increase wear resistance and corresponding to improve the corrosion resistance Workpieces.
Das Borieren zum Verschleißschutz von Eisen, Stahl und Refraktärmetallen ist ein schon lange bekanntes Verfahren. Durch Eindiffusion des Elementes Bor in die Oberfläche des behandelten Werkstückes und Reaktion mit dem Grundwerkstoff entstehen dichte, gleichmäßige Schichten des jeweiligen Borides, auf Eisen z.B. die Boride FeB, Fe2B. Die Boride besitzen gegenüber den reinen Metallen erheblich veränderte Eigenschaften, insbesondere sind die meisten Boride sehr hart, korrosionsbeständig und damit überaus verschleißfest. Aufgrund ihrer Erzeugung durch Diffusion und Festkörperreaktion sind die Boridschichten mit dem Grundwerkstoff fest verbunden. Hinsichtlich ihrer Verschleißfestigkeit sind z.B. borierte Stähle teilweise den durch Nitrieren oder Aufkohlen behandelten Stählen überlegen.Boronizing for wear protection of iron, steel and refractory metals has been a well-known process. By diffusing the element boron into the surface of the treated workpiece and reacting with the base material, dense, uniform layers of the respective boride are formed, on iron, for example, the borides FeB, Fe 2 B. The borides have significantly changed properties compared to the pure metals, in particular they are Most borides are very hard, corrosion-resistant and therefore extremely wear-resistant. Due to their generation by diffusion and solid-state reaction, the boride layers are firmly connected to the base material. With regard to their wear resistance, borated steels, for example, are sometimes superior to steels treated by nitriding or carburizing.
Es wurden deshalb in der Vergangenheit eine Vielzahl von Mitteln und technische Verfahrensvarianten entwickelt, mit denen man Boridschichten, insbesondere auf Stahl, herstellen kann.Therefore, a large number of Developed means and technical process variants with which you have boride layers, especially on steel, can manufacture.
In der Praxis wird überwiegend das Borieren in festen Boriermitteln angewendet. Dabei werden die zu behandelnden Teile in eiserne Kästen in Pulvermischungen gepackt, die im wesentlichen aus borabgebenden Substanzen, aktivierenden Substanzen und im Rest aus feuerfesten, inerten Streckmitteln bestehen. Die geschlossenen Kästen werden für eine gewisse Zeit geglüht, wobei in direkter Festkörperreaktion oder durch Transport des Bors über die Gasphase auf den Teilen die erwünschten Boridschichten gebildet werden.In practice, boroning is mainly done in solid Borating agents applied. Thereby, the ones to be treated Parts packed in iron boxes in powder mixtures, which in the essentially from boron-releasing substances, activating Substances and the rest of refractory, inert Extenders exist. The closed boxes are for annealed for a while, being in direct Solid state reaction or by transporting the boron over the Gas phase on the parts the desired boride layers be formed.
Die Borierung wird üblicherweise bei Temperaturen zwischen 800 und 1100 °C und insbesondere zwischen 850 und 950 °C durchgeführt. Die erzielbaren Schichtdicken der Boridschichten liegen normalerweise im Bereich zwischen 30 und 300 µm.Boronization is usually carried out at temperatures between 800 and 1100 ° C and especially between 850 and 950 ° C carried out. The achievable layer thicknesses of the Boride layers are usually in the range between 30 and 300 µm.
In Boriermitteln kommen als borabgebende Substanzen amorphes und kristallines Bor, Ferrobor, Borcarbid und Borate wie Borax in Frage. Als aktivierende Substanzen eignen sich Chlorid- oder Fluorid-abgebende Verbindungen wie Alkali- und Erdalkalichloride bzw. -fluoride. Besonders gebräuchlich als Aktivatoren sind Fluoroborate wie insbesondere Kaliumtetrafluoroborat. Typische Streckmittel sind Aluminiumoxid, Siliziumdioxid und Siliciumcarbid. Boriermittel dieser Art sind beispielsweise in DE-PS 17 96 216 beschrieben. Eine typische Zusammensetzung die sich bis heute als Boriermittel bewährt hat, enthält etwa 5 Gew.% Borcarbid, 5 Gew.% Kaliumtetrafluoroborat und 90 Gew.% Siliciumcarbid. Boriermittel der genannten Art kommen normalerweise als Pulvermischungen zum Einsatz. Sie können aber auch als Granulate (z.B. DE-OS 21 27 096) oder als Pasten (z.B. DE-OS 26 33 137) formuliert sein. Im Falle von Granulaten und Pasten enthalten die Zusammensetzungen noch untergeordnete Mengen an Bindemitteln bzw. an Wasser.In boriding agents come as boron-releasing substances amorphous and crystalline boron, ferroboron, boron carbide and Borates like Borax in question. As activating substances Chlorine- or fluoride-releasing compounds are suitable such as alkali and alkaline earth chlorides or fluorides. Especially Fluoroborates such as are commonly used as activators especially potassium tetrafluoroborate. Typical extenders are aluminum oxide, silicon dioxide and silicon carbide. Borating agents of this type are described, for example, in DE-PS 17 96 216. A typical composition that extends up to proven today as a borating agent, contains about 5% by weight Boron carbide, 5% by weight potassium tetrafluoroborate and 90% by weight Silicon carbide. Borating agents of the type mentioned come normally used as powder mixtures. You can but also as granules (e.g. DE-OS 21 27 096) or as Pastes (e.g. DE-OS 26 33 137). In case of The compositions still contain granules and pastes minor amounts of binders or water.
Desweiteren wurden auch Verfahren entwickelt, die mit gasförmigen Boriermitteln wie Diboran, Borhalogeniden oder aber in Salzschmelzen mit Borcarbid und Borax als borabgebenden Stoffen arbeiteten. Diese letztgenannten Verfahren konnten sich wegen der Giftigkeit der Verbindungen und der Verfahrensnachteile, wie dem hohen Kontrollaufwand zum Erhalt einer gleichbleibenden Borierwirkung, nicht durchsetzen. Neue Versuche, mit Plasmaverfahren Boridschichten zu erzeugen, sind aufgrund der Einflüsse von Chargierung und komplexen Geometrieformen nicht für alle Anwendungen geeignet. Außerdem ist der apparative Aufwand recht hoch. Daher haben feste Boriermittel, die teils auch in pastöser Form angewandt werden, aufgrund ihrer Vorteile der einfachen Anwendungen und guter Boridschichten auch heute ihre Vorrangstellung für das Oberflächenborieren erhalten.Furthermore, processes have also been developed that use gaseous borating agents such as diborane, boron halides or but in molten salts with boron carbide and borax as boron-releasing substances worked. The latter Procedures could change because of the toxicity of the Compounds and the procedural disadvantages, such as the high Control effort to maintain a constant Borier effect, do not enforce. New attempts with Plasma processes are due to produce boride layers the influences of batching and complex geometrical shapes not suitable for all applications. In addition, the apparatus expenditure quite high. Therefore have fixed Borating agents, some of which are also used in pasty form due to their advantages of simple applications and good boride layers are still their priority today obtained for surface boriding.
Die gebräuchlichen Borierverfahren mit den bekannten festen Boriermitteln haben jedoch den Nachteil, daß es verfahrenstechnisch sehr schwierig ist, mit ihnen insbesondere auf Eisenwerkstoffen einphasige Eisenboridschichten zu erzeugen (siehe z.B. EP 0 387 536 B1).The usual Borier process with the known solid However, borating agents have the disadvantage that it procedurally very difficult with them single-phase especially on ferrous materials To produce iron boride layers (see e.g. EP 0 387 536 B1).
Da die beiden Boride Fe2B und FeB unterschiedliche Eigenschaften besitzen und mehrphasige Schichten meist schlechtere Eigenschaften aufweisen als einphasige Schichten, ist man bemüht, beim Borieren einphasige Schichten zu erzeugen.Since the two borides Fe 2 B and FeB have different properties and multi-phase layers usually have poorer properties than single-phase layers, efforts are made to produce single-phase layers during boriding.
So ist insbesondere die borreichere FeB-Phase wesentlich spröder als die Fe2B-Phase, was sich negativ auf die Verschleißfestigkeit der borierten Bauteile auswirkt. Bei Boridschichten über 50 µm kommt es auch leicht zur Bildung einer FeB-Randschicht, was aus dem genannten Grund möglichst zu vermeiden ist.In particular, the boron-rich FeB phase is much more brittle than the Fe 2 B phase, which has a negative effect on the wear resistance of the borated components. With boride layers over 50 µm, an FeB boundary layer is easily formed, which should be avoided as far as possible for the reason mentioned.
Bei den bisher bekannten Borierpasten sind unter üblichen Prozeßbedingungen einphasige Schichten nur bei Schichtdicken unter 50 µm zu erzielen. Für stärkere Boridschichten muß eine aufwendige Glühung im Vakuum oder Salzbad zum Nachdiffundieren angewendet werden oder es sind spezielle Boriermittel (z.B. nach der deutschen Patentanmeldung 198 30 654.7) erforderlich. Weiterhin sind bei den üblichen Borierpasten Fluoridemissionen im Abgas festzustellen. Sowohl durch das Nachdiffundieren als auch die Fluoridemissionen wird eine Porosität in der Schicht verursacht, die sich negativ auf die Schichteigenschaften auswirkt.In the previously known boron pastes are among the usual Process conditions for single-phase layers only To achieve layer thicknesses below 50 microns. For stronger ones Boride layers have to be elaborately annealed in a vacuum or Salt bath can be used for subsequent diffusion or it is special borating agents (e.g. after the German Patent application 198 30 654.7) required. Furthermore are with the usual Borier pastes fluoride emissions in the exhaust gas determine. Both through the post-diffusion as well the fluoride emission becomes a porosity in the layer causes that adversely affect the layer properties effect.
Durch die bekannten Borierpasten wird bei vielen Werkstoffen ein Korrosionsangriff an dem beschichteten Werkstück während der Trocknungsphase bewirkt. Dadurch haften Pastenrückstände nach der Behandlung so fest an der Werkstückoberfläche, daß ein Reinigen der Bauteile mit Wasser nicht ausreichend ist und ein zusätzlicher Strahlvorgang erforderlich wird, wobei außerdem noch die Gefahr besteht, daß hierbei die erzeugte Boridschicht in Mitleidenschaft gezogen wird. Der Korrosionsangriff kann so stark ausgeprägt sein, daß die Anwendung des Pastenborierens bei bestimmten Stahltypen bisher nicht möglich ist, da dort regelrechte Anfressungen auftreten.The well-known Borierpaste is used in many Materials a corrosion attack on the coated Workpiece effected during the drying phase. Thereby paste residues adhere so firmly to the skin after treatment Workpiece surface that a cleaning of the components with Water is insufficient and an additional Blasting process is required, and also the There is a risk that the boride layer produced in Is affected. The corrosion attack can do so be pronounced that the application of the So far, paste boriding has not been possible with certain steel types is possible because there are real gnawings.
Weiterhin weisen die bekannten Borierpasten Lagerinstabilitäten insbesondere bei erhöhten Temperaturen auf, die durch die Dissoziation des Aktivators KBF4 mit Absenkung des pH-Wertes hervorgerufen wird.Furthermore, the known boron pastes have storage instabilities, in particular at elevated temperatures, which is caused by the dissociation of the activator KBF 4 with a lowering of the pH.
Der Erfindung lag daher die Aufgabe zugrunde, ein Boriermittel in Form einer Paste zu entwickeln, mit dem insbesondere auf Eisenwerkstoffen praktisch ausschließlich einphasige, Fe2B-enthaltende Boridschichten erzeugt werden können. Weiterhin sollte in diesem pastenförmigen Boriermittel der Gehalt an wasserlöslichen Fluoriden gesenkt sein und bei bestimmungsgemäßem Gebrauch eine reduzierte Fluoridemission einhergehen. Insbesondere sollte auch die Porosität der gebildeten Boridschicht vermindert werden. Weiterhin sollten die Korrosionsangriffe verhindert und so auch die Reinigung der Bauteile erleichtert werden. Zusätzlich sollte die Lagerstabilität der Borierpaste verbessert werden. The invention was therefore based on the object of developing a borating agent in the form of a paste with which, in particular on iron materials, practically exclusively single-phase, Fe 2 B-containing boride layers can be produced. Furthermore, the content of water-soluble fluorides in this paste-like borating agent should be reduced and, when used as intended, there should be a reduced fluoride emission. In particular, the porosity of the boride layer formed should also be reduced. Furthermore, the corrosion attacks should be prevented and the cleaning of the components should be made easier. In addition, the storage stability of the boron paste should be improved.
Überraschend wurde nun gefunden, daß bei pastenförmigen Boriermitteln die im wesentlichen aus borabgebenden Substanzen, aktivierenden Substanzen und im Rest aus feuerfestem, inerten Streckmittel sowie Wasser und gegebenenfalls für die Formulierung einer Paste erforderliche Hilfsmittel bestehen, diese Nachteile durch Zusatz von geringen Mengen bestimmter Additive beseitigt werden können.Surprisingly, it has now been found that pasty Borating agents which are essentially made of boron Substances, activating substances and in the rest refractory, inert extenders as well as water and if necessary for the formulation of a paste necessary aids exist to overcome these disadvantages Addition of small amounts of certain additives eliminated can be.
Es wurde zum einen gefunden, daß durch Zusatz von Alkali- oder Erdalkalicarbonaten, beispielsweise Calciumcarbonat, die Porosität der Boridschicht deutlich vermindert werden kann. Hierdurch wird eine höhere Standzeit der Bauteile bewirkt. Zusätzlich werden auch die Fluorwasserstoffemissionen verringert, indem Fluoride, z.B. HF, als CaF2 gebunden werden. Das gegebenenfalls entstehende CaF2 entfaltet nebenbei die in der deutschen Patentanmeldung 198 30 654.7 beschriebenen positiven Auswirkungen.On the one hand, it was found that by adding alkali or alkaline earth carbonates, for example calcium carbonate, the porosity of the boride layer can be significantly reduced. This results in a longer service life for the components. In addition, the hydrogen fluoride emissions are also reduced by binding fluorides, for example HF, as CaF 2 . The CaF 2 which may arise also has the positive effects described in German patent application 198 30 654.7.
Es wurde zum anderen gefunden, daß durch Zusatz von Alkali- oder Erdalkalinitriten, beispielsweise Natriumnitrit, die Korrosionsangriffe der Borierpaste bei allen untersuchten Stahltypen vollständig unterdrückt werden konnten. Dadurch lassen sich sowohl höhere Oberflächenqualitäten erreichen als auch eine Borierung bislang pastenuntauglicher Stähle durchführen. Versuche mit anderen bekannten Korrosionsschutzmitteln führten dagegen zu keinem Erfolg; teilweise traten sogar stärkere Anfressungen auf als bei Abwesenheit von üblichen Korrossionsschutzzusätzen.On the other hand, it was found that by adding alkali or Alkaline earth nitrites, for example sodium nitrite, the Corrosion attacks of the Borier paste in all examined Steel types could be completely suppressed. Thereby both higher surface qualities can be achieved as well as a boronization of pastes unsuitable for pastes carry out. Try other known ones Corrosion protection agents, however, were unsuccessful; in some cases there were even stronger seizures than with Absence of usual anti-corrosion additives.
Weiterhin wurde gefunden, daß durch Zusatz von wasserlöslichen Alkali- oder Erdalkaliboraten, beispielsweise Natriumtetraborat (Borax), eine Verbesserung der Lagerstabilität der Borierpaste erzielt werden kann. Die stets in Wasser auftretende Dissoziation des Aktivators KBF4 führt zur Bildung von HF und somit zur Ansäuerung der Paste mit verstärktem Korrosionsangriff und gegebenenfalls auftretender Instabilität von Pastenhilfsmitteln wie etwa des Verdickungsmittels. Durch den Zusatz von Borat wird dies vollständig unterdrückt. Die Borierpaste erhält dadurch eine wesentlich höhere Lagerstabilität. Versuche, die Absenkung des pH-Wertes allein durch Zusatz von löslichen Carbonaten, wie beispielsweise Natriumcarbonat, zu verhindern, führten zu einer Veränderung der Viskosität und der rheologischen Eigenschaften der Paste, was sich negativ auf die Anwendung auswirkt.Furthermore, it was found that by adding water-soluble alkali or alkaline earth borates, for example sodium tetraborate (Borax), an improvement in the storage stability of the boron paste can be achieved. The dissociation of the activator KBF 4 , which always occurs in water, leads to the formation of HF and thus to the acidification of the paste with increased corrosion attack and possibly occurring instability of paste auxiliaries such as the thickener. This is completely suppressed by the addition of borate. This gives the boron paste a much higher storage stability. Attempts to prevent the lowering of the pH alone by adding soluble carbonates, such as sodium carbonate, led to a change in the viscosity and the rheological properties of the paste, which has a negative effect on the application.
Darüberhinaus hat sich gezeigt, daß die Reinigung der Bauteile und das Oberflächenaussehen durch Zumischung von Borat verbessert werden kann, da dieses einen sehr dünnen glasurartigen Film auf dem Bauteil bildet und so eine Entfernung der Paste nach dem Borieren erleichtert. Zusammen mit dem oben beschriebenen Korrosionsschutz läßt sich so das Strahlen der Bauteile nach dem Borieren vermeiden.In addition, it has been shown that the cleaning of the Components and the surface appearance by adding Borate can be improved as this is a very thin one forms a glaze-like film on the component and so one Removal of the paste after boriding made easier. Together with the corrosion protection described above the blasting of the components after boriding avoid.
Gegenstand der Erfindung ist somit ein Boriermittel in Form
einer Paste zur Erzeugung von Boridschichten auf
metallischen Werkstücken, das im wesentlichen aus
borabgebenden Substanzen, aktivierenden Substanzen und im
Rest aus feuerfestem, inerten Streckmittel sowie Wasser und
gegebenenfalls für die Formulierung einer Paste
erforderlichen Hilfsstoffen besteht und die dadurch
gekennzeichnet ist, daß es als Zusätze
Die erfindungsgemäße Borierpaste enthält vorzugsweise, bezogen auf den Feststoffanteil, 0,1-5 Gew.% an Verbindungen gemäß (a), 0,1-2 Gew.% an Verbindungen gemäß (b) und 0,1-2 Gew.% an Verbindungen gemäß (c).The borating paste according to the invention preferably contains based on the solids content, 0.1-5% by weight Compounds according to (a), 0.1-2% by weight of compounds according to (b) and 0.1-2% by weight of compounds according to (c).
Insbesondere enthält die Borierpaste, bezogen auf den Feststoffanteil, 1-3 Gew.% an Verbindungen gemäß (a), 0,2-1 Gew.% an Verbindungen gemäß (b) und 0,2-1 Gew.% an Verbindungen gemäß (c).In particular, the boron paste contains, based on the Solids content, 1-3% by weight of compounds according to (a), 0.2-1 % By weight of compounds according to (b) and 0.2-1% by weight Compounds according to (c).
Als Verbindungen gemäß (a) kommen insbesondere die Carbonate von Natrium, Kalium, Calcium und Magnesium in Frage. Besonders bevorzugt ist Calciumcarbonat.Particularly suitable compounds according to (a) are Carbonates of sodium, potassium, calcium and magnesium in Question. Calcium carbonate is particularly preferred.
Als Verbindungen gemäß (b) kommen vorzugsweise Alkalinitrite wie insbesondere Natrium- und Kaliumnitrit in Frage. Besonders bevorzugt ist Natriumnitrit.Preferred compounds according to (b) are Alkali nitrites such as sodium and potassium nitrite in particular Question. Sodium nitrite is particularly preferred.
Aus der Gruppe von Verbindungen gemäß (c) kommen vorzugsweise Alkaliborate wie insbesondere Natrium- und Kaliumborat in Frage. Besonders bevorzugt ist Natriumtetraborat (Borax).Come from the group of compounds according to (c) preferably alkali borates such as in particular sodium and Potassium borate in question. Is particularly preferred Sodium tetraborate (borax).
Die erfindungsgemäße Borierpaste enthält vorzugsweise als borabgebende Substanz Borcarbid, als aktivierende Substanz Kaliumtetrafluoroborat und als Streckmittel Siliciumcarbid.The borating paste according to the invention preferably contains as Boron-releasing substance Boron carbide, as an activating substance Potassium tetrafluoroborate and as an extender silicon carbide.
In einer besonders bevorzugten Ausführungsform enthält die Borierpaste als aktivierende Substanz eine Kombination aus Kaliumtetrafluoroborat und Calciumfluorid.In a particularly preferred embodiment, the Borier paste as an activating substance a combination of Potassium tetrafluoroborate and calcium fluoride.
Es hat sich nämlich weiterhin gezeigt, daß mit einem an sich konventionell zusammengesetzten Boriermittel, dem neben üblichen Aktivatorsubstanzen Calciumfluorid als weitere aktivierende Substanz zugesetzt wird, eine gezielte Beeinflussung und Steuerung im Hinblick auf die Art der Boridbildung in der Werkstückoberfläche erfolgen kann. Hierbei lassen sich insbesondere bei Werkstücken aus Eisenwerkstoffen ohne sonstige aufwendige verfahrenstechnische Maßnahmen ohne weiteres praktisch FeB-freie, einphasige Fe2B-Schichten erzeugen.It has also been shown that a conventional borating agent, to which calcium fluoride is added as a further activating substance in addition to the usual activator substances, can be used to specifically influence and control the type of boride formation in the workpiece surface. In this case, in particular in the case of workpieces made of iron materials, without other complex procedural measures, practically FeB-free, single-phase Fe 2 B layers can be produced without further ado.
Weitere Untersuchungen haben dabei gezeigt, daß bei einem vollständigen Ersatz von KBF4 durch CaF2 in dem gebräuchlichen Boriermittel nach dem Stand der Technik unter normalen Verfahrensbedindungen keine ausreichenden Boridschichten auf den Werkstückoberflächen gebildet werden. Gleiches ergibt sich, wenn zum Zwecke der Reduktion der Fluoremission der Gehalt an KBF4 in dem Boriermittel lediglich verringert wird.Further investigations have shown that when KBF 4 is completely replaced by CaF 2 in the conventional boriding agent according to the prior art, under normal process conditions, sufficient boride layers are not formed on the workpiece surfaces. The same results if the content of KBF 4 in the borating agent is only reduced for the purpose of reducing the fluorine emission.
Die erfindungsgemäße Borierpaste enthält zweckmäßigerweise als aktivierende Substanz eine Kombination aus 1 bis 15 Gew.% Kaliumtetrafluoroborat und 5 bis 40 Gew.% Calciumfluorid, jeweils bezogen auf den Feststoffanteil.The borating paste according to the invention expediently contains as a activating substance a combination of 1 to 15 % By weight potassium tetrafluoroborate and 5 to 40% by weight Calcium fluoride, each based on the solids content.
In dem erfindungsgemäßen pastenförmigen Boriermittel können die üblichen borabgebenen Substanzen, wie amorphes oder kristallines Ferrobor und insbesondere Borcarbid (B4C), enthalten sein. Vorzugsweise enthält es 1 bis 15 Gew.% Borcarbid, bezogen auf den Feststoffanteil.The pasty boroning agent according to the invention can contain the usual boron-releasing substances, such as amorphous or crystalline ferroboron and in particular boron carbide (B 4 C). It preferably contains 1 to 15% by weight of boron carbide, based on the solids content.
Weiterhin enthält die erfindungsgemäße Borierpaste im Rest die gängigen Streckmittel, wie insbesondere Siliciumcarbid (SiC), weiterhin Wasser und gegebenenfalls Hilfsstoffe.The Borierpaste according to the invention also contains the rest the usual extenders, in particular silicon carbide (SiC), further water and optionally auxiliary substances.
Vorzugsweise enthält die erfindungsgemäße Borierpaste, bezogen auf den Feststoffanteil, 8 bis 10 Gew.% Borcarbid, 5 bis 10 Gew.% Kaliumtetrafluoroborat, 10 bis 30 Gew.% Calciumfluorid, 1-3 Gew.% Calciumcarbonat, 0,2-1 Gew.% Natriumnitrit, 0,2-1 Gew.% Natriumtetraborat und im Rest als Streckmittel Siliciumcarbid, weiterhin Wasser und gegebenenfalls Hilfsstoffe.The borating paste according to the invention preferably contains based on the solids content, 8 to 10% by weight boron carbide, 5 to 10% by weight potassium tetrafluoroborate, 10 to 30% by weight Calcium fluoride, 1-3% by weight calcium carbonate, 0.2-1% by weight Sodium nitrite, 0.2-1% by weight sodium tetraborate and the rest as an extender silicon carbide, water and optionally auxiliary substances.
Eine typische Zusammensetzung besteht etwa aus 10 Gew.% Borcarbid, 7 Gew.% Kaliumtetrafluoroborat, 15 Gew.% Calciumfluorid, 1,5 Gew.% Calciumcarbonat, 0,5 Gew.% Natriumnitrit, 0,5 Gew.% Natriumtetraborat und im Rest aus Siliciumcarbid, bezogen auf den Feststoffanteil.A typical composition consists of approximately 10% by weight Boron carbide, 7% by weight potassium tetrafluoroborate, 15% by weight Calcium fluoride, 1.5% by weight calcium carbonate, 0.5% by weight Sodium nitrite, 0.5% by weight sodium tetraborate and the rest Silicon carbide, based on the solids content.
Die Formulierung des erfindungsgemäßen pastenförmigen Boriermittels kann etwa durch Zugabe von Wasser und gegebenenfalls untergeordneter Mengen von Hilfsstoffen, wie z.B. handelsüblicher Bindemittel und/oder Verdickungsmittel, aus der entsprechenden Pulvermischung erfolgen.The formulation of the pasty according to the invention Borating agent can be added by adding water and if necessary, minor amounts of auxiliaries, such as e.g. commercially available binders and / or Thickener, from the corresponding powder mixture respectively.
Je nach Anwendungserfordernis kann der Wasseranteil, bezogen auf die Gesamtmenge, 25 bis 40 Gew.% betragen. Vorzugsweise enthält die Paste 30 bis 35 Gew.% und insbesondere etwa 30 Gew.% an Wasser.Depending on the application requirement, the water content, based on the total amount, 25 to 40 wt.%. The paste preferably contains 30 to 35% by weight and in particular about 30% by weight of water.
Als etwaige weitere Hilfsstoffe kommen Verdickungsmittel und Bindemittel, wie sie bei der Formulierung von Pasten üblich sind, in Frage. Ein besonders geeignetes Verdickungsmittel ist Bentonit. Dieses wird in geringer Menge, typisch etwa 1 Gew.%, bezogen auf die Gesamtmenge, in der Borierpaste eingesetzt.Thickeners may be used as other auxiliary substances and binders as used in the formulation of pastes are common in question. A particularly suitable one Bentonite is a thickener. This will decrease Amount, typically about 1% by weight, based on the total amount used in the borier paste.
Die erfindungsgemäße Borierpaste kann sehr vorteilhaft zur Erzeugung von Boridschichten auf metallischen Werkstücken verwendet werden.The borating paste according to the invention can be very advantageous for Generation of boride layers on metallic workpieces be used.
Durch Carbonat-Zusatz wird die Porosität der Boridschicht verringert und so die Haltbarkeit der Bauteile erhöht. Durch den Zusatz von Nitrit wird die Neigung bekannter Borierpasten zu Korrosionsangriffen auf das Bauteil eliminiert. Hieraus resultiert ein sehr gutes Oberflächenaussehen. Dadurch, daß gegenüber bekannten Zusammensetzungen der Gehalt an KBF4 durch teilweisen Ersatz mit dem wasserunlöslichen CaF2 verringert werden kann, ist das erfindungsgemäße Mittel in Bezug auf Fluoridemissionen wesentlich unkritischer, was insbesondere die Entsorgung von Abwässern nach dem Waschen der borierten Bauteile und von erschöpftem Boriermittel betrifft. Ein reduzierter KBF4-Gehalt ist weiterhin beim bestimmungsgemäßen Gebrauch des Mittels von Vorteil, da entsprechend geringere fluoridhaltige Gasemissionen auftreten. Durch den Zusatz von Carbonat werden diese Emissionen nochmals verringert, was zu einer erhöhten Umweltverträglichkeit des Verfahrens führt. Die Probleme bekannter Borierpasten bezüglich der Lagerstabilität werden durch Zusatz von Borat beseitigt. Das Borat führt auch zusammen mit dem Nitritzusatz zu einer gegenüber bekannten Borierpasten wesentlich leichteren Reinigung der Bauteile.The addition of carbonate reduces the porosity of the boride layer and thus increases the durability of the components. The addition of nitrite eliminates the tendency of known boron pastes to cause corrosion attack on the component. This results in a very good surface appearance. Because the content of KBF 4 can be reduced compared to known compositions by partial replacement with the water-insoluble CaF 2 , the agent according to the invention is significantly less critical with regard to fluoride emissions, which in particular means the disposal of waste water after washing the borated components and of depleted borating agent concerns. A reduced KBF 4 content is also an advantage when the agent is used as intended, since correspondingly lower fluoride-containing gas emissions occur. By adding carbonate, these emissions are further reduced, which leads to an increased environmental compatibility of the process. The problems of known borating pastes with regard to storage stability are eliminated by adding borate. The borate, together with the nitrite additive, also makes the components much easier to clean than known boron pastes.
Ein besonderer Verfahrensvorteil der erfindungsgemäßen Borierpaste ist, daß sich auf Werkstücken aus Eisenwerkstoffen ohne weiteres und problemlos einphasige, Fe2B-enthaltende, porenarme Boridschichten erzeugen lassen. Dies ist auf die vorzugsweise Wahl einer Kombination von 1 bis 15 Gew.% Kaliumtetrafluoroborat und 5 bis 40 Gew.% Calciumfluorid, bezogen auf die Menge der Feststoffe in der Borierpaste, als aktivierende Substanz zurückzuführen.A particular process advantage of the boron paste according to the invention is that single-phase, Fe 2 B-containing, low-pore boride layers can be easily and easily produced on workpieces made of ferrous materials. This is due to the preferred choice of a combination of 1 to 15% by weight of potassium tetrafluoroborate and 5 to 40% by weight of calcium fluoride, based on the amount of solids in the borating paste, as the activating substance.
In dem erfindungsgemäßen Verfahren zur Erzeugung von porenarmen, vorzugsweise einphasigen, Fe2B-enthaltenden Boridschichten auf Werkstücken aus Eisenwerkstoffen wird die Oberfläche der Werkstücke mit der Borierpaste bedeckt und diese dann bei Temperaturen zwischen 800 und 1100 °C behandelt, bis sich eine Boridschicht der gewünschten Dicke gebildet hat. Hierzu wird die Oberfläche der Teile mit der Boriermittelpaste bestrichen. Dies ist insbesondere dann vorteilhaft, wenn eine nur teilweise borierte Oberfläche gewünscht wird. Alternativ kann das Boriermittel auch durch Eintauchen der Teile in die Paste oder durch Aufspritzen der Paste aufgebracht werden.In the process according to the invention for producing low-pore, preferably single-phase, Fe 2 B-containing boride layers on workpieces made of iron materials, the surface of the workpieces is covered with the borating paste and this is then treated at temperatures between 800 and 1100 ° C. until a boride layer of the desired size Has formed thickness. For this purpose, the surface of the parts is coated with the borating agent paste. This is particularly advantageous when a partially borated surface is desired. Alternatively, the borating agent can also be applied by dipping the parts into the paste or by spraying on the paste.
Die Borierung erfolgt vorzugsweise bei Temperaturen zwischen 850 und 980 °C über einen Zeitraum von 20 Minuten bis 2 Stunden. Hierbei lassen sich insbesondere einphasige Fe2B-Schichten von einer Dicke von 30 bis 150 µm erhalten. Boronation is preferably carried out at temperatures between 850 and 980 ° C. over a period of 20 minutes to 2 hours. In particular, single-phase Fe 2 B layers with a thickness of 30 to 150 μm can be obtained.
Es wurden Bauteile aus dem Werkstoff 42CrMo4 bei 930 °C
unter Schutzgas 45 min lang mit einer Borierpaste folgender
erfindungsgemäßer Zusammensetzung boriert:
Das Boriermittel ließ sich nach der Wärmebehandlung problemlos und rückstandsfrei mit Wasser entfernen, die Bauteile wiesen keinerlei Korrosionsangriffe oder Flecken auf. Die Boridschicht war FeB-frei, porenarm und hatte eine Dicke von ca. 50 µm. Die Paste zeigte auch nach längerer Lagerung bei erhöhter Temperatur keine Veränderung der Verarbeitungseigenschaften. Der pH-Wert lag bei ca. 7,5.The borating agent was left after the heat treatment remove easily and residue-free with water, the Components showed no corrosion attacks or stains on. The boride layer was FeB-free, low in pores and had one Thickness of approx. 50 µm. The paste also showed after a long time Storage at elevated temperature does not change the Processing properties. The pH was around 7.5.
Es wurden Bauteile aus dem Werkstoff 42CrMo4 bei 930 °C
unter Schutzgas 45 min lang mit einer Borierpaste folgender
herkömmlicher Zusammensetzung boriert:
Das Boriermittel ließ sich nach der Wärmebehandlung mit Wasser nicht vollkommen rückstandsfrei entfernen, erst nach Bürsten oder Strahlen waren die Bauteile ausreichend gereinigt. Die Bauteile wiesen leichte Korrosionsangriffe und eine starke Fleckigkeit auf. Die Boridschicht hatte eine Dicke von ca. 50 µm, war jedoch zweiphasig; die FeB-Nadeln reichten bis in 14 µm Tiefe. Es war ein gegenüber Beispiel 1 stärkerer Porensaum zu erkennen. Nach längerer Lagerung bei erhöhter Temperatur war die Viskosität der Paste gesunken und es hatte eine stärkeres Absetzen der Feststoffe stattgefunden. Der pH-Wert der Paste betrug ca. 4. The borating agent was acceptable after the heat treatment Do not remove water completely without residue, only after The components were sufficient for brushing or blasting cleaned. The components showed slight corrosion attacks and a strong spotting. The boride layer had a thickness of about 50 microns, but was two-phase; the FeB needles reached to a depth of 14 µm. It was opposite Example 1 recognizing stronger pore hem. After a long time Storage at elevated temperature was the viscosity of the Paste dropped and it had a stronger settling of the Solids occurred. The pH of the paste was approx. 4.
Es wurden Bauteile aus dem Werkstoff Cf52 bei 940 °C unter
Schutzgas 60 min lang mit einer Borierpaste folgender
erfindungsgemäßer Zusammensetzung boriert:
Das Boriermittel ließ sich nach der Wärmebehandlung problemlos und rückstandsfrei mit Wasser entfernen, die Bauteile wiesen keinerlei Korrosionsangriffe oder Flecken auf. Die Boridschicht war FeB-frei, porenarm und hatte eine Dicke von ca. 70 µm.The borating agent was left after the heat treatment remove easily and residue-free with water, the Components showed no corrosion attacks or stains on. The boride layer was FeB-free, low in pores and had one Thickness of approx. 70 µm.
Es wurden Bauteile aus dem Werkstoff C 60 bei 950 °C unter
Schutzgas 120 min lang mit einer Borierpaste folgender
erfindungsgemäßer Zusammensetzung boriert:
Das Boriermittel ließ sich nach der Wärmebehandlung problemlos und rückstandsfrei mit Wasser entfernen, das Bauteil wies keinerlei Korrosionsangriffe oder Flecken auf. Die Boridschicht war FeB-frei, porenarm und hatte eine Dicke von ca. 140 µm.The borating agent was left after the heat treatment remove easily and residue-free with water Component showed no corrosion attacks or stains. The boride layer was FeB-free, low in pores and had one Thickness of approx. 140 µm.
Es wurden Bauteile aus dem Werkstoff 42CrMo4 bei 930 °C
unter Schutzgas 45 min lang mit einer Borierpaste folgender
erfindungsgemäßer Zusammensetzung boriert:
Das Boriermittel ließ sich nach der Wärmebehandlung problemlos und rückstandsfrei mit Wasser entfernen, die Bauteile wiesen keinerlei Korrosionsangriffe oder Flecken auf. Die Boridschicht war FeB-frei, porenarm und hatte eine Dicke von ca. 52 µm. Die Emissionen an Fluor-Verbindungen lagen ca. 25 % über denjenigen aus Beispiel 1.The borating agent was left after the heat treatment remove easily and residue-free with water, the Components showed no corrosion attacks or stains on. The boride layer was FeB-free, low in pores and had one Thickness of approx. 52 µm. The emissions of fluorine compounds were approximately 25% higher than those from Example 1.
Es wurden Bauteile aus dem Werkstoff 42CrMo4 bei 930 °C
unter Schutzgas 45 min lang mit einer calciumcarbonat- und
calciumfluoridfreien Borierpaste folgender Zusammensetzung
boriert:
Das Boriermittel ließ sich nach der Wärmebehandlung problemlos und rückstandsfrei mit Wasser entfernen, die Bauteile wiesen keinerlei Korrosionsangriffe oder Flecken auf. Die ca. 50 µm dicke Boridschicht war zweiphasig, die FeB-Nadeln reichten bis in 10 µm Tiefe. Die Schicht war stärker porös als in Beispiel 5. Die Emissionen an Fluor-Verbindungen lagen ca. 40 % über denjenigen aus Beispiel 1.The borating agent was left after the heat treatment remove easily and residue-free with water, the Components showed no corrosion attacks or stains on. The approximately 50 µm thick boride layer was two-phase, the FeB needles reached a depth of 10 µm. The shift was more porous than in example 5. The emissions of fluorine compounds were approximately 40% higher than those from example 1.
Claims (12)
dadurch gekennzeichnet,
daß es als Zusätze enthält:
characterized,
that it contains as additives:
dadurch gekennzeichnet,
daß es, bezogen auf den Feststoffanteil, 0,1-5 Gew.% an Verbindungen gemäß (a), 0,1-2 Gew.% an Verbindungen gemäß (b) und 0,1-2 Gew.% an Verbindungen gemäß (c) enthält.Borating agent according to claim 1,
characterized,
that, based on the solids content, 0.1-5% by weight of compounds according to (a), 0.1-2% by weight of compounds according to (b) and 0.1-2% by weight of compounds according to ( c) contains.
dadurch gekennzeichnet,
daß es, bezogen auf den Feststoffanteil, 1-3 Gew.% an Verbindungen gemäß (a), 0,2-1 Gew.% an Verbindungen gemäß (b) und 0,2-1 Gew.% an Verbindungen gemäß (c) enthält.Borating agent according to claim 1 or 2,
characterized,
that, based on the solids content, 1-3% by weight of compounds according to (a), 0.2-1% by weight of compounds according to (b) and 0.2-1% by weight of compounds according to (c) contains.
dadurch gekennzeichnet,
daß es als Verbindungen gemäß (a) Erdalkalicarbonate, vorzugsweise Calciumcarbonat, als Verbindungen gemäß (b) Alkalinitrite, vorzugsweise Natriumnitrit, und als Verbindung gemäß (c) Alkaliborate, vorzugsweise Natriumtetraborat, enthält.Borinating agent according to claims 1 to 3,
characterized,
that it contains as compounds according to (a) alkaline earth carbonates, preferably calcium carbonate, as compounds according to (b) alkali nitrites, preferably sodium nitrite, and as compounds according to (c) alkali borates, preferably sodium tetraborate.
dadurch gekennzeichnet,
daß es als borabgebende Substanz Borcarbid, als aktivierende Substanz Kaliumtetrafluoroborat und als Streckmittel Siliciumcarbid enthält.Borinating agent according to claims 1 to 4,
characterized,
that it contains boron carbide as the boron-donating substance, potassium tetrafluoroborate as the activating substance and silicon carbide as the extender.
dadurch gekennzeichnet,
daß es als aktivierende Substanz eine Kombination aus Kaliumtetrafluoroborat und Calciumfluorid enthält.Borating agent according to claims 1-5,
characterized,
that it contains a combination of potassium tetrafluoroborate and calcium fluoride as the activating substance.
dadurch gekennzeichnet,
daß es als borabgebende Substanz 1 bis 15 Gew. % Borcarbid und als aktivierende Substanz eine Kombination aus 1 bis 15 Gew.% Kaliumtetrafluoroborat und 5 bis 40 Gew.% Calciumfluorid enthält, jeweils bezogen auf den Feststoffanteil.Borating agent according to Claims 1 to 6,
characterized,
that it contains 1 to 15% by weight of boron carbide as the boron-releasing substance and a combination of 1 to 15% by weight of potassium tetrafluoroborate and 5 to 40% by weight of calcium fluoride as the activating substance, in each case based on the solids content.
dadurch gekennzeichnet,
daß es, bezogen auf den Feststoffanteil, 8 bis 10 Gew. Borcarbid, 5 bis 10 Gew.% Kaliumtetrafluoroborat, 10 bis 30 Gew.% Calciumfluorid 1-3 Gew.% Calciumcarbonat, 0,2-1 Gew.% Natriumnitrit, 0,2-1 Gew.% Natriumtetraborat und im Rest als Streckmittel Siliciumcarbid, weiterhin Wasser und gegebenenfalls Hilfsstoffe enthält.Borinating agent according to claims 1 to 7,
characterized,
that, based on the solids content, 8 to 10% by weight boron carbide, 5 to 10% by weight potassium tetrafluoroborate, 10 to 30% by weight calcium fluoride 1-3% by weight calcium carbonate, 0.2-1% by weight sodium nitrite, 0, 2-1 wt.% Sodium tetraborate and the rest as an extender silicon carbide, further contains water and optionally auxiliaries.
dadurch gekennzeichnet,
daß es, bezogen auf den Feststoffanteil, aus etwa 10 Gew.% Borcarbid, 7 Gew.% Kaliumtetrafluoroborat, 15 Gew.% Calciumfluorid, 1,5 Gew.% Calciumcarbonat, 0,5 Gew.% Natriumnitrit, 0,5 Gew.% Natriumtetraborat und im Rest aus Siliciumcarbid besteht.Borinating agent according to claims 1 to 8,
characterized,
that it, based on the solids content, from about 10% by weight boron carbide, 7% by weight potassium tetrafluoroborate, 15% by weight calcium fluoride, 1.5% by weight calcium carbonate, 0.5% by weight sodium nitrite, 0.5% by weight Sodium tetraborate and the rest of silicon carbide.
dadurch gekennzeichnet,
daß man die Oberfläche der Werkstücke mit einem pastenförmigen Boriermittel gemäß den Ansprüchen 1 bis 7 bedeckt und diese dann bei Temperaturen zwischen 800 und 1100°C behandelt, bis sich eine Boridschicht der gewünschten Dicke gebildet hat.Process for producing low-pore, preferably single-phase, Fe 2 B-containing boride layers on workpieces made of ferrous materials,
characterized,
that the surface of the workpieces is covered with a paste-like borating agent according to claims 1 to 7 and then treated at temperatures between 800 and 1100 ° C until a boride layer of the desired thickness has formed.
dadurch gekennzeichnet,
daß man zur Erzeugung von Fe2B-Schichten einer Dicke von 30 bis 150 µm bei Temperaturen zwischen 850 und 950°C über einen Zeitraum von 20 Minuten bis 2 Stunden behandelt.A method according to claim 11,
characterized,
that is treated to produce Fe 2 B layers with a thickness of 30 to 150 microns at temperatures between 850 and 950 ° C over a period of 20 minutes to 2 hours.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19904629A DE19904629C2 (en) | 1999-02-05 | 1999-02-05 | Paste-shaped borating agent, its use and method for producing low-pore Fe¶2¶B-containing boride layers |
DE19904629 | 1999-02-05 |
Publications (3)
Publication Number | Publication Date |
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EP1026282A2 true EP1026282A2 (en) | 2000-08-09 |
EP1026282A3 EP1026282A3 (en) | 2000-10-18 |
EP1026282B1 EP1026282B1 (en) | 2003-03-19 |
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ID=7896498
Family Applications (1)
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EP00100550A Expired - Lifetime EP1026282B1 (en) | 1999-02-05 | 2000-01-12 | Paste boriding agent |
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EP (1) | EP1026282B1 (en) |
JP (1) | JP4360728B2 (en) |
AT (1) | ATE234946T1 (en) |
BR (1) | BR0000249B1 (en) |
CA (1) | CA2298046A1 (en) |
CZ (1) | CZ295247B6 (en) |
DE (2) | DE19904629C2 (en) |
TR (1) | TR199903326A2 (en) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1314828C (en) * | 2004-11-23 | 2007-05-09 | 江苏工业学院 | Method and apparatus for DC electric field accelerating solid powder boriding |
WO2010046672A1 (en) * | 2008-10-21 | 2010-04-29 | Wellstream International Limited | Flexible pipe having increased acid resistance and/or corrosion resistance |
CN102154616A (en) * | 2011-03-23 | 2011-08-17 | 常州大学 | Boronizing method and device for inner surface of tubular component by using direct-current electric field enhanced powder method |
WO2018169827A1 (en) * | 2017-03-14 | 2018-09-20 | Bwt Llc | Boronizing powder compositions for improved boride layer quality in oil country tubular goods and other metal articles |
RU2684803C2 (en) * | 2015-02-16 | 2019-04-15 | Хан Ён Стил Вайе Ко., Лтд. | Method of processing metallic material with layer of non-phosphate coating for cold-heading plastic treatment |
CN115094370A (en) * | 2022-07-05 | 2022-09-23 | 山东九环石油机械有限公司 | Special anti-corrosion wear-resistant boronizing petroleum pipe and manufacturing method thereof |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2007297650A (en) * | 2006-04-27 | 2007-11-15 | Fuji Kihan:Kk | Boronization method |
CN102409287A (en) * | 2011-12-01 | 2012-04-11 | 常州大学 | Direct-current electric field enhanced powder alumetizing method of inner surface of tubular part and device for same |
US10870912B2 (en) | 2017-03-14 | 2020-12-22 | Bwt Llc | Method for using boronizing reaction gases as a protective atmosphere during boronizing, and reaction gas neutralizing treatment |
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GB1258372A (en) * | 1969-01-21 | 1971-12-30 | ||
FR2153416A1 (en) * | 1971-09-24 | 1973-05-04 | Kempten Elektroschmelz Gmbh | Boronising compsn - in form of paste, suspension or emulsion |
US3770512A (en) * | 1970-07-28 | 1973-11-06 | A Bopp | Method for surface hardening steel and cemented carbides |
DD140676A1 (en) * | 1978-12-14 | 1980-03-19 | Horst Kemnitz | POWDERFUL BORING AGENT |
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US4555326A (en) * | 1984-05-17 | 1985-11-26 | Betz Laboratories, Inc. | Methods and compositions for boronizing metallic surfaces |
-
1999
- 1999-02-05 DE DE19904629A patent/DE19904629C2/en not_active Expired - Lifetime
- 1999-12-30 TR TR1999/03326A patent/TR199903326A2/en unknown
-
2000
- 2000-01-12 AT AT00100550T patent/ATE234946T1/en active
- 2000-01-12 EP EP00100550A patent/EP1026282B1/en not_active Expired - Lifetime
- 2000-01-12 DE DE50001473T patent/DE50001473D1/en not_active Expired - Lifetime
- 2000-02-01 CZ CZ2000366A patent/CZ295247B6/en not_active IP Right Cessation
- 2000-02-02 BR BRPI0000249-6A patent/BR0000249B1/en not_active IP Right Cessation
- 2000-02-04 CA CA002298046A patent/CA2298046A1/en not_active Abandoned
- 2000-02-04 JP JP2000028339A patent/JP4360728B2/en not_active Expired - Lifetime
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GB1258372A (en) * | 1969-01-21 | 1971-12-30 | ||
US3770512A (en) * | 1970-07-28 | 1973-11-06 | A Bopp | Method for surface hardening steel and cemented carbides |
FR2153416A1 (en) * | 1971-09-24 | 1973-05-04 | Kempten Elektroschmelz Gmbh | Boronising compsn - in form of paste, suspension or emulsion |
DD140676A1 (en) * | 1978-12-14 | 1980-03-19 | Horst Kemnitz | POWDERFUL BORING AGENT |
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Title |
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CHEMICAL ABSTRACTS, vol. 101, no. 6, 6. August 1984 (1984-08-06) Columbus, Ohio, US; abstract no. 41796, WU, SHISHI ET AL: "Pack boriding and control of the carbon content in the transition layers" XP002145323 & JINSHU RECHULI (1984), (2), 2-7 , 1984, * |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1314828C (en) * | 2004-11-23 | 2007-05-09 | 江苏工业学院 | Method and apparatus for DC electric field accelerating solid powder boriding |
WO2010046672A1 (en) * | 2008-10-21 | 2010-04-29 | Wellstream International Limited | Flexible pipe having increased acid resistance and/or corrosion resistance |
US8900377B2 (en) | 2008-10-21 | 2014-12-02 | Ge Oil & Gas Uk Limited | Flexible pipe having increased acid resistance and/or corrosion resistance |
CN102154616A (en) * | 2011-03-23 | 2011-08-17 | 常州大学 | Boronizing method and device for inner surface of tubular component by using direct-current electric field enhanced powder method |
RU2684803C2 (en) * | 2015-02-16 | 2019-04-15 | Хан Ён Стил Вайе Ко., Лтд. | Method of processing metallic material with layer of non-phosphate coating for cold-heading plastic treatment |
WO2018169827A1 (en) * | 2017-03-14 | 2018-09-20 | Bwt Llc | Boronizing powder compositions for improved boride layer quality in oil country tubular goods and other metal articles |
CN115094370A (en) * | 2022-07-05 | 2022-09-23 | 山东九环石油机械有限公司 | Special anti-corrosion wear-resistant boronizing petroleum pipe and manufacturing method thereof |
Also Published As
Publication number | Publication date |
---|---|
CZ295247B6 (en) | 2005-06-15 |
EP1026282A3 (en) | 2000-10-18 |
DE19904629A1 (en) | 2000-08-10 |
EP1026282B1 (en) | 2003-03-19 |
DE50001473D1 (en) | 2003-04-24 |
CZ2000366A3 (en) | 2000-12-13 |
DE19904629C2 (en) | 2003-08-21 |
JP2000226647A (en) | 2000-08-15 |
ATE234946T1 (en) | 2003-04-15 |
TR199903326A2 (en) | 2000-09-21 |
JP4360728B2 (en) | 2009-11-11 |
CA2298046A1 (en) | 2000-08-05 |
BR0000249A (en) | 2000-10-17 |
BR0000249B1 (en) | 2009-01-13 |
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