US3787245A - Method for the boration of titanium and titanium alloys - Google Patents

Method for the boration of titanium and titanium alloys Download PDF

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US3787245A
US3787245A US00084229A US3787245DA US3787245A US 3787245 A US3787245 A US 3787245A US 00084229 A US00084229 A US 00084229A US 3787245D A US3787245D A US 3787245DA US 3787245 A US3787245 A US 3787245A
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titanium
borating agent
boration
borating
noble gas
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US00084229A
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H Kunst
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INST fur HAERTEREITECHN DT
INST HAERTEREITECHN
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INST HAERTEREITECHN
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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 accordingly is intended to propose a novel borating agent as well as a method for the boration of metals, especially titanium and titanium alloys, which, through the indiffusion of boron considerably improves the hardness and wear-and-tear resistance of the surfaces of work pieces, especially made of titanium and titanium alloys, without impairing the abovedescribed favorable properties of the work material.
  • the borating agent according to the invention consists of a boron source, for example, a material containing boron, as a boron donor under a noble gas, especially argon (the very purestargon), the boron here being amorphous and being annealed and then again cooled down.
  • a boron source for example, a material containing boron, as a boron donor under a noble gas, especially argon (the very purestargon), the boron here being amorphous and being annealed and then again cooled down.
  • the borating agent from the above-described boron source when used is best provided with additives, more specifically, with suitable activators, especially alkali, alkalineearth-, or ammonium-halides, for example, ammonium chloride, ammonium fluoride, barium fluoride, sodium bromide, and the like.
  • suitable activators especially alkali, alkalineearth-, or ammonium-halides, for example, ammonium chloride, ammonium fluoride, barium fluoride, sodium bromide, and the like.
  • This activator has the effect that the hardness layer, made with the borating agent according to the invention, comes out thicker on the working material treated.
  • an inert substance in other words, a substance that does not participate in the reaction, is added to the borating agent.
  • the following are particularly suitable for this purpose: aluminum oxide, magnesium oxide, zirconium oxide, beryllium oxide, and other stable oxides, but also talc, asbestos, and the like can be used.
  • Such inert substances keep the borating agent in a disintegrated, gaspermeable state also during boration and make it easier to take the borated work pieces out of the borating agent after boration.
  • a noble gas especially argon
  • the inert substances facilitate the passage of the noble gas.
  • Borated work pieces, according to the invention, made of titanium or titanium alloys, are provided with a surface layer which possesses a surface hardness of 3,000-3,500 I-IV kglmm In the experiments that were conducted, this hardness was measured in the known manner according to Vickers with a stress of 500 g. The thickness of this hardened surface layer is between 0.004 and 0.1 mm. It was furthermore ascertained that the hardened surface layer, made according to the invention, consists of the titanium borides TiB and TiB. This layer is hard and wear-and-tear proof, without the base working material that is, the titanium or titanium alloy being made brittle due to the admission of oxygen, nitrogen, or hydrogen.
  • amorphous boron is annealed between 850C and l, l 00C for a period of about 1-3 hours, with simultaneous constant conduction therethrough of a noble gas, especially argon (purest argon) and is then cooled, accompanied by further through-conduction of a noble gas, down to about room temperature.
  • a noble gas especially argon (purest argon)
  • the amorphous boron is in a container that is sealed against the entry of air and against the entry of foreign gases; this container is provided with a feeder line'and an evacuation line for the noble gas.
  • the boron source can readily be used as a borating agent without any further additives.
  • Boration with the borating agent according to this invention is best accomplished by packing the work piece to be treated into the borating agent in a suitable vessel and heating it to a temperature between 900 and 1,400C in an oven.
  • pecially argon (purest argon), is constantly conducted through the borating agent.
  • the vessel is closed off against the entry of air and other foreign gases and it is provided with an inlet and an outlet for the noble gas.
  • the duration of the boration is at least 3 hours. This is followed by a slow cooling of the working material.
  • EXAMPLE I 1 kg of amorphous boron was annealed for 2 hours, accompanied by the conduction therethrough of argon, at a temperature of 1 ,000C. This was followed by cooling over a period of 3 hours, accompanied by further conduction therethrough of argon, down to about room temperature. This boron source was then used as the borating agent for a work piece of pure titanium.
  • the work piece was packed in the treated amorphous boron powder and was borated for a period of 15 hours at a temperature of 1,000C. During boration, the argon was conducted through the borating agent.
  • the work piece thus treated had a hard surface layer with a thickness of 0.04 mm and a hardness of 3,0003,500 HV kg/mm
  • EXAMPLE II 950 g of amorphous boron was treated as described in Example I above, in other words, it was annealed. 50 g of barium fluoride was then admixed as an activator into the amorphous boron which had been cooled down to room temperature.
  • a work piece, made of a titanium alloy TiAl V was borated, more specifically, for a period of 5 hours, while argon was being conducted through the borating agent, as well as at a temperature of 1,200C.
  • the layer produced here had a thickness of 0.08 mm with a hardness of 3,0003,500 HV kg/mm What is claimed is:
  • a method for borating a titanium metal workpiece which comprises:
  • said borating agent being prepared by a method which comprises:
  • an activator is added to said borating agent, said activator being a member selected from the group consisting of an alkali metal halide, an alkaline earth metal halide, and an ammonium halide.
  • said activator is a member selected from the group consisting of ammonium chloride, ammonium fluoride, barium fluoride and sodium bromide.

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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)
  • Powder Metallurgy (AREA)

Abstract

Metals, especially titanium and titanium alloys, are borated with a borating agent prepared by annealing amorphous boron at a temperature between 850*C and 1,300*C in an inert gas, especially a noble gas. The boration is best accomplished by packing the metal into the borating agent and heating it to a temperature between 900*C and 1,400*C while passing a noble gas through the borating agent. Activators and inert substances can be added to the borating agents.

Description

Ilnited States Patent [191 METHOD FOR THE DURATION OF TITANIUM AND TITANIUM ALLOYS [75] Inventor: llelmut Eduard Kunst,
Osterholz-Scharmbeck, Germany [73] Assignee: Institut Fur l-Iarterei-Technik,
Bremen-Lesum, Germany 22 Filed: 0ct.26, 1970 21 Appl.N0.:84,229
[51] Int. Cl. C23f 7/00 [58] Field of Search 148/63, 31.5, 20.3, 6; 23/209; ll7/107.2 P, DIG. 10, 106; 423/298 [56] References Cited UNITED STATES PATENTS 5/1963 Commanday et al. 117/107.2 P 10/1960 Dorner 117/107.2 P 5/1959 Llewelyn et al 117/1072 P ,Ian. 22, I974 2,528,454 10/1950 Schlesinger et a1 117/DIG. 10 3,551,105 12/1970 Cooper 23/209 3,029,162 4/1962 Samuel et a1. 148/63 2,949,390 8/1960 Feder et a1 148/63 3,382,048 5/1968 Lindberg, Jr 23/204 R FOREIGN PATENTS OR APPLICATIONS 851,208 10/1960 Great Britain 148/63 Primary ExaminerEdward J. Meros Attorney, Agent, or Firm-Sughrue, Rothwell et a1.
[5 7 ABSTRACT 5 Claims, No Drawings METHOD FOR THE BORATION OF TTTANIUM AND TITANIUM ALLOYS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a borating agent as well as a method for the boration of metals, especially titanium and titanium alloys. The invention furthermore concerns work pieces made of titanium or titanium alloys which are borated according to this method.
2. Description of the Prior Art The extensive use of titanium and titanium alloys is thus far prevented, among other things, by the fact that there are no suitable methods known which are practical for increasing the hardness and wear-and-tear resistance of the surface of work pieces made of titanium and titanium alloys, without at the same time impairing the positive properties of the titanium (high strengthweight ratio, good toughness, and good corrosion properties).
The invention accordingly is intended to propose a novel borating agent as well as a method for the boration of metals, especially titanium and titanium alloys, which, through the indiffusion of boron considerably improves the hardness and wear-and-tear resistance of the surfaces of work pieces, especially made of titanium and titanium alloys, without impairing the abovedescribed favorable properties of the work material.
SUMMARY OF THE INVENTION The borating agent according to the invention consists of a boron source, for example, a material containing boron, as a boron donor under a noble gas, especially argon (the very purestargon), the boron here being amorphous and being annealed and then again cooled down.
DETAILED DESCRIPTION OF THE INVENTION The borating agent from the above-described boron source when used is best provided with additives, more specifically, with suitable activators, especially alkali, alkalineearth-, or ammonium-halides, for example, ammonium chloride, ammonium fluoride, barium fluoride, sodium bromide, and the like. This activator has the effect that the hardness layer, made with the borating agent according to the invention, comes out thicker on the working material treated.
Furthermore, according to the invention, an inert substance, in other words, a substance that does not participate in the reaction, is added to the borating agent. The following are particularly suitable for this purpose: aluminum oxide, magnesium oxide, zirconium oxide, beryllium oxide, and other stable oxides, but also talc, asbestos, and the like can be used. Such inert substances keep the borating agent in a disintegrated, gaspermeable state also during boration and make it easier to take the borated work pieces out of the borating agent after boration.
If, according to another embodiment of the invention, a noble gas, especially argon, is conducted through the borating agent during the boration of the work pieces, the inert substances facilitate the passage of the noble gas.
Borated work pieces, according to the invention, made of titanium or titanium alloys, are provided with a surface layer which possesses a surface hardness of 3,000-3,500 I-IV kglmm In the experiments that were conducted, this hardness was measured in the known manner according to Vickers with a stress of 500 g. The thickness of this hardened surface layer is between 0.004 and 0.1 mm. It was furthermore ascertained that the hardened surface layer, made according to the invention, consists of the titanium borides TiB and TiB. This layer is hard and wear-and-tear proof, without the base working material that is, the titanium or titanium alloy being made brittle due to the admission of oxygen, nitrogen, or hydrogen.
In detail, we proceed as follows in making the boron source, a component of the borating agent: amorphous boron is annealed between 850C and l, l 00C for a period of about 1-3 hours, with simultaneous constant conduction therethrough of a noble gas, especially argon (purest argon) and is then cooled, accompanied by further through-conduction of a noble gas, down to about room temperature. During this process, the amorphous boron is in a container that is sealed against the entry of air and against the entry of foreign gases; this container is provided with a feeder line'and an evacuation line for the noble gas.
The boron source can readily be used as a borating agent without any further additives.
It is advantageous, however, to add the abovedescribed substances, that is, an inert substance as a diluent, as well as an activator. Optimum conditions are obtained when the borating agent contains about 18-40 percent of amorphous boron, treated in accordance with this invention, 80 percent of the inert substance, and 2-8 percent of the activator.
Boration with the borating agent according to this invention is best accomplished by packing the work piece to be treated into the borating agent in a suitable vessel and heating it to a temperature between 900 and 1,400C in an oven. During boration, the noble gas, es-
pecially argon (purest argon), is constantly conducted through the borating agent. For this purpose the vessel is closed off against the entry of air and other foreign gases and it is provided with an inlet and an outlet for the noble gas. The duration of the boration is at least 3 hours. This is followed by a slow cooling of the working material.
EXAMPLE I 1 kg of amorphous boron was annealed for 2 hours, accompanied by the conduction therethrough of argon, at a temperature of 1 ,000C. This was followed by cooling over a period of 3 hours, accompanied by further conduction therethrough of argon, down to about room temperature. This boron source was then used as the borating agent for a work piece of pure titanium.
The work piece was packed in the treated amorphous boron powder and was borated for a period of 15 hours at a temperature of 1,000C. During boration, the argon was conducted through the borating agent. The work piece thus treated had a hard surface layer with a thickness of 0.04 mm and a hardness of 3,0003,500 HV kg/mm EXAMPLE II 950 g of amorphous boron was treated as described in Example I above, in other words, it was annealed. 50 g of barium fluoride was then admixed as an activator into the amorphous boron which had been cooled down to room temperature. Afterward, boration was performed over a period of 5 hours on a work piece of pure titanium, accompanied by the conduction of argon through the borating agent, at a temperature of 1,300C. The layer thus produced on the work piece had a thickness of 0.07 mm with a hardness of 3,0003,500 HV kg/mm EXAMPLE Ill 300 g of amorphous boron was once again treated as described in Example I above. After cooling, 600 g of aluminum oxide was added to the boron powder as an inert substance, along with 30 g of ammonium chloride as an activator which was likewise mixed in. With the borating agent thus produced, a work piece, made of a titanium alloy TiAl V was borated, more specifically, for a period of 5 hours, while argon was being conducted through the borating agent, as well as at a temperature of 1,200C. The layer produced here had a thickness of 0.08 mm with a hardness of 3,0003,500 HV kg/mm What is claimed is:
1. A method for borating a titanium metal workpiece which comprises:
contacting said titanium metal workpiece with a borating agent at a temperature of between 900 and 1400 C., for a period of at least 3 hours while simultaneously conducting a substantially pure noble gas through the borating agent, during bora- 4 tion,
said borating agent being prepared by a method which comprises:
annealing amorphous boron at a temperature of between 850 and 1 C, for a period ranging from about 1 to 3 hours, while simultaneously passing a substantially pure noble gas therethrough, and subsequently, cooling said boron while simultaneously passing a substantially pure noble gas therethrough.
2. The method of claim 1 wherein said noble gas is argon.
3. The method of claim 1, wherein an activator is added to said borating agent, said activator being a member selected from the group consisting of an alkali metal halide, an alkaline earth metal halide, and an ammonium halide.
4. The method of claim 3, wherein said activator is a member selected from the group consisting of ammonium chloride, ammonium fluoride, barium fluoride and sodium bromide.
5. The method of claim 1, wherein an inert substance is added to said borating agent, said inert substance being a member selected from the group consisting of aluminum oxide, magnesium oxide, zirconium oxide,
beryllium oxide, talc and asbestos.

Claims (4)

  1. 2. The method of claim 1 wherein said noble gas is argon.
  2. 3. The method of claim 1, wherein an activator is added to said borating agent, said activator being a member selected from the group consisting of an alkali metal halide, an alkaline earth metal halide, and an ammonium halide.
  3. 4. The method of claim 3, wherein said activator is a member selected from the group consisting of ammonium chloride, ammonium fluoride, barium fluoride and sodium bromide.
  4. 5. The method of claim 1, wherein an inert substance is added to said borating agent, said inert substance being a member selected from the group consisting of aluminum oxide, magnesium oxide, zirconium oxide, beryllium oxide, talc and asbestos.
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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3870569A (en) * 1972-05-25 1975-03-11 Degussa Process for boriding refractory metals and their alloys
US4011107A (en) * 1974-06-17 1977-03-08 Howmet Corporation Boron diffusion coating process
US4251297A (en) * 1976-08-16 1981-02-17 Matsushita Electric Industrial Co., Ltd. Method for manufacturing magnetic head using boronizing treatment
US4268582A (en) * 1979-03-02 1981-05-19 General Electric Company Boride coated cemented carbide
US5455068A (en) * 1994-04-28 1995-10-03 Aves, Jr.; William L. Method for treating continuous extended lengths of tubular member interiors
DE19845463A1 (en) * 1998-10-02 2000-04-06 Stiftung Inst Fuer Werkstoffte Wear resistant boride layers are produced, e.g. on steel or titanium alloy substrates, by gas boriding using volatile boron compounds containing boron-oxygen and/or boron-nitrogen bonds
US20050208213A1 (en) * 2002-11-15 2005-09-22 University Of Utah Research Foundation Titanium boride coatings on titanium surfaces and associated methods
US20060074491A1 (en) * 2004-09-30 2006-04-06 Depuy Products, Inc. Boronized medical implants and process for producing the same
US20070018139A1 (en) * 2005-05-10 2007-01-25 Chandran K S R Nanostructured titanium monoboride monolithic material and associated methods
US20090293993A1 (en) * 2008-05-28 2009-12-03 Universal Global Products, Llc. Boronization Process and Composition with Improved Surface Characteristics of Metals
US20100176339A1 (en) * 2009-01-12 2010-07-15 Chandran K S Ravi Jewelry having titanium boride compounds and methods of making the same
US8316679B2 (en) 2010-10-04 2012-11-27 Siemens Industry, Inc. Boronized laying pipe

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US2528454A (en) * 1946-11-07 1950-10-31 Hermann I Schlesinger Coating process
US2887420A (en) * 1956-04-06 1959-05-19 Bristol Aero Engines Ltd Surface treatments for articles made from heat resisting alloys
US2949390A (en) * 1957-08-07 1960-08-16 Harold M Feder Method of protecting tantalum crucibles against reaction with molten uranium
US2955957A (en) * 1956-09-21 1960-10-11 Interchrome S A Coating metals
GB851208A (en) * 1958-01-17 1960-10-12 Metallgesellschaft Ag Process for the production of titanium boride coatings
US3029162A (en) * 1959-05-21 1962-04-10 Chromalloy Corp Process for the production of metallic borides on the surface of metals
US3090702A (en) * 1961-01-23 1963-05-21 Chromizing Corp Protective coating of refractory metals
US3382048A (en) * 1965-03-18 1968-05-07 John E. Lindberg Jr. Method of pretreating metallic hydrides
US3551105A (en) * 1966-02-01 1970-12-29 Walter M Weil Purification of elemental boron

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2528454A (en) * 1946-11-07 1950-10-31 Hermann I Schlesinger Coating process
US2887420A (en) * 1956-04-06 1959-05-19 Bristol Aero Engines Ltd Surface treatments for articles made from heat resisting alloys
US2955957A (en) * 1956-09-21 1960-10-11 Interchrome S A Coating metals
US2949390A (en) * 1957-08-07 1960-08-16 Harold M Feder Method of protecting tantalum crucibles against reaction with molten uranium
GB851208A (en) * 1958-01-17 1960-10-12 Metallgesellschaft Ag Process for the production of titanium boride coatings
US3029162A (en) * 1959-05-21 1962-04-10 Chromalloy Corp Process for the production of metallic borides on the surface of metals
US3090702A (en) * 1961-01-23 1963-05-21 Chromizing Corp Protective coating of refractory metals
US3382048A (en) * 1965-03-18 1968-05-07 John E. Lindberg Jr. Method of pretreating metallic hydrides
US3551105A (en) * 1966-02-01 1970-12-29 Walter M Weil Purification of elemental boron

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3870569A (en) * 1972-05-25 1975-03-11 Degussa Process for boriding refractory metals and their alloys
US4011107A (en) * 1974-06-17 1977-03-08 Howmet Corporation Boron diffusion coating process
US4251297A (en) * 1976-08-16 1981-02-17 Matsushita Electric Industrial Co., Ltd. Method for manufacturing magnetic head using boronizing treatment
US4268582A (en) * 1979-03-02 1981-05-19 General Electric Company Boride coated cemented carbide
US5455068A (en) * 1994-04-28 1995-10-03 Aves, Jr.; William L. Method for treating continuous extended lengths of tubular member interiors
DE19845463A1 (en) * 1998-10-02 2000-04-06 Stiftung Inst Fuer Werkstoffte Wear resistant boride layers are produced, e.g. on steel or titanium alloy substrates, by gas boriding using volatile boron compounds containing boron-oxygen and/or boron-nitrogen bonds
US7264682B2 (en) 2002-11-15 2007-09-04 University Of Utah Research Foundation Titanium boride coatings on titanium surfaces and associated methods
US20050208213A1 (en) * 2002-11-15 2005-09-22 University Of Utah Research Foundation Titanium boride coatings on titanium surfaces and associated methods
US20060074491A1 (en) * 2004-09-30 2006-04-06 Depuy Products, Inc. Boronized medical implants and process for producing the same
US20070018139A1 (en) * 2005-05-10 2007-01-25 Chandran K S R Nanostructured titanium monoboride monolithic material and associated methods
US20070235701A1 (en) * 2005-05-10 2007-10-11 Chandran K S R Nanostructured titanium monoboride monolithic material and associated methods
US7459105B2 (en) 2005-05-10 2008-12-02 University Of Utah Research Foundation Nanostructured titanium monoboride monolithic material and associated methods
US7501081B2 (en) 2005-05-10 2009-03-10 University Of Utah Research Foundation Nanostructured titanium monoboride monolithic material and associated methods
US20090293993A1 (en) * 2008-05-28 2009-12-03 Universal Global Products, Llc. Boronization Process and Composition with Improved Surface Characteristics of Metals
US8187393B2 (en) 2008-05-28 2012-05-29 Universal Global Products, LLC Boronization process and composition with improved surface characteristics of metals
US20100176339A1 (en) * 2009-01-12 2010-07-15 Chandran K S Ravi Jewelry having titanium boride compounds and methods of making the same
US8316679B2 (en) 2010-10-04 2012-11-27 Siemens Industry, Inc. Boronized laying pipe

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