US3268372A - Surface hardening of titanium - Google Patents

Surface hardening of titanium Download PDF

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Publication number
US3268372A
US3268372A US307350A US30735063A US3268372A US 3268372 A US3268372 A US 3268372A US 307350 A US307350 A US 307350A US 30735063 A US30735063 A US 30735063A US 3268372 A US3268372 A US 3268372A
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Prior art keywords
titanium
range
temperature
cyanate
surface layer
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Expired - Lifetime
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US307350A
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Brotherton Peter Albert John
Dawes Cyril
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ZF International UK Ltd
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Lucas Industries Ltd
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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
    • C23C8/40—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 liquids, e.g. salt baths, liquid suspensions
    • C23C8/52—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 liquids, e.g. salt baths, liquid suspensions more than one element being applied in one step

Definitions

  • a method in accordance with the invention comprises heating the titanium in a fused salt mixture of potassium and/or sodium cyanide and cyanate at a temperature in the range of 550 C. to 800 C. so as to form a surface layer of titanium combined with nitrogen and oxygen, and maintaining the temperature within said range for sifiicient time to form a surface layer of the required depth.
  • a suitable mixture is 5% to of cyanate and 10% to 30% cyanide by weight.
  • the upper limit of the cyanate range can be increased to 30%.
  • a typical period of time is between two and six hours.
  • titanium was heated to 700 C. and maintained at this temperature for four hours in a fused salt mixture containing by weight 25% sodium cyanide and 10% sodium cyanate, the remainder being alkaline earth metal carbonates, chlorides or oxides. The titanium was then cooled in air or by quenching. A hardened layer was formed which was 0.0-0.4 inch thick and had a hardness of the order of 700 Hv.
  • a method of hardening the surface of titanium comprising heating the titanium in a fused salt mixture of potassium land/or sodium cyanide and cyanate at a temperature in the range of 550 C. to 800 C. so as to form a surface layer of titanium combined with nitrogen and oxygen, and maintaining the temperature within said range for sufiicient time to form a surface layer of the required depth.

Description

3 ,268,372 Ce Patented August 23, 1966 3,268,372 SURFACE HARDENING F TITANIUM Peter Albert John Brotherton and Cyril Dawes, Wednesbury, England, assignors to Joseph Lucas (Industries) Limited, Birmingham, England No Drawing. Filed Sept. 9, 1963, Ser. No. 307,350 Claims priority, application Great Britain, Sept. 12, 1962, 34,801/ 62 4 Claims. (Cl. 148-20) The object of this invention is to provide a convenient method of hardening the surface of titanium.
A method in accordance with the invention comprises heating the titanium in a fused salt mixture of potassium and/or sodium cyanide and cyanate at a temperature in the range of 550 C. to 800 C. so as to form a surface layer of titanium combined with nitrogen and oxygen, and maintaining the temperature within said range for sifiicient time to form a surface layer of the required depth.
It is found that for temperatures in the range 550 C. to 650 C. a suitable mixture is 5% to of cyanate and 10% to 30% cyanide by weight. However, for temperatures in the range 650 C. to 800 C. the upper limit of the cyanate range can be increased to 30%. A typical period of time is between two and six hours.
In one example, titanium was heated to 700 C. and maintained at this temperature for four hours in a fused salt mixture containing by weight 25% sodium cyanide and 10% sodium cyanate, the remainder being alkaline earth metal carbonates, chlorides or oxides. The titanium was then cooled in air or by quenching. A hardened layer Was formed which was 0.0-0.4 inch thick and had a hardness of the order of 700 Hv.
Having thus described our invention what we claim as new and desire to secure by Letters Patent is:
1. A method of hardening the surface of titanium, comprising heating the titanium in a fused salt mixture of potassium land/or sodium cyanide and cyanate at a temperature in the range of 550 C. to 800 C. so as to form a surface layer of titanium combined with nitrogen and oxygen, and maintaining the temperature within said range for sufiicient time to form a surface layer of the required depth.
2. A method as claimed in claim 1 in which the temperature is in the range 550 C. to 650 C., the cyanate range is from 5% to 10% by weight, and the cyanide range is from 10% to 30% by weight.
3. A method as claimed in claim 1 in which the temperature is in the range 650 C. to 800 C., the cyanate range is from 5% to 30% by weight, and the cyanide range is from 10% to 30% by Weight.
4. A method as claimed in claim 1 in which said time is between one and twenty four hours.
References Cited by the Examiner UNITED STATES PATENTS 2,453,896 11/1948 Dean 1486.11 2,892,743 6/1959 Griest et a1 148-315 X 2,927,875 3/1960 Muller 148l5.5
DAVID L. RECK, Primary Examiner.
C. N. LOVELL, Examiner.

Claims (1)

1. A METHOD OF HARDENING THE SURFACE OF TITANIUM, COMPRISING HEATING THE TITANIUM IN A FUSED SALT MIXTURE OF POTASSIUM AND/OR SODIUM CYANIDE AND CYANATE AT A TEMPERATURE IN THE RANGE OF 550*C. TO 800*C. SO AS TO FORM A SURFACE LAYER OF TITANIUM COMBINED WITH NITROGEN AND OXYGEN, AND MAINTAINING THE TEMPERATURE WITHIN SAID RANGE FOR SUFFICIENT TIME TO FORM A SURFACE LAYER OF THE REQUIRED DEPTH.
US307350A 1962-09-12 1963-09-09 Surface hardening of titanium Expired - Lifetime US3268372A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB3480162 1962-09-12

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3643658A (en) * 1968-09-03 1972-02-22 Straumann Inst Ag Implants of titanium or a titanium alloy for the surgical treatment of bones
US3915758A (en) * 1972-05-04 1975-10-28 Metal Leve Sa Surface hardening of aluminum alloys
FR2461762A1 (en) * 1979-07-21 1981-02-06 Mtu Muenchen Gmbh PROCESS FOR MANUFACTURING TURBINE BLADES
US5525165A (en) * 1994-06-06 1996-06-11 National Science Council Method of surface modification of titanium alloy
US20040040630A1 (en) * 2002-09-04 2004-03-04 Parker Netsushori Kogyo K.K. Method of producing metal member with enhanced corrosion resistance by salt bath nitriding

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2453896A (en) * 1942-06-26 1948-11-16 Chicago Dev Co Treatment of titanium
US2892743A (en) * 1953-01-29 1959-06-30 Andrew J Griest Surface hardening of titanium
US2927875A (en) * 1957-06-26 1960-03-08 Degussa Process for carburizing and carboni-triding iron and steel

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2453896A (en) * 1942-06-26 1948-11-16 Chicago Dev Co Treatment of titanium
US2892743A (en) * 1953-01-29 1959-06-30 Andrew J Griest Surface hardening of titanium
US2927875A (en) * 1957-06-26 1960-03-08 Degussa Process for carburizing and carboni-triding iron and steel

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3643658A (en) * 1968-09-03 1972-02-22 Straumann Inst Ag Implants of titanium or a titanium alloy for the surgical treatment of bones
US3915758A (en) * 1972-05-04 1975-10-28 Metal Leve Sa Surface hardening of aluminum alloys
FR2461762A1 (en) * 1979-07-21 1981-02-06 Mtu Muenchen Gmbh PROCESS FOR MANUFACTURING TURBINE BLADES
US5525165A (en) * 1994-06-06 1996-06-11 National Science Council Method of surface modification of titanium alloy
US20040040630A1 (en) * 2002-09-04 2004-03-04 Parker Netsushori Kogyo K.K. Method of producing metal member with enhanced corrosion resistance by salt bath nitriding
EP1396553A1 (en) * 2002-09-04 2004-03-10 Parker Netsushori Kogyo K.K. Producing metal member with enhanced corrosion resistance by salt bath nitriding
US7217327B2 (en) 2002-09-04 2007-05-15 Parker Netsushori Kogyo K.K. Method of producing metal member with enhanced corrosion resistance by salt bath nitriding

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