Abstract: The present invention relates to a method of case hardening a Group IV metal or a Group IV metal alloy and to components hardened in the method. The method comprising the steps of: providing a workpiece of a Group IV metal or a Group IV metal alloy, the workpiece being in its final shape; nitriding the workpiece in a nitriding atmosphere comprising NHs as a nitriding species at a first temperature in the range of 450° C. to 750° C. for a nitriding duration of at least 16 hours to provide a hydrogen containing diffusion zone; removing hydrogen from the hydrogen containing diffusion zone at a second temperature of up to 750° C. and a partial pressure of H2 of up to 10?4 mbar over a hydrogen removal duration of at least 4 hours to provide a hydrogen depleted diffusion zone. The method and the component are useful for implants, in particular dental implants.

Abstract: The present invention relates to a Group IV metal or alloy component having a protective oxide surface layer, the Group IV metal or alloy component having a core hardness, a diffusion zone having oxygen in solid solution in the range of a level providing a hardness of 120% of the hardness of the material core to the saturation level of the Group IV metal or alloy, and a Group IV metal oxide layer at the surface of the component, the diffusion zone being between the Group IV metal oxide layer and the material core. In another aspect, the invention relates to a method of producing a protective oxide surface layer on a Group IV metal or alloy comprising: providing a workpiece of a Group IV metal or alloy, oxidising the Group IV metal or alloy in a first and a second oxidation step.

Abstract: The present invention relates to a method of oxygen hardening a Group IV metal, the method comprising the steps of: providing a workpiece of a Group IV metal in its final shape; oxidising the Group IV metal over an oxidising duration of at least 10 minutes in an oxidising atmosphere at a first temperature to provide a non-stratified Group IV metal oxide on the surface of the workpiece using a gaseous oxidising species having an upper temperature limit of up to 800° C. wherein the first temperature is in the range of 500° C. and the upper temperature limit of the gaseous oxidising species; diffusing oxygen from the non-stratified Group IV metal oxide into the Group IV metal in an inert atmosphere at a second temperature in the range of 500° C. to 800° C. and at a partial pressure of the gaseous oxidising species of up to 10-4 mbar over a diffusive duration of at least 0.1 hour to provide a superficial diffusion zone comprising oxygen in solid solution.

Abstract: The present invention relates to a case hardened component of a titanium alloy, the component having a diffusion zone of a thickness of at least 50 ?l?l, as calculated from the surface of the component, the diffusion zone comprising oxygen and carbon in solid solution and having a distinct phase of a carbo-oxide compound having the composition TiOxC1-x, wherein x is a number in the range of 0.01 to 0.99, which diffusion zone has a microhardness of at least 800 HV0.025 and which carbo-oxide compound has a microhardness of at least 1200 HV0.025. In another aspect the invention relates to a method of producing the case hardened component. In a further aspect the invention relates to a method of oxidising a component of a Group IV metal.

Abstract: The present invention relates to a case hardened component of a titanium alloy, the component having a diffusion zone of a thickness of at least 50 ?ltl, as calculated from the surface of the component, the diffusion zone comprising oxygen and carbon in solid solution and having a distinct phase of a carbo-oxide compound having the composition TiOxC1-x, wherein x is a number in the range of 0.01 to 0.99, which diffusion zone has a microhardness of at least 800 HV0.025 and which carbo-oxide compound has a microhardness of at least 1200 HV0.025. In another aspect the invention relates to a method of producing the case hardened component. In a further aspect the invention relates to a method of oxidising a component of a Group IV metal.

Abstract: A method for method for solution hardening of a cold deformed workpiece of a passive alloy containing at least 10% chromium, which method includes dissolving at least nitrogen in the workpiece at a temperature T1, which is higher than the solubility temperature for carbide and/or nitride and lower than the melting point of the passive alloy, wherein dissolution of nitrogen at temperature T1 is performed to obtain a diffusion depth in the range of 50 ?m to 5 mm, and cooling the workpiece after the dissolution step at temperature T1 to a temperature which is lower than the temperature at which carbides and/or nitrides form in the passive alloy, wherein the cooling step takes place in an inert gas not containing nitrogen. Further, a member, such as a lock washer for securing bolts or nuts prepared using the method.

Abstract: The invention relates to a method for method for formation of expanded austenite and/or expanded martensite by solution hardening of a cold deformed workpiece of a passive alloy, which method comprises a first step of dissolving at least nitrogen in the workpiece at a temperature T1, which is higher than the solubility temperature for carbide and/or nitride and lower than the melting point of the passive alloy, and a subsequent second step of dissolving nitrogen and/or carbon in the work piece at a temperature T2, which is lower than the temperature at which carbides and/or nitrides form in the passive alloy. The invention further relates to a member, such as a lock washer for securing bolts or nuts prepared using the method.

Abstract: A method for method for solution hardening of a cold deformed workpiece of a passive alloy containing at least 10% chromium, which method includes dissolving at least nitrogen in the workpiece at a temperature T1, which is higher than the solubility temperature for carbide and/or nitride and lower than the melting point of the passive alloy, wherein dissolution of nitrogen at temperature T1 is performed to obtain a diffusion depth in the range of 50 ?m to 5 mm, and cooling the workpiece after the dissolution step at temperature T1 to a temperature which is lower than the temperature at which carbides and/or nitrides form in the passive alloy, wherein the cooling step takes place in an inert gas not containing nitrogen. Further, a member, such as a lock washer for securing bolts or nuts prepared using the method.

Abstract: A method of activating an article of passive ferrous or non-ferrous metal by heating at least one compound containing nitrogen and carbon, wherein the article is treated with gaseous species derived from the compound. The activated article can be subsequently carburized, nitrided or nitrocarburized in shorter time at lower temperature and resulting superior mechanical properties compared with non-activated articles and even articles of stainless steel, nickel alloy, cobalt alloy or titanium based material can be carburized, nitrided or nitrocarburized.

Abstract: The invention relates to a method for method for formation of expanded austenite and/or expanded martensite by solution hardening of a cold deformed workpiece of a passive alloy, which method comprises a first step of dissolving at least nitrogen in the workpiece at a temperature T1, which is higher than the solubility temperature for carbide and/or nitride and lower than the melting point of the passive alloy, and a subsequent second step of dissolving nitrogen and/or carbon in the work piece at a temperature T2, which is lower than the temperature at which carbides and/or nitrides form in the passive alloy. The invention further relates to a member, such as a lock washer for securing bolts or nuts prepared using the method.

Abstract: A method of activating an article of passive ferrous or non-ferrous metal by heating at least one compound containing nitrogen and carbon, wherein the article is treated with gaseous species derived from the compound. The activated article can be subsequently carburised, nitrided or nitrocarburised in shorter time at lower temperature and resulting superior mechanical properties compared with non-activated articles and even articles of stainless steel, nickel alloy, cobalt alloy or titanium based material can be carburised, nitrided or nitrocarburised.