PURPOSE: To improve wear resistance of the surface of titanium or a titanium alloy used as a material of e.g. the leisure bicycle parts.
CONSTITUTION: In the method for reforming the surface of titanium or a titanium alloy, the surface of titanium or the titanium alloy is irradiated with high energy density beams while supplying an inert gas to the surface and the irradiated part of the surface is melted. Thereafter, gaseous oxygen or a gaseous assistant contg. oxygen is supplied to the surface in a half-melted state and absorbed and dissolved in the surface layer to form a solid solution so that the concn. of oxygen is increased in the direction from the inside to the uppermost surface to form a gentle hardness gradient within the surface layer. By forming this hardened layer having a gradual hardness gradient from the uppermost surface to the base material and an enough thickness in the titanium or titanium alloy material, the material, in which the pitting is not generated by any severe sliding and which is therefore useful as a material of e.g. the bicycle parts, can be obtained.
UCHIBORI KATSUYUKI
TAMURA ITARU
HAYASHI YUKIHIKO
| JPH01119682A | 1989-05-11 | |||
| JPH0368721A | 1991-03-25 | |||
| JPH04200557A | 1992-07-21 |