Method of coating titanium and its alloys

DETAILED DESCRIPTION We claim: 1.
A process for improving the wear resistance of titanium and its alloys comprising the operations of coating a surface of a workpiece made of titanium or an alloy of titanium and which is likely to be subject to wear with a layer of a metal selected from the group consisting of aluminium, copper, iron, tin, nickel, platinum, zinc and zirconium, and then subjecting the coated surface to bombardment with ions of a light species the mass of which is insufficient to cause a harmful degree of sputtering of the surface during implantation, so as to cause the metal to migrate into the workpiece.
2.
A process according to claim 1 wherein the metal is tin or aluminium.
3.
A process according to claim 1 or claim 2 wherein the bombarding ion species is selected from the group comprising N.
sup.
+, B.
sup.
+, C.
sup.
+ and Ne.
sup.
+.
4.
A process according to claim 3 wherein the light ion species is N.
sup.
+.
5.
A process according to claim 1 wherein the bombardment with the light ion species is continued until a dose of the order of 10.
sup.
17 ions per cm.
sup.
2 has been implanted into the workpiece.
6.
A process according to claim 1 wherein the temperature of the workpiece is raised to at least 400.
degree.
C.
while it is being bombarded with the light ion species.
7.
A process according to claim 6 wherein the temperature of the workpiece is raised to 600.
degree.
C.
8.
A process according to claim 6 or claim 7 wherein the bombardment with the light ion species is carried out at a power level such as to cause the temperature of the workpiece to rise to the specified level.
9.
A process according to claim 8 wherein the workpiece is bombarded with a beam of ions having an energy of 400 kev and a current density of 30 .
mu.
A per cm.
sup.
2.
10.
A process according to claim 1 wherein the coating is by electron beam evaporation in a vacuum.




Description:
The invention relates to the improvement of the wear resistance of titanium and its alloys.
Titanium and its alloys possess excellent properties as regards lightness and strength, but they are prone to adhesive wear and galling