| 摘要 |
PURPOSE:To form a surface coating film of Al2O3 at a high growth rate on a base body by bringing a base material of a sintered hard alloy, etc. heated to a high temp. into contact with reactive gas contg. an adequate amt. of additive such as TiCl4, etc. and consisting of H2, AlCl3, an oxidizing agent, etc. CONSTITUTION:The surface coating of Al2O3 at a high rate of growing the film at which industrial production is permitted is made possible by adding 0.5- 30vol% >=1 kind among TiCl4, ZrCl4 and HfCl4 to the reactive gas consisting of H2, AlCl3, an oxidizing agent and/or hydrolyzing agent in a surface coating method by which a base material consisting of a sintered hard alloy, cermet or ceramics heated to 500-1,500 deg.C is brought into contact with the above-mentioned reactive gas and Al2O3 is coated on the surface of said substrate. If the amt. of the TiCl4, etc. to be added is <=0.5%, the growing rate of the film depends on the concn. of the TiCl4, etc. and therefore such amt. is undesirable. If >=30%, the hardness of the Al2O3 coated film decreases considerably and therefore such amt. is undesirable. |
