| 摘要 |
PURPOSE:To manufacture a coated superhard alloy tool with superior wear and sheat resistance at a low cost by coating the surface of a superhard alloy tool with laminated layers of Al2O3 having different grain sizes with Ti carbide, nitride carbonitride or boronitride in-between. CONSTITUTION:The surface of a superhard alloy tool formed by binding metallic carbide or carbonitride grains of high hardness with an iron group metal is coated with a layer of Ti carbide, nitride, carbonitride or boronitride. The coated tool is then heated and held in a mixed gaseous flow of AlCl3, H2, CO2 and CO. By regulating the heating temp., the pressure of the mixed gaseous flow and the holding time, an inner layer contacting with the Ti compound, an intermediate layer and an outer layer are laminated with hard Al2O3 having <=1mum, 1-5mum and <=1mum grain sizes in 0.5-1mum, 2-4mum and 0.5-3mum thicknesses, respectively. Thus, a superhard alloy tool with superior heat and wear resistances is obtd. using inexpensive Al2O3 in place of expensive metallic carbide, etc. |
