| 摘要 |
PURPOSE:To improve the thermal shock resistance and durability of a ceramic surface layer by providing a primary transition layer consisting of Ni-Cr-Al alloy and ZrO2.8Y2O3 on an Al-alloy base material via an undercoat layer and further providing a secondary transition layer in which ceramics with low coefficient of thermal expansion is blended on the above via an intermediate layer. CONSTITUTION:An undercoat layer 11 of Ni-Cr-Al alloy is formed on the surface of a base material 10 made of Al alloy, on which a primary transition layer 12 where Ni-Cr-Al alloy and ZrO2.8Y2O3 are mixed and the proportion of Ni-Cr-Al alloy is decreased with the approach to the outside is continuously formed. Subsequently, an intermediate layer 13 composed essentially of ZrO2.8Y2 O3 is formed, and then, a secondary transition layer 14 in which ceramics of <=9X10<-6>/ deg.C coefficient of thermal expansion and ZrO2.8Y2O3 are mixed and the proportion of ZrO2.8Y2O3 is decreased with the approach to the outside is continuously formed. By this method, thermal stress is reduced when heat cycle is applied, and thermal shock resistance is improved and, as a result, this surface layer has no possibility of causing peeling and falling. |
