| 摘要 |
PURPOSE:To stick tightly alumina to a base material without applying a plast process, by melt-spraying aluminum or a mixture obtained by adding <=30wt% alumina to the aluminum in order to form an intermediate layer. CONSTITUTION:An aluminum base material 1 is formed into a dome and washed. A mixture obtained by adding 15% alumina to aluminum is melt- sprayed to the washed material 1 to form an intermediate layer 3 on the surface of the material 1. Then alumina is melt-sprayed on the layer 3 to form an alumina layer 2. Thus both expansion and shrinkage factors due to the heat produced by the melt-spraying process are almost equal between the material 1 and the mixture since the primary component of the mixture is aluminum. This minimizes the generation of stress. In addition, the coupling force is extremely intensified between the layers 3 and 2 since the empty holes of the layer 3 absorb the stress produced between both layers and at the same time the rough surface of the layer 3 increases the biting and contact areas between both layers. |
