| 摘要 |
PURPOSE:To obtain a thermal spraying layer which is dense and excellent in the bonding strength in case of forming a coated layer such as ceramic on the surface of metal with a plasma thermal spraying method by heating previously the surface of the above-mentioned metal in the vacuum and performing the thermal spraying in the prescribed degree of vacuum. CONSTITUTION:The surface of metal is previously heated in the vacuum and a ceramic layer, a metallic layer, a ceramic-metal composite single layer or multilayer is formed thereon by the plasma arc thermal spraying in <=200Torr vacuum and the porosity is regulated to <=3%. In such a way, when heating the surface of a metallic base material in the nonoxidizable atmosphere such as the vacuum, the surface is clearly kept and the bonding strength of the heated thermal spraying layer is made high. Also the oxidation of the above-mentioned base material is suppressed by keeping <=200Torr vacuum and the flow velocity of the plasma jet can be made high, and the thermal spraying layer excellent in the bonding strength is obtained. Furthermore when the porosity is regulated to <=3%, even if holding it at high temp. for a long period, the inner oxidation is hardly caused between the base material and the thermal spraying layer and the trouble such as the peeling is not caused and besides the increase of the elaboration and the bonding strength is easily attained with the post- treatment. |
