| 摘要 |
PURPOSE:To easily obtain a heat insulating thermally sprayed layer which is uniform, has a high porosity and excellent in the thermal insulation property and, further, to improve the adhesive strength of the boundary between a base layer and the heat insulating thermally sprayed layer and the oxidation resistance, as well. CONSTITUTION:The base layer 11 is formed on a base material 10 and the thermally sprayed layer 12 of fine ceramic powders excellent in the thermal insulation property is formed thereon and further, powders mixed with the ceramic powders excellent in the thermal insulation property and a specific amount of Si3N4 powders is melt-sprayed to form the thermally sprayed layer 13 having a high porosity. The Si3N4 powders in the mixed powders are heated to a high temperature in the plasma-thermal spraying process and then gasified. Consequently, many porosities remain in the thermally sprayed layer 13 formed in the above-mentioned manner developing the thermally sprayed layer having a high porosity and excellent in the thermal insulation property. On the other hand, since the thermally sprayed layer 12 is dense, it tightly adheres to the base layer 11 and excellent in resistance to oxidation, as well. |
