| 摘要 |
PURPOSE:To form a thermally sprayed film which is dense and has excellent adhesive power, corrosion resistance and wear resistance by enclosing the circumference of a plasma flame with a shielding gas such as air at the time of subjecting powder of a high melting point material such as oxide ceramics to plasma thermal spraying. CONSTITUTION:A shielding gas unit 12 is mounted on a spraying gun head 1 and the plasma flame 2 is injected from a flame nozzle 3 at the time of subjecting the powder of the high melting point oxide ceramics such as Al2O3, ZrO2 or Y2O3 to plasma thermal spraying. The powder 4 of said ceramics is simultaneously fed by a small amt. of a carrier gas 4a into the plasma flame 2 and the shielding gas 11 such as air introduced from an introducing pipe 13 in the side part of the shielding unit 12 is ejected in parallel with the flame 2 from many fine pores 16 provided at the bottom end face of the shielding unit 12 at the same speed as the speed of the flame 2. A reduced pressure state is thereby maintained around the flame 2. The thermally sprayed film 18 of the oxide ceramics having the high m.p. is thus formed on a material 17 for thermal spraying without lowering the temp. of the flame 2. |
