| 摘要 |
PROBLEM TO BE SOLVED: To obtain a film excellent in thermal conductivity, heat resistance and erosion resistance by plasma-spraying Cr3C2 cermet on the surface of a heat resistant metallic member in an inert gas atmosphere which does not contain oxygen and changing a part or the whole of metallic Cr in the sprayed coating into chromium carbide. SOLUTION: A Cr3C2 cermet material using Cr or a Cr alloy (such as Cr-Ni, Cr-Co or the like) as a binder metal is plasma-sprayed in an inert gas atmosphere of He or the like which does not contain oxygen, which is held at 500 to 900 deg.C for >=10 min to obtain cermet sprayed coating having 1100 to 1250 Hv hardness. The amt. of the binder metal to be added is desirably controlled to 5 to 60 wt.%. Prior to the thermal spraying working, the body to be thermal- sprayed is heated at 500 to 900 deg.C to improve the adhesion of the sprayed coating. The pressure in the thermal spraying atmosphere is 50 to 1100 hPa. For the purpose of improving its erosion resistance, the thickness of the Cr3C2 cermet sprayed coating is preferably controlled to 50 to 800μm. It is suitable for surface treated coating for the protecting tube of a thermometer.
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