Abstract
Heat-resisting characteristics at temperatures between 900-1000°C, of the steel plate coated with ceramics by flame spraying were studied, and the following result was obtained. Flame spraying was carried out by powder method or rod method.
1. Steel plate coated with fused Al2O3 is nearly 3 times more resistant to oxidation than bare steel. But the coating technique in this case is not easy and the film is liable to strip out.
2. When metallic Cr is added to Al2O3, the porosity of the film is reduced and the oxidation resistivity is increased. The maximum of the porosity was found between the Cr content of 20-50%.
3. The film is more closely adhered if the steel surface is at first covered with Fe-Al alloy and the flame spray is carried out on the alloy. Covering with Co metal with electroplating gives nearly the same effect.
4. When the fused Al2O3 tube connected through hole with metal wire is used as spraying rod, very resistant coating is obtained as in the case of (2).
