The authors, et al. have succeeded in the practical application of the abradable flame spray coating, used in aircraft engines for the prevention of air leakage and the improvement of efficiency, to automobile turbochargers for the first time in the world.
Two layers consisting of a bond coated layer and an abradable layer used to be coated by separate spray nozzles under the conventional technique.
In this paper, equations of relations between various flame spray coating conditions and the quality of coated film, which were derived from measured results, will be described. Flame spray coating conditions, that allow the double layer coating by the same spray nozzle, have been determined for each layer. Temperatures and speeds of the flame were measured by means of two-color type high-speed cameras, and equations of their relations with the flame spray coating conditions are derived from the measured result. Melting conditions of spray powders were also considered based on the foregoing, and the validity of flame spray coating conditions determined under this study is verified.