1993 年 42 巻 478 号 p. 874-880
Low pressure plasma spraying is well suited for high-temperature protective coatings. In this coating process, coating adhesion is an important problem, and so surface roughness and cleaning achieved by the transferred arc method with negative substrate polarity have to be investigated in order to improve adhesion. In this paper, an experimental investigation was conducted to clarify the effect of the transferred arc treatment on the bonding strength of coatings. As a result, it was verified by SEM micrographs that the oxide scales could be removed by the transferred arc and the surface roughening effect was remarkable. It was also confirmed that grid blasting before the transferred arc treatment was effective for the uniformity of surface cleaning and roughening, and the thicker preoxidizing treatment was undesirable for the reason of insufficient surface cleaning. Namely, it was clear that the bonding strength of coatings was improved constantly by the grid blasting before the transferred arc treatment.