EFFECT OF SUBSTRATE-TEMPERATURE ON SPLATT ING BEHAVIOR OF PLASMA-SPRAYED NI PARTICLES

Size-restricted Ni powder particles were plasma sprayed on the flat SU S304 substrate surface, and the effect of substrate temperature on the splatting behavior of the particles was evaluated. The results obtain ed are summarized as follows: 1) In the splat behavior of Ni powder on the heated SUS304 substrate, intense splashing of the powder was obse rved in the substrate temperature range up to 573 K. The splashing beh avior, on the other hand, did not occur in the substrate temperature r ange over 623 K. 2) Transition temperature, Tt, was defined in this st udy, on which the powder's splat pattern changed to the form without s plashing from the one with splashing. Tt was about 600 K in the case o f Ni splat on the SUS304 substrate. 3) From the observation results of splat behavior on both the heat-treated substrate at room temperature and the Au coated substrate at elevated temperatures the transition b ehavior of splatting seemed to depend not on the oxide layer formed bu t on the other factors relating to substrate temperature.