long was propelled with 7 5 mm of bore and 6 kg cm 2 of working pressure step 2 plasma spray coating pure metallic material on the surface of parent material the pure metal si was coated to a thickness of 90 microns on the sample pre treated in step 1 in the following manner lcp rev a sulzer metcol was used as the plasma equipment and argon ar was used as the inactive or inert gas with use of twin 100c feeders high purity silicon si powder jungsei was propelled through ar inlet under pressure of 100 mpadml and the plasma spray coating was performed three times each for 20 sec according to the programming to propel the molten powder against the surface of the sample in zigzag pattern the plasma gun and the sample were maintained at a 10 cm distance from each other the sample coated in step 2 was heat treated with a general box type heat treating machine in an inert argon ar gas atmosphere 350 u00b0 c 4 h to prevent oxidation fabrication of zirconium alloy coated with pure metal plasma spray coating except for the variations in the condition of fabrication and coating thicknesses listed in the following table the zirconium alloy coated with the pure metal plasma spray coating was fabricated in the same manner as in example 1 in order to compare oxidation characteristics of the coating layers at high temperature condition only one surface of each of the samples of the example was coated while the other surface was left un.