Estimation of the coating/substrate interface temperature during deposition by impulse plasma excitation

Abstract

The metallic coatings of the complex FeCoNiAlCuTi alloy were deposited by the impulse plasma method under the following conditions : the capacitance of the condenser battery : 200 μF; the discharge voltage : 8 kV; the plasma gas (hydrogen) pressure : 20 Pa; the plasma impulse duration : 100 μs; the frequency of impulse repetition: 0.1 Hz; and a total impulse number of about 1000. The coatings were deposited on titanium and molybdenum substrates. The substrates were not heated by any external heat source, but they were heated only by the impulse plasma itself. It was found previously that the stationary temperature of the substrate was not higher than 500 K in the near surface area. In this work based on the material examinations and approximative calculations, the coating/substrate interface temperature was estimated as high as 1000 K during the plasma impulse. It means that the heat state of the substrate is more complex than it was supposed previously. The present studies show that the interface temperature depends on the thermal properties of the coating/substrate pair of materials.