EBSD study on microstructure and crystalline orientation of plasma sprayed molybdenum splat

Atmospheric plasma sprayed molybdenum splats were collected on polished 1Cr13 stainless steel. The morphology, microstructure and crystalline orientation distribution of the splat was characterized by surface profiler, energy dispersive spectrometer (EDS), scanning electron microscope (SEM) and electron-backscattered diffraction (EBSD). The results show that the morphology of splat is flower-like type with spread splashing. Because of substrate melting and droplet impacting, substrate beneath the splat center forms a crater with the average depth of 0.7 μm. Fine columnar grains whose sizes ranging from 0.75 to 9.25 μm with average valve of 2.30 μm form in the central region of splat. The splat has radially elongated grains with sizes between 4.25 to 18.25 μm in the peripheral region. The average grain size of elongate grains is 8.50 μm. The thermal resistance of peripheral region is higher than that of central region due to curling, thus the grain is coarser. Regardless of central region of splat or peripheral region, grains show random crystalline orientation and no evident texture is observed.