STRUCTURE ANALYSIS OF THE PLASMA SPRAYED Al2O3-SiO2 ON METALLIC SUBSTRATE

The results of investigations of structure of Al2O3 + 30 wt.%, SiO2 oxide layer plasma sprayed onto a steel substrate with a NiCrFeAl transition layer were presented in the work, in which scanning; (SEM) and transmission (TEM) techniques along with electron diffraction (SAED) and analysis of composition in microareas (EDX) were applied. Based on the X-ray phase analysis of the oxide layer at various distances from the Surface it was showed that mulite (25 wt.% SiO2) and corundum (Al2O3 -gamma) was found at 10 mu m depth as well as across the whole 200 mu m thickness of the layer. The change of the background intensity confirmed the occurrence of the amorphous phase. Its appearance was also observed in TEM examinations together with differentiated composition of the phase based on Al2O3 with SiO2 addition.