Experimental study of ceramic coatings on lower-density ceramic substrates

Adhesion and homogeneity of the coating-substrate were analyzed on basis establishment coating mineralogy. Substrate raw materials used kaolin clay a calcined alumina 4 µm; series higher density ceramic coatings deposited using aluminas 0.5 µm µm, silica fume, talc. The dip technique was applied to all substrates later sintered at 1300 ºC. Shrinkage mixtures substrate separately evaluated. X-ray diffraction utilized identify crystalline phases present in coatings, while optical electron microscopy employed for structural characterization coatings. Coatings exhibited lower shrinkage compared substrate. Among specimens that good adhesion, cracks observed extend parallel surface. presence cristobalite indicated failure mechanism involved buckling. crack dimension presented decreased after adding talc mixture.