2016-08-242016-08-241996-10-15http://hdl.handle.net/10919/72324Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) protective coatings have been developed for both dense and porous substrates, such as SiC and Si.sub.3 N.sub.4, using a chemical solution processing method involving the hydrolysis and condensation of magnesium, aluminum and titanium precursors. The solution viscosities, pH values, H.sub.2 O/alkoxide molar ratios, and dip coating withdrawal rates which are optimum for crack-free Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) are 1.0 to 6.2 cP, pH 1-4.5, molar ratio 1.5-10, and withdrawal rate of 2.2-8.0 cm/min, respectively. Conversion of the amorphous coating to crystalline Mg.sub.x Al.sub.2-2x Ti.sub.1+x O.sub.5 (x.ltoreq.0.2) is achieved by a succession of calcination below 450.degree. C. and a final heat treatment above 1000.degree. C. for ten hours with controlled heating and cooling rates.application/pdfen-USPatenthttp://pimg-fpiw.uspto.gov/fdd/45/652/055/0.pdf8396242106/286.2106/286.4106/286.5427/430.1427/226501/127501/128501/131501/134501/136C01G23/003C01P2006/22C01P2006/32C04B35/478C04B35/6264C04B41/009C04B41/5041C04B41/87C04B41/4537C04B41/4554C04B41/463C04B41/5016C04B35/565C04B35/584C04B38/00C04B2235/3206C04B2235/441C04B2235/443C04B2235/656C04B2235/6562C04B2111/00112C23C18/1216C23C18/1254C23C18/1283C23C18/12955565245