Use of ultrasound in preparation of powders for plasma spraying of stabilized zirconium dioxide

The effect of ultrasonic processing on dispergation of dried zirconium-yttrium hydroxide (0.9Zr02x0.1Y2O3) in preparation of stabilized zirconium dioxide powders has been studied. Ultrasonic processing has been carried out at 20 deg C, at normal pressure, with the use of ammonia solution (pH 8.5) as a working fluid. The best powders for plasmic sputtering are obtained, when the ratio solid/liquid phase is 1:3, the time of processing is 5-10 minutes and surface active species are added. The surfactants recommended are polyacrylamide and sodium carboxymethylcellulose salt in amounts 5-10 mg/l. The processing results in 2-3 times smaller average size of particles. The use of powders thus obtained makes it possible to prepare by means of plasmic method coatings with open porosity less than 2.5%