Abstract:
Agglomerated YSZ (Y2O3 partially stabilized ZrO2) particles with 0wt%, 1wt%, 2wt% and 3wt% of whiskers (named as 0#,1#, 2# and 3# powders, respectively) were prepared by spray granulation technology. Four groups of coatings (0#, 1#, 2# and 3# coating) were prepared by APS (atmospheric plasma spraying). The dispersion and quantitative characterization of SiC whiskers, morphology of agglomerated particles and microstructure of the coatings were studied by SEM (scanning electron microscopy) and light-optical microscopy, and the forming process of the coating containing SiC whiskers was analyzed. The result shows that as the stirring time increases to 5 h, the whiskers show better dispersion and the corresponding area percentage of whiskers of the specimen is 11.03%. The particles containing whiskers are mainly “droplet shaped” and “spindle shaped”, and the percentage of these two streamlined particles in 1#, 2# and 3# powders is 16.5%, 22.7% and 39.3%, respectively. Due to the obstructing effect of non-horizontal state whiskers on impacting and spreading process of unmelted raw powders, the porosity increases as the whiskers content increases. The porosity of 0# coating is 3.89%, while the porosity of 1#, 2# and 3# coatings is 3.15, 4.17 and 7.52 times larger than that of 0# coating, respectively.