Microstructure and Properties of Al2O3–ZrO2–Y2O3 Composite Coatings Prepared by Plasma Spraying

Abstract

Al2O3–ZrO2–Y2O3 composite coatings were prepared by plasma spraying Al2O3–ZrO2 composite powder with varying amounts of Y2O3. The effects of Y2O3 on the microstructure and properties of the plasma-sprayed Al2O3–ZrO2 composite coatings were investigated, and the results showed that the composition of the composite powder had a significant influence on the microstructure and properties of the Al2O3–ZrO2–Y2O3 coatings. The Al2O3–ZrO2 and Al2O3–ZrO2–Y2O3 coatings were composed of yttria-stabilized zirconia (YSZ), α-Al2O3, and γ-Al2O3. The Al2O3–ZrO2–Y2O3 coating had a lower friction coefficient and wear rate compared with the Al2O3–ZrO2 coating. The Al2O3–ZrO2–Y2O3 coating showed the most uniform and compact microstructure, highest microhardness, good toughness, and adhesive strength when 3 wt.%Y2O3 was added. This method of adding rare-earth Y2O3 to improve the overall performance of Al2O3–ZrO2 coatings has potential application value.