Wettability, surface tension, and reactivity of the molten manganese/zirconia-yttria ceramic system

A basic research study for improvement of plasma-sprayed zirconia coatings has been conducted. The contact angle and surface tension of the molten manganese/zirconia-yttria ceramic system were measured at 1573 K by the sessile drop method, suggesting that molten manganese would spontaneously infiltrate open pores in zirconia coatings. Structure and elementary composition development of zirconia ceramics caused by reaction with manganese were examined by using scanning electron microscopy (SEM), an electron probe microanalyzer (EPMA), and an X-ray diffractometer (XRD). Manganese not only stabilized cubic zirconia but also contributed to the growth and volume increase of zirconia particles. In this article, the mechanism of making zirconia coatings dense with manganese is discussed based on the results of experiments.