Grain size effect on the plasma etching behavior of spark plasma sintered yttria-stabilized zirconia ceramics

Abstract

Yttria-stabilized zirconia (YSZ) ceramics with various grain sizes were fabricated via a spark plasma sintering (SPS), and their plasma etching properties were investigated, particularly focusing on the effect of grain size on plasma etching behavior. All the sintered YSZ ceramics were fully densified (∼99.8 % relative density) and the grain size was varied by controlling the sintering conditions. The plasma etching test was conducted by an inductively coupled plasma (ICP) chamber using CF4. The sintered YSZ ceramics exhibited a low etching rate compared to that of the conventional plasma-resistant materials such as Al2O3 and SiC. The superior plasma erosion resistance of YSZ ceramics can be attributed to the yttrium (Y) enrichment and YF3 formation in the plasma etched surface. Interestingly, the grain size of the YSZ ceramics barely affected the etching depth and mass loss. On the other hand, the surface roughness increased with the increasing grain size. The YSZ ceramics with the large grain size showed a much rough surface after the plasma exposure. The obtained results indicated that the grain size could affect the surface properties of the ceramics during plasma etching, which should be considered when fabricating the future plasma-resistant materials.