Speaker
Semin Chun
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.3004.pdf
Surface treatment of coarse Y2O3 ceramic powders by a microwave
plasma torch: Their mobility improvement and densification
S. M. Chun1, Y.C. Hong1
1
Plasma Technology Research Center, National Fusion Research Institute, Gunsan, Korea
In a ceramic powder coating processing, the coarse surface and the pores of small size ceramic
powders (<25μm) are caused to porosity generation problems of coating layer and non-quantitative
feeding rate. These issues are recovered by a thermal sintering technique. In this regard, a microwave
plasma torch is applied to improve mobility and densification of ceramic powders. The microwave
plasma treatment is carried out by suitable reaction conditions, showing both high density and
mobility of ceramic powders. The Y2O3 ceramic powders (Shin-Etsu chemical) were treated by the
microwave plasma torch. The ceramic powders were modified by active species in high temperature
plasma flame of 6000K at atmospheric pressure. Eventually, the coarse surface on the ceramic
powder was modified instantaneously by high chemical reactivity in the plasma, revealing a smooth
surface, functionalization on surface. The treated small ceramic powders lubricate between coarse
powders to improve mobility. In addition, the ceramic powder is polarized on the surface due to the
high chemical reactivity of the plasma, so that the ceramic powders have a high repulsive force. In
this test, the densification and the mobility strongly depend on the applied plasma power and feeding
gas ratio of N2/O2 at a fixed powder feeding rate. The experimental results show that the microwave
torch plasma will be attractive for a sintering process, which is necessary for short treatment time and
high heat flux.
Figure 1. The Y2O3 powder images of before and after treated by microwave plasma torch.
References:
1. Rachman, C., Amit, S., Claude, E. (2009) Densification of nanocrystalline Y2O3 ceramic powder by spark
plasma sintering, Journal of the European Ceramic Society., 29, 91-98.
