Nano-indentation of SiC and Si{sub}3N{sub}4/SiC ceramic materials

摘要

The present paper deals with the nano-indentation of SiC-micro and Si{sub}3N{sub}4/SiC-micro/nano ceramic materials. The investigated SiC-micro and Si{sub}3N{sub}4/SiC-micro/nano ceramics were prepared by liquid phase sintering. Liquid phase was formed from different sintering additives (Y{sub}2O{sub}3, Yb{sub}2O{sub}3, Sm{sub}2O{sub}3). In the case of Si{sub}2N{sub}4/SiC-micro/nano ceramics the SiC nano-grains were created from SiNC amorphous powder. SiNC precursor decomposed to SiC and Si{sub}3N{sub}4 particles during sintering. The comparison of nano- and macro-hardness of investigated ceramic materials showed that nano-hardness is significantly higher. The indentation modulus correlated with the measured nano-hardness. Remarkable influence of grain boundaries and SiC nano-inclusions on hardness was observed.