抄録
Due to its filterability and thermostability, porous ceramics have a large attention as a suitable material for filters such as a diesel particulate filter. Since damages induced by contact stress on filters cause serious degradation of their strength and life span, the standardization of sphere indentation test is necessity to evaluate the indentation strength of porous ceramics quantitatively. The sphere indentation examination was carried out to investigate the effects of pore diameter on indentation strength under different conditions of indentation sphere sizes and indentation speed. Three porous ceramics were tested; each porous ceramic contains different pore diameter. The result shows that indentation load increased monotonically along with an increase in indentation depth when the porous ceramics has small pore diameter. However, with large pore diameter, the graph of load-displacement displays load increases with vertical fluctuation along with increasing indentation depth. The strength of specimen with large pore diameter relies on indentation sphere size not depending on indentation sphere material. While the fracture strength of specimen with small pore stays constant, the strength of specimen with large pores rises with increasing sphere diameter. The strength of specimen with large pore is also dependent on indentation speed. The strength of specimen with large pore rises in the company of increasing indentation speed, although the strength of specimen with small pore is relatively constant.
