Effects of sinterability of YSZ powder and NiO content on characteristics of Ni-YSZ cermets

The sintering characteristics and physical properties of Ni/YSZ cermets were investigated in connection with the sinterability of YSZ powders and the amount of NiO. Commercial YSZ and pre-calcined YSZ were used for the cermets. The sintering shrinkage of Ni/YSZ powder was affected by the kind of YSZ powder and the amount of NiO. The effects of the amount of NiO on the sintering shrinkage was higher for the cermets made from commercial YSZ. In the sintering region, the shrinkage characteristics were revealed to be affected predominantly by the amount of NiO. The constants in the sintering equation were determined and the equations were revealed to express the actual shrinkage behavior well. Conductivity as well as porosity were improved by the use of pre-calcined YSZ powder, and these improvements were derived from the decrease of the shrinkage caused by the degradation of the YSZ powder and the formation of a distinct Ni metal network between YSZ granules. (C) 1998 Elsevier Science B.V. All rights reserved.