FABRICATION AND PROPERTIES OF (Y, CE)-TZP AL2O3 SUBSTRATES

The effect of alumina content on the electrical and thermal properties of substrates consisting of tetragonal zirconia polycrystals and various volume fractions of Al2O3 was studied. The substrates were fabricated by the doctorblade casting, using an Al2O3 powder and coprecipitated zirconia powders with compositions 4 mol%YO1.5-4 mol%CeO2-ZrO2 and 3 mol%Y2O3-ZrO2, and their surface roughness and microstructure were investigated. The average surface roughness (R(a)) of the substrates was smaller than 0.1-mu-m. The dielectric constant (e), dielectric loss tangent (tan-delta) and thermal expansion coefficient of the substrates decreased with increasing alumina content. The volume resistivity of the substrates was not sensitive to the alumina content in the range of 33.9 to 69.8 vol%. It depended on the volume resistivity of TZP.