y-tzp has both high sinterability and superior mechanical properties, but the fracture strength is degraded by annealing at such low temperatures as 100 approximately 300 degrees c. in order to improve the heat degradation of tzp containing 3 mol percent -y/sub 2/o/sub 3/, a fabrication technique for surface modification of tzp was developed. the method consists of infiltrating a porous powder compact with open porosity of about 53 percent by the application of y(no/sub 3/)/sub 3/ solution using a suitable brush and subsequently firing at 1400 degrees c in air to decompose the infiltrant and to densify the powder compact. y-tzp surface-modified by infiltration of y(no/sub 3/)/sub 3/ solution did not show the tetragonal to monoclinic zirconia transformation after aging in hot water of 200 degrees c for 100 hours at all even through the examination by thin film x-ray diffraction. therefore, this infiltration technique may prove to be very valuable when designing tzp for structural applications