Processing, microstructure and mechanical properties of yttria stabilized zirconia reinforced hydroxyapatite coatings

It has been proved that adding yttria stabilized zirconia (YSZ) to hydroxya patite (HA) could improve the mechanical properties of hydroxyapatite coati ngs and reduce the formation of calcium oxide which is brittle and not desi rable in HA coatings. In this work, processing, microstructure and mechanic al properties of yttria stabilized zirconia reinforced HA coatings have bee n studied. 30 wt.% yittria stabilized zirconia was added to HA. Two process es were applied. One included ball-milling the mixture of YSZ and HA powder s, then plasma spheroidizing ball-milled powders (BMSP) and spraying of the coating. Another included ball-milling YSZ powders, blending with HA as pu rchased, plasma spheroidizing blended powders (BSP) and spraying of the coa ting. Experimental results showed that mechanical properties of the BMSP an d BSP coatings were improved significantly, comparing to the pure HA coatin g. HA/YSZ solid solution formed and played a very important role in mechani cal properties of yttria stabilized zirconia reinforced HA coatings. HA/YSZ solid solution in BSP coating was more than that in BMSP coating, and the properties of BSP coating were better than that of BMSP coating. Tensile te sts showed that unmelted YSZ particles were the potential weakness of the y ttria stabilized zirconia reinforced HA coatings. (C) 2001 Elsevier Science B.V. All rights reserved.