effect of niti addition on the wear resistance of ysz coatings

In this study,a small fraction of niti particles (5 wt.%) was added to yttria stabilized zirconia (ysz) top coat to improve its sliding wear resistance. the measurement of width of wear tracks after wear tests under a 15 n load for 100 m sliding distances showed that the width of wear track in niti-ysz coating is shorter than that of the ysz coating which depicts the higher wear resistance of niti-ysz coating samples. it is believed that the higher hardness/elastic modulus (h/e)value and pseudoelasticity effect of niti are two important factors which improved the wear performance of applied coatings. also, to evaluate the role of addition of a niti (5 wt%)–ysz buffer layer on the durability of ysz coatings during wear operation, wear tests with a 20 n normal load and with a constant frequency were conducted on coated samples. it was observed that the conventional ysz coating cracked and delaminated after about 60 m sliding distance. however, in samples which contain a niti (5 wt%) –ysz buffer layer, delamination was not observed until 100 m sliding distance which is attributed to the ability of niti for accommodation of interface stresses and hindering of premature delamination during wear test under higher loads.