Microstructure and performance of YTaO4 coating deposited by atmospheric plasma spraying on TC4 titanium alloy surface

Abstract

In view of the good thermal insulation , good high-temperature phase stability, high thermal expansion coefficients and ferroelastic transformation of YTaO 4 ceramics, which can be prepared as thermal insulation and anti-oxidation coating material on Ti6Al4V alloy (TC4). Herein, a bond coating (BC, NiCrAlY) and top coating (TC, YTaO 4 ) were deposited on a TC4 surface via atmospheric plasma spraying (APS), the microstructure, multi-scale mechanical properties and failure mode of TC were investigated. XRD results demonstrate YTaO 4 coating has good phase stability below 900 °C, both average particle size and intrinsic strain are calculated by Williamson-Hall (W H) method. The surface hardness, wear resistance and service life of YTaO 4 coating deposited on TC4 is higher than that of pure TC4, and thermal shock tests results (>300 times at 900 °C; 269 times at 1000 °C; 79 times at 1100 °C) exhibits YTaO 4 coating has an excellent protective effect against thermal shock and oxidation for TC4. • Thermal shock tests results (>300 cycles at 900 °C) exhibits that YTaO 4 coating has an excellent protective effect against thermal shock and oxidation for TC4 • YTaO 4 coating has good phase stability below 900°C. • The hardness of both bond coating and top coating is higher than that of the TC4. Young's modulus(88 to180 GPa) of YTaO 4 coating is much lower than that of YSZ (210 and 250 GPa) • Failure mode of YTaO 4 coating after the thermal shock test includes longitudinal cracks in coating, phase transformation, stress relief and thermal expansion coefficient mismatch.