3 / 2017-03-17 14:59:15

Preparation and Properties of Composite Coating on Ti6Al4V by Micro-arc Oxidation and Sol-gel with Au Particles

Ti6Al4V；micro-arc oxidation；sol-gel；ZrO2；Au particles

Ti6Al4V alloy is easy to be oxidized at high temperature and in general it cannot work over 500℃. In order to improve its application range, micro-arc oxidation (MAO) was used to produce ceramic oxide layer which acted as the oxygen barrier and heat insulating on the surface of Ti6Al4V alloy. On the other hand the MAO layer, grew from the Ti substrate, can be used as the bonding layer of the thermal barrier coating ZrO2. Then ZrO2 composite coating was prepared by sol-gel method with the addition of nano Au particles after MAO. The phase structure of the coating was analyzed by XRD, the morphology observed by SEM. The oxidation kinetic curves of coating at 700 ℃ were determined, thermal insulation performance and property of thermal shock had been measured. The results show that the composite coating consisted of outer layer, mainly ZrO2, with the thickness of 100 μm the inner layer Al2O3 with about 10μm. The weight gain of oxidation after 200h at 700℃ of titanium alloy with composite coating is only 14% of that Ti6Al4V alloy. Thermal insulation property of the composite coatings has improved significantly. And thermal shock property was improved by the addition of Au particles.