Effect of sputtering time on the microstructure and properties of MAO/CoCrFeNi composite coatings on TC11 alloy

Abstract

In order to further improve the wear resistance and high-temperature oxidation resistance of titanium alloys, MAO/CoCrFeNi composite coatings with different sputtering times were prepared on TC11 alloy by micro-arc oxidation combined with radio frequency magnetron sputtering. The microstructure and phase composition of the composite coatings were investigated by scanning electron microscope and X-ray diffractometer. The wear performance at different temperature and high-temperature oxidation resistance of the composite coatings were studied. The results showed that as the sputtering time increases, the phase structure of composite coatings were all FCC phase, and the number of micropore on the composite coatings decreased; At room temperature, since the film thickness is proportional to the hardness, and higher hardness is conducive to the reduction of actual contact area between coating and grinding ball, so the composite coatings sputtered for 6 h had the narrowest wear scar width and the smallest wear weight loss, and its wear mechanisms were oxidative wear and adhesive wear; At 673 K, since the softening of the abrasive chips played a lubricating role, the composite coatings sputtered for 4 h produced the most abrasive chips, so it had the narrowest wear scar width and the smallest wear weight loss, and the wear mechanisms were mainly oxidative wear and adhesive wear, with slight abrasive wear; The composite coatings sputtered for 6 h was still tightly bonded to the substrate after oxidation at 1000 K, and its weight gain is smaller than TC11, which indicated that it has the best high-temperature oxidation resistance.

Keywords

• Micro-arc oxidation
• Magnetron sputtering
• CoCrFeNi high entropy film
• Wear resistance
• High-temperature oxidation resistance