发动机用镍合金表面烧结制备Cr_(3)C_(2)涂层组织和摩擦性能分析

Microstructure and friction properties analysis of Cr_(3)C_(2) coating on Ni alloy surface prepared by sintering

运用等离子喷涂工艺与电接触烧结技术在发动机用镍合金表面制备Cr3C2涂层,同时对涂层显微组织、耐磨性及力学性能进行了测试分析。研究结果表明:采用电接触烧结工艺制备的涂层孔隙率比等离子喷涂工艺制备的更低,基体内形成均匀分布的碳化物,涂层组织的致密度获得显著提高。采用电接触烧结方法可以显著提高涂层结合强度。涂层的摩擦因数随温度先增加后降低;在各温度下涂层磨损率基本保持稳定。试样磨损形貌在室温至400℃之间并未发生明显变化,当温度到达600℃时引起基材与涂层的氧化和氟化物软化,并生成更多氧化物。随温度增加,Cr3C2涂层磨损面中Cr和C元素先增加后降低,O元素先降低后增加。

The Cr_(3)C_(2) coating was prepared on the surface of nickel alloy used in engine by plasma spraying and the electric contact sintering. The microstructure, wear resistance and other mechanical properties of the coating were tested and analyzed. The results show that the porosity obtained by electrical contact sintering is lower than that obtained by the plasma spraying, and some well-distributed carbides are formed in the substrate, and the density of coating microstructure is significantly increased. The electrical contact sintering method can significantly improve the bonding strength of coating. The friction coefficient increases firstly and then decreases with the changing of temperature. The wear rate of coating remains basically stable at each temperature. The wear morphology of samples does not change significantly between room temperature and 400 ℃. When the temperature reaches 600 ℃,oxidation of the substrate and coating is caused, and fluoride is softened and more oxides generates. With the increasing of temperature, Cr_(3) and C_(2) elements in the wear surface of Cr_(3)C_(2) coating first increase and then decrease,while O element shows first decreases and then increases.