铝合金异形曲面热喷涂涂层的制备及性能研究

Study on Preparation and Performance of Thermal Spraying Coatings onto Aluminum Alloy Abnormity Bent Surface

采用大气等离子喷涂(APS)(液态CO2气化冷却和未冷却)和超音速火焰喷涂(HVOF),在模拟加力泵涡壳的异形铝合金工件内曲面,制备了耐气蚀性较好的3种涂层,并考察涂层和异形曲面基体的结合情况及涂层的相组成、显微硬度和孔隙率。结果表明:HVOF在其焰流无法垂直喷涂的部位涂层与基体结合较差;未使用CO2冷却的APS涂层卷曲,涂层中有明显裂纹;使用CO2冷却的APS涂层与基体结合良好,涂层中没有裂纹,该工艺是目前在铝合金异形曲面制备热喷涂涂层的有效途径。

Three types coating that had fine cavitaion erosion resistance,derived from NiCr feedstock,were fabricated on abnormity bent surface of aluminum alloy workpieces using air plasma spraying（APS） with and without cooling by gasified CO2 and high velocity oxy-fuel（HVOF）.The combination between coatings and substrate,and the composition,microharness and porosity of the coatings were reviewed.The obtained results shows that HVOF sprayed coating has bad combination with substrate where the flame can＇t vertically sprayed on;APS sprayed coating without cooling by gasified CO2 curls and has distinct crack;APS sprayed coating cooled by gasified CO2 has good combination with substrate in anyplace and has not crack.It can be concluded that APS is an effective method to produce functional coatings on aluminum abnormal bent surface at present.