低压冷喷涂铝涂层微观结构与沉积特性研究

低压冷喷涂技术是一种不同于高压冷喷涂技术的新型喷涂工艺。本文以体积比为3:7的氧化铝粉末和铝粉的混合粉末为原料,以压缩空气为工作气体,利用低压冷喷涂设备在Q235钢基体上制备Al涂层,研究了温度、喷距、送粉速率和喷嘴横向移动速度等工艺参数对涂层沉积效率的影响。采用光学显微镜、扫描电镜,研究了涂层的微观结构和沉积特性。实验结果表明:在工作气体压力保持0.6 MPa不变的情况下,温度400℃、喷距25 mm、送粉速率为30—40 g/min、喷嘴横向移动速度4.0 m/min时,铝涂层沉积效率最佳;同时Al2O3陶瓷相的加入有利于涂层的沉积。

Research on Microstructure and Deposition Mechanism of Aluminium Coatings Prepared by Low Pressure Cold Spray

The low pressure cold spray is a new spray technology,which is different from the high pressure cold spray,in aspects of temperature,spraying distance,powder feeding rate and traverse speed as the main technology parameter.With the mixture of aluminium powder and the alumina powder as raw material and compressed air as the working gas,aluminium coating was prepared on Q235 steel substrate by low-pressure cold spray equipment.The effect of technology parameter on deposition efficiency of aluminum coating was studied and the microscopic structure and depositional mechanism of aluminum coating were investigated by means of optical microscopy,scaning electron microscope and X-ray diffraction.The results show that at 400 ℃,in spraying distance 25mm,feeding rate 30.6 g/min and traveres speed 4.0 m/min,the depositing efficency reaches the highest provided the pressure of working gas keeps under 0.6 MPa and aiumina as the ceramic phase may contribute to coating deposition.