基于冷喷涂工艺的Mg-Zn-Al-Sn-Mn合金防腐Al涂层制备

Fabrication of Al coating for corrosion protection of Mg−Zn−Al−Sn−Mn alloy based on cold spraying process

采用冷喷涂技术在Mg-Zn-Al-Sn-Mn合金表面制备Al涂层,以提高其耐腐蚀性能。研究工作气体温度和压力对Al涂层显微组织和腐蚀行为的影响。结果表明,随着气体温度和压力的升高,Al涂层的致密度和厚度均明显增加。高的气体温度能降低颗粒沉积的临界速度,并提高沉积效率。高的气体压力不仅提升机械结合质量,而且对沉积的涂层具有较强的夯实作用。由于孔隙的减少,Al涂层的耐蚀性随着气体温度和压力的升高而提高。Al(OH)_(3)和Al_(2)O_(3)等腐蚀产物可以堵塞涂层中的孔隙,并作为阻碍腐蚀的物理屏障,从而有效保护Mg合金免受腐蚀。

Al coating was fabricated on the surface of Mg−Zn−Al−Sn−Mn alloy by cold spraying process to enhance its corrosion resistance.The effects of temperature and pressure of working gas on the microstructure and corrosion behaviors of Al coating were investigated.The results show that as gas temperature and pressure increase,the densification and thickness of Al coating obviously increase.High gas temperature declines the critical velocity of powder deposition and increases the deposition efficiency.High gas pressure not only improves the quality of mechanical bonding,but also provides strong tamping effect on the deposited coating.Due to the reduction of porosity,the corrosion resistance of Al coating is improved with the increase of gas temperature and pressure.The corrosion products of Al(OH)_(3) and Al_(2)O_(3) can block the pores in Al coating and act as physical barriers to corrosion,which effectively protects Mg alloy from being corroded.