ANTICORROSION PROPERTIES OF Zn-Al-Mg-ZnO COMPOSITE COATING PREPARED BY COLD SPRAYING

Two kinds of composite coatings, Zn45Al35Mg5ZnO15 and Zn65Al15Mg5ZnO15, were prepared on steel matrix (Q235) by cold spraying. The Zn, Al, Mg, and ZnO in raw materials were calculated by percentage of mass. The morphology of the original coating was observed by scanning electron microscopy (SEM) and characterized by energy dispersive spectroscopy (EDS). It was found that the microstructures of Zn45Al35Mg5ZnO15 and Zn65Al15Mg5ZnO15 composite coatings prepared by cold spraying were compact without oxidation products, and the plastic deformation of powder particles was significant. The friction and wear test data of the two coatings showed that the Zn45Al35Mg5ZnO15 coating had longer-lasting protective properties and wear resistance under the same conditions. Neutral salt spray test (NSS) and electrochemical accelerated corrosion test were carried out on samples at different time periods. The results of samples' corrosion microstructure and electrochemical curves showed that Zn45Al35Mg5ZnO15 and Zn65Al15Mg5ZnO15 have good electrochemical protection performance, and Zn45Al35Mg5ZnO15 coating has better protection effect.