A new hot dip Zn-5%Al-0.3%Mg alloy coating was performed on cold rolled common steel. The hot-dip process was executed by self-made hot dip galvanising simulator (China patent, No.201010160353). The corrosion resistance of alloy-coated steels was detected by neutral salt spray test . SEM and EDS test results demonstrate that Mg is mainly distributed in the crystal boundary. XRD test results shows corrosion product of Zn-5%Al-0.3%Mg alloy coating is mainly Zn5(OH)8Cl2•H2O. The characteristic of Zn5 (OH)8Cl2•H2O is dense and insoluble, so it is protective. In order to study the anticorrosion mechanism, all the tests of the Zn-5%Al-0.3%Mg alloy were carried out with Zn-5%Al coating together.

Hot-dip galvanized steels are widely used in modern industry. The corrosion resistance and formability of them are closely related to the thickness and cross section microstructure of the hot-dip coating. In this paper, the effects of Si and RE on the thickness of Zn-6Al-3Mg alloy coating (ZAM) were investigated. Steel sheets were coated by using an experimental hot-dip galvanizing simulator. The thickness and cross section microstructure of ZAM coating alloyed with different content of Si and RE were characterized by using optical microscope and SEM, and element distribution was study by EDS. The results demonstrated that the reaction between Al from the bath and Fe form the steel sheets was suppressed by the addition of 0.1 wt. % Si to the Zn-6Al-3Mg bath, and the addition of RE effectively decreased the thickness of coating by means of improving the flowing property of the zinc alloy bath. Under the combined effects of Si and RE, the thickness of Zn-6Al-3Mg alloy coating went down from 33 μm to 10.1 μm.

High current pulsed electron beam (HCPEB), a novel high-power energetic beam technology, has been developed as a useful tool for surface modification of materials. In the present work, the effect of HCPEB treatment on microstructure and wear resistance of Al-15Si and ZK60-1Y Mg alloys was investigated. The results show that a supersaturated solid solution of (Al) and (Mg) is formed on top surface of melted layer induced by rapid heating and cooling during HCPEB process. In addition, the melted layer of approximately 5~11μm thickness is obtained on the ZK60-1Y Mg alloy surface. Wear resistance of Al-15Si and ZK60-1Y Mg alloys are significantly improved after HCPEB treatment. It is demonstrated that HCPEB technology has a good application future in enhancing surface properties of Al-Si and Mg alloys.