Investigation of zinc thermal diffused coatings by solid state diffusion method

摘要

One of the most destructive effects of environment on the metal surface is corrosion. The metal surface can be protected against corrosion by forming a high corrosion resistance layer such as zinc coating. In this research, zinc coating on St37 steel samples were formed by thermal diffusion zinc coating method. The substrate sample in contact with powder mixture was heated in resistant furnace using both rotary and fix states. Surface characteristics were studied by optical and scanning electron microscope. Corrosion resistant was evaluated by potantiodynamic polarization technique in 3.5 wt percent NaCl. The present phases in the surface layer were identified using XRD analysis. The results showed that the layer formed by 95:5 Zn:Cr_2O_3 powder mixture at 375+-10 deg C for 2-3 hours had superior corrosion resistant and the layer formed using rotary state had higher quality than layer formed at fix state.