Research on secondary friction coating aluminizing and induction heat diffusion process

Friction coating aluminizing is a new type of metal coating preparation technology that allows molten aluminum to adhere to the surface of the substrate material through friction heat generation. It can improve surface properties without changing the matrix material, such as corrosion resistance, oxidation resistance and other properties. Due to the low aluminum content attached to the substrate surface, the thickness of the subsequent FeAl alloy layer is insufficient. This article studies the effect of secondary coating method on friction coating aluminizing and induction heating process, as well as the phase composition of the coating.The experimental results show that under a single coating test, a coating with a thickness of about 55 μm can be prepared at 600 °C, and a coating with a thickness of 60 μm can be prepared at 800 °C. The hardness of the coating gradually increases from 260 HV to 590 HV from the inside out, and the coating is a composite coating of solid solution aluminum→Fe3Al → FeAl. Under secondary coating method, a coating with a thickness of about 65 μm can be prepared at 600 °C, while a coating with a thickness of about 110 μm can be prepared at 800 °C. The hardness of the coating gradually increases from 290 HV to 660 HV from the inside out, and the coating is a composite coating of solid solution aluminum→Fe3Al → FeAl→Fe2Al5. This method can prepare a ductile FeAl alloy layer dominated by low aluminum phase in a short time.