Study On Preparation Of High Temperature And Oxidation Resistance Coating On Pure Titanium Surface By Laser Remelting

Titanium and titanium alloys are an important metal developed in the 1950s.Due to their excellent quality,high strength,corrosion resistance and good bio-compatibility,they are widely used in aerospace,marine,and in the fields of chemical industry and medical equipment,it has created enormous economic and social benefits.However,the high-temperature oxidation resistance of titanium and titanium alloys is poor,especially when the temperature exceeds 600?the oxidation and oxygen embrittlement of titanium and its alloys,which reduce the excellent properties of titanium and titanium alloys,and restrict its use range.Therefore,the surface modification of titanium and titanium alloys,the combination of the matrix and the modified coating,while improving the high temperature oxidation resistance,ensures the excellent performance of the titanium alloy has great and far-reaching significance.In this paper,pure Ti?TA1?was used as the substrate.Pure Al coating and Ni/Al composite coating were prepared on the surface by plasma spraying and arc spraying.Laser re-melted treatment with different parameters was applied to the metallurgy between the coating and the substrate.The reaction was carried out,and the well-reactive coating was subjected to a high-temperature oxidation test at the same time and at different temperatures,and the coating analysis and performance tests were carried out by means of scanning electron microscopy?SEM?X-ray diffraction?XRD?and the like.The microstructure change of the coating under different process parameters,the diffusion law between the elements and the oxidation resistance of the coating after oxidation at different temperatures.The research shows that for pure Al coating,the main phase in the coating is TiAl₃phase,when the reaction is sufficient after laser re-melted treatment.The phase has good resistance to high temperature oxidation.During high temperature oxidation at different temperatures,As an aluminum-rich phase,it can provide enough Al element to combine with O to form Al₂O₃.The formation of Al₂O₃ establishes a continuous and dense oxide film on the surface,thereby slowing down the oxidation rate.For the Ni/Al composite coating,when the reaction is sufficient after laser re-melted,the main phase in the coating is Ni₂Al₃ phase,which has good resistance to high temperature oxidation.After high temperature oxidation at different temperatures,the Ni element in the coating As a barrier layer,the interdiffusion between Ti and Al elements is well blocked,while the surface of the coating forms continuous and dense Al₂O₃ oxide film and a large amount of NiAl phase.The aluminum-rich phase in the surface diffusion layer provides sufficient aluminum for the surface.Provides effective high temperature oxidant protection for pure titanium substrates.