Study Of Ni-Al System Intermetallic Coating By Plasma Cladding

Ni-Al intermetallic compound has a good resistance to the high temperature oxidation and has a good mechanical behavior ender high temperature. As a high temperature construction material and a coating material, it has a good application foreground.In this discourse, thermal explosion compound technology is adopted for the first time to obtain Ni-Al intermetallic compound, because the traditional plasma melting intermetallic compound has some limitations. The coating structure is not compact, nonuniform as well as the coating material has a oversized loss. The melting point of the Ni,Al reaction system can be reduced by appending Fe with different match to the system. It also can improve the coating combining condition of the Ni-Al systematic intermetallic compound. Finally the intermetallic compound is melted to the basal body of Q235 steel. Comparing the coating material with different match in the reacting system, we can have a exploration to the ideal coating system.In this experiment, various analytical methods are used such as light microscope, SEM, microhardness instrument and X-ray diffraction meter to analyse the acquired sample. The result shows that:When the Ni-Al mixed-powder has different match, the cladding coating ingredient of the intermetallic compound is different, and the quality of the obtained coating surface is different too. The test indicates that good coating quality can be obtained when the percent rate of the Ni powder is 50%wt or 75%wt. The obtained coating component is NiAl intermetallic compound when the percent ratio of Ni is 50%wt, and the obtained coating component is Ni₃Al and NiAl₃ when the percent ratio is 75%wt.The Fe under different match is appended when the Ni-Al mass ratio is 2:1, and the obtained coating contains two intermetallic compound-NiAl and Fe₃Al. By hardness analyzing, both of the two intermetallic compounds can improving the surface hardness of the basal body obviously.This paper also analyse the influence on the cladding coating under different parameter by the plasma equipment. it shows that the composition of the coating remains the same under different parameter ,but the microscopic structure of the coating is changed a lot.