Microstructure And Properties Of Cu-14Al-X Alloy Powder Coatings Prepared By Supersonic Plasma Spraying

The novel kind of aluminum bronze alloy (Cu-14Al-X) powders was produced by water atomization technology in the present test. The main composition of aluminum bronze alloy powders are Cu75～85%, Al12～16%, Fe2.0～4.0%. Other alloying elements are Mn, Ni , Co, etc. Surface morphology, microstructural characteristics, and properties of aluminum bronze alloy powders were studied and tested. And then, welding the powder to the substrate of 45# steel, with the technology of supersonic plasma spraying.The microstructure of coatings were studied by Scanning Electron Microscopy(SEM). The results showed that the microstructure of coatings have the typical characters of thermal spraying. The coatings were deposited by particles which were extended and deformed when they strike on the substrate. And there are also many flaws and holes. Through the analysis of XRD, we could find out that the coatings and particles have the same phases, which were Cu9Al4 , Cu3Al, etc. The elements analysis were studied by SEM spectrum. The results show that the compositions of coatings and particles were the same to each other. By the elements line analysis with SEM, we could find that there was phenomenon of the rising of oxygen in the interface between coatings and substrate and welding surface among extended particles. The same results were proved by the surface analysis of elements with EPMA. The coatings microhardness were uniform from bottom to top and there were not drastic changeness. The binding force between coatings and substrate is 59.3 Mpa which was studied by scratch test.Compare the coatings which were made by supersonic plasma spraying and plasma welding. The results showed that those two coatings microstructure were clearly different. The coatings of supersonic plasma spraying was made up of white phases and some flaws and holes, but the coatings of plasma welding was made up of white phases and black phase with big block. And the microstructure of supersonic plasma spraying was better than the plasma welding coatings because there are not full element diffusion in the first coatings. Those two coatings have the same phases, but those hard phases are different because the plasma spraying coatings got too much Fe from substrate, which also influenced coatings hardness.