Unlubricated Sliding Wear Mechanisms Of Ce Additions Novel Luminum Bronze Coating Against Steel

The novel aluminum bronze alloy powder developed is successfully prepared bywater cooled gas atomizing. Sprayed coating is formed on45#carbon steel by plasmaspraying in order to take place the novel aluminum bronze alloy for dies. The effectsof Ce in the coatings microstructure have been studied by option microscope,scanning electron microscope, electron probe microanalyser, X-ray diffraction andtransmission electron microscope. Unlubricated reciprocating sliding wear tests ofnovel aluminum bronze coatings with different Ce contents against steel have beencarried out on the RFT-Ⅲ tester. The effects of rare earth Ce on wear resistance ofplasma spray coatings and the wear mechanism have been investigated in order to findthe guideline to effectively improve the performance of aluminum bronze coating.The main conclusions are given as follows:1. A small amount of Ce (0.1%) in novel aluminum bronze coating can refine thecoating microstructure. When the Ce comes to0.6%，к phases grows up and more Fecan be found in the coating. The Ce has been found to stimulate the transition of theFe-containing intermetiallics from FeAl to Fe3Al. Ce can also make the coatings haveless stacking fault energy (SFE). The hardness of0.6%Ce coatings is15.8%higherthan0%Ce coatings for microstructure refining and Fe diffusion from the commercialcarbon45#steel substrate.2. The wear properties have an intesting variation with different Ce addition. Thecoatings with0.1%Ce have the best wear properties.0%Ce plasma spray coatingshave better wear properties at low load, but the wear loss increased rapidly withincreasing wear load. The wear mechanism also shows variation under different wearload. The0.6%Ce coatings have the worst wear properties for more к phases、Feelements and less stacking fault energy (SFE), but have also the highest hardness.3. Four processes in the unlubricated sliding behavior of novel aluminum bronzecoatings are described. These processes are (1) oxidation film formation and removal,(2) adhesion and element transfer,(3) plastic deformation to obtain a high deformedlayer (HDL),(4) mechanically mixed layer (MML) formation and produce flake-likedebris,(5) cyclic surface deterioration. The0%Ce coatings under196N stay inoxidation film show some varision of formation and removal. MML would be formedat the wear load of294N, the main wear mechanisms of the coatings are both abrasive and adhesive wear. When the wear load comes to392N, the main wear mechanisms ofthe coatings would become complex and will stay in cyclic surface deterioration.More Fe elemnt and k phases can be found in the0.6%Ce coatings which would makeadhesion and element take palce at the low wear load. The0.6%Ce coatings underdifferent wear load stay in cyclic surface deterioration. Abrasive、adhesive and fatiguewear would be found on the worn surface. The0.1%Ce coatings stay in oxidation filmformation and removal during the wear process.Through the above investigations, we have given the clear idea of how themicrostucture and wear property of the coatings vary, which are influenced by the rareearth addition. New wear mechanism of the coating under unlubricated reciprocatingsliding condition has been presented. The main conclusions obtained by this workprovide the theoretical foundation and experimental basis for the production of highperformance complex aluminum bronze.