Effect Of Sliding Speed And Load On Wear Behavior Of Fe-Al Intermetallic Compounds Coating

Fe-Al intermetallic compounds were a new kind of engineering materials and coating materials. So far, The research was mainly focused on the preparation 、high temperature oxidation resistance 、 corrosion resistance and so on of Fe-Al intermetallic compounds or its coating at home and abroad. The wear behavior and wear resistance of Fe-Al intermetallic compounds were not comprehensive. Therefore, The study on the wear properties of Fe-Al intermetallic compounds coating that was important significances in both theory and engineering. Fe-Al intermetallic compounds coating were prepared on 45 steel via hot-dipped aluminizing and subsequently high-temperature diffusion treatment. Effect of sliding speed and load on the dry sliding wear behavior of Fe-Al intermetallic compounds was investigated on a MPX-2000 pin-on-disk wear tester; And in contrast to the wear behavior of matrix 45 steel. The structure, morphology, component and micro-hardness of worn surfaces and subsurface were examined and analyzed by XRD, SEM, EDS and micro-hardness tester. The wear mechanism of Fe-Al coating was emphatically studied in different sliding conditions.Results showed that the coating was mainly composed of ductile phase FeAl and Fe3 Al after hot-dipped aluminizing and subsequently high-temperature diffusion treatment, And the coating was good bond with the substrate. It was found that the sliding speed and load had a significant influence on wear behavior of the coating. With the load increasing, the wear rate of the coating rapidly increased at 0.5m/s and 4m/s. But at the speed of 4m/s, the wear rate was significantly higher than that at 0.5m/s. When the speed was 0.75- 2.68m/s, the wear rate dramatically decreased(except under 40 N at the speed of 2.68m/s). And with the load increased, the wear rate was decreased at first and then increased and obtained a minimum value under 20 N. But at 2.68m/s under 40 N,the wear rate was significantly increased. So, Fe-Al intermetallic compounds does not always present a worse room temperature wear resistance. It was found that the formation of tribo-oxide layers was a major factor for wear-improving through micro-analysis of worn surface and subsurface. The tribo-layer was formed on Fe-Al intermetallic compounds coating under dry sliding condition. The attributes of tribo-layer formed under different sliding conditions result in different wear mechanism and direct effects on the wear behavior. At 0.5-2.68m/s, The tribo-layer was mechanical-mixing layer including the oxide, and fitting Wilson model, At 4m/s, the tribo-layer was in-stiu tribo-layer, and fitting Quinn model, At 0.5m/s, the main wear mechanism was fatigue wear. At 0.75m/s、1.5m/s and 2.68m/s、10-30 N, oxidative mild wear prevailed. While at 4m/s and 2.68m/s 、40N, the main wear mechanism was fatigue wear and the plastic extrusion of the substrate.