Study On The Friction And Wear Property Of Fe-based Bulk Amorphous Alloy And Amorphous Coating

In this thesis, Fe24+XCo24-XCr15Mo14C15B6Y2(X=0, 2, 4, 6, 8, 17)bulk amorphous alloy samples were prepared by water-cooling copper mold suction casting under a vacuum arc melting, and Fe41Co7Cr15Mo14C15B6Y2 amorphous alloy coating was prepared by High Velocity Oxygen-Fuel technology. The amorphous structure of the bulk amorphous alloy and amorphous coating were characterized by X-ray diffraction(XRD). The heat analysis for the amorphous wear-resisting was provided by different methods of thermal analysis such as differential thermal analysis, thermal expansion and thermal conductivity. Moreover, the wear resisting performance and wear mechanism of the Fe24+XCo24-XCr15Mo14C15B6Y2(X=0, 2, 4, 6, 8, 17) bulk amorphous alloy at different parameters were measured by M- 2000 friction and wear tester,which was kept in dry and wet conditions. Meanwhile, amorphous coating was researched when the content of Co is 7%.Fe-based amorphous alloy and amorphous alloy coating on friction and wear testing will produce a higher temperature, by heating the change regularity of amorphous materials to analyze the wear test of Fe24+XCo24-XCr15Mo14C15B6Y2(X=0,2, 4, 6, 8, 17) bulk amorphous alloy and amorphous coating. Thermal analysis results show that: different Co content in Fe-base amorphous alloy minimum crystallization temperature can reach 650℃, and the thermal conductivity remain in a lower position(7.5~9.46 W ? m-1 ? K-1) after 700 ℃ annealing treatment. The results of thermal analysis indicated that Fe-based amorphous alloy has higher thermal stability properties, and amorphous alloys can still keep complete amorphous after the friction and wear experiments.The dry and wet wear experiment of amorphous alloys proved that Fe24+XCo24-XCr15Mo14C15B6Y2(X=0, 2, 4, 6, 8, 17) bulk amorphous alloys have excellent wear resistance, and the wear-resisting performance is best when the content of Co is 20%, the abrasion loss of wear 90 min in dry and wet friction were 3.2 mg and 1.1 mg. Amorphous alloy wear is overall increases over time, and the wear of different Co content in Fe-base amorphous alloy is showed a trend of increase after decrease with the Co content decreasing. According to the SEM, the early stage friction and wear mechanism of the Fe-base amorphous alloys is given priority to with fatigue wear, and the later stage wear mechanism exhibits abrasive and fatigue mechanism in dry wear experiment. The wet friction and wear is given priority towith abrasive wear, and the wear morphology exhibits more furrow belt. Furrows density distribution has been reduced to increase trend, and the furrow belt width first increases then decreases with the Co content decreasing. Wear-resisting is best when the content of Co is 20%, which have the largest furrows belt spacing and the furrows distribution is osteoporosis. Amorphous surface adhesion materials belong to amorphous silicon chip, and crystallization phenomenon does not exist after dry friction wear test through the XRD and DES analysis.The initial crystallization temperature is 638 ℃,according to the DSC curves of Fe41Co7Cr15Mo14C15B6Y2 amorphous alloy coating. Due to the amorphous coating special microstructure, the porosity of the coating rate is 7.25% that lead to amorphous coating hardness value is about 788 Kg/mm2, and the corresponding components bulk amorphous hardness can be up to 1155 Kg/mm2。For these reasons,there is a big gap between the wear of bulk amorphous alloy and amorphous coating under the same dry friction and wear conditions, and dry friction wear volume is about 7 times the amount of wet friction and wear under the lubrication coating.Amorphous alloy coating dry friction and wear mechanism exhibits abrasive and fatigue mechanism, and the wet friction wear mechanism is presented fatigue wear.The Fe41Co7Cr15Mo14C15B6Y2 bulk amorphous alloy exhibits abrasive and fatigue mechanism.