硫酸盐固体润滑材料的制备与高温润滑机理研究
发布时间：2019-01-03 08:12
【摘要】：硫酸盐高温稳定性与润滑性良好,是一种性能优异的环境友好型高温固体润滑剂,具有广阔的应用前景(如导弹、太空飞行器、燃气涡轮发动机、涡轮增压发动机、核工业等)。系统的研究硫酸盐固体润滑材料的摩擦学性能并揭示其高温自润滑机理,可为其实际应用提供理论支持,同时对丰富固体润滑剂体系也具有重要意义。本文采用热压烧结法制备了致密的SrSO_4块体材料。材料在中低温时摩擦学性能较差,磨损机理以脆性断裂和剥层磨损为主。高温下SrSO_4块体材料的摩擦系数和磨损率大大降低。从室温到800℃,材料的平均摩擦系数从0.65下降为0.37,磨损率从10-3 mm3/(Nm)数量级降低到10-4 mm3/(Nm)数量级。结合高温磨痕截面的TEM观察与分析,得出了硫酸盐固体润滑材料的高温自润滑机理:高温下SrSO_4材料本身滑移系易于开动,塑性变形能力增强,并在磨损表面形成了一层低剪切强度的润滑膜,其主要是由纳米细晶构成。同时在对磨Al2O3球表面也形成了连续光滑的SrSO_4相转移膜,故有效地缓解了摩擦副间的摩擦应力,使材料具有良好的高温自润滑性能。SrSO_4固体润滑剂具有优异的高温自润滑性能,本文采用放电等离子烧结制备了不同粒度的SrSO_4自润滑涂层,该涂层材料可在高温环境下应用。不同粒度涂层在600℃条件下的摩擦系数和磨损率均比室温条件下降低。其中纳米尺度SrSO_4自润滑涂层在不同温度下的摩擦学性能比另外两种粒度涂层更好。为改善SrSO_4固体润滑材料的烧结性能,采用放电等离子烧结法制备了不同Ag含量的纳米SrSO_4-Ag复合材料自润滑涂层。纳米SrSO_4-Ag复合材料涂层在不同温度下的平均摩擦系数随着Ag含量的增加不断降低,磨损率随着Ag含量的增加先上升后下降。其中,20wt.%Ag含量的纳米SrSO_4-Ag复合材料涂层具有最优的摩擦学性能。室温时,材料的平均摩擦系数为0.57,磨损率在10-3 mm3/(Nm)数量级。600℃时摩擦系数降低为0.22,磨损率降低了一个数量级。所以SrSO_4和Ag润滑剂的协同作用能够显著改善SrSO_4-Ag复合材料涂层广域温度下的摩擦学性能。
[Abstract]:Sulfate is a kind of environment-friendly high temperature solid lubricant with good high temperature stability and lubricity. It has a wide application prospect (such as missile, space vehicle, gas turbine engine, turbocharged engine, etc.) Nuclear industry, etc. A systematic study of the tribological properties of sulphate solid lubricating materials and its high temperature self-lubricating mechanism can provide theoretical support for its practical application and also play an important role in enriching solid lubricant systems. In this paper, dense SrSO_4 bulk materials were prepared by hot pressing sintering method. The tribological properties of the materials at moderate and low temperatures are poor, and the wear mechanism is mainly brittle fracture and delamination. The friction coefficient and wear rate of SrSO_4 bulk materials are greatly reduced at high temperature. From room temperature to 800 鈩，
本文编号：2399105
[Abstract]:Sulfate is a kind of environment-friendly high temperature solid lubricant with good high temperature stability and lubricity. It has a wide application prospect (such as missile, space vehicle, gas turbine engine, turbocharged engine, etc.) Nuclear industry, etc. A systematic study of the tribological properties of sulphate solid lubricating materials and its high temperature self-lubricating mechanism can provide theoretical support for its practical application and also play an important role in enriching solid lubricant systems. In this paper, dense SrSO_4 bulk materials were prepared by hot pressing sintering method. The tribological properties of the materials at moderate and low temperatures are poor, and the wear mechanism is mainly brittle fracture and delamination. The friction coefficient and wear rate of SrSO_4 bulk materials are greatly reduced at high temperature. From room temperature to 800 鈩，
本文编号：2399105
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