电力复合脂广泛应用于电力设备的电接触部位，具有减缓金属连接部位氧化与腐蚀，降低接触电阻，防止电接触失效的作用。然而在湿热环境下电力复合脂存在自身容易发生加速老化，未达到预期使用寿命就失效的问题。因此，本文针对电力复合脂湿热老化特性开展研究。电力复合脂基础油类型是影响其使用寿命的重要因素。选择基础油为烃类、甲基硅氧烷类以及甲基苯基硅氧烷类的电力复合脂进行高温、高温高湿、盐雾腐蚀以及带电湿热条件下的人工加速老化试验，指出了运行温度是影响电力复合脂老化加速的一个重要原因，烃类电力复合脂容易因热老化而导致失效，且干热与湿热条件下的老化过程不同。湿热环境下，电力复合脂劣化过程主要包括基础油氧化分解的化学变化以及基础油析出的物理变化。电力复合脂老化后无法排出金属接触面且失去密封作用导致水分进入，引起接触电阻增大。盐雾导致电力复合脂中金属填料发生腐蚀，改变电力复合脂的防水性。气相法白炭黑对甲基苯基硅氧烷增稠的稳定性优于聚四氟乙烯微粉，甲基苯基硅氧烷型电力复合脂在人工加速老化试验过程中的稳定性优于甲基硅氧烷型电力复合脂与基础油为烃类的电力复合脂。开发一种适合在湿热环境使用的甲基苯基硅氧烷型电力复合脂。通过电力复合脂静接触载流试验验证了所制备电力复合脂具有良好的温升特性，并筛选出最优材料组分以及组分比例。通过电力复合脂在载流与非载流条件下振动试验验证了制备电力复合脂具有良好润滑性与导电性。将所制备的电力复合脂进行现场试运行，通过红外测温、接触电阻测量以及采样分析其热稳定与官能团变化，初步验证了所制备电力复合脂在湿热环境下的适用性。
Electric joint compound is widely used in electrical contact parts of power equipment, which has the effect of slowing down oxidation and corrosion of metal connection parts, reducing contact resistance, and preventing electrical contact failure. However, in the hydrothermal environment, the electric joint compound itself is prone to accelerated aging and fails before reaching the expected working life. The hydrothermal aging characteristics of electric joint compound were studied in this thesis.The type of base oil is an important factor that affects the working life of electric joint compound. The electric joint compound which contain hydrocarbon grease, polydimethylsiloxane and polymethylphenylsiloxane were selected for artificial accelerated aging test under high temperature, high temperature and humidity, salt spray corrosion and electrically charged damp heat conditions. It is pointed out that the operating temperature is an important reason for the accelerated aging of electric joint compound. Electric joint compound which contains hydrocarbon is prone to failure due to thermal aging, and the aging process is different between thermal and hydrothermal conditions. The oxidation, decomposition and precipitation of base oil under humid and hot environment are the main reasons for the failure of electric joint compound. The inability to discharge the metal contact surface after aging lead to moisture entering, which causes an increase in contact resistance with time. Salt will cause corrosion of the metal filler on the surface of the electric joint compound, changing the waterproof property of the electric joint compound. The stability of polymethylphenylsiloxane thickening of fumed silica is better than that of PTFE powder, and the stability of polymethylphenylsiloxane -type electric joint compound prepared by the former is better than that of the electric joint compound which contact polydimethylsiloxane and hydrocarbon electric compound grease during the artificial accelerated aging test.A preparation method of the electric joint compounds which consist of polydi-methylsiloxane suitable for hydrothermal environment was developed; Based on the static contact current-carrying conditions of electric joint compound, the good temperature rise characteristics of the electric joint compounds were verified, and the optimal material components and component ratios were selected. Through the vibration test analysis of the electric joint compounds under current-carrying and non-current-carrying conditions, the good lubricity and electric conductive capacity were verified.The thermal stability and functional group changes of the prepared electric joint compound were preliminarily verified by infrared temperature measurement, contact resistance measurement and sampling analysis.
