柴油机铝合金活塞表面自修复耐磨陶瓷层制备及性能研究

发布时间：2018-03-03 09:45

本文选题：铝合金　切入点：微弧氧化　出处：《大连海事大学》2016年硕士论文　论文类型：学位论文

【摘要】：铝合金在船舶柴油机活塞上的应用具有重要意义,然而其表面硬度、耐磨性、耐腐蚀性等性能上的缺陷制约了铝合金活塞的广泛应用。因此,需要对其进行表面强化处理。微弧氧化技术可以在铝合金表面制备一层具有高硬度、耐磨、耐腐蚀等性能的陶瓷层。在电解液中添加蛇纹石自修复微纳米颗粒后,可以得到一层具有自修复性能的耐磨陶瓷层。本文利用正交试验法设计了电解液参数和电源参数的优化方案,使用扫描电镜探究了膜层的表面形貌、截面形貌及元素组成,测量了膜层厚度、粗糙度、显微硬度,进行了摩擦磨损试验,确定了制备陶瓷层的最佳工艺参数;使用高能球磨法制备了蛇纹石微纳米颗粒,将蛇纹石粉体添加到电解液中进行微弧氧化试验,以得到含有蛇纹石微纳米颗粒的复合陶瓷层,并对添加蛇纹石的浓度进行了优化;对试件进行摩擦磨损试验,并对试验前后膜层的表面形貌和元素组成进行分析,来研究膜层的自修复性能。通过设计正交试验对微弧氧化过程中的电解液参数、电源参数进行优化。综合陶瓷膜的膜厚、硬度、粗糙度、以及表面形貌、截面形貌等指标,对电解液参数、电源参数进行优化。所得电解液参数为:硅酸钠浓度为8g/L、氢氧化钾浓度为2.5g/L、钨酸钠浓度为5g/L、EDTA2g/L;电源参数为:正向电压为420V、负向电压为130V、占空比为20%、频率为500Hz、氧化时间为1h。按照得到的最优工艺参数制备复合陶瓷层,当蛇纹石浓度为6g/L时,陶瓷层性能最优。贫油状态下,在摩擦磨损试验中与陶瓷膜对磨,复合陶瓷膜中Si元素的含量升高,摩擦表面生成一层保护膜,制备的复合陶瓷膜具有较好自修复性。
[Abstract]:The application of aluminum alloy in the piston of marine diesel engine is of great significance. However, the defects of surface hardness, wear resistance and corrosion resistance restrict the wide application of aluminum alloy piston. It is necessary to strengthen the surface of aluminum alloy by micro-arc oxidation. A ceramic layer with high hardness, wear resistance and corrosion resistance can be prepared on the surface of aluminum alloy. A wear-resistant ceramic layer with self-repairing properties can be obtained. In this paper, the optimization scheme of electrolyte parameters and power supply parameters is designed by orthogonal test, and the surface morphology, cross-section morphology and element composition of the film are investigated by SEM. The thickness, roughness and microhardness of the coating were measured, and the friction and wear tests were carried out to determine the optimum technological parameters for the preparation of the ceramic coating, and the serpentine microparticles were prepared by high-energy ball milling. By adding serpentine powder into electrolyte for micro-arc oxidation test, the composite ceramic layer containing serpentine microparticles was obtained, and the concentration of serpentine was optimized. The surface morphology and element composition of the film before and after the experiment were analyzed to study the self-repairing performance of the film. The electrolyte parameters and power supply parameters in the process of micro-arc oxidation were optimized by orthogonal design. Hardness, roughness, surface morphology, cross-section morphology, etc., for electrolyte parameters, The parameters of the electrolyte are as follows: sodium silicate 8 g / L, potassium hydroxide 2.5 g / L, sodium tungstate 5 g / L EDTA 2 g / L, and forward voltage 420 V, negative voltage 130 V, duty cycle 20 g / L, frequency 500 Hz, when oxidized, the power supply parameters are as follows: sodium silicate 8 g / L, potassium hydroxide 2.5 g / L, sodium tungstate 5 g / L EDTA 2 g / L, forward voltage 420 V, negative voltage 130 V, duty cycle 20 g / L, frequency 500 Hz. The composite ceramic layer was prepared according to the optimum process parameters. When the concentration of serpentine is 6 g / L, the performance of ceramic layer is optimal. In the condition of lean oil, the content of Si in the composite ceramic film increases with the friction and wear test, and a protective film is formed on the friction surface. The prepared composite ceramic film has good self-repairing property.
【学位授予单位】：大连海事大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U664.121

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