Cu-coated graphite composites were prepared by an electroless plating method,and the composites were examined by scanning electron microscopy(SEM). The copper content of the composites was measured to reach 73%(mass f...Cu-coated graphite composites were prepared by an electroless plating method,and the composites were examined by scanning electron microscopy(SEM). The copper content of the composites was measured to reach 73%(mass fraction). Brush samples made with composites contents of 10%,15% and 20% and with copper powders content of 11% were obtained. The results show that the resistivity of the brush samples decreases and hardness becomes higher with increasing composites content. Copper is dispersively distributed in the brush samples made with the composites,whereas copper agglomerates in Cu-graphite mechanical mixture. For the same Cu content,Cu-coated graphite composites possess lower resistivity and higher hardness than Cu-graphite mechanical mixture. A new type of electric brush was obtained by using Cu-coated graphite composites,the wear and durability tests carried out on a HGH5435M120 AC motor indicate that its service life reaches 250 h. The electric brushes possess relatively low resistivity(275 μΩ·m) and good wear resistance,so they are very suitable for high-speed micromotors.展开更多
在铜基上化学镀Fe Ni P B四元合金,研究了FeSO4/(FeSO4+NiSO4)金属盐比值对沉积速率、镀层结构的影响,测试了镀层在不同介质中的电化学稳定性。结果表明,镀层沉积速率随FeSO4/(FeSO4+NiSO4)金属盐比值的增加先增后减,金属盐比值为0.5... 在铜基上化学镀Fe Ni P B四元合金,研究了FeSO4/(FeSO4+NiSO4)金属盐比值对沉积速率、镀层结构的影响,测试了镀层在不同介质中的电化学稳定性。结果表明,镀层沉积速率随FeSO4/(FeSO4+NiSO4)金属盐比值的增加先增后减,金属盐比值为0.5时,沉积速率达到极大值。镀层沉积速率影响镀层的结构,沉积速率增大,镀层出现非晶结构。镀层在不同介质溶液中的稳定性不同,在酸性介质中,由于镀层的溶解,电极电位向正方向移动;而在中性和碱性介质中,由于氧的扩散缓慢,体系的电极电位会随时间负移。展开更多
基金Project (59972009) supported by the National Natural Science Foundation of China
文摘Cu-coated graphite composites were prepared by an electroless plating method,and the composites were examined by scanning electron microscopy(SEM). The copper content of the composites was measured to reach 73%(mass fraction). Brush samples made with composites contents of 10%,15% and 20% and with copper powders content of 11% were obtained. The results show that the resistivity of the brush samples decreases and hardness becomes higher with increasing composites content. Copper is dispersively distributed in the brush samples made with the composites,whereas copper agglomerates in Cu-graphite mechanical mixture. For the same Cu content,Cu-coated graphite composites possess lower resistivity and higher hardness than Cu-graphite mechanical mixture. A new type of electric brush was obtained by using Cu-coated graphite composites,the wear and durability tests carried out on a HGH5435M120 AC motor indicate that its service life reaches 250 h. The electric brushes possess relatively low resistivity(275 μΩ·m) and good wear resistance,so they are very suitable for high-speed micromotors.
文摘 在铜基上化学镀Fe Ni P B四元合金,研究了FeSO4/(FeSO4+NiSO4)金属盐比值对沉积速率、镀层结构的影响,测试了镀层在不同介质中的电化学稳定性。结果表明,镀层沉积速率随FeSO4/(FeSO4+NiSO4)金属盐比值的增加先增后减,金属盐比值为0.5时,沉积速率达到极大值。镀层沉积速率影响镀层的结构,沉积速率增大,镀层出现非晶结构。镀层在不同介质溶液中的稳定性不同,在酸性介质中,由于镀层的溶解,电极电位向正方向移动;而在中性和碱性介质中,由于氧的扩散缓慢,体系的电极电位会随时间负移。
