行波管用Ni-Cu合金密封失效分析及其电沉积制备

Failure Analysis and Electrodeposition of Ni-Cu Alloy Used as Traveling Wave Tube

行波管密封垫镍铜合金材料常用粉末冶金方法制备,高温工作一段时间后易因气密性变差而失效。利用扫描电子显微镜(SEM)和X射线能谱仪(EDS)分别对行波管密封垫现用镍铜合金样品的失效原因进行分析,研究发现粉末冶金方法制备的镍铜合金内存在固有孔隙和杂质碳、锰元素,是导致其高温使用条件下气密性变差的主要原因。为了克服粉末冶金镍铜合金的固有缺陷,本实验摸索了电沉积法制备镍铜合金的工艺条件,并利用X射线荧光光谱仪(XRF)和扫描电子显微镜对镍铜合金沉积层成分和组织形貌进行分析。结果表明:电流密度和电解液温度影响镍铜合金沉积层的表面平整度及晶粒大小;电沉积镍铜试样不含其他杂质元素;采用合适的工艺参数可获得相对致密度较高的镍铜合金。

Traveling wave tube gasket using nickel-copper alloy is traditionally prepared by powder metallurgy. It was easy to fail because the air tightness became poor after working a period of time at high temperature. The failure reason of the gasket was analyzed by means of scanning electron microscope（ SEM） and X-ray energy disperse spectrometer（ EDS）. The results showed that the failure of the gasket was mainly attributed to both original poles and impurity manganese. To avoid the drawbacks primarily existing in metallurgical Ni-Cu alloys,Ni-Cu alloys were synthesized by electrodepositing. The composition and morphology of Ni-Cu alloys were analyzed by X-ray fluorescence（ XRF） spectrometer and scanning electron microscope. The results indicated that current density and electrolytic temperature affected the grain size and surface flatness of Ni-Cu alloy. No impurity was observed in electrodeposited Ni-Cu alloys. NiCu alloys with higher density could be obtained by adjusting electrodeposition parameters.