超声辅助电铸钨丝–镍复合层的微观结构和抗拉强度  

Microstructure and tensile strength of tungsten fiber–nickel composite coating prepared by ultrasound-assisted electroforming

作　　者：钱王欢[1] 秦丰[1] 缪小梅[1] 

机构地区：[1]无锡职业技术学院机械技术学院,江苏无锡214121

出　　处：《电镀与涂饰》2016年第11期551-555,共5页Electroplating & Finishing

基　　金：国家自然科学基金(51505192);无锡职业技术学院博士科研启动基金(BT2014-05)

摘　　要：在钨丝–镍的复合电铸过程中施加超声辅助,以改善复合电铸层的组织结构,提高其抗拉强度。电铸液组成和工艺条件为:氨基磺酸镍400 g/L,氯化镍15 g/L,硼酸30 g/L,p H=4.5,温度43°C,电流密度4 A/dm^2,超声波频率100 k Hz,超声波功率120 W。研究了超声波辅助对钨丝–镍复合电铸层表面形貌、断口形貌、结晶取向、晶粒尺寸等微观结构及其抗拉强度的影响。结果表明:超声空化伴随的微射流和冲击波能够有效避免复合电铸层表面孔隙的形成,显著细化晶粒,减少内部空洞。超声波的应用改变了镍晶体的生长方式,显著提高了(200)面的择优程度。超声条件下获得的钨丝–镍复合电铸层具有更高的抗拉强度。当钨丝体积分数为50%时,超声辅助下所得复合电铸层的抗拉强度为1 502 MPa,比无超声条件下的复合电铸层高13.8%。Ultrasound was applied to tungsten fiber-nickel composite electroforming to improve the structure and tensile strength of electroformed composite coating. The electroforming bath composition and process conditions are as follows： nickel sulfamate 400 g/L, nickel chloride 15 g/L, boric acid 30 g/L, temperature 43 ℃, pH 4.5, current density 4 A/dm2, ultrasonic frequency 100 kHz and ultrasonic power 120 W. The effect of ultrasound assistance on the microstructure including surface morphology, fracture morphology, crystal orientation and grain size of electroformed W fiber-Ni composite coating and its tensile strength were studied. The results showed that the surface porous formation can be effectively avoided, the grain size is refined significantly, and the internal voids of electroformed coatings are decreased as a result of the micro-jet and shockwave accompanied with ultrasound cavitation. The growth of nickel crystal is changed by ultrasound, resulting in an increasing degree of（200） preferential orientation. The W fiber-Ni composite coating electroformed with ultrasound assistance has higher tensile strength. The composite coating containing 50vol% W fiber electroformed with ultrasound assistance has a tensile strength of 1 502 MPa, which is 13.8% higher than that of the composite electroformed without ultrasound assistance.

关 键 词：镍 钨丝 复合镀层 电铸 超声波 微观结构 抗拉强度 

分 类 号：TQ153.2[化学工程—电化学工业] TG662[金属学及工艺—金属切削加工及机床]