氨基磺酸镍体系电沉积纳米镍的力学性能及热稳定性研究  

Investigation on mechanical properties and thermal stability in an electrodeposited nanocrystalline Ni prepared by nickel sulfamate system electrolyte

作　　者：许伟长[1] 林芬[2] 陈颖[2] 伍文杰[1] 戴品强[1] 

机构地区：[1]福州大学材料科学与工程学院,福建福州350108 [2]福州大学测试中心,福建福州350108

出　　处：《福州大学学报（自然科学版）》2008年第3期387-392,共6页Journal of Fuzhou University(Natural Science Edition)

基　　金：福建省自然科学基金资助项目(E0410011);福建省科技计划重点项目(2006H0020)

摘　　要：采用氨基磺酸镍体系镀镍液代替瓦特型镀镍液,应用脉冲电沉积技术,制备了平均晶粒尺寸为16.7 nm的纳米镍.在静拉伸应变速率范围（5×10^-5-10^-2s^-1）内,纳米镍的强度和塑性均随应变速率的增加而增加,断裂形式表现为韧窝韧性断裂,获得的最高断裂强度和最大断裂延伸率分别为1 332MPa和5.31%.在退火温度为100、150和200℃保温1 h后,室温应变速率为10^-3s^-1时,纳米镍的强度和塑性随退火温度的升高而显著下降,原因为退火过程中晶内硫元素向晶界强烈偏聚引起材料变脆,断裂形式表现为晶间脆性断裂.XRD和TEM的观测结果表明,纳米镍在250℃退火时,晶粒发生显著长大,硬度快速下降.热分析仪测得的放热峰表明,275℃以后,大量的纳米晶粒发生异常长大.Nickel sulfamate system electrolyte was used to substitute for Watts＇ s electrolyte. A nano- crystalline Ni with average grain size of 16.7 nm was prepared by pulse electrodeposition. In the static tensile strain rate region ranged from 5×10^-5s-1to 10^-2s^-1, there is an increase in strength and plasticity of nanocrystalline Ni with increased strain rate. The fracture type shows ductile fracture. The maximum tensile ultimate strength and elongation to fracture are 1 332 MPa and 5.31% , respectively. The strength and plasticity decrease with an increase in annealing temperatures ranged from 75 ℃ to 200 ℃ in the presence of holding time of 1 h and strain rate of 10^-3s^-1. At 200 ℃nanocrystalline Ni turns brittle responsible for strong segregation of sulfur into grain boundary showing intergranular fracture. The observations of XRD and TEM show after annealing at 250℃, grains grow markedly causing a quick decrease in hardness. The exothermic peak measured by DSC shows that after 275℃ a large number of grains happen to abnormal growth.

关 键 词：纳米镍 脉冲电沉积 力学性能 应变速率 退火 热稳定性 

分 类 号：TG174.441[金属学及工艺—金属表面处理]