晶粒尺寸对电沉积取向性金属Ni镀层抗氧化性能的影响  

Effect of grain size on oxidation behavior of oriented nickel coatings

作　　者：马莉[1] 周科朝[1] 李志友[1] 常通[1] 

机构地区：[1]中南大学粉末冶金国家重点实验室,长沙410083

出　　处：《粉末冶金材料科学与工程》2011年第4期537-546,共10页Materials Science and Engineering of Powder Metallurgy

基　　金：国家重点基础研究发展规划(973计划)资助项目(2005CB623703);国家高技术研究发展计划(863计划)资助项目(2008AA030501);国家自然科学基金创新团队项目(50721003);湖南省博士研究生创新基金资助项目(CX2009B032);中南大学优秀博士论文扶持基金资助项目(2009ybfz02);中南大学贵重仪器开放共享基金资助项目(ZKJ2009024)

摘　　要：通过调控电沉积过程中的阴极电流密度制备晶粒尺寸和择优取向均不相同的2种Ni镀层,并研究它们的高温氧化行为。采用透射电镜(TEM)、扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和热增重仪对2种镀层氧化前后进行分析表征,比较2种镀层分别经过600℃和960℃空气氧化后所得氧化膜的表面与截面的形貌与结构。结果表明:高电流密度下易获得晶粒细小,平均晶粒尺寸为120 nm,具有较强<100>择优取向的Ni镀层;低电流密度下所得Ni镀层晶粒粗大,平均晶粒尺寸为925 nm,且具有较弱的<111>择优取向。在空气中600℃氧化时,与高电流密度下所得Ni镀层相比,低电流密度下所得Ni镀层具有更好的抗氧化性能。在960℃氧化时,高电流密度下获得的Ni镀层氧化膜结构致密且具有更好的抗氧化性能。在960℃氧化时,低电流密度下获得的Ni镀层氧化过程中氧化膜生长遵循抛物线定律且氧化膜/金属界面较弯曲;而高电流密度下获得的Ni镀层氧化膜生长遵循立方定律,氧化膜/金属界面较平直。Two kinds of Ni coatings with different grain size and preferred orientation were fabricated by controlling the cathode current density in the electro deposition procedure.Oxide film structure,morphology,phase composition and mass gain before and after oxidation of two Ni coatings with oxidation experiments carried out in air at 600 °C and 960 °C respectively were studied by transmission electron microscope（TEM）,scanning electron microscopy/energy dispersive spectroscopy（SEM/EDS）,X-ray diffraction meter（XRD） and thermo mass analyzer.The results show that,Ni coatings with the finer particle size of 120 nm and the stronger preferred orientation of 100 can be easier obtained at higher current density,while as,Ni coatings with the bigger particle size of 925 nm and the weaker preferred orientation of 111 can be easier obtained at lower current density.An important and interesting result is that after oxidation at 600 °C,the Ni coating obtained at lower current density has a better oxidation resistance,whereas after oxidation at 960 °C,the Ni coating obtained at higher current density has a more compact scale and a better oxidation resistance.For Ni coating obtained at low current density,the oxidation kinetic curves follows a parabolic law,while for Ni coating obtained at high current density,the oxidation kinetic curves follows a cubic law.The oxide film / metal interface is more curved for Ni coating obtained at low current density,compared with Ni coating obtained at high current density.

关 键 词：电沉积 高温氧化 镍 晶粒尺寸 择优取向 

分 类 号：TQ153.12[化学工程—电化学工业]