球磨时间对Ti-13Nb-5Sn牙科合金耐蚀与耐磨性能的影响

Effect of ball milling time on corrosion and wear resistance of Ti-13Nb-5Sn dental alloys

采用粉末冶金法制备了Ti-13Nb-5Sn牙科合金,研究了不同球磨时间(3,12,24,48 h)对粉末特性、材料微观结构、电化学腐蚀和摩擦学行为的影响规律。结果表明:随着球磨时间从3 h增加至48 h,粉末形貌由大块状逐渐变成细小颗粒,部分Nb和Sn原子扩散到Ti晶格中,形成了一定体积的Ti(Nb)和Ti(NbSn)固溶体;等轴α-Ti减少转变为柱状的晶界α-Ti,网篮组织转变为魏氏组织;动电位极化曲线显示,合金在人工唾液(AS)和模拟体液(SBF)中的腐蚀电位(E_(corr))和极化电阻(R_(p))呈上升趋势,腐蚀电流密度(I_(corr))呈下降趋势,α-Ti减少,β-Ti增多,使得合金耐腐蚀性能提升;合金的硬度升高,而摩擦因数、磨痕深度和磨损率逐渐降低,细化粉末在烧结中会产生更多的晶界,使得合金的耐磨性能提升。机械合金化结合模压烧结制备的Ti-13Nb-5Sn合金显示了良好的耐蚀与耐磨性能,在牙科领域具有潜在的应用前景。

Ti-13Nb-5Sn dental alloy was prepared by powder metallurgy method.The effects of ball milling time(3,12,24 h and 48 h)on powder performances,material microstructure,electrochemical corrosion and tribological behavior were investigated.The results show that with the increase of ball milling time from 3 h to 48 h,the powder morphology gradually changes from bulky to fine particles,and a part of Nb and Sn atoms diffuse into Ti lattice to form a certain volume of Ti(Nb)and Ti(NbSn)solid solutions.Moreover,equiaxedα-Ti decreases and shifts into columnar grain boundaryα-Ti,and the basket structure changes to Widmandelsteiner structure.The potentiodynamic polarization curves show that the corrosion potential(E_(corr))and polarization resistance(R_(p))of the alloy display an upward trend,the corrosion current density(I_(corr))reveals a downward trend in artificial saliva(AS)and simulated body fluid(SBF).The corrosion resistance of the alloy is improved because of reduction ofα-Ti and increase ofβ-Ti.The hardness of the alloy increases,while the friction coefficient,wear depth and wear rate gradually decrease.More grain boundaries generate in sintering of the fine powder,resulting in the wear resistance of the alloy intensifying.The Ti-13Nb-5Sn alloy prepared by mechanical alloying combined with molding and sintering shows good corrosion and wear resistances,and has a great potential in the dental field.