【作者】 祁韶鹏；

【导师】 张玉梅；

【作者基本信息】 第四军医大学 ， 口腔临床医学， 2009， 硕士

【摘要】 钛瓷间的结合依赖钛表面的氧化膜作为介质,钛瓷结合强度无法达到传统金瓷系统的水平,主要原因是钛具有高亲氧性,在高温下可以从瓷粉氧化物中吸收氧原子,发生继续氧化,表面氧化膜变得疏松,与基底结合强度降低,从而影响了钛瓷结合强度。利用微弧氧化技术（MAO）可在钛表面形成陶瓷化氧化膜,该膜与基底呈冶金结合,结合强度高;其内层致密,可阻止烤瓷过程中钛基底继续氧化;外层多孔,可增加与瓷的接触面积;同时可通过调整电解液参数改变膜的性质和成分,增强与瓷粉的化学结合,是一种理想的中间层。在对微弧氧化电压参数进行研究的基础上,本研究通过调整电解液的成分、浓度等参数,研究电解液对微弧氧化膜性质及钛瓷结合强度的影响,以期筛选出有利于钛瓷结合的微弧氧化参数,为该技术应用于临床提供理论依据。目的:从微弧氧化的原理入手,探讨微弧氧化过程中电解液成分、浓度对氧化过程的影响,研究在不同电解液中微弧氧化处理对钛瓷结合强度的影响,筛选能够提高钛瓷结合强度的电解液配方。方法:首先选择NaH₂PO₄、Na₂B₄O₇、Na₂SiO₃、KF四种电解质,以去离子水配制浓度为20g/L的溶液作为电解液,在不锈钢容器（兼作阴极）中对纯钛片进行微弧氧化处理后,表面烤瓷（NoritakeTi22）,以三点弯曲试验测得的钛瓷结合强度为主要评价指标,辅以SEM/EDS对氧化膜表面、截面进行分析,筛选对钛瓷结合最有利的电解液种类。在此基础上,改变电解液浓度,仍以三点弯曲试验测试钛瓷结合强度,SEM/EDS分析氧化膜表面、钛瓷结合界面,对电解液浓度的影响进行评价和分析。再根据上述实验的结果,对高浓度电解液的电源参数进行调整,通过对钛瓷结合强度研究以及膜层结构的分析,优化针对不同成分与浓度的电解液的微弧氧化电压参数。结果:在浓度为20g/L的NaH₂PO₄、Na₂B₄O₇、Na₂SiO₃、KF四种电解液中,阳极电压达到300V时钛片试样均能起弧,肉眼观察氧化膜均匀,为黑灰色。SEM显示Na₂SiO₃组与KF组膜层表面微孔的直径均匀,KF组略增大,有部分微孔融合,表面仍比较平整。NaH₂PO₄、Na₂B₄O₇组表面微孔数量极少,布满团块状熔融物,表面较粗糙,电镜下观察NaH₂PO₄、Na₂B₄O₇两组膜层中间有宽1μm左右连续的缝隙,说明该膜层强度较差。Na₂SiO₃、KF组膜层较薄,紧密均匀无缝隙,与基底结合牢固。三点弯曲试验发现微弧氧化处理组的钛瓷结合强度明显高于未作微弧氧化的对照组,在处理组中Na₂SiO₃、KF组高于NaH₂PO₄、Na₂B₄O₇组, Na₂SiO₃组与KF组之间无统计学差异,NaH₂PO₄组与Na₂B₄O₇组之间无统计学差异。采用钛瓷结合强度较高的Na₂SiO₃、KF为电解液,发现随着电解液浓度升高,膜层质量下降,SEM显示30g/L组与40g/L组表面氧化膜孔洞出现搭接、熔合,膜表面不平整,出现大量熔融的颗粒。三点弯曲试验显示钛瓷结合强度随电解液浓度增加而减小。采用40g/L Na₂SiO₃及KF溶液,通过调整微弧氧化电压参数,将反应电流控制在1A,可以制得较为致密的微弧氧化膜,表面烧结瓷粉后,该膜与瓷粉结合良好,达到了较高的钛瓷结合强度。结论:在Na₂SiO₃溶液中微弧氧化制得的陶瓷膜含有Si元素,KF溶液中微弧氧化制得的陶瓷膜含有F元素,均可有效的提高钛瓷间结合力;在电压为300V的情况下,随着电解液浓度升高,反应电流增大,对膜层产生不利影响,钛瓷间结合强度降低;通过应用较低的电压,可将反应电流控制在合适的范围,制得较理想的陶瓷氧化膜,有利于提高钛瓷结合强度。本实验结果提示:选用40g/L Na₂SiO₃在260V电压下或KF溶液在220V电压下进行微弧氧化,可达到较高的结合强度。更多还原

【Abstract】 Titanium receives considerable amount of interests as a ceramic fused metal. But the bonding strength of titanium-porcelain system is still lower than that of conventional Ni-Cr/porcelain system, primarily because of the strong reactivity of Ti to non-metallic elements, such as oxygen, hydrogen, and nitrogen at high temperatures. Micro-arc oxidation is a recently developed surface treatment technology. To improve the bond strength of titanium-porcelain system, a protective ceramic film was created via micro-arc oxidation on titanium before porcelain fused on it. Electrolyte has strong influences on the structure and property of ceramic coatings created by micro-arc oxidation.Objectives: This study was made to evaluate the influence of electrical parameters including electrolyte and concentration at micro-arc oxide treatment on the bond strength of titanium to porcelain.Methods: Experiment1: NaB₄O₇、NaH₂PO₄、Na₂SiO₃ and KF were selected to be studied in this part. CP titanium specimens in the size of 25mm×3mm×0.5mm were treated with micro-arc oxidation（MAO） in this 4 solution respectively. Then the ceramic coating was observed by scanning electron microscope（SEM）.After the porcelain was fused, the effect of the electrolyte on bonding strength of tatinium/porcelain were determine via a three-point-flexure-test according to ISO9693.The electrolytes used in the group which had the highest bonding strangth value were selected for experiment2. CP titaniunm specimens in the size of 25mm×3mm×0.5mm were treated with micro-arc oxidation（MAO） in solution of three different concentration respectively. After an ultra-low-fusing porcelain were applied, a three-point-flexure-test was employed to evaluate the bond strength of titaniunm to porcelain. The surface of the specimens was observed by SEM and EDS , as well as the interface between titanium and porcelain.In order to reduce the thickness and improve the quality of the film created in high concentration solutions, a lower voltage was applied in MAO treatment, and the effect on bonding strength was identified by three-point-flexure-test and SEM.Results: The bond strength values between porcelain and titanium treated with MAO in Na₂SiO₃ and KF solution was significantly higher then the control group’s and other two group’s. SEM indicated there was a crack in the ceramic coating created in NaH₂PO₄ and NaB₄O₇, implying the weakness of the coating. The bonding strength of this two group was lower then that of Na₂SiO₃ group and KF group.The bond strength of ceramic and titanium treated in solutions with deferent electrolyte concentration were compared in experiment2. Group 20g/L had the highest bond strength values in both Na₂SiO₃ and KF solutions according to the three-point-flexure-test. SEM /EDS suggested that a porous thin layer of oxide which contains Si or F element was created by MAO in Na₂SiO₃ or KF solutions. Higher concentration of Na₂SiO₃ （KF） lead to more Si （F） element in oxide, but a lower in bond strength values paradoxically. Increasing in electrolyte concentration lead to larger current in MAO procedure ,which brought faster film grown and thicker coating during the same time. SEM photograph of the interface area of ceramic and titanium indicated that there were tiny cracks between oxide film and the Ti substrata in group 30g/L and 40g/L, while group 20g/L had no defect.Bonding strength value of group Na₂SiO₃ 20g/L treated with 300V and group 40g/L treated with 260V has no statistical significance,and group KF 20g/L treated with 300V and group 40g/L treated with 220V has no statistical significance according to the three-point-flexure-test. SEM photograph indicated that the coating created in 40g/L Na₂SiO₃ solutions with 260V and 40g/L KF solutions with 220V was compacted and well bonded to the substrata.Conclusions: MAO treating can improve bonding strength between titanium and ceramic. Na₂SiO₃ and KF are better than NaB₄O₇ or NaH₂PO₄ as electrolyte used for titanium MAO. Higher concentration of Na₂SiO₃ （KF） lead to lower bonding strength value under a consistent voltage of 300V. But 40g/L Na₂SiO₃,in pairs of 260V,or 40g/L KF in pairs of 220V, brought excellent bonding between titanium and ceramic.更多还原