摘要:二氧化锆作为一种现代齿科医疗领域新型的陶瓷材料，其具有优异的力学性能和耐蚀等良好性能，因此可以作为齿科陶瓷涂层保护基体义齿。但是，传统的电泳沉积是使用直流电场制备二氧化锆陶瓷层，在直流电场中，水的分解会导致制备的产品存在力学方面的缺陷以及裂纹气泡不光滑等影响其美观性的缺陷。因此，本文采用交变电场来对二氧化锆陶瓷层的制备工艺进行改进。

本文为了制备高性能齿科氧化锆涂层，以水代替有机物作为溶剂利用交变电场进行电泳沉积制备二氧化锆陶瓷涂层。利用X射线衍射分析法、扫描电镜、纳米压痕分析法等测试了交变电场脉冲直流电压的变化及空占比的变化对二氧化锆陶瓷层样貌、密度及力学性能的影响。首先保持电源空占比不变，探究不同脉冲电压对氧化锆陶瓷层密度及力学性能的影响。其次，选择出最佳脉冲电压，探究不同空占比对氧化锆陶瓷层硬度及弹性模量的影响，筛选出最佳空占比。最后，对最佳脉冲电压和空占比参数下制备的氧化锆陶瓷层进行力学性能分析。

结果表明：脉冲交变电场可以有效抑制水的电解，通过SEM表面形貌观察发现，样品表面致密且无缺陷。交变电场电泳沉积氧化锆的最佳工艺参数设定是脉冲直流方波电压为9V，空占比为50ms/200ms。此工艺参数下制备的二氧化锆陶瓷层美观有光泽度；晶粒尺寸为150nm；密度最大，为6.0g/cm3；硬度较大，为16.5GPa；弹性模量较小，为235GPa左右，符合高性能齿科材料的需求。对该工艺参数下的氧化锆镀层进行力学性能测试。随着加载率从2mN/min增加到10mN/min，抵抗塑性变形的阻力稳定在70〜80GPa左右。加载速率对HT影响在20-60mN/min时变得更加显著。弹性位移在不同加载速率变化时始终保持恒定，而塑性位移随着加载速率的增加而增加。EPD氧化锆薄膜的塑性形变在全部形变百分比随着加载速率的增加，从0.44提高到0.51。实验结果表明，EPD氧化锆薄膜的形变机制在高加载速率时以塑性为主。

关键词：二氧化锆；水基电泳；交变电场

Abstract:Due to the perfect mechanical properties and high corrosion resistance, zirconia was wildly used as a new kind of ceramic material in modern dental medicine. However, the zirconia ceramic layer was prepared by electrophoretic deposition under DC electric  field in convention. Under DC electric field, the surface and mechanical properties  were affected by electrolysis of water. This paper provides a new method of pulsed DC electric field instead of traditional method.

In order to prepare high performance ceramic, water can be used as the solvent for electrophoretic deposition(EPD). The microstructure, mechanical  properties  and surface are analyses by using X-ray diffraction analysis, scanning electron microscope(SEM) and nanoindentation. The influence of pulsed DC voltage and pulse duty cycle to the surface, density and mechanical properties are investigated.

In conclusion, the pulse DC electric fields can restrain the electrolysis of water. The optimum parameter for EPD- ZrO2 is that the pulse DC voltage is at 9V and pulse duty cycle is 50ms/200ms. The grain size of EPD-ZrO2 is ~150nm, with the highest density value of 6.0g/cm3. The hardness and the elastic modulus are 16.5GPa and235 GPa, respectively. The EPD-ZrO2 can meet the requirements of high-performance dental materials with high aesthetic performance. Then, the mechanical properties of the EPD- ZrO2 were tested with the increased loading rate from 2 mN/min to 10mN/min. The resistance of plasticity remained stable around 80~90 GPa. The influence of loading rate on HT response becomes more remarkable at 20-60 mN/min. It is clearly that the elastic displacement remained constant with different loading rates, while the plastic displacement increased with increment of loading rate. The D value of EPD zirconia increased from 0.44 to 0.51, indicating that the ductility index is sensitive to loading rate. The above results revealed that the plastic displacement of EPD zirconia became dominant at higher loading rates.