Pecnik Christina Martina, Courty Diana, Muff Daniel, Spolenak Ralph
Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Zurich, Switzerland.
Laboratory for Nanometallurgy, Department of Materials, ETH Zurich, Zurich, Switzerland.
J Mech Behav Biomed Mater. 2015 Jul;47:1-11. doi: 10.1016/j.jmbbm.2015.03.006. Epub 2015 Mar 19.
Improving the esthetics of Ti-based dental implants is the last challenge remaining in the optimization process. The optical issues were recently solved by the application of highly and selectively reflective coatings on Ti implants. This work focuses on the mechanical durability of these esthetic ceramic based coating systems (with and without adhesion layers). The coating systems (Ti-ZrO2, Ti-Al-ZrO2, Ti-Ti-Al-ZrO2, Ti-Ag-ZrO2, Ti-Ti-Ag-ZrO2, Ti-Bragg and Ti-TiO2-Bragg) were subjected to nanoindentation experiments and examined using scanning electron microscopy and focused ion beam cross sectional analysis. Three coating systems contained adhesion layers (10nm of Ti or 60nm of TiO2 layers). The fracture toughness of selected samples was assessed applying two different models from literature, a classical for bulk materials and an energy-based model, which was further developed and adjusted. The ZrO2 based coating systems (total film thickness<200nm) followed a circumferential cracking behavior in contrast to Bragg coated samples (total film thickness around 1.5μm), which showed radial cracking emanating from the indent corners. For Ti-ZrO2 samples, a fracture toughness between 2.70 and 3.70MPam(1/2) was calculated using an energy-based model. The classical model was applied to Bragg coated samples and their fracture toughness ranged between 0.70 and 0.80MPam(1/2). Furthermore, coating systems containing an additional layer (Ti-Ti-Al-ZrO2, Ti-Ti-Ag-ZrO2 and Ti-TiO2-Bragg) showed an improved adhesion between the substrate and the coating. The addition of a Ti or TiO2 layer improved the adhesion between substrate and coating. The validity of the models for the assessment of the fracture toughness depended on the layer structure and fracture profile of the samples investigated here (classical model for thick coatings and energy-based model for thin coatings).
改善钛基牙科植入物的美学效果是优化过程中剩下的最后一项挑战。光学问题最近通过在钛植入物上应用高选择性反射涂层得以解决。这项工作聚焦于这些基于美学陶瓷的涂层系统（有或没有粘附层）的机械耐久性。对涂层系统（Ti-ZrO2、Ti-Al-ZrO2、Ti-Ti-Al-ZrO2、Ti-Ag-ZrO2、Ti-Ti-Ag-ZrO2、Ti-Bragg和Ti-TiO2-Bragg）进行了纳米压痕实验，并使用扫描电子显微镜和聚焦离子束截面分析进行了检查。三种涂层系统包含粘附层（10nm的Ti层或60nm的TiO2层）。应用文献中的两种不同模型评估所选样品的断裂韧性，一种是用于块状材料的经典模型，另一种是基于能量的模型，该模型经过了进一步开发和调整。与布拉格涂层样品（总膜厚约1.5μm）相比，基于ZrO2的涂层系统（总膜厚<200nm）呈现出圆周开裂行为，布拉格涂层样品显示出从压痕角发出的径向开裂。对于Ti-ZrO2样品，使用基于能量的模型计算出的断裂韧性在2.70至3.70MPam(1/2)之间。经典模型应用于布拉格涂层样品，其断裂韧性在0.70至0.80MPam(1/2)之间。此外，包含附加层的涂层系统（Ti-Ti-Al-ZrO2、Ti-Ti-Ag-ZrO2和Ti-TiO2-Bragg）在基底和涂层之间表现出更好的附着力。添加Ti层或TiO2层改善了基底与涂层之间的附着力。用于评估断裂韧性的模型的有效性取决于此处研究的样品的层结构和断裂轮廓（厚涂层用经典模型，薄涂层用基于能量的模型）。
