Abstract

The sol–gel coating method is considered to be simple and easy to implement to lead to organic/inorganic hybrid coatings. In addition, the application of thin films by this technique is inexpensive and applicable on large substrates without form restriction. In this context, thin sol–gel coatings based on a mixture of three alkoxysilanes and synthesized in purely aqueous phase with different thicknesses and with the presence or not of ZrO₂ nanoparticles, were applied on metallic and glass substrates. After application and curing, the mechanical properties of sol–gel coatings were characterized by Berkovich nanoindentation with continuous stiffness measurement mode (CSM). The effective elastic moduli as well as the hardness values were estimated for each coating along the indentation depth and as a function of the substrate material and sol–gel characteristics. The effect of a annealing at higher temperature was also studied. Then, the failure modes of sol–gel coatings were investigated using both Berkovich nanoindentation and nanoscratch technique with a 5 µm radius spherical diamond tip. Careful microscopic observations of residual imprints and residual grooves both exhibit chipping in case of thick coating especially on glass substrate and no dramatic failure for thin coating applied on both substrates. It is shown in this work that the mechanical properties of the sol–gel and the mechanical stability of coatings on substrates are influenced dramatically by the presence of nanoparticles and the thermal treatment. Finally, interfacial fracture toughness of sol–gel coatings on substrate was estimated using analytical model from the literature and Ashby map based on experimental results was created using performance indices in order to proceed to sol–gel coating selection.

中文翻译：

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金属和玻璃基材上的溶胶-凝胶涂层的机械性能和脱粘

抽象的

溶胶-凝胶涂层法被认为是简单易行的方法，可用于有机/无机杂化涂层。另外，通过该技术施加薄膜是廉价的，并且可以在没有形状限制的情况下适用于大型基板。在这种情况下，基于三种烷氧基硅烷混合物的薄溶胶-凝胶涂料，是在纯水相中合成的，具有不同的厚度，是否存在ZrO ₂将纳米颗粒施加到金属和玻璃基材上。涂布和固化后，通过具有连续刚度测量模式（CSM）的Berkovich纳米压痕来表征溶胶-凝胶涂层的机械性能。沿压痕深度估算了每个涂层的有效弹性模量和硬度值，并根据基材和溶胶-凝胶特性进行了估算。还研究了在较高温度下退火的效果。然后，使用Berkovich纳米压痕技术和半径为5 µm的球形金刚石尖端的纳米划痕技术研究了溶胶-凝胶涂层的破坏模式。在厚涂层的情况下（尤其是在玻璃基板上），仔细观察残留的痕迹和残留凹槽的显微镜观察均会出现碎裂现象，而在两个基板上施涂的薄涂层均无严重破坏。这项工作表明，溶胶-凝胶的机械性能和基底上涂层的机械稳定性会受到纳米粒子的存在和热处理的极大影响。最后，使用文献中的分析模型评估了溶胶-凝胶涂层在基材上的界面断裂韧性，并根据性能结果创建了基于实验结果的Ashby图，以进行溶胶-凝胶涂层的选择。这项工作表明，溶胶-凝胶的机械性能和基底上涂层的机械稳定性会受到纳米粒子的存在和热处理的极大影响。最后，使用文献中的分析模型评估了溶胶-凝胶涂层在基材上的界面断裂韧性，并根据性能结果创建了基于实验结果的Ashby图，以进行溶胶-凝胶涂层的选择。这项工作表明，溶胶-凝胶的机械性能和基底上涂层的机械稳定性会受到纳米粒子的存在和热处理的极大影响。最后，使用文献中的分析模型评估了溶胶-凝胶涂层在基材上的界面断裂韧性，并根据性能结果创建了基于实验结果的Ashby图，以进行溶胶-凝胶涂层的选择。