表面涂层的多极图案化与晶体结构定向化设计及服役基础

How to further optimize the structure and improve the service performance of surface coatings, the design and micro processing of surface and interface patterning and crystal orienting of surface coatings is one of the hot research directions worth exploring. In this project, supersonic plasma sprayed coatings are intended to be used as the research object. Based on the texture pattern treatment of the substrate / coating interface and coating surface, as well as crystal orientation optimization and reorganization of coating grains formed by the rapid solidification of droplets, the coating structure will be significantly optimized, and the mechanical and tribological properties of coatings will be improved. The geometry and appearance design of texture pattern of surface and interface are intended to be studied in-depth to resolve the deformation and micro fracture problems of micro pattern under the high-temperature and high-speed plasma jet. The orientation texture between different grains, i.e. staggered layers of light and shade, is attempted to be studied to settle the problems of thermal stress transfer from subsequent droplets to former spread droplets during the coating formation, as well as erosion and oxidation of coating material elements, and realize the continuation and integrity of layers of light and shade under the action of different coefficient of thermal expansion and hot and cold gradient alternating. The mapping relations between coating texture pattern and damages such as crack initiation and propagation are planned to be studied to educe the equations of acting forces and bearing forces of 3D geometric parameters of texture, and solve the difficulty in characterization and evaluation of excellent wear resistance and anti fatigue as well as geometry texture pattern parameters of internal and surface/interface under mixed boundary lubrication conditions.

如何进一步优化表面涂层的结构并提高其服役性能，涂层的表界面图案化与晶体定向化的设计与微处理是值得探索的热点方向之一。本研究拟以超音速等离子喷涂层为研究对象，通过对基体/涂层界面、涂层表面进行织构图案化处理，以及对由熔滴快速凝固而成的涂层晶粒进行晶体取向优化与重组，明显改善涂层的力学与摩擦学性能。拟深入研究表界面织构图案的几何与形貌设计，解决微图案在高温、高速等离子射流作用下的变形、微断裂问题；研究涂层中不同晶粒即明暗交错层之间的定向化织构难题，解决在涂层成形过程中后续溶滴对前续已铺展溶滴即晶粒的热应力传递，以及涂层材料元素的烧蚀与氧化问题；实现明暗层在不同热膨胀系数作用下、冷热梯度交变过程中的连续与完整；研究涂层织构图案与涂层裂纹萌生、扩展等损伤的映射关系，推导织构三维几何参数受力方程和承载方程，解决混合-边界润滑条件下涂层优异的耐磨抗疲劳性能与内部和表界面几何织图案参数的表征与评价难题。

本文将织构图案制备于涂层界面来提高Ni60喷涂涂层的结合强度，结合图像处理软件（Image Pro Plus）对织构化图案提高喷涂层结合强度的机理进行了探讨；利用单个颗粒收集技术获得颗粒的沉积形貌，分析织构参数对喷涂颗粒铺展行为的影响，研究了喷涂涂层在织构化处理的基体表面的成形机理；探索了织构图案粗糙度参数对喷涂颗粒高温润湿性能的影响，并建立了喷涂涂层结合强度与粗糙度参数的关系；同时，将仿生织构图案制备于喷涂涂层表面，利用YS-2疲劳实验机对涂层的滚动接触疲劳寿命进行考察，并对不同结合强度下喷涂涂层的滚动接触疲劳寿命进行预测。.研究了织构图案形状（沟槽形、正方形及六边形）对喷涂涂层结合强度的影响，并与喷砂处理后的结合强度（50MPa）进行对比，分析了织构化图案影响涂层结合强度的机理。结果表明，对比于喷砂处理，沟槽形织构化处理后界面处增加接触面积率（CZR）提高了1.28倍，涂层的结合强度为58MPa。正方形形织构化处理后涂层的结合强度最低为33MPa，导致涂层结合强度差异的原因为织构图案形状改变了界面处增加接触面积率、织构图案的密度及界面处平面区的面积。.研究了织构图案的深度（H）、直径（D）及间距（L）对喷涂涂层填充行为及成形机制的影响，并探讨了织构图案参数的交互作用对涂层结合强度的影响。结果表明，随织构图案深度的增加织构内部逐渐产生气孔，涂层的结合强度取决于增加接触面积率与织构内气孔体积（Vt）的竞争机制；涂层结合强度随织构直径的增大呈整体上升趋势，随织构间距的增大而降低。织构图案的直径会影响喷涂颗粒在凹坑内部的润湿行为，而织构图案的间距会改变喷涂液滴在平面区域的结合类型；.研究了表面织构化图案直径和密度对涂层接触疲劳性能的影响，结果表明，随着织构图案直径的增加，凹坑内部及边缘的堆积物质逐渐增多，涂层的接触疲劳性能先上升后降低。