很多参数都决定着热喷涂涂层的质量,如喷涂粉末性质、供粉状态、粉末的形貌、动力系统以及喷涂环境等。但在这些因素中,涂层与基材间的结合力是最基本的评价指标。为了使涂层和基材间具有良好的结合力,需要对基材进行表面清洁和预处理。通常使用有机溶剂对基材除油去污,并进行喷砂处理增大基材的表面粗糙度。但由于基材（如陶瓷）本身的性质以及形状,机械处理易造成基材的剥落或对整体性能产生不利影响。为获取一种合适的预处理工艺,科研工作者开展了大量预处理方式的研究,如水射流技术,干冰喷射清理,热处理等。其中激光烧蚀法是进行基材预处理的有效技术手段。此工作的目的是为了研究持续时间为10ns的Q开关Nd：YAG近红外激光发射的单束或复合式脉冲激光所引发的改性效应以及对界面结合力的影响,以陶瓷基复合材料上喷涂的氧化铝涂层为研究对象。结果表明,激光处理手段可引发材料的机械效应（锥形结构的形成）和化学效应,对涂层的结合性能可以起到良好的改性作用。%The quality of thermally sprayed coatings depends on a lot of parameters （spraying power,feedstock injection,morphology of the parts,kinetics and environment）. But among them,adherence between the coating and the substrate appears as the fundamental point. To favor a good interaction and also a good adherence between the coating and the substrate, it is often necessary to clean and prepare the substrate surface. Conventionally, solvents and sand-blasting are applied to remove the contaminants and increase the surface roughness for a mechanical anchorage. But according to the substrate nature （ceramic） or the substrate morphology, it can be prejudicial to apply a mechanical treatment due to a peeling of the surface or a decrease of the global properties. By this way some other treatments have to be investigated in order to obtain an appropriate preparation. From all of them （water jet,ice blasting,heating treatment,etc.）, laser ablation can be an interesting technology to prepare the substrate surface. The aim of this work was to study the modifications induced by 10 ns single or cumulative pulses of a Q-switched Nd：YAG near-infrared laser and its influence on the interface adhesion. The case of an alumina coating sprayed on a Ceramic Matrix Composite （CMC） has been studied.In these conditions, the laser treatment seems favorable from the adherence point of view according to the mechanical effect （induced by a cone-like structure） and the chemical effect.
展开▼
