基于界面-内表面微观组织结构演变分析的等离子电解氧化陶瓷涂层形成-放电-生长机理研究

PEO ceramic coating / substrate interfacial region is “the main battlefield” of the coating growth process. Therefore, it is very important for us to establish more objective coating formation - discharge - growth mechanism through the observation and analysis of the development and evolution rules of internal surface morphology and interfacial zone microstructure with the experimental conditions such as process parameters. However, due to the firm metallurgical between the coating and substrate, it is difficult to prepare the detached coating samples with complete internal surface morphology, so that it is impossible to conduct the investigation of the internal surface and interface region, and over the years, the formation - discharge - growth mechanisms of PEO coatings have been being investigated mainly through the observation and analysis of the topography and grinding section structure of the coated specimens, and the online observations and records of the experimental phenomena and data during the PEO process. A recent license technology of this research group can be used to prepare the detached coating samples with complete morphology and microstructure. This application project intends to conduct a systematic and deep investigation on the development and evolution rules of internal surface morphology and microstructure in the interfacial zone by means of the change of the experimental conditions such as process parameters, and the observation and analysis of the detached coating samples, with the combination of routine methods of observation and analysis in order to study the characteristics of development and evolution of the whole PEO coating, further, to establish a more objective formation - discharge - growth mechanism of PEO ceramic coatings.

PEO陶瓷涂层/基体界面区域是该涂层生长过程的“主战场”，因此，通过观测分析涂层内表面形貌及界面区域组织结构随工艺参数等实验条件发展和演化规律，对于建立更加客观的涂层形成-放电-生长机理的意义非常重要。然而，由于涂层/基体间冶金结合牢固而难于制取内表面形貌完整的剥离涂层试样，无法进行涂层内表面及界面区域研究，因此，多年来人们主要通过观测分析涂层试样外表面形貌和磨断面组织结构，以及线上观测记录实验现象和数据来研究PEO涂层形成-放电-生长机理。本课题组近期一项授权专利技术可用于制取内表面形貌及界面区域组织结构完整的剥离涂层试样。本申请项目拟现有研究基础上采用剥离涂层试样观测分析为主，结合常规观测分析方法，通过改变PEO工艺参数等实验条件，深入系统研究涂层内表面形貌及界面区域组织结构发展和演化规律，进而研究整个PEO涂层的发展和演化规律，以期建立更加客观的PEO陶瓷涂层形成-放电-生长机理。

等离子体电解氧化（PEO），或称微弧氧化（MAO），是一种新型环境友好型的表面改性技术，可在阀金属及其合金表面原位生长与基体冶金结合的陶瓷膜层。该膜层具有优良的腐蚀防护效果和摩擦磨损性能。然而，该膜层的生长方式，以及该膜层生长的主要驱动力—等离子体放电的产生与发展仍没有客观的理论指导。这导致制备特定性能的PEO膜层仍依靠大量尝试实验。本项目主要基于对膜层/基体界面区的形貌、组织结构与工艺参数等实验条件的关系，建立更加客观的膜层形成-放电-生长机理。本项目主要从影响PEO膜层的三个主要方面展开研究工作，即电解液参数、电参数和基体参数。通过电化学膜层剥离技术，配合传统的膜层组织结构、显微硬度及化学元素组成检测技术，探究了不同基体上、不同电解液中、不同电参数下制备的PEO膜层在不同阶段的结构特征及演变方式，并通过电化学分析手段和摩擦磨损性能分析，评估了各参数对PEO膜层耐蚀性和摩擦磨损性能的影响。通过引入PEO膜层半导体性质研究（载流子密度和阻抗分析），并将膜层的传统组织结构分析与膜层的电学性能分析相结合，为膜层的形成-生长与等离子体放电的诱发建立了有机联系。提出并建立了不同条件下膜层形成-放电-生长的机制。为进一步深入理解PEO膜层的生长与等离子体放电间的关系提供了研究思路。为有效、准确地控制和合成复合型PEO膜层打下了理论基础。项目组全体成员通力合作，开展了一些基础型和应用型研究，取得可观的成果。