水工金属机件长效防护陶瓷涂层的制备和防护机理研究

The research aims at understanding a novel method to improve efficiently long-term protection of hydraulic metal parts due to their poor working life and reliability under water environment, caused by complicated corrosion environment and therefore resulted in high rate of corrosion and severe damage on parts. The novel method will be performed by preparing ceramic composite coatings on the surface of metal parts using plasma sprayed process, combining an innovative sealing treatment with ultrasonic excitation as well as a dispersion strengthing treatment.The proper strengthing treatment will bring an ideal conditions of diffusion reaction and will accordingly increase extremely bond strength of the coating/metal matrix. The sealing treatment with ultrasonic excitation will seal efficiently pores of the coatings to prevent corrosion of corrosive medium on metal matrix throughout pores.Furthermore, some environment-friendly modified additives will be added into sealing agents to decrease surface energy of coatings for improving biosorption-resitance property of coatings.The research will is useful to understand the preparation of ceramic coatings for long-term protection of hydraulic metal parts with good corrosion-resistance, wear-resistance and biosorption-resitance properties, as well as long-term protection mechanism. Accordingly hydraulic metal parts will be suitable to meet severe working demand from environment. Moreover, the research will overcome those key technical defects of plasma sprayed coatings worked in water environment including high porosity, low bond strength and poor biosorption-resitance, and will improve extremely effects of long-term protection of parts. The results will undoubtly have important theory and practice significance for broadening application of metal parts under water environment.

针对水环境下腐蚀体系复杂，对零部件腐蚀速度快，破坏性强，造成水工金属机件寿命低，可靠性差的背景特点，首次提出一种结合独创的超声场辅助封孔和融和强化处理，在金属表面制备等离子喷涂陶瓷防护层，有效提升水工金属机件长效防护效果的新方法。一方面，借助融合强化处理，创造涂层间扩散反应条件，改善涂层与金属基体的结合强度；另一方面，借助超声场耦合辅助，制备和掌握新型涂层微孔封闭材料和技术，有效阻隔腐蚀介质通过孔洞对金属基体的腐蚀；并引入环境友好型改性助剂，降低涂层表面能和生物吸附能力。掌握耐腐蚀、耐磨损和抗水生物吸附性能优异的防护涂层制备方法和长效防护机理，满足水工金属机件苛刻的使用环境要求。本项目克服了等离子喷涂层孔隙率高、结合强度低，防水生物吸附性能差等用于水工机件防护层的关键技术缺陷，有望大幅提高机件的长效防护效果，研究成果对拓展金属机件在水环境下的长效应用具有重要的理论价值和现实意义。

针对水环境下腐蚀体系复杂，对零部件腐蚀速度快，破坏性强，造成水工金属机件寿命低，可靠性差的背景特点，研究了一种结合超声场辅助封孔和融和强化处理，在金属表面制备等离子喷涂陶瓷防护层的新方法，有效提升水工金属机件长效防护效果。主要研究内容包括：借助融合强化处理改善涂层与金属基体的结合强度；借助超声场耦合辅助，掌握新型涂层微孔封闭材料和技术，有效阻隔腐蚀介质通过孔洞对金属基体的腐蚀；引入环境友好型改性助剂，降低涂层表面能和生物吸附能力；借助等离子熔覆和自蔓延熔铸技术，对比研究不同制备技术对涂层性能的影响；掌握耐腐蚀、耐磨损和抗水生物吸附性能优异的防护涂层制备方法和长效防护机理。重要结果包括：在等离子涂层融合强化处理研究方面，掌握了Al2O3-13wt.%TiO2和Cr2O3-8wt.%TiO2两类等离子喷涂层最优化工艺参数及其与涂层微结构、性能间的科学关系，掌握最优化的涂层融合强化处理方案，阐明了涂层与涂层间、涂层与基体间的扩散反应条件及相关机理，提出改善陶瓷涂层与基体结合强度的方法；在涂层封孔材料和封孔方法研究方面，掌握了两种效果优秀的封孔材料的最优化配方，掌握了两种效果优秀的最优化封孔方法，掌握了封孔涂层的最优化性能及涂层防护性能提高的科学机理；在涂层抗水生物吸附研究方面，掌握了改性涂层成分和工艺与涂层抗水生物吸附性能的关系，最终掌握了本研究长效防护涂层的作用机理。关键数据包括：涂层与基体结合强度≥45MPa；涂层冲击功≥3J的能量；涂层硬度达到1300Hv。封孔后涂层表面孔隙率低于1%，且不存在开孔；涂层耐5%NaCl盐雾腐蚀寿命≥2500小时，是传统镀铬层的10倍以上。现场海试半年以上，涂层无明显水生物吸附，呈现了良好的超疏水和耐腐蚀性能。本项目克服了等离子喷涂层孔隙率高、结合强度低，防水生物吸附性能差等用于水工机件防护层的关键技术缺陷，有效提高机件的长效防护效果，研究成果对拓展金属机件在水环境下的长效应用具有重要的理论价值和现实意义。