水介质空化溃灭作用下不锈钢表面损伤实验及教学拓展  

Experiment and teaching expansion on surface damage of stainless steel under the effect of water medium cavitation collapse

作　　者：刘磊[1] 赵继云[2] 郭华锋[1] 满家祥[1,2] 于萍 LIU Lei;ZHAO Jiyun;GUO Huafeng;MAN Jiaxiang;YU Ping(School of Mechanical and Electrical Engineering,Xuzhou Institute of Technology,Xuzhou 221000,China;School of Mechanical and Electrical Engineering,China University of Mining and Technology,Xuzhou 221000,China)

机构地区：[1]徐州工程学院机电工程学院,江苏徐州221000 [2]中国矿业大学机电工程学院,江苏徐州221000

出　　处：《实验技术与管理》2023年第7期194-198,219,共6页Experimental Technology and Management

基　　金：国家自然科学基金重点项目(U1910212);徐州市科技计划项目(KC21002)。

摘　　要：针对水介质空化溃灭作用下不锈钢材料的气蚀损伤问题,研究了空化气蚀后的形貌、物相、化学态、电化学等特性。研究结果表明:纯水中金属离子的加入,强化了空泡溃灭的动力学作用,由于相较于纯水空化中的水锤作用,金属离子的硬度远大于水,因此造成的动力学作用更强,气蚀损伤也更剧烈;空化溃灭时能够在短时间内释放高温传递至不锈钢表面,并经过纯水介质的快速冷却,导致出现马氏体结构,但是大量金属离子的存在使得热传导速度降低且部分热量被吸收;经空泡溃灭作用后,不锈钢表面钝化膜出现早期微孔,微孔相较于周边基体区域较低,孔内外的溶液难以分散,形成浓度差,导致孔底电流密度升高,从而使p H值降低;相较于纯水,3.5%NaCl溶液含有更多的自由离子,其形成的局部电流密度更大,因此耐蚀性更差;随着空化时间的延长,试样对应的钝化区逐渐消失。The morphology,phase,chemical state,and electrochemical characteristics of stainless steel materials subjected to cavitation erosion and collapse in aqueous media were studied.The research results indicate that the addition of metal ions in pure water enhances the dynamic effect of bubble collapse.Compared to the water hammer effect in pure water cavitation,the hardness of metal ions is much greater than that of water,resulting in stronger dynamic effects and more severe cavitation damage;Cavitation collapse can release high temperature in a short time and transfer it to the surface of stainless steel,and after rapid cooling by pure water medium,martensite structure will appear,but the existence of a large number of metal ions will reduce the heat conduction speed and part of the heat will be absorbed;After bubble collapse,early micropores appear in the passivation film on the surface of stainless steel.Compared to the surrounding matrix area,the micropores are lower,making it difficult for the solution inside and outside the pores to disperse,resulting in a concentration difference and an increase in the current density at the bottom of the pores,thereby reducing the pH value;Compared to pure water,3.5%NaCl solution contains more free ions,resulting in a higher local current density and poorer corrosion resistance;As the cavitation time prolongs,the corresponding passivation zone of the sample gradually disappears.

关 键 词：水介质 不锈钢 气蚀 模型 

分 类 号：O359[理学—流体力学]