紧固件表面无铬锌铝涂层的腐蚀行为研究

Study on Testing Method of Corrosion Behavior of Fastener Coating

紧固件实际安装使用时,表面涂层会受到一定的力矩使其发生破坏,为了探究螺栓在实际安装使用情况下的腐蚀行为,本论文选用具有无铬锌铝涂层的螺栓为研究对象,通过扭矩扳手在螺栓上加载60 N·m的力对表面涂层进行破坏,以模拟涂层实际安装使用时的表面状态,并通过中性盐雾试验探究加载力矩后涂层的腐蚀行为。研究表明锌铝涂层具有很好的防护性,加载力矩的螺栓表面涂层被破坏后仍能表现出很好的耐蚀性,经过60d试验涂层表面破损处未观察到红锈,电化学测量结果表明加载力矩后的破损涂层仍然具有很好的屏蔽和阴极保护作用。

During the actual installation of fasteners,the loaded torque damages the integrity of the surface coating.In order to explore the corrosion behavior of bolts under the actual installation and use,this paper select the bolts with chrome-free zinc aluminum coating as the research object,and used a torque wrench to load 60 N•m force on the bolts to damage the surface coating,so as to Simulate the surface state of the coating during the actual use,The corrosion behavior of the coating after loading torque was investigated by neutral salt spray test.The research showed that the zincaluminum coating had good protection,and the bolt surface coating loaded with torque can still show good corrosion resistance after being damaged.After 60 days of test,no red rust was observed at the damaged part of the coating surface.The electrochemical measurement resuIts showed that the damaged coating loaded with torque still had good shielding and cathodic protection.