紧固件的机械能助渗锌-低铬达克罗复合防护技术

摘要

The fasteners were treated via mechanical energy-assisted sherardizing followed by low-chromium dacromet coating. The microscopic structure of sherardizing-low chromium dacromet compositecoating was studied using X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy-dispersive spectrometer (EDS). Its adhesion and corrosion resistance were characterized.Zn and Al in dacromet coating are mainly existed as simple substances, while Cr is amorphous. The composite coating has a lamellar structure, which can effectively prevent the diffusion of corrosive medium in it. Its corrosion resistance time to ammonium nitrate is up to 7.8 h and its adhesion grade is 5.%采用机械能助渗锌-低铬达克罗复合防护技术处理紧固件,采用X射线衍射仪(XRD)、扫描电镜(SEM)、能谱仪(EDS)等研究了复合涂层的微观组织结构,表征了它的结合强度和耐蚀性.达克罗涂层中Zn、Al主要以单质形式存在,Cr以非晶态形式存在.复合防护涂层呈层片状结构,能有效阻止腐蚀介质扩散;耐硝酸铵腐蚀时间可达7.8 h,结合强度为5级.