Kania Henryk, Sipa Jacek
Silesian University of Technology, Institute of Materials Engineering, Krasińskiego 8, 40-019 Katowice, Poland.
Remix S.A., Poznańska 36, 66-200 Świebodzin, Poland.
Materials (Basel). 2019 Apr 29;12(9):1400. doi: 10.3390/ma12091400.
The article presents the results of research on the application of innovative thermal diffusion zinc coating technology with the recirculation of the reactive atmosphere to high-strength grade 10.9 bolts. The innovation of this method consists in the introduction of reactive atmosphere recirculation and the application of coating powder mix which contains zinc powder and activator. Recirculation of the reactive atmosphere ensures its uniform composition, while the presence of an activator intensifies the process of saturating steel surface with zinc, which boosts the efficiency of active agents. Coatings were created at 440 °C and a heat soaking time of 30-240 min. Coating structure (SEM) was exposed, chemical composition in microsites (EDS) was defined, and coating phase structure (XRD) was identified. The kinetics of coating growth were defined. It was found that the increment of coating thickness was controlled by square root of soaking time. Coatings obtained using innovative thermal diffusion zinc coating technology had a two-layer structure. At the substrate, a compact layer of phase Γ (FeZn) was created, which was covered with a layer of phase δ (FeZn). The new method of thermal diffusion zinc coating will alow for the creation of coatings of very good corrosion resistance while maintaining strength properties of bolts defined as strength class 10.9.
本文介绍了将具有反应性气氛再循环的创新热扩散镀锌技术应用于高强度10.9级螺栓的研究结果。该方法的创新之处在于引入了反应性气氛再循环，并应用了包含锌粉和活化剂的涂层粉末混合物。反应性气氛的再循环确保了其成分均匀，而活化剂的存在则强化了钢表面锌饱和的过程，从而提高了活性剂的效率。涂层在440°C下制备，保温时间为30 - 240分钟。对涂层结构（扫描电子显微镜）进行了观察，确定了微区的化学成分（能谱分析），并识别了涂层的相结构（X射线衍射）。确定了涂层生长的动力学。结果发现，涂层厚度的增加受保温时间平方根的控制。采用创新热扩散镀锌技术获得的涂层具有双层结构。在基体上形成了致密的Γ相（FeZn）层，其上覆盖着一层δ相（FeZn）。这种新的热扩散镀锌方法将能够在保持定义为10.9强度等级的螺栓强度性能的同时，制备出具有非常好耐腐蚀性的涂层。
