Lencová Kateřina, Frank Netrvalová Marie, Vostřák Marek, Lukáč František, Mušálek Radek, Česánek Zdeněk, Houdková Šárka
Research and Testing Institute Plzen, 30100 Pilsen, Czech Republic.
Institute of Plasma Physics of CAS, 18200 Prague, Czech Republic.
Materials (Basel). 2023 Feb 18;16(4):1712. doi: 10.3390/ma16041712.
In order to extend the life of boilers by applying an anti-corrosion coating without the need to dismantle them, it is advisable to find coatings that can be applied using cheaper and portable techniques, such as Twin Wire Arc Spray technology (TWAS). In this study, we compare selected NiCr-based coatings and two uncoated steel substrates (steel 1.7715 and 1.4903). Two coatings, CrC - 25% NiCr and Hastelloy C-276 are deposited using High velocity oxygen-fuel technology (HVOF) and three coatings, NiCrTi, NiCrMo, and Inconel 625, are deposited using TWAS. In addition to the corrosion weight gain during 50 cycles of loading in an 18% NaSO and 82% Fe(SO) salt environment at 690 °C evaluated using the gravimetric method, the microstructure and phase composition of the coatings were analyzed on the samples after the exposure in order to compare the properties and gain a deeper understanding of the corrosion kinetics. Coating cross-sections and free-surfaces were observed with a scanning electron microscope (SEM) with an energy-dispersive (EDX) system. The phase composition was investigated using X-ray diffraction (XRD) and Raman spectroscopy. No significant differences were observed between the TWAS and HVOF coating methods for the coatings compared. Due to the similar corrosion products found on all coatings, a very effective corrosion protective layer was formed on the surface, forming a barrier between the corrosive environment and the coating regardless of the used deposition technology. Therefore, for industrial use on the inner surface of coal-fired boilers we recommend NiCrTi, NiCrMo, or Inconel coatings prepared with the more cost-effective and portable TWAS technology.
为了在不拆卸锅炉的情况下通过应用防腐涂层来延长其使用寿命，建议找到可以使用更便宜且便于携带的技术（如双丝电弧喷涂技术（TWAS））来应用的涂层。在本研究中，我们比较了选定的镍铬基涂层和两种未涂层的钢基材（1.7715钢和1.4903钢）。两种涂层，CrC - 25% NiCr和哈氏合金C - 276，采用高速氧燃料技术（HVOF）沉积，三种涂层，NiCrTi、NiCrMo和因科镍合金625，采用TWAS沉积。除了使用重量法评估在690°C的18% NaSO和82% Fe(SO)盐环境中50次加载循环期间的腐蚀增重外，还对暴露后的样品涂层的微观结构和相组成进行了分析，以便比较性能并更深入地了解腐蚀动力学。使用配备能量色散（EDX）系统的扫描电子显微镜（SEM）观察涂层横截面和自由表面。使用X射线衍射（XRD）和拉曼光谱研究相组成。对于所比较的涂层，TWAS和HVOF涂层方法之间未观察到显著差异。由于在所有涂层上发现了相似的腐蚀产物，在表面形成了非常有效的腐蚀保护层，无论使用何种沉积技术，都在腐蚀环境和涂层之间形成了屏障。因此，对于燃煤锅炉内表面的工业应用，我们推荐使用更具成本效益且便于携带的TWAS技术制备的NiCrTi、NiCrMo或因科镍合金涂层。
