Senderowski Cezary, Chodala Michal, Bojar Zbigniew
Department of Advanced Materials and Technologies, Faculty of Advanced Technologies and Chemistry, Military University of Technology, 2 Kaliskiego St., Warsaw 00-908, Poland.
Materials (Basel). 2015 Mar 13;8(3):1108-1123. doi: 10.3390/ma8031108.
The detonation gun sprayed Fe-Al type coatings as an alternative for austenitic valve steel, were investigated using two different methods of testing corrosion resistance. High temperature, 10-hour isothermal oxidation experiments at 550, 750, 950 and 1100 °C show differences in the oxidation behavior of Fe-Al type coatings under air atmosphere. The oxide layer ensures satisfying oxidation resistance, even at 950 and 1100 °C. Hematite, α-Al₂O₃ and metastable alumina phases were noticed on the coatings top surface, which preserves its initial thickness providing protection to the underlying substrate. In general, only negligible changes of the phase composition of the coatings were noticed with simultaneous strengthening controlled in the micro-hardness measurements, even after 10-hours of heating at 1100 °C. On the other hand, the electrochemical corrosion tests, which were carried out in 200 ppm Cl (NaCl) and pH ~4 (H₂SO₄) solution to simulate the acid-rain environment, reveal higher values of the breakdown potential for D-gun sprayed Fe-Al type coatings than the ones for the bulk Fe-Al type alloy and Cr21Mn9Ni4 austenitic valve steel. This enables these materials to be used in structural and multifunctional applications in aggressive environments, including acidic ones.
研究了用爆轰枪喷涂的Fe-Al型涂层作为奥氏体阀门钢的替代涂层，并采用两种不同的方法测试其耐腐蚀性。在550、750、950和1100℃下进行的10小时高温等温氧化实验表明，在空气气氛下Fe-Al型涂层的氧化行为存在差异。即使在950和1100℃下，氧化层也能确保令人满意的抗氧化性。在涂层顶表面发现了赤铁矿、α-Al₂O₃和亚稳氧化铝相，其保持了初始厚度，为下层基体提供了保护。一般来说，即使在1100℃加热10小时后，在涂层相组成仅有可忽略不计变化的同时，显微硬度测量中的强化作用也得到了控制。另一方面，在200 ppm Cl（NaCl）和pH约为4（H₂SO₄）的溶液中进行的电化学腐蚀试验，以模拟酸雨环境，结果表明，爆轰枪喷涂的Fe-Al型涂层的击穿电位值高于块状Fe-Al型合金和Cr21Mn9Ni4奥氏体阀门钢。这使得这些材料能够用于侵蚀性环境（包括酸性环境）中的结构和多功能应用。
