A Comparative Study on the Effects of Different Thermochemical Coating Techniques on Corrosion Resistance of STKM-13A Steel

• Published in: Metallurgical and materials transactions. A, Physical metallurgy and materials science Physical metallurgy and materials science, 2018-11, Vol.49 (11), p.5833-5847
• Main Authors: Günen, Alİ, Kanca, Yusuf, Karahan, İsmaİl Hakkı, Karakaş, Mustafa Serdar, Gök, Mustafa Sabrİ, Kanca, Erdoğan, Çürük, Ahmet
• Format: Article
• Language: English
• Subjects: Boriding; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coating effects; Corrosion effects; Corrosion resistance; Corrosion resistant steels; Corrosion tests; Hastelloy (trademark); Immersion tests (corrosion); Materials Science; Metallic Materials; Microhardness; Monel (trademark); Nanotechnology; Nickel base alloys; Nuclear power plants; Optical microscopy; Protective coatings; Scanning electron microscopy; Sodium chloride; Structural Materials; Superalloys; Surfaces and Interfaces; Thin Films; Uranium
• ISSN: 1073-5623; 1543-1940
• DOI: 10.1007/s11661-018-4862-2

The corrosion resistances of three different thermochemical coatings (grown using titanizing, boriding, and borotitanizing treatments) applied to STKM-13A steel surfaces were investigated. The coatings were characterized using optical microscopy, scanning electron microscopy, energy dispersive spectroscopy, X-ray diffractometry, 2D profilometry, and microhardness experiments. The corrosion tests were conducted using both electrochemical and static immersion methods, in 3.5 pct NaCl and 40 pct HF acid solutions, respectively. The corrosion resistance of STKM-13A steel was enhanced after the coating process. The specimens were exposed to more corrosion in the HF solution than in the NaCl solution. The best corrosion resistance was obtained in the borotitanized and borided specimens immersed in the NaCl and HF solutions, respectively. The borided STKM-13A steel sample showed even less cumulative weight loss than Inconel 625 in the static immersion HF acid solution test. This suggests potential use of the borided STKM-13A steel in the uranium production units of nuclear power plants as an alternative to more costly alternatives such as Monel, Inconel, and Hastelloy.