Characterization of Ta–W alloy films deposited by molten salt Multi-Anode Reactive alloy Coating (MARC) method. (November 2015)

• Record Type: Journal Article
• Authors: Lee, Young-Jun; Lee, Tae-Hyuk; Nersisyan, Hayk H.; Lee, Kap-Ho; Jeong, Seong-Uk; Kang, Kyoung-Soo; Bae, Ki-Kwang; Park, Kyoung-Tae; Lee, Jong-Hyeon
• Is Part Of: International journal of refractory metals & hard materials. Volume 53:Part A(2015:Nov.)
• Page Start: 23
• Page End: 31
• Publication Date: 2015-11
• Subjects: EDX energy-dispersive X-ray spectroscopic analysis -- FESEM field emission scanning electron microscopy -- TEM transmission electron microscopy -- XRD X-ray diffractometer; Tantalum -- Tantalum alloy -- Tungsten alloy -- Electroplating -- Molten salt; Heat resistant alloys -- Periodicals; Refractory materials -- Periodicals; Metallography -- Periodicals; Alliages réfractaires -- Périodiques; Matériaux réfractaires -- Périodiques; Métallographie -- Périodiques; Heat resistant alloys; Metallography; Refractory materials; Periodicals; Electronic journals; 669.73
• DOI: 10.1016/j.ijrmhm.2015.04.022
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: The harsh atmosphere of the sulfur–iodine process used for producing hydrogen requires better corrosion resistance and mechanical properties than are possible to obtain with pure tantalum. Ta–W alloy is superior to pure tantalum but is difficult to alloy due to its high melting temperature. In this study, substrate samples were coated with Ta–W (Ta–7W, Ta–4W and Ta–1W) using the Multi-Anode Reactive alloy Coating (MARC) process in molten salt (LiF–NaF–K2 TaF7 ), with varying distances between cathode and anode. In the case of Ta–4W, a corrosion rate of less than 0.011 mm/year was attained in hydriodic acid at 160 °C, and thickness uniformity was 80.3 ± 2.15 μm. Also, the resulting coated films had hardnesses up to 12.9% stronger than pure tantalum coated film. The alloy coating films also contributed to significant enhancement of corrosion resistance. Graphical abstract: Highlights: Ta–W alloy was coated onto a SUS substrate by molten salt MARC method. Ta–W alloy layer related to the microstructural changes associated with W contents. Microstructure of Ta–W alloy coating layer was investigated by OIM and FE-SEM. Ta–4.36W alloy layer showed 0.011 mm/year corrosion rate in hot conc. HI acid.