Black rhenium coating prepared on graphite substrate by electrodeposition in NaCl-KCl-CsCl-K2ReCl6 molten salts. (November 2017)

• Record Type: Journal Article
• Authors: Wang, Jiangfan; Zhu, Li'an; Ye, Yicong; Zhang, Hong; Bai, Shuxin
• Is Part Of: International journal of refractory metals & hard materials. Volume 68(2017)
• Page Start: 54
• Page End: 59
• Publication Date: 2017-11
• Subjects: Black rhenium coating -- Electrodeposition -- Molten salt -- Surface emittance; 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.2017.06.010
• Languages: English
• ISSNs: 0263-4368

Abstract

Abstract: A compact and continuous rhenium coating with black appearance was obtained on the surface of graphite substrate in chloride molten salts with high efficiency and low cost. The rhenium coating prepared at a cathodic current density of 50mA/cm 2 at 850 °C has a preferential growth orientation of 〈110〉 and a high deposition rate of ~ 40 μm/h. The rhenium coating is composed of a fine equiaxed-grain zone and a spired columnar-grain zone. The surface emittance is as high as 0.73, which is comparable with black rhenium coating reported by Ultramet. The microhardness of the coating as deposited is 350 ± 16.4 kg/mm 2 . The bond strength of rhenium/graphite interface tested at room temperature is ~ 10.2 MPa and is greatly improved after heat treatment at 1200 °C for 3 h in vacuum. Graphical abstract: Highlights: Black Re coating was prepared in molten salts with a deposition rate of ~ 40 μm/h. Re coating has textured pyramidal surface with 〈110〉 preferred growth orientation. The surface emittance is 0.73, which is comparable with Ultramet's report. Bond strength of interface is ~ 10.2 MPa and greatly improved after heat treatment.