Preparation of chemical conversion super-black films on ZK61M magnesium alloy. (2nd December 2018)

• Record Type: Journal Article
• Authors: Yan, Zhenwei; Tan, Zhaojun; Yuan, Xianjie
• Is Part Of: Surface engineering. Volume 34:Number 12(2018)
• Page Start: 884
• Page End: 891
• Publication Date: 2018-12-02
• Subjects: Super-black conversion films -- corrosion resistance -- high emissivity -- ZK61M magnesium alloy; Surfaces (Technology) -- Periodicals; Coatings -- Periodicals; 620.4405
• DOI: 10.1080/02670844.2017.1386924
• Languages: English
• ISSNs: 0267-0844

Abstract

ABSTRACT: Four different super-black conversion films on ZK61M magnesium alloys were investigated in this work. Macro- and micro-morphologies of the conversion films were observed using a digital camera and scanning electron microscope, respectively. Salt spray testing and electrochemical measurements were used to examine the corrosion resistance of the conversion films. The emissivities of the conversion films were measured using the Fourier transform infrared spectrometry. The results show that all conversion films reduced the corrosion rate of the magnesium alloy substrates effectively; in particular, the film prepared using 230 g L −1 HF + 150 g L −1 Na2 Cr2 O7 ·2H2 O + 2.5 g L −1 CaF2 mixed solution had a higher corrosion resistance. Moreover, the emissivities of the conversion films prepared using 230 g L −1 HF + 180 g L −1 Na2 Cr2 O7 ·2H2 O + 270 g L −1 HNO3 and 230 g L −1 HF + 150 g L −1 Na2 Cr2 O7 ·2H2 O + 2.5 g L −1 CaF2 mixed solutions were very high; the values exceeded 0.9 at room temperature.