Corrosion behaviour of hot dip zinc and zinc-aluminium coatings on steel in seawater

	Corrosion behaviour of hot dip zinc and zinc-aluminium coatings on steel in seawater
	Li, Y
	2001-08-01
发表期刊	BULLETIN OF MATERIALS SCIENCE
ISSN	0250-4707
卷号	24 期号:4 页码:355-360
文章类型	Article
摘要	A comparative investigation of hot dip Zn-25Al alloy, Zn-55Al-Si and Zn coatings on steel was performed with attention to their corrosion performance in seawater. The results of 2-year exposure testing of these at Zhoushan test site are reported here. In tidal and immersion environments, Zn-25Al alloy coating is several times more durable than zinc coating of double thickness. At long exposure times, corrosion rate for the Zn-25Al alloy coating remains indistinguishable from that for the Zn-55Al-Si coating of similar thickness in tidal zone, and is two to three times lower than the latter in immersion zone. The decrease in tensile strength suggested that galvanized and Zn-55Al-Si coated steel suffer intense pitting corrosion in immersion zone. The electrochemical tests showed that all these coatings provide cathodic protection to the substrate metal; the galvanic potentials are equal to - 1,050, - 1,025 and - 880 mV (SCE) for zinc, Zn-25Al alloy and Zn-55Al-Si coating, respectively, which are adequate to keep the steel inside the immunity region. It is believed that the superior performance of the Zn-25Al alloy coating is due to its optimal combination of the uniform corrosion resistance and pitting corrosion resistance. The inferior corrosion performance by comparison of the Zn coating mainly results from its larger dissolution rate, while the failure of the Zn-55Al-Si coating is probably related to its higher susceptibility to pitting corrosion in seawater.; A comparative investigation of hot dip Zn-25Al alloy, Zn-55Al-Si and Zn coatings on steel was performed with attention to their corrosion performance in seawater. The results of 2-year exposure testing of these at Zhoushan test site are reported here. In tidal and immersion environments, Zn-25Al alloy coating is several times more durable than zinc coating of double thickness. At long exposure times, corrosion rate for the Zn-25Al alloy coating remains indistinguishable from that for the Zn-55Al-Si coating of similar thickness in tidal zone, and is two to three times lower than the latter in immersion zone. The decrease in tensile strength suggested that galvanized and Zn-55Al-Si coated steel suffer intense pitting corrosion in immersion zone. The electrochemical tests showed that all these coatings provide cathodic protection to the substrate metal; the galvanic potentials are equal to - 1,050, - 1,025 and - 880 mV (SCE) for zinc, Zn-25Al alloy and Zn-55Al-Si coating, respectively, which are adequate to keep the steel inside the immunity region. It is believed that the superior performance of the Zn-25Al alloy coating is due to its optimal combination of the uniform corrosion resistance and pitting corrosion resistance. The inferior corrosion performance by comparison of the Zn coating mainly results from its larger dissolution rate, while the failure of the Zn-55Al-Si coating is probably related to its higher susceptibility to pitting corrosion in seawater.
关键词	Galvanization By Hot Dipping Zn-al Alloy Coating Seawater Corrosion Pitting Corrosion Cathodic Protection
学科领域	Materials Science, Multidisciplinary
收录类别	SCI
语种	英语
WOS记录号	WOS:000170363400002
引用统计	被引频次：40[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/2344
专题	海洋环境腐蚀与生物污损重点实验室
作者单位	Chinese Acad Sci, Inst Oceanol, Qingdao 266071, Peoples R China
推荐引用方式 GB/T 7714	Li, Y. Corrosion behaviour of hot dip zinc and zinc-aluminium coatings on steel in seawater[J]. BULLETIN OF MATERIALS SCIENCE,2001,24(4):355-360.
APA	Li, Y.(2001).Corrosion behaviour of hot dip zinc and zinc-aluminium coatings on steel in seawater.BULLETIN OF MATERIALS SCIENCE,24(4),355-360.
MLA	Li, Y."Corrosion behaviour of hot dip zinc and zinc-aluminium coatings on steel in seawater".BULLETIN OF MATERIALS SCIENCE 24.4(2001):355-360.

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