THE HOT‐DIP GALVANIZED COATING AND CORROSION RESISTANCE: Part 1

1959 ◽  
Vol 6 (9) ◽  
pp. 275-284
Author(s):  
John H. Nicholls
Keyword(s):  
Corrosion Resistance ◽  
Galvanized Coating

Effect of Bismuth on the Microstructure and Corrosion Resistance of Galvanized Coating

2011 ◽  
Vol 391-392 ◽  
pp. 1183-1188 ◽  
Author(s):  
Jian Hua Wang ◽  
Xing Ming Wang ◽  
Chun Mei Liu ◽  
Xu Ping Su ◽  
Chang Jun Wu ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Electrochemical Corrosion ◽  
Energy Dispersive ◽  
Phase Layer ◽  
Corrosion Tests ◽  
X Ray ◽  
Galvanized Coating ◽  
Scanning Electron

The microstructure of the galvanized coating was investigated using scanning electron microscope equipped with energy dispersive X-ray spectroscope. The immersing and electrochemical corrosion tests were carried out to study the corrosion resistance of the galvanized coating. The addition of Bi in Zn-bath affects remarkably the morphology of the galvanized coating. The thickness of δ + ζ phase layer in the coating reaches the maximum when the content of Bi in Zn-bath is 0.5 wt.%. The corrosion resistance of the galvanized coating declines with the increase of the content of Bi.

The Impact of Zinc Coating Specifications on Corrosion Resistance аnd Durability of Steels

2019 ◽  
Vol 945 ◽  
pp. 740-745
Author(s):  
I.A. Kovalenko ◽  
D.V. Laskin ◽  
A.Y. Trifonova
Keyword(s):  
Corrosion Resistance ◽  
Statistical Analysis ◽  
Chemical Composition ◽  
Service Life ◽  
Zinc Coating ◽  
Useful Life ◽  
Galvanized Coating ◽  
Zinc Coatings ◽  
The Impact ◽  
High Chloride

The article contains the findings on impact of zinc coating specifications on corrosion resistance and service life of steels of various chemical composition used often in modern industries. Characteristics such as type, class, chemical compound and thickness of zinc-based coatings are also addressed. Experiments were performed in which corrosion rate and useful life of zinc coatings in probable operating-like conditions — i.e., in environments of varying degrees of corrosive power (humid and high-chloride environments) were determined. It has been established which one of the environments is the most corrosive for steels depending on the zinc-based coatings’ specifications. Qualitative (visual) and quantitative (gravimetric) assessment of corrosion resistance and service life of chosen steels is presented. Optimal hot dip galvanized coating specifications were determined using statistical analysis.

Effects of lanthanum addition on the microstructure and corrosion resistance of galvanized coating

2019 ◽  
Vol 784 ◽  
pp. 859-868 ◽  
Author(s):  
Wencan Xu ◽  
Liang Wei ◽  
Zhihong Zhang ◽  
Yubao Liu ◽  
Kuo-Chih Chou ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Galvanized Coating

Enhancing adhesion and anti-corrosion performance of hot-dip galvanized steels by sandblasting/phosphating co-treatment

2021 ◽  
Author(s):  
Jingwen Zhang ◽  
Gang Kong ◽  
Wenjun Wang ◽  
Shuanghong Zhang ◽  
Chunshan Che
Keyword(s):  
Corrosion Resistance ◽  
Steel Structures ◽  
Corrosion Damage ◽  
Organic Coating ◽  
Grit Blasting ◽  
Duplex Coating ◽  
Galvanized Steels ◽  
Zinc Plating ◽  
Long Time ◽  
Galvanized Coating

Abstract The substations outdoor steel structures employed in aggressive marine environments can accelerate corrosion damage and cause incredible degradation of performance. Hot-dip galvanizing and organic coating dual-coated anticorrosion system is currently the most effective and efficient protection strategy. In present paper, sandblasting and phosphating technique were applied to the surface of zinc plating, the effect of various grit-blasting and phosphating technology conditions on the adhesion performance and corrosion resistance of duplex-coated system were systematically investigated. Results revealed that the bonding strength of the duplex coating after grit-blasting and phosphating pretreatment was 3.25 and 2.71 times higher than that of the untreated, respectively. In particular, sandblasting and phosphating coprocessing of duplex coating could furtherly improve the adhesion behavior and corrosion resistance, which mainly due to their synergistic effect. Sandblasting can rough the surface of galvanized coating and generate many pits and scratches. Thus, phosphating can form more needle-like zinc phosphate crystals in those positions, anchoring and pinning firmly the interface between galvanized coating and organic coating. Meanwhile, the phosphating film still acted as an anti-corrosion physical barrier to hinder the intrusion of corrosive medium and protect galvanized steels from storage rust before painting for a long time.

Effect of under layer metallic coating composition on phosphating and the corrosion performance for automobile applications

CORROSION ◽  
10.5006/3748 ◽  
2021 ◽  
Author(s):  
Chandrashekhar Savant ◽  
Poorwa Gore ◽  
VS Raja
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Zinc Coating ◽  
Organic Coating ◽  
Phosphate Coating ◽  
Corrosion Performance ◽  
Epoxy Primer ◽  
Phosphate Coatings ◽  
Galvanized Coating ◽  
Salt Fog

Automobile coating system consists of a metallic underlayer followed by a phosphate coating and, lastly, multilayer organic coating. In this work, the effect of the underlying metallic coatings, namely, a Mg-Al-Zn alloy coating (Magizinc) and a conventional galvanized Zn coating on the phosphate coatings formed thereon, and its corrosion performance was investigated. The corrosion resistance offered by the phosphate coating formed on the Magizinc coating was higher than the phosphate coating on the galvanized Zn coating (a reference coating employed in the study) in NaCl solution, as revealed by potentiodynamic polarization, electrochemical impedance spectroscopy, and salt-fog tests. In-depth characterization of the phosphate coatings was carried out using scanning electron microscopy and glow discharge optical emission spectroscopy. It was revealed that the phosphate crystals formed on the Magizinc coating were more fine-grained, compact, and crack-free as compared to that formed on the galvanized coating and contained Mg aiding 4-10 times increase in the corrosion resistance as determined by the electrochemical studies. However, it only improved marginally against the appearance of red rust in a salt-fog test over the unphosphated Magizinc coating. The phosphate coating on Magizinc marginally improved the adhesion of an epoxy primer coating applied on the phosphated Magizinc coating and significantly (>3.5 times longer exposure) retarded the deterioration of the epoxy primer coating in the salt-fog environment in comparison with the similar studies carried out on the phosphated conventional galvanized zinc coating. Notably, phosphating the Magizinc coating caused a ten times reduction in the H pickup compared to that in the galvanized coating under identical phosphating conditions, suggesting the former coating lowered the propensity for hydrogen embrittlement in the steel.

Surface characteristics and corrosion resistance of spangle on hot-dip galvanized coating

2017 ◽  
Vol 728 ◽  
pp. 1002-1008 ◽  
Author(s):  
Shu Peng ◽  
Shi-Kun Xie ◽  
Jin-Tang Lu ◽  
Lai-Chang Zhang
Keyword(s):  
Corrosion Resistance ◽  
Surface Characteristics ◽  
Galvanized Coating

Microstructures of Ti-1.5 w/o Ni Alloys with Mo and A1 Additions

1975 ◽  
Vol 33 ◽  
pp. 54-55
Author(s):  
Anna C. Fraker
Keyword(s):  
Corrosion Resistance ◽  
Beneficial Effect ◽  
Crevice Corrosion ◽  
Local Corrosion ◽  
Precipitate Size ◽  
Ni Alloys

Small amounts of nickel are added to titanium to improve the crevice corrosion resistance but this results in an alloy which has sheet fabrication difficulties and is subject to the formation of large Ti2Ni precipitates. These large precipitates can serve as local corrosion sites; but in a smaller more widely dispersed form, they can have a beneficial effect on crevice corrosion resistance. The purpose of the present work is to show that the addition of a small amount of Mo to the Ti-1.5Ni alloy reduces the Ti2Ni precipitate size and produces a more elongated grained microstructure. It has recently been reported that small additions of Mo to Ti-0.8 to lw/o Ni alloys produce good crevice corrosion resistance and improved fabrication properties.

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