Study on Chromium-Free Color Passivation for Zinc Coating Treated with Silicate

2010 ◽  
Vol 154-155 ◽  
pp. 1301-1304 ◽  
Author(s):  
Xiao Ke Yang ◽  
Yun Ying Fan ◽  
Ye Hua Jiang ◽  
Zu Lai Li
Keyword(s):  
Hexavalent Chromium ◽  
Salt Spray ◽  
Zinc Coating ◽  
Liquid Composition ◽  
Passive Films ◽  
Neutral Salt ◽  
White Rust ◽  
Zinc Plating ◽  
Zinc Coatings ◽  
Better Than

This paper mainly focuses on how the silicate liquid composition of chromium-free color passivation affects on passivation result, and confirmes the optimum passivation conditions, and uses two zinc plating system of alkaline and acid deposition. Silicate passivation system is compared with hexavalent chromium passivation technology and the results showed that: the appearance and corrosion resistance of passive films formed on zinc coatings plated with alkaline system are better than samples plated with acid system, and have the same corrosion resistanc with hexavalent chromium passivation. The silicate passivation films can keep 200 hours with no white rust in neutral salt spray test.

Corrosion Resistance of Zn-31AlMg Coatings Obtained by Batch Hot Dip Method

2013 ◽  
Vol 212 ◽  
pp. 167-172 ◽  
Author(s):  
Henryk Kania ◽  
Marzena Bierońska
Keyword(s):  
Corrosion Resistance ◽  
Sulphur Dioxide ◽  
Salt Spray ◽  
Zinc Coating ◽  
Neutral Salt ◽  
Corrosion Tests ◽  
Good Corrosion Resistance ◽  
Zinc Coatings ◽  
Resistance Tests ◽  
Better Than

In the paper the authors present the results of corrosion resistance tests on coatings obtained in zinc-aluminium baths with the addition of Mg by use of the batch hot dip method. The content of Al in the bath was 31%, while the content of magnesium was 3 and 6%. In order to define corrosion resistance, two standard corrosion tests were performed in neutral salt spray and inmoist atmosphere containing sulphur dioxide. Corrosion resistance of tested pieces was compared with the corrosion resistance of a traditional zinc coating. It was established that Zn-31AlMg coatings have very good corrosion resistance in the tested environments, better than that of zinc coatings.

Thermally Sprayed Ternary Materials for Enhanced Corrosion Protection

1997 ◽  
Author(s):  
T. Lester ◽  
S.J. Harris ◽  
D. Kingerley ◽  
S. Matthews
Keyword(s):  
Barrier Layer ◽  
Salt Spray ◽  
Thermal Spraying ◽  
Steel Structures ◽  
Deposition Efficiency ◽  
Aqueous Corrosion ◽  
Metal Coatings ◽  
Zinc Coatings ◽  
Thermally Sprayed ◽  
Better Than

Abstract Thermal spraying has been used to protect many steel structures from aqueous corrosion using Zinc and Aluminium, and to some extent their alloy coatings to provide galvanic protection. The lifetimes of the coatings can approach 50 years even when exposed in severe marine environments. Zinc coatings work by continuously sacrificing themselves and slowly dissipating over time. Aluminium coatings passivate more readily and form a barrier layer, the passivity makes them less able to protect damaged areas and to self heal. A new ternary coating system involving Aluminium, Zinc and Magnesium has been shown to be capable of providing both a passive barrier layer as well as being able to give galvanically active protection. Salt spray tests have shown that the resistance to red rust of these new coatings increases by 300% over similar thicknesses of the separate metal coatings. Processing by arcspray is straightforward and both adhesion and deposition efficiency are better than where Zinc is sprayed alone.

scholarly journals Impact of Bi and Sn on Microstructure and Corrosion Resistance of Zinc Coatings Obtained in Zn-AlNi Bath

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3788
Author(s):  
Henryk Kania ◽  
Mariola Saternus ◽  
Jan Kudláček
Keyword(s):  
Corrosion Resistance ◽  
Salt Spray ◽  
Neutral Salt ◽  
Energy Dispersion Spectroscopy ◽  
Humid Atmosphere ◽  
Alloying Additions ◽  
Electrochemical Parameters ◽  
Zinc Coatings ◽  
Structural Research ◽  
The Impact

The paper presents results of studies on the impact of bismuth and tin additions to the Zn-AlNi bath on microstructure and corrosion resistance of hot dip galvanizig coatings. The structure at high magnifications on the top surface and cross-section of coatings received in the Zn-AlNiBiSn bath was revealed and the microanalysis EDS (energy dispersion spectroscopy) of chemical composition was determined. The corrosion resistance of the coatings was tested relatively in a neutral salt spray test (NSS), and tests in a humid atmosphere containing SO2. Electrochemical parameters of coatings corrosion were determined. It was found that Zn-AlNiBiSn coatings show lower corrosion resistance in comparison with the coatings received in the Zn-AlNi bath without Sn and Bi alloying additions. Structural research has shown the existence of precipitations of Sn-Bi alloy in the coating. It was found that Sn-Bi precipitations have more electropositive potential in relation to zinc, which promotes the formation of additional corrosion cells.

scholarly journals Structural Aspects of Decreasing the Corrosion Resistance of Zinc Coating Obtained in Baths with Al, Ni, and Pb Additives

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 385 ◽  
Author(s):  
Henryk Kania ◽  
Mariola Saternus ◽  
Jan Kudláček
Keyword(s):  
Corrosion Resistance ◽  
Salt Spray ◽  
Zinc Coating ◽  
Neutral Salt ◽  
Zinc Bath ◽  
Coating Structure ◽  
Humid Atmosphere ◽  
Pure Zinc ◽  
Si Content ◽  
Structural Aspects

The article presented the results of tests determining the synergistic effect of Al, Ni, and Pb additions on a zinc bath on the structure and corrosion resistance of coatings obtained on low silicon steel. Analyzed coatings were produced on S235JRG2 steel with Si content of 0.02 mass%. The corrosion resistance of the coatings was compared with the corrosion resistance of the coating obtained in the "pure" zinc bath. Structure at high magnifications (SEM) was determined, as well as coating thickness and chemical composition in microspheres. The corrosion resistance of the coatings was established comparatively in standard corrosion tests in neutral salt spray and a humid atmosphere containing SO2. It was found that the addition of Pb to the zinc bath reduced the corrosion resistance of the coatings. In the coating structure obtained in the Zn-AlNiPb bath, lead precipitation was observed in both the outer layer and the intermediate layer of the coating. Grain boundaries were the preferred site for lead precipitation. The presence of Pb precipitates favored conditions for the creation of additional corrosion cells, which led to a decrease in the corrosion resistance of the coatings.

Effects of Silanes on the Structure and Properties of Chromium-Free Passivation

2020 ◽  
Vol 12 (7) ◽  
pp. 1012-1018
Author(s):  
Fu Haiyang ◽  
Gao Bo ◽  
Zhou Yingwei ◽  
Xing Pengfei
Keyword(s):  
Photoelectron Spectroscopy ◽  
Film Formation ◽  
Resin Composite ◽  
Salt Spray ◽  
Neutral Salt ◽  
Silane Coupling Agents ◽  
Passivation Film ◽  
White Rust ◽  
Steel Surfaces ◽  
Corrosion Of Steel

Steel is one of the most widely used metal materials, and corrosion of steel surfaces is a serious problem. Traditional chromate passivation produces hexavalent chromium with high toxicity and carcinogenicity. To solve toxicity and pollution problems, a chromium-free passivation method was adopted to replace the traditional process. Based on the reaction mechanisms of some silane coupling agents, a new method of chromium-free passivation and anti-white rust production is presented in this paper. The chromium-free passivation process of an inorganic material-silane-resin composite was used in the study. The microstructure and corrosion resistance of a hot-dip galvanized sheet and silane passivation film were compared by using a neutral salt spray test, scanning electron microscopy, infrared spectroscopy and X-ray photoelectron spectroscopy. The mechanism of film formation was studied. The results show that the surface of the passivation film is dense and smooth without sharp protrusions and has a stable skeleton structure inside. The structure of the passive film is C=O, Si–O, C–Si, C–H, Si–O–Zn, Si–O–Si, etc. A chromium-free passivation film prepared with a disilane can effectively prevent penetration between the corrosive medium and matrix. After a 96 h corrosion test, the corrosion area is less than 5%, which meets the requirements of some industrial production processes.

Structural Properties of Zinc and ZnMgAl Coatings on Steel Sheets

2014 ◽  
Vol 782 ◽  
pp. 623-626 ◽  
Author(s):  
Mária Kollárová ◽  
Lucia Hrabčáková ◽  
Juraj Graban ◽  
Marta Šohajová
Keyword(s):  
Corrosion Resistance ◽  
Salt Spray ◽  
Neutral Salt ◽  
Coating Structure ◽  
Properties Of Coatings ◽  
Steel Sheets ◽  
Mutual Comparison ◽  
Excellent Adhesion ◽  
Interdendritic Phase ◽  
Zinc Coatings

In the paper mutual comparison of zinc coatings enriched with small additions of Mg and Al (up to 1 wt.% Mg and 1 wt.% Al) and traditional zinc coatings produced by hot dip galvanizing, concerning some important properties of coatings like coating structure, cracks formation after deformation and corrosion resistance of deformed samples was studied. It was shown, that while traditional hot-dip zinc coatings are formed by homogenous zinc layer, exhibiting only low amount of soluble aluminium, coatings enriched by small amounts of Mg and Al, namely 0.6% Mg and 0.8% Al are formed by dendritic zinc matrix and interdendritic phase containing Zn-Mg-Al eutectics. Development of cracks was investigated in the area of maximal deformation of the samples subjected to stretching. It was found, that while traditional zinc coatings showed sporadic long fine cracks, zinc coatings enriched with Mg and Al exhibited aggregation of short thick cracks in the deformed area. Samples of both materials after stretching were also exposed in neutral salt spray atmosphere in corrosion chamber. It can be concluded, that material with coatings enriched with Mg and Al showed better results in corrosion tests contrary to the presence of massive cracks in the coating. This significantly increased corrosion resistance is possible due to excellent adhesion of zinc coatings, containing Mg and Al on drawing steels.

PENGARUH ARUS DAN WAKTU TERHADAP LAPISAN ZINC PLATING PADA MATERIAL SGD400-D DENGAN MENGGUNAKAN PROSES ELEKTROPLATING

2020 ◽  
Vol 7 (1) ◽  
pp. 32-39
Author(s):  
Ari Setiawan ◽  
Novi Laura Indrayani ◽  
Budi Herawan
Keyword(s):  
Salt Spray ◽  
Thickness Measurement ◽  
Media Analysis ◽  
White Rust ◽  
Zinc Plating ◽  
Weight Loss Method ◽  
Loss Method ◽  
Good Coating ◽  
A Current ◽  
The Ideal

This research was conducted to find the ideal current and time used during the plating process, because in every industry the most frequent problems are the thickness that coats the material and the corrosion rate of the material that causes the material to become damaged or no good. This study uses SGD400 carbon steel and zinc as a coating. The research was carried out on a tank containing various kinds of chemical liquids and using electric current as conductivity for the coating media. Analysis using layer thickness measurement using vernier caliper measuring instrument and weight loss method. The results obtained from searching the current and the ideal time using a current of 900 A and a time of 60 minutes is 0.015 mm or 15 μm thick and the SST test (Salt Spray Test) at 72 hours No White Rust and 168 Hours No Red Rust. And good coating results can be seen in microstructure testing using keyence microscope media

Abrasion Resistance and Corrosion Resistance of Chromium-Free Fingerprint-Resistant Zn and Zn-Al-Mg Coating Cold-Rolled Steel Sheets

2021 ◽  
Vol 1035 ◽  
pp. 545-553
Author(s):  
Yan Huang ◽  
Ren Bo Song ◽  
Huan Jun Wei ◽  
Zhe Rui Zhang ◽  
Li Fang Yang
Keyword(s):  
Corrosion Resistance ◽  
Salt Spray ◽  
Zinc Coating ◽  
Neutral Salt ◽  
Rolled Steel ◽  
Pure Zinc ◽  
Cold Rolled Steel ◽  
Steel Sheets ◽  
Long Time ◽  
Cold Rolled

The wear resistance and corrosion resistance of chromium-free fingerprint-resistant pure zinc and Zn-Al-Mg coated cold-rolled steel sheets were studied by micro-friction wear experiments and neutral salt spray experiments. Two products are worn for a long time with a large load (5N load, 50 times abrasion), the depth of wear zone of Zn-Al-Mg coating product is 9% shallower than that of pure zinc coating product, and the width of wear zone is 15.4% smaller. Both products still meet the requirements of use after corrosion. The corrosion resistance of two products after degreasing treatment was significantly reduced. The Mg and Al in the Zn-Al-Mg coating can hinder the progress of corrosion, so it has better corrosion resistance.

Passivation Effect of Rare Earth Lanthanum on Galvanized Steel

2014 ◽  
Vol 525 ◽  
pp. 31-34
Author(s):  
Xiao Feng Liu
Keyword(s):  
Corrosion Resistance ◽  
Rare Earth ◽  
Electrochemical Impedance ◽  
Orthogonal Experiment ◽  
Salt Spray ◽  
Conversion Coating ◽  
Galvanized Steel ◽  
Neutral Salt ◽  
White Rust ◽  
Order Of Magnitude

By way of chemical marinate method, carrying out rare earth lanthanum to corrosion protect galvanized steel. The process of rare earth lanthanum conversion coating for galvanized steel was studied by using orthogonal experiment to get the optimized passivation parameters when the concentration of La (NO3) is 30g/L, H2O2is 20ml/L, pH=4 and was passivated at 40°C for 30s. The corrosion resistance was examined by weight loss tests, neutral salt spray tests (NSS) and electrochemical impedance spectroscopy (EIS). The results showed that the corrosion impedance of the pretreated sample was significantly improved, the corrosion rate was decreased by one order of magnitude, and the anti-white rust time was 54h.

scholarly journals Comparative Study on the Corrosion Resistance of Inorganic Zinc-Rich Coating and Thermal-Spray Zinc Coating

2021 ◽  
Author(s):  
Weiliang Ni ◽  
Peng Li ◽  
Yajun Zhu ◽  
Zhigang Di ◽  
Liangliang Guo ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Thermal Spray ◽  
Salt Spray ◽  
Zinc Coating ◽  
Steel Structures ◽  
Salt Spray Test ◽  
Shielding Effect ◽  
Corrosion Mechanism ◽  
Time Varying ◽  
Zinc Coatings

Abstract The corrosion resistance of two steel coatings (inorganic zinc-rich coating and thermal-spray zinc coating) was studied in detail by using the electrochemical and salt spray test, and the salt spray corrosion thickness was calculated by the time-varying equation established from the mathematical fitting method. The result show that the corrosion mechanism of the two types of coatings was the same that based on the sacrificed of zinc through anodizing phenomenon. The main reason for the difference of corrosion resistance between the two anticorrosive coatings was that the coating density and shielding effect of corrosion products were different. The 7500-hours salt spray test showed that the corrosion rates and microstructure characteristics of both types of zinc coatings were homogeneous on the premise of ensuring coating reliability. The time-varying equation can be used to evaluate the service life of the zinc coatings and judge their corrosion resistance quickly, that providing theoretical support for the maintenance of steel structures as well as the accelerated selection and design of coating formulations.

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