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 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.

The effect of epoxy‐polyester sealing of sprayed metal coatings for additional corrosion protection

2011 ◽  
Vol 58 (1) ◽  
pp. 26-30 ◽  
Author(s):  
A. Akinci ◽  
F. Yilmaz
Keyword(s):  
Salt Spray ◽  
Chloride Salt ◽  
Metal Coatings ◽  
Content Type ◽  
Double System ◽  
Polymeric Layer ◽  
Coated Surfaces ◽  
Steel Substrates ◽  
Sealing Layer ◽  
Better Than

PurposeThe purpose of this paper is to report salt spray testing of epoxy‐polyester top‐coating applied on Zn‐sprayed, Al‐sprayed and 85Zn‐15Al‐sprayed steel samples.Design/methodology/approachIn these tests, steel substrates sprayed with Zn, Al and 85Zn‐15Al coatings of different average thicknesses ranging from 120 to 210 μm were top‐coated with an epoxy‐polyester sealing layer. The corrosion test was performed with salt solution for over 2,000‐h. The degree of damage to the samples was evaluated quantitatively in terms of ratio of scribed to unscribed area of coating.FindingsIt was evident that the corrosion resistance of Al‐sprayed top‐coated surfaces was better than coated Zn‐spray or coated 85Zn‐15Al‐spray systems. As a result, when Al‐coated surfaces were top‐coated with polymeric layer, it was found that their surfaces were remarkably unaffected by the salt spray environment.Originality/valueThe salt spray measurements indicated that the Al‐spray epoxy‐polyester polymer double system was more durable than the other two systems (polymeric top‐coated Zn‐spay, and polymeric top‐coated 85Zn‐15Al‐spray), so far as protection from the chloride salt spray environment was concerned.

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.

scholarly journals Corrosion Resistance of Zinc Coatings With Aluminium Additive

2014 ◽  
Vol 17 (2) ◽  
pp. 49-52
Author(s):  
Jiří Votava
Keyword(s):  
Corrosion Resistance ◽  
Protective Coating ◽  
Salt Spray ◽  
Salt Spray Test ◽  
Metal Coatings ◽  
Laboratory Conditions ◽  
Anticorrosion Protection ◽  
Zinc Coatings ◽  
Galvanized Coatings ◽  
Scratch Tests

Abstract This paper is focused on evaluation of anticorrosion protection of inorganic metal coatings such as hot-dipped zinc and zinc-galvanized coatings. The thickness and weight of coatings were tested. Further, the evaluation of ductile characteristics in compliance with the norm ČSN EN ISO 20482 was processed. Based on the scratch tests, there was evaluated undercorrosion in the area of artificially made cut. Corrosion resistance was evaluated in compliance with the norm ČSN EN ISO 9227 (salt-spray test). Based on the results of the anticorrosion test, there can be stated corrosion resistance of each individual protective coating. Tests were processed under laboratory conditions and may vary from tests processed under conditions of normal atmosphere.

The Application of Thermal Spraying Technology in the Oil and Gas Industry

1998 ◽  
Author(s):  
J.C. Price
Keyword(s):  
Life Cycle ◽  
Oil And Gas ◽  
Thermal Spraying ◽  
Steel Structures ◽  
Oil And Gas Industry ◽  
Pressure Vessels ◽  
Gas Production ◽  
Life Cycle Costs ◽  
Gas Industry ◽  
Thermally Sprayed

Abstract The last decade has seen a rapid increase in the use of Thermally Sprayed Coatings for Oil and Gas production applications. In particular, since 1982 the Offshore Oil and Gas Industry has considered Thermally Sprayed Aluminum (TSA) for protection of steel structures in the splash zone and other areas in the marine environment. Experience to date has indicated that when TSA is properly applied with a specific sealer system a service life in excess of 30 years with zero maintenance is possible. This produces a corresponding reduction in life cycle costs. Other coating systems such as Nickel - based alloys, Ceramics and Thermoplastics are also finding useful applications. This paper discusses recent advances in thermal spraying technology and current and future applications in the Oil and Gas Industry. This is illustrated with reference to several projects and details on life cycle costs. In particular, thermal spraying of pressure vessels, risers, pipelines and structural components are detailed.

A Comparative Study of the Structure and Properties of Zinc Coatings Deposited with Various Methods

2007 ◽  
Vol 130 ◽  
pp. 207-212
Author(s):  
G. Vourlias ◽  
N. Pistofidis ◽  
D. Chaliampalias ◽  
F. Stergioudis
Keyword(s):  
Salt Spray ◽  
Thermal Spraying ◽  
Structure And Properties ◽  
Spray Chamber ◽  
Corrosion Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Negative Effect ◽  
Coating Methods ◽  
Zinc Coatings

One of the most effective methods for the protection of ferrous substrates from corrosion is zinc hot-dip galvanizing. Although this method has many advantages, it is characterized by a very negative effect on the environment. In the present work Zn coatings were formed with thermal spraying, pack cementation and fluidized bed reactor, which are friendlier to the environment. Their microstructure was characterized with X-ray diffraction and scanning electron microscopy, while their corrosion performance was estimated with exposure in a salt spray chamber. From this investigation it was deduced that CVD coatings are composed by two layers referring to Γ-Fe11Zn40 and δ-FeZn10 phase of the Fe-Zn phase diagram. By contrast the thermal coatings are very porous and composed by pure Zn. However, the corrosion performance of all coatings is similar. This conclusion is very important because it verifies that hot-dip galvanizing could be replaced by the other coating methods.

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.

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