November 24, 2021

Galva-X Coating

What is Galva-X coating?

Galva-X stands for “G”alvanizing with e”X”tra intermediate metallic coating layer. Galva-X or GX coating is a novel galvanizing process with pre-coating technique that creates special metallic formation of steel that can withstand severe degree of corrosion. GX coating has been tested in the laboratory using ASTM B117 and ASTM G85 salt spray test standards and then proven in the Offshore field test that shows superior performance over traditional hot dip galvanized steel and stainless steel.

How does GX provide corrosion resistance?

Corrosion is a natural process when iron is exposed to oxygen with presence of water, which creates a red iron oxide commonly called rust. Traditional galvanization process having Zinc coating layer helps protect against rust but it will wear away especially when exposed to saline environment or high levels of acidity. Excess Zinc coating thickness will also create brittle intermediate layers that may result in delamination and spalling of the coatings. GX coating has a unique intermediate metallic layer that provides extra protection against corrosion. It also helps to regulate the thickness of Zinc layer giving uniform Zinc coating thickness irrespective of different types of steel therefore eliminating galvanizing coating overgrowth, the root cause of embrittlement.

Comparison between Hot Dip Galvanized (HDG) and Galva-X (GX)

Laboratory testing according to ASTM B117 salt spray test has shown superior performance of GX over HDG by tenfold. Pictures below show comparison among steel bolts with different coating techniques. Pictures below show surface appearances of the samples after 2,000 hours of salt spray test (ASTM B117). It can be seen that Galva-X can provide much better rust protection than HDG and is in the same range as coating techniques such as Fluoropolymer.

Surface appearances after 2,000 hours of salt spray test ASTM B117.
Source: Metallurgy and Materials Science Research Institute, Chulalongkorn University
Key technical data comparison among Galva-X, Hot Dip Galvanizing, and Fluoropolymer.
Source: Metallurgy and Materials Science Research Institute, Chulalongkorn University

Offshore Field Test (Thai Gulf) in 2003

Galva-X fasteners has been tested in the actual saline environment in 2003. The fasteners were used in the offshore oil rig in the Gulf of Thailand for two years. Pictures below show the comparison between GX and fluoropolymer coating. It is shown that rust has not been found on GX fasteners after two years of exposure to the saline environment.

Surface appearances of Galva-X fasteners after two years of exposure in Offshore oil rig in the Gulf of Thailand. No sign of rust.
Source: Metallurgy and Materials Science Research Institute, Chulalongkorn University
Surface appearances of Fluoropolymer fasteners after two years of exposure in Offshore oil rig in the Gulf of Thailand. Signs of rust around the threads of the fasteners.
Source: Metallurgy and Materials Science Research Institute, Chulalongkorn University

Duplex coating for extreme durability

Duplex coating is Zinc coating covered with a paint system resulting in exceptionally prolonged service lifetime and is suitable for severe corrosive environment. Duplex coating is naturally applied where extreme durability is required for example, offshore plants in remote locations or critical infrastructures such as bridges. The lifetime of duplex coating is more than the sum of the individual coatings and this is called the synergistic effect: The paint protects the zinc and the zinc supports the paint.

Surface appearances of moisture cure paint polyurethane (SGP-001) on carbon steel from 0 hours to 1440 hours of ASTM G85 salt spray test.
Source: Metallurgy and Materials Science Research Institute, Chulalongkorn University

Galva-X coating can be used with a paint system, which yield exceptional results in laboratory testing and is now being used in the industry.

Surface appearances of Galva-X duplex coating with moisture cure paint polyurethane (SGP-001) from 0 hours to 1440 hours of ASTM G85 salt spray test.
Source: Metallurgy and Materials Science Research Institute, Chulalongkorn University

Galva-X product ranges

  • Galva-X metal sheets
  • Galva-X metal profiles such as angles, channels, pipes
  • Galva-X fasteners
  • Any fabricated products that can be hot dip galvanized can be made with Galva-X!!

Galva-X Application

Our latest application is Galva-X metal shade for IRPC natural gas metering station power plant in Rayong, Thailand. The purpose of metal shade is to protect gas metering station from saline environment and other chemicals from nearby industrial plants. Galva-X metal shades are made from 1.0 mm thick steel sheets with SGP-001 Moisture cure paint polyurethane.

Galva-X metal shade installation in December 2021