Metallising

Metallising is a term used broadly to describe the application of a metallic coating to a substrate, but in the context of tube and pipe corrosion protection, it usually refers specifically to Thermal Spraying—a process distinct from hot-dip galvanizing.

Process and Purpose

Metallising involves melting a metallic wire or powder (often pure zinc or a zinc-aluminum alloy) and propelling the molten droplets onto the prepared steel pipe surface using a stream of compressed gas. This is commonly achieved via arc spraying or flame spraying techniques.

Unlike hot-dip galvanizing, which forms a metallurgical bond by high-temperature diffusion, metallising creates a mechanical bond where the coating adheres to the roughened surface profile of the steel.

Key Advantage: It allows for the application of exceptionally thick coatings (well over 200 microns) that provide long-term corrosion resistance, especially suitable for large structures, field repairs, or areas where the intense heat of the galvanizing bath is impractical or could cause distortion.

Application: It is often used for high-specification projects where maximum durability is required and is highly effective when applied over a carefully grit-blasted substrate.