Sherardising

Sherardising involves heating ferrous metals (particularly steel) in a sealed rotating drum containing zinc dust and an inert filler (often alumina or silica) at temperatures typically between 320°C and 500°C. Under these conditions, zinc vaporises and diffuses into the substrate’s surface, forming a tightly adherent zinc-iron alloy layer.

This diffusion layer is metallurgically bonded to the substrate, offering superior durability compared to mechanically or electrochemically applied coatings. This process also avoids hydrogen embrittlement, making it suitable for high-strength steels. In addition, it produces a precise and uniform coating even on the most complex geometries and internal surfaces. The resulting matte grey finish is of the highest possible quality, which can then be further treated or painted as required.

Sherardised coatings are valued when applications and components are required to perform to their maximum, even when operating in corrosive or aggressive environments. At the LoneStar Group, we often sherardise high-performance parts that are trusted to strengthen assets deployed within the automotive, defence, marine and energy industries.