aluminising

Aluminising is a surface treatment process that involves applying a layer of aluminum or an aluminum alloy to the surface of another metal, typically steel. This process is primarily used to improve the corrosion resistance and high-temperature oxidation resistance of the base material. The aluminum coating forms a protective oxide layer when exposed to oxygen, which acts as a barrier against further degradation. There are several methods for achieving aluminisation, including hot-dipping, spraying, and diffusion processes.

Hot-dipping involves immersing the base metal into a bath of molten aluminum. The molten metal adheres to the surface, and upon cooling, forms a metallurgical bond. Spray aluminising involves atomizing molten aluminum and spraying it onto the prepared surface of the substrate. Diffusion aluminising, also known as pack aluminising or calorising, uses a mixture of aluminum powder and a halide activator, heated to high temperatures. The aluminum diffuses into the surface of the base metal, creating an aluminum-rich layer.

Aluminised materials find applications in various industries. They are commonly used in exhaust systems for vehicles, heat exchangers, industrial furnaces, and in the aerospace sector for components exposed to high temperatures. The effectiveness of aluminising depends on factors such as the composition of the aluminum alloy, the thickness of the coating, and the surface preparation of the base metal. The process enhances the lifespan and performance of metal components in demanding environments.