Thermal diffusion galvanising is an alternative process used to galvanise steel rather than the much used and traditional hot tip galvanising process. There are numerous benefits to galvanising steel using thermal diffusion; however the greatest must be the benefit this process has on the environment.
When galvanising steel with thermal diffusion, the required temperature is much lower than that needed for galvanising structural steel items for example when using the hot tip galvanisation process. This means there are fewer natural resources used in the thermal process – making a large difference to the strain placed on the environment.
The steel products to be galvanised are placed in large drums which are sealed. This further benefits the environment as no dangerous gasses are emitted during the galvanisation process. The drums are then rotated to coat the steel products with a specialised powder consisting primarily of zinc and other materials. The temperature of the drum is increased to just below zinc’s melting point which is roughly between 230°C and 400°C. The temperature needed when using the hot tip galvanising process can range from 440 to 455°C. More energy and resources are needed to maintain these high temperatures. The zinc that is left over in the process can easily be recycled.
Smaller steel products that have intricate parts or indentations are commonly protected from rust by thermal diffusion galvanising. Galvanised steel that has undergone this process can be protected further by applying powder coatings or paint which is said to form a better bond with the zinc alloys than with other galvanising processes.
There are less harmful chemicals or hazardous materials in the water used for rinsing when galvanising steel with thermal diffusion as there are no acids used in the process. Steel products do also not have to be pre-treated before being galvanised when using this method.