Properties

No hydrogen embrittlement

Hydrogen embrittlement

Sherardised products show no hydrogen embrittlement.
This is important for safety components and products made from spring steel, hardened or high-strength steel.
Hydrogen embrittlement is caused by the rapid diffusion of atomic hydrogen in iron and is responsible for unpredictable failure.
The zinc diffusion coating process is hydrogen-free and completely dry.
A water-free pretreatment such as shot blasting, hydrogen embrittlement is precluded.
During the warm-up phase of the process existing hydrogen has the opportunity to escape before the product is sherardized.

Comparison

Parts for electro plating or hot dip galvanizing, need to be pre-treated by pickling and degreasing. In this case the surface will absorb hydrogen. During the electroplating process can hydrogen formation not be avoided.

To counteract the hydrogen embrittlement, it is advisable, that after the coating process a low temperature hydrogen effusion process is carried out. This takes several hours.

But these measures can only reduce the risk of hydrogen embrittlement.