During the process, a modulated electrical current is passed through a bath of proprietary Keronite electrolyte solution. Parts are suspended from a bus bar and submerged in the chrome-free, low concentrate alkaline electrolyte inside a stainless steel electrode cage. Different electrolytes are required for aluminium and magnesium or new electrolytes can be designed to meet specific surface requirements, but all are free from chrome and other heavy metals and contain no ammonia or any acids.
As the pulsed alternating current is passed through the bath, a controlled plasma discharge is formed and sparks are generated on the substrate surface. This plasma discharge converts the surface of the substrate into a complex ceramic by:
- Oxidation of the surface
- Elementary co-deposition
- Fusion of the ceramic layer
Because of the insulating nature of the Keronite layer, the process is somewhat self-regulating and impressive uniformity of coating thickness can be achieved if required, unlike many conventional electroplating processes. As an immersion process, Keronite has much greater throwing power than plasma sprayed ceramic surfaces or other line-of-sight processes. Parts can be selectively coated by masking, or greater protection can be provided in critical areas by focussing the growth accordingly.
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