Klaus Gross

KLAUS GROSS KG  |   Fon +49 (0) 5141 / 48 70 78-0

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Surface Technology



Our Phosphating process consists the degreasing of multiple rinse as well as the preactivation and the manganphosphating. Finally the hot rinsing and the postcurrent oiling takes place.


Phosphating is a chemical process wherein a thin, microcrystaline phosphate layer which is insoluble in water is produced on metal surfaces using an immersion process with phosphoric acid solutions.

The light- to dark-grey metal phosphate layers are firmly anchored in the metal surface as they arise from a chemical reaction with the base metal and exhibit numerous cavities and capillaries. This property gives the phosphate layers an optimal capacity to absorb oils, waxes, colour pigments and varnishes, making them ideal for corrosion protection and as a primer for paint and varnishes.

A further property of the phosphate layer is its ability to reduce frictional forces (such as those arising from deformation, surface quality or slip processes). Along with an improvement in the surface quality of the treated piece, this reduced friction increases the processing speed considerably, while also increasing the service life of the tools.

  • Light- to dark-grey manganese layer, consisting of secondary and tertiary manganese phosphates
  • Firmly anchored in the base metal
  • Microcrystalline to coarse crystalline appearance (depending on process)
  • Layer thickness (3-20 micrometres) – must be taken into account with fitting parts
  • Due to the presence of many capillaries in the layer, corrosion protection oils and varnishes can be absorbed well, which enables very good corrosion protection
  • Phosphate layers are electrically non-conducting, i.e. the insulation resistance is relatively high
  • Damaged layers are rarely affected by rust