DEMARTIN hard chrome

DEMARTIN hard chrome

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Hard chrome plating is an electrolytic process for applying a hard chrome layer to ferrous materials, aluminium, stainless steel, copper or brass. In contrast to decorative bright chrome plating, the layers are thicker and are applied directly to the material without intermediate layers. They are primarily used to improve the functionality of mechanically stressed surfaces.

Hard chrome layers are primarily used as classic wear protection. The coatings are characterised by high hardness and high stability. They also have tribological advantages and a very low coefficient of friction. The corrosion resistance of chromium is further improved by the low wettability of aqueous solutions and oil. The coating thickness ranges from 0.1 - over 1000 µm*. Hard chrome coatings are therefore ideal for precise dimensional coatings with tight tolerances as well as for levelling out large dimensional differences when repairing components.

Arguments

  • High hardness between 800 and 1,100 HV without material distortion
  • Low coefficient of friction
  • High friction resistance
  • Very high reflectivity
  • Homogeneous layer structure
  • Low adhesion
  • Resistance to chemical stress
  • Temperature stability, melting point > 1800°C

Applications

  • Medical technology
  • Machinery industry
  • Semiconductor industry/semiconductors
  • Textile machinery industry
  • Energy and electrical engineering
  • Mould and tool making
  • Plant and apparatus engineering
  • Armaments industry
  • Automotive industry
  • 3D printed metal parts

Physical properties

Density
approx. 7.0 +/-0.1 g/cm³
(depends on porosity).
Melting temperature
approx. 1,857°C (3,375°F).
Thermal conductivity
93 W/mK at 20°C.
Thermal expansion
6.6 x 10-6 /K
Electrical conductivity
Moderate to high, comparable to steel.
E-modulus (modulus of elasticity)
approx. 200 GPa, comparable to steel.
Hardness
800-1100 HV (Vickers hardness).

Coatable materials

  • Steel
  • Stainless steel
  • Cast iron
  • Non-ferrous metal
  • Aluminium
  • Titanium
  • Nickel and alloys

Processing behaviour after coating

  • Behaviour 1
  • Behaviour 2
  • Behaviour 3

Process variants

  • Protective chrome plating
  • Different layer thicknesses; as corrosion protection, wear protection and anti-adhesion layer, 0.001 - 0.010mm layer thickness
  • Mass hard chrome plating
  • Different layer thicknesses; as a finished mass coating that achieves the tolerances in dimensional accuracy and surface quality without mechanical reworking, 0.001 - 0.030mm layer thickness
  • Oversize chrome plating
  • Different layer thicknesses; for all components that require additional mechanical finishing, 0.030 - 0.500 mm layer thickness
  • Repair chrome plating
  • Different layer thicknesses; e.g. compensation of undersize in moulded parts, 0.010 - 0.500mm layer thickness
  • Orange skin chrome plating
  • Structured hard chrome layer with freely selectable Rz value, 0.010 - 0.030mm layer thickness
  • Multiplex coating also known as double. Multiple hard chrome plating
  • The coating is interrupted during the process and continued after an etching process, which increases the corrosion resistance of the layer. 0.020 - 0.500mm layer thickness