Chrome Conversion

Reducing any detrimental impact on the environment is a focus of the worldwide aerospace industry and Bodycote can assist in the drive towards carbon reduction and environmentally friendly approaches in a number of ways.

REACH legislation

REACH is a European Union regulation concerning the Registration, Evaluation, Authorisation and restriction of Chemicals. It came into force on 1st June 2007 and replaced a number of European Directives and Regulations with a single system.

As part of this legislation, the use of hexavalent chrome will be phased out, with new platforms no longer allowed to use chrome, whilst use is still permitted for existing platforms. Chrome must be replaced with an alternative, less harmful material which meets the legislation criteria.

A direct alternative for chrome is thermally sprayed HVOF tungsten carbide, which has many benefits over chrome for wear and corrosion resistance, as well as being an environmentally friendly process.

Some key benefits of thermal spray over chrome:

  • Less environmental impact with no major ecological and health & safety concerns
  • WC/Cr/Co coating has abrasion wear resistance 4-5 times higher than hard chrome
  • Coatings have negligible impact on substrate fatigue performance, whilst hard chrome plating can reduce substrate fatigue performance by up to 50%
  • Extended seal life on hydraulic components
  • Requires less masking than hard chrome plating and offers improved deposition quality adjacent to holes and keyways
  • Hard chrome plated high strength steels require heat treatment to prevent hydrogen embrittlement; this is not required with HVOF coatings
  • Coating of a wide range of materials with coating material tailored to the application, e.g. WC/Co/Cr, WC/Co, Cr3C2/NiCr, WC/Ni coatings, and nickel-based corrosion resistant alloys
  • Whole-life cycle costs of carbide coatings estimated to be 50% of hard chrome plating

Thermal spray is the preferred replacement for many applications of hard plating applications, such as the hard chrome plating of landing gear, and is increasingly being specified by companies that are environmentally aware. HVOF coatings are already being designed-in and used as a direct alternative for hard chrome plate for specific components including:

  • Aircraft landing gear
  • Flight control – actuation
  • Propeller hubs
  • Gas turbine journals