// Chemical Conversion Coatings

At RSC we offer a comprehensive range of chemical conversion coating services. We are true experts, so find out more about each of the processes below and feel free to get in touch for advise and quotations.

SurTec 650 & 650v

Chromium (VI)-Free Passivation for Aluminium for the Electronics, Automotive and Aerospace Industry.

  • SurTec 650 is a chromium (VI)-free trivalent passivation for aluminium. The liquid concentrate delivers an excellent corrosion protection, comparable with the corrosion protection of a hexavalent passivation.
  • SurTec 650 is suitable for alloyed and casted aluminium and pre-treatment before lacquering, powder coating and gluing. It is easy to handle in immersion, spray and wipe application and produces an iridescent, faintly blue to tan and visible layer.
  • These coatings meet or exceeds MIL-DTL-81706 and MIL 5541 for bare corrosion (336 h in NSS per ASTM B-117, respectively, DIN 50021 SS) and has a low contact resistance low contact resistance: < 5000 µOhm per square inch.
  • It is also heat resistant up to 60 °C (212 °F) with minimal loss in corrosion resistance.

Alocrom 1200

A rapid non-electrolytic dip which gives excellent protection against corrosion to both painted and unpainted aluminium surfaces.

  • Alocrom 1200 coatings are integral with the metal and will withstand bending and denting of the surface.
  • Alocrom 1200 provides an excellent foundation for paint and other organic finishes.
  • Light to medium Alocrom coatings have minimum effect on surface electrical resistance.
  • Alocrom 1200 is approved to DEF STAN 03-18 & MIL-C-5541 (classes 1A & 3).
  • Alocrom 1200 is ideal for coating all types of aluminium and aluminium alloys including high silicon pressure die-castings. It should be used on aluminium wherever maximum corrosion resistance is required, and is suitable for articles which are to be painted or left unpainted. Its uses include general industrial work, electrical components, domestic appliances, car body parts and aircraft components. Alocrom 1200 is unaffected by steel, brass or copper inserts inthe articles being processed and can be used for treating zinc and aluminium in the same bath.
  • Alocrom 1200 is unsuitable for producing a decorative effect on unpainted alloys which are subject to exterior weathering since some change in colour may occur under these conditions. The process should not be used to treat foodstuffs containers.

Iridite NCP

Non-Chrome Passivate has been developed in response to the ELV, RoHS and WEEE directives. The Iridite NCP does not contain Lead, Cadmium, Chromium (hexavalent or trivalent), Mercury or PBB / PBDE compounds.

  • Iridite NCP is an environmentally friendly chemical process that produces a protective conversion coating on aluminium and its alloys. This coating exhibits bare, unpainted, corrosion resistance that is equal to hexavalent chromates on many aluminium alloys. The coating can be used as a final finish and can also serve as a base for paints, high performance topcoats, powder paints, lacquers, or as a base for rubber bonding.
  • Provides corrosion protection that rivals conventional chromate conversion coatings when tested in accordance with ASTM B 117.
  • The conversion coating passes the requirement of MIL-C-5541 for electrical contact resistance for Class 3 coatings.


Passivation of stainless steel is a process that removes free iron from the surface of a stainless component and at the same time promotes the formation of a thin, dense oxide protective barrier.

Specifications Covered:

  • NGPS 61
  • AMS2700F
  • BS EN 2516
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