Special Processes

Hexavelent Passivation

Hexavalent Passivation

We apply hexavalent chromium (classified as a special process) products upon request of the client. However, as the industry is changing, many OEMs have changed their process specification requirements and have begun looking for suitable green replacements.

The Diamond Metal Finishing Co Ltd strives to educate clients on the benefits of using our alternative trivalent or non-chromate options and are glad to offer the relevant advice.

Alocrom 1200

  • Offers good electrical conductivity with excellent corrosion resistance.
  • Provides an ideal base for powder coating and paint.
  • A rapid, non-electrolytic, chromate conversion treatment.
  • Excellent corrosion protection with or without paint.
  • Excellent paint or powder coating adhesion allowing metal deformation after painting.
  • The coating has a low electrical resistance (less than 5k micro-ohms/square inch).
  • Can be used to repair anodised coatings and refresh them before painting.
  • We also offer a pen touch up if so required (please discuss beforehand)
  • Alocrom 1200 Hexavalent in nature we offer alternative green replacements including Surtec 650V and Iridite NCP.
Alocrom 1200
Cytec BR27

Cytec BR127

BR-127 Is a modified epoxy primer which is yellow in appearance and is the most common adhesive bond and corrosion inhibiting primer used in commercial and defence Aircraft and Motorsport applications.

BR-127 primer is used to inhibit corrosion on metal parts and provides excellent bonding with the majority of all film adhesives and offers optimal structural performance at temperatures ranging from -67°F to 302°F (-55°C to 150°C). BR-127 is offered by The Diamond Metal Finishing Co Ltd with several options of pre-treatment application, either by chemical etching, chemical conversion coatings, but mainly with our Phosphoric acid anodising (PAA) treatment. The latter being the ultimate preferred choice for most aerospace applications.


Many metal surfaces prepared with AC-130-2 yield comparable mechanical results to surfaces prepared with the PAA process.

AC-130-2 is a sol-gel surface preparation for adhesive bonding of aluminium alloys, steel and titanium. It promotes enhanced adhesion because of the chemical interaction at the interfaces between the metal, the AC-130-2 and aerospace primers.

Ask us to apply AC-130-2 to your parts. Telephone +44 (0) 1782 822442

3M AC-130-2

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Experience would be preferred, but not essential. Apply by email to employment@diamondmetalfinishing.co.uk

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