Conversion Coating

Chromate Conversion Coatings

Chromate conversion coating is primarily used as a decorative finish (can be dyed) with a corrosion inhibitor that retains electrical conductivity. Unlike anodizing this makes it an excellent finish for electrical and electronic components.

Alocrom 1000 & Alocrom 1200

Alocrom was the first conversion coating created to be chemically applied to aluminium to provide corrosion protection. Applied prior to painting or powder coating, it is used when protection and electrical conductivity is required.

  • Electrical components.
  • Domestic appliances.
  • Car body parts.
  • Aircraft components.
  • Alocrom is unaffected by steel, brass or copper inserts in the articles being processed.
  • Alocrom is unsuitable for decorative effect on unpainted alloys which are subject to exterior weathering since some change in colour can occur in these conditions.

Alocrom 1000 produces a clear protective coating on aluminium without significantly changing the appearance of the aluminium surface.

Alocrom 1200 produces a golden coloured chromate coating on the aluminium but is a more rapid non-electrolytic dip which provides excellent protection against corrosion for painted and unpainted aluminium surfaces.

Treatment specifications
• Def Stan 03-18
• MIL-DTL-5541 (replaces MIL-C-5541) Type 1
• Class 1A or Class 3
• Def Stan 21-5 3-1 (replaces NWS 1005/3-2 and
• NWS 1005/3-1)
• TS112 D6 and TS112 D6A
• TS112 D6B
• DS26.00 D6, D6A and D6B
• EN 2437
• JP201
• AIM Altitude Specs OP37/ 2-08

Non-chromate Conversion Coatings

Non-chromate conversion coating produces a very similar electrically conductive result but is the new environmentally friendlier coating which is RoHS compliant (Restriction of Hazardous Substances).

Iridite NCP

Iridite NCP is able to withstand high temperatures and so suitable for high operating temperature items such as automotive engine components and electronic heat sinks. This unique property (not found in chromates) also allows increased dry-off oven temperatures prior to painting which increases throughput and productivity. Unlike traditional Chromate treatments that require up to 24 hours to cure to a hard film, Iridite NCP provides a hard amorphous crystalline coating as formed. This highly corrosion-resistant conversion coating can be painted or left as a stand-alone corrosion resistant barrier.

Treatment specifications
• MIL-C-81706
• MIL-DTL-5541
• MIL-C-5541
• Def Stan 03-38

SurTec 650V

SurTec 650V is a hexavalent chromium-free passivation for alloyed and casted aluminium. Optimally used in the electronics industry due to low surface resistance (less than 5000 μOhm per square inch) and aerospace industry due to high corrosion protection on unlacquered surfaces. It is also used as a pre-treatment before lacquering, powder coating or gluing.