CHEMICAL CONVERSION COATINGS FOR ALUMINUM

Chromate Conversion

These conversion coating leave no measurable build-up and provide excellent corrosion resistance. Film thickness can range from 0.000001 to 0.000004 inches in thickness based on chromate concentration, solution temperature and immersion time. In many paint or adhesive applications, chromate is used as a base for superior bonding. The coatings are conductive and offered in yellow iridescent (MIL-C-5541 Class 1A) to clear iridescent (MIL-C-5541 Class 3). Electrical resistance increases with the(Class 1A) heavier coating.

The chromate conversion process produces a thin, soft and gelatinous film when first applied. All chromate conversion coatings use chromic acid in the form of its soluble salts. Preparation and pre-cleaning prior to conversion processing are critical when achieving a uniform decorative finished product. Curing of conversion coatings can be done at room temperature but can also be accelerated by baking up to 140 degrees F.

The appearance of the conversion coatings is also largely dependent on the specific alloy being coated. Processing different alloys using a given set of treatment parameters could produce colors ranging from pale yellow to light brown. A high silicon aluminum casting verses a low silicon wrought product could have widely different hues.

Non–Chromate Conversion Coating

Industraplate Corporation is proud to offer this environmentally friendly process in keeping with global innovation to help provide better and safer alternatives. (RoHS Compliant “Restriction of Hazardous Substances”).

For customers that require a non chromate conversion coating to comply the requirements of the RoHS directives, we offer Iridite NCP which is an environmentally safe, free of Lead, Cadmium, Chromium (hexavalent or trivalent), Mercury or PBB/PBDE compounds, designed specifically for aluminum alloys. It provides a highly corrosion-resistant conversion coating ideally suited to be painted or left as a stand-alone corrosion resistant barrier. The electrical conductivity of Iridite NCP is the perfect pretreatment system for most electrical grounding applications. And with excellent paint adhesion characteristics, Iridite NCP is able to pass all standard paint industry corrosion and adhesion tests.