Products & Services

Protocase manufactures fully finished custom electronic enclosures and associated parts from a wide variety of materials and components, in 2-3 days with no minimum order. Protocase also provides expert and affordable enclosure design services.

Chemical Conversion Coating for Aluminum

"Chem Film"

Protocase is pleased to offer in-house Chemical Conversion Coating for Aluminum.

What is it?

Chemical Conversion Coating Tanks

Chemical Conversion Coating is often referred to as chem film, chromate coating, or yellow chromate coating. This coating process applies chromate to the metal substrate, creating a surface that is corrosion resistant, durable, and exhibits stable electrical conductivity.

Chemical Conversion Coating is used to protect enclosures and metal parts from corrosion, and to ensure that reliable electrical connections can be made to aluminum chassis and components. It is also an effective pretreatment for powdercoat. Protocase's Chemical Conversion Coating process meets a number of specifications, and qualifies as Type II, Class 1a and 3 under MIL-DTL-5541F. In simple terms, 'Type II' means the process does not utilize toxic and dangerous hexavalent chrome. Class 1a refers its ability to protect against corrosion. Class 3 refers to its ability to provide reliable electrical conductivity. Details are given below.

Chem-Film Coating is sometimes also referred to by its brand names, including Alodine, Iridite and Alocrom.

What do we coat?

Protocase will process a) aluminum parts, panels and enclosures that have been manufactured in our own facilities, or b) aluminum parts that have been fabricated or machined elsewhere, so long as they meet our dimension constraints.

Size Restrictions:

We are able to process aluminum parts with maximum dimensions of 43.5“ x 34” x 30“ (1104.9mm x 863.6mm x 762mm).

Lead Times:

With Protocase-fabricated parts, because the coating is done in-house, chemical conversion coating can be applied to enclosures and parts within 1 day. This means we can offer fully fabricated and finished sheet metal enclosures and components with chemical conversion coating, in as little as 3-4 days. Customer-supplied parts Protocase can apply chemical conversion coating to customer-supplied parts in as little as 3-4 days after receipt of parts.

Finishes Before Chem-Film Coating:

We do not recommend applying Chemical Conversion Coating to unfinished aluminum parts. Bare-metal aluminum parts with No Finish will have surface scratches, swirl marks and blemishes. The application of Chemical Conversion Coating will not mask or hide the blemishes of No Finish parts. For the best end result, we recommend choosing Grained Finish or Vibratory Finish for your aluminum parts before they are treated with chemical conversion coating. If you require your chem-filmed parts to be powdercoated in certain areas, we can do that. Once we apply chem film conversion coating, the part will be masked in the required areas before it is powdercoated.

Gallery of Parts With Finish:


Aluminum parts with Chemical Conversion Coating can have graphics in the form of direct digital printing and silkscreen. For more information about your finishing options in combination with chem film conversion coating, please contact us.


Protocase uses Chemeon TCP-HF®. The coating subtly changes the appearance of the surface, which exhibits nearly clear iridescence, with a subtle gold to violet tint.

Chemeon TCP-HF® is an environmentally friendly trivalent chromium formulation, free of toxic and dangerous hexavalent chromium. Chemeon TCP-HF® conforms to a wide variety of environmental and workplace safety regulations, such as RoHS, WEEE, ELV, REACH and the OSHA PEL.

Protocase qualifies its process to pass the requirements of MIL-DTL-5541F Type 2 Class 1A & 3, and -81706B.

Chemeon TCP-HF® is a proprietary chemistry developed by Pratt and Whitney Aircraft®, one of the world's leaders in the manufacturing of civil and military aircraft engines and as such, this technologically advanced product was tested against the most rigorous standards used in high performance chromate conversion for aerospace applications.


  • RoHS (Restriction of Hazardous Substances Directive)
  • ELV (End of Life Vehicle Directive)
  • WEEE (Waste, Electrical and Electronic Equipment Directive)
  • OSHA Hexavalent Chromium PEL (Permissible Exposure Limit)
  • REACH (Registration, Evaluation and Authorization of Chemicals)
  • EO 13148 (Executive Order)
  • MIL-DTL-5541F, class 1A and class 3*
  • MIL-DTL-81706B*

*Protocase meets the requirements of Mil-DTL-5541F and MIL-DTL-81706B.

For more information, email or call 1-866-849-3911.