1 Jun Q. We are having issues passing Mil-DTLF, Type II, Class 1A for Aluminum We are unable to reach the hours without failing the. Title: Chemical Conversion Coatings on Aluminum and Aluminum Alloys. Scope: This specification covers chemical conversion coatings formed by the reaction. Chemical Films are also known as chem film, alodine, iridite, chemical conversion coatings, or chromate conversion coatings. We offer Mil-Spec and RoHS.
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Chemical Films (Alodine)
December 9, A. The customer is giving us a hard time. I think the confusion is that there are RoHS compliant trivalent conversion coatings which are yellow through the addition of dye — but they are not compliant with MIL-DTL Chemical conversion coating Class 1A using Alodine or equivalent?
RoHS is short for the European Parliament’s directives on Reduction of Hazardous Substances, and refers to the constitution of the parts, not the processes used to manufacture the parts. Views Read Edit View history. Retrieved from ” https: Note that chromate conversion coatings have been used for over 50 years as treatment to coated or as-fabricated surfaces to boost corrosion resistance and provide a good basis for the subsequent application of paint.
Is the part processed per type I hazardous in any way?
Or just the chemical solution used in the process? Processing parts per Type I does put hexavalent chromate on the parts, and they are unlikely to pass a test of their RoHS compliance.
The military specification referred to as MIL-DTL, “Military Specification, Chemical Conversion Coatings on Aluminum and Aluminum Alloys” covers chemical conversion coatings formed by the reaction of chemical conversion materials with the surfaces of aluminum and aluminum alloys. A former governor of NJ once remarked that ” ‘toxic’ is a matter of statute, not opinion”and I think we can look at the word ‘hazardous’ the same way.
When Type I is mentioned, the conversion coat contains Hexavalent Chrome but it may not necessarily be yellow. Mike, Further readings on earlier posts at finishing. The situation is simply that parts processed in Type II solutions do not put hexavalent chromium on the parts, so the parts are very likely to be RoHS complaint. Class 1A is the same for both standards.
MIL-DTL – Wikipedia
However, these treatments use hexavalent nil-dtl-5541 chemicals that are extremely toxic. This is a requirement due to their use on military aircraft.
The conversion coatings are intended for use on aluminum and aluminum alloy substrates that are not anodized. Many domestic and non-European customers are requiring RoHS compliance, so it is understandable that the customer is giving you a hard time — he may not be able to use the parts. All information presented is for general reference and does not represent a professional opinion nor the policy of an author’s employer.
They are designated as a post treatment to ion-vapor deposition IVD aluminum used on many military platforms as a cadmium alternative or galvanic corrosion inhibitor. As far as I am concerned, there is no yellow conversion coat yellow chromate if you prefer that is Type II. So it probably isn’t correct to call them Type II They are mil-ctl-5541 to repair anodized coatings on aluminum. Although prepared specifically for DoD applications, the standard is used for many commercial applications as well.
Please let me know. If you have time check out http: We appended your question to thread where Cheah Sin Kooi had answered the question: This has led to progressively greater restrictions, imposed by national and international legislation, related to concerns over health mil-dtl-55441 safety and environmental protection, on the use of these treatments. It has gained world wide use across many fields versus the more verbose ISO equivalent i.
We appended your question to a thread which answers it.
What is the difference between these two mil standards? We have parts processed per type I versus required type II. It’s not possible to diagnose a finishing problem or the hazards of an operation via these pages. Type I and II conversion coatings provide corrosion protection on unpainted items, as well as improve adhesion of paint finish systems on aluminum and aluminum alloys. mil-dtl-55441
The conversion coatings covered by this specification exceed most commercially available products. This page was last edited on 26 Septemberat