What is MIL DTL 5541F
This specification describes chromate conversion coatings and their reactions with aluminum alloys. These coating compositions are divided into Type I (containing hexavalent chromium) and Type II (containing no hexavalent chromium). They are further divided into Class 1A (maximum corrosion protection, painted or unpainted) and Class 3 (corrosion protection where low electrical resistance is required). Approved chemical compositions can generally be used for both Class 1A or Class 3, by varying the immersion time and the subsequent film thickness.
Approved products for this specification have been evaluated per MIL-DTL-81706 and are listed on QPL-81706.
These conversion coatings are typically too thin to be measured accurately, and color (especially with hex chrome) is used as an indicator of relative thickness, gold/bronze being thickest to iridescent/clear being thinnest.
To maintain compliance with MIL-DTL-5541F, applicators must test samples on a monthly basis, as outlined in the table (Table 1 of the standard):
You can download MIL-DTL-5541F from the link below:
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