Chemical conversion coatings/pretreatments for aluminum
Chemical conversion coatings/pretreatments for aluminum
(OP)
Is there a difference between specifying a "5 stage chrome phosphate" pretreatment versus "clear chemical conversion coating per MIL-DTL-5541F Type 2 Class 3 (ROHS compliant)"
Is the later just more specific? I guess the question is if I specify the MIL spec am I essentially getting a 5 stage chrome phosphate coating?
I always see a chrome phosphate pretreatment referred to as a chemical conversion coating.
This will be a pretreatment for powdercoated aluminum with some areas masked for grounding reasons.
Is the later just more specific? I guess the question is if I specify the MIL spec am I essentially getting a 5 stage chrome phosphate coating?
I always see a chrome phosphate pretreatment referred to as a chemical conversion coating.
This will be a pretreatment for powdercoated aluminum with some areas masked for grounding reasons.





RE: Chemical conversion coatings/pretreatments for aluminum
So, regardless, does "5 stage chrome phosphate" pretreatment mean anything at all? Is that your acceptance criteria? Do you specify what each of the 5 stages is supposed to be? Is that something you really should be caring about? Does the end product meet the corrosion resistance, adhesion, and electrical resistance requirements that you've specified?
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RE: Chemical conversion coatings/pretreatments for aluminum
The MIL spec on unpainted/grounding surfaces meets my requirements but wanted to make sure it is an equivalent to their requirements. In the case of issues with the powdercoating or whatever I want to make sure that I know I at least did my part and used an equivalent pretreatment.
RE: Chemical conversion coatings/pretreatments for aluminum
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RE: Chemical conversion coatings/pretreatments for aluminum
I was planning on using the MIL callout anyways. I was just hoping someone would say that yes that "should" be a suitable "equivalent" to the generic 5 stage chrome phosphate or equivalent call out the powder manufacturer recommends.
RE: Chemical conversion coatings/pretreatments for aluminum
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RE: Chemical conversion coatings/pretreatments for aluminum
Seems you make a point of calling out "RoHS", if this is important to you then I'd be even more inclined to call out the relevant version of the mil-dtl. Who knows what "5 stage chrome phosphate" has in it, except presumably chrome (which may be a bad thing) and phosphate.
Are you really asking if the RoHS version is equivalent to the non RoHS version for your application? Again, I'd check with your powder coat supplier.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?