In a type i coating, the chemical composition contains hexavalent chrome. We also offer the more traditional process for gold and yellow mildtl5541f class 1a requirements. What is the difference between these two mil standards. Mildtl5541f type ii class 1a, mildtl5541f type ii class 3 rohs compliant weee and rohs compliance metal finishing tech also offers a trivalent chromate process that complies with the european unions directive on the restriction of hazardous substances rohs and european unions directive on waste electrical and electronic. Type ii compositions containing no hexavalent chromium. Type 1 this includes all coatings that have hexavalent chromium. Mildtl5541f chemical conversion coatings on aluminum.
The military specification referred to as mil dtl 5541, 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. The current specification 2009 is mildtl5541f, which superseded milc5541e in july 2006. The current specification 2009 is mildtl5541f, which superseded. Mildtl5541f chemical conversion coatings on aluminum and. Addresses compositions containing hexavalent chromium.
Class 3 chemical conversion coatings are intended for use as a corrosion preventive film for electrical and electronic applications where lower resistant contacts, relative to class 1a coatings, and anodic coatings in accordance with mila8625, are required see 6. Chemical film or chromate conversion is widely used plating for the protection on aluminum and is. Aluminum chromate conversion coatings per milc5541 mildtl5541. Class 1a is used as a corrosion preventative film unpainted or to improve adhesion of paint finish systems. The current specification 2009 is mil dtl 5541f, which superseded milc5541e in july 2006. Qualified under specification mil dtl 81706b, class 1a, form ii, method a, b, c. We offer an rohscompliant clear trivalent chromium process that is free from hexavalent chromium and complies with the requirements of mildtl5541f class 3. Tolerances as illustrated in drawing and are critical for mating with other components. Process specification for the heat treatment of aluminum.
If the inline pdf is not rendering correctly, you can download the pdf file here. Electrical contact resistance testing shall be as specified in the contract or order see 6. Color can vary from colorless to golden iridescent brown. Mildtl5541 type ii, class 1a and class 3 rohs compliant astm b921 class 1a and class 3 rohs compliant we are an approved supplier for. Difference between milc5541 class 1a and mildtl5541. Mildtl81706b corrosion specification technical standard. Class 3 however, also maintains electrical conductivity. Is one for a clear rohs compliant and the other for a yellow rohs compliant. Because class 3 coatings are thinner they are more susceptible to corrosion than class 1a coatings.
Aluminum chromate conversion coatings, often referred to as chemical film or under the trade names alodine or irridite, produce a thin coating in the range of 0. Chemical conversion coatings on aluminum plating per mildtl5541 and mil c5541. Aluminum chromate conversion coating advanced plating. Mil mil dtl 5541f chemical conversion coatings on aluminum and aluminum alloys superseding mil c5541e standard by military specifications and standards, 07112006 amendments available. Dft of 34 mils and then overcoated with mildtl24441b type iii. A recognized expert in the aluminum finishing industry since 1987, weve been providing high quality finishing services to industries throughout the united states. If you are processing parts and have no obligation to conform to mildtl5541 link is to free spec at defense logistics agency, dla.
Mft currently offers both gold and clear chromate, the conversion processes conforms to the following specifications. This family of compounds is formulated to provide a conversion coating on aluminum that will meet a military specification, mildtl5541f, which describes chemical conversion coatings on aluminum and aluminum alloys, and mildtl81706 that describes the processes certified for use. Mildtl5541 covers all chemical conversion coatings which are known to create protection through chemical reaction with metals like aluminum and aluminum alloy. Mil prf23377 class c2 over the waterreducible epoxy primer. Difference between milc5541 class 1a and mildtl5541 type.
The trivalent chromium process tcp provides a non hexavalent chrome coating compliant with rohs, elv and weee directives. Pins to be used for the chemical conversion materials for coating aluminum and aluminum alloys acquired to this specification are created as follows. These chemical conversion coatings provide a corrosion preventive film for electrical and electronic applications where lower resistant contacts, relative to class 1a coatings, and anodic coatings in accordance with mila8625, are required. And yes there is a sweet spot, 60 seconds chromate immersion time and i found not to use the caustic etch. We offer an rohscompliant clear trivalent chromium process that is free from hexavalent chromium and complies with the requirements of mil dtl 5541f class 3. Notes this section contains information of a general or explanatory nature that may. Anodize sulfuric nondyed clear sulfuric acid anodize mila8625 type ii, class 1 ams2471 astm b580 type b thru f 7. Milc class 1a, type 1, gold or mil dtl 5541 class 3.
Difference between milc5541 class 1a and mildtl5541 type 2 class 1a january 28, 2008. Even after 168 hours of salt spray testing, class 3 coatings must exhibit electrical resistance at no greater than 10,000 microhms per square inch. Because class 3 coatings are thinner they are more susceptible to corrosion than class 1a. A class 1a maximum corrosion protection b class 3 protection against corrosion where low electrical resistance is required type see 1. It is sometimes applied alongside type ii anodizing and can be used to repair minor damage to anodized surfaces. Mildtl81706b, type i, class 3, form ii, method c milc5541. Mildtl5541f detail specification, chemical conversion coatings on aluminum and aluminum alloys 7. Class 3 for protection against corrosion where low electrical. Provides protection against corrosion where low electrical resistance is required. Class 3 for protection against corrosion where low electrical resistance is required. Mildtl5541 chemical conversion coatings on aluminum and. Class 3 chemical conversion coatings provide a corrosion preventive film for electrical and electronic applications where lower resistant contacts, relative to class 1a coatings, and anodic coatings in accordance with mila8625, are required. The best corrosion protection is provided by chem film per mildtl5541 class 1a.
The military specification referred to as mildtl5541, military specification, chemical. Class 3 is used as a corrosion preventive film for electrical and electronic applications, where low resistance contacts are required. Or is the milc5541 for clear rohs and mildtl5541 link is to free spec at defense logistics agency, dla. Chemical film coatings are gelatinous films which provide some sort of a barrier medium to retard corrosion on aluminum surfaces and enhance adhesion of subsequent coatings such as paints and primers. If touchup is permitted for mechanically damaged areas see 3. Mildtl5541 chemical conversion coatings on aluminum. Aluminum chromate conversion coatings aluminum chromate conversion coatings properties. The mil dtl 5541 specification covers chemical conversion coatings that form protective coatings by chemical reaction with aluminum and aluminum alloy.
The name, alodine is a registered trade name of henkel surface technologies. Mildtl5541f type i class 1a, mildtl5541f type i class 3 hexachrome. The test method, frequency of testing, and required resistance values shall be specified by the acquisition activity to meet the needs of a particular application see 6. The supplier shall perform chemical conversion coat per mildtl5541f type i or ii, class 1a and shall submit documentation to engineered machining solutions llc. Chem film per mildtl5541 class 3 is electrically conductive. This film typically appears to be gold or brown in color, but in. Milc5541, class i a, 3 mildtl5541 type i, ii class ia, 3 ams 2473 type i, class ia coating yellow in appearance maximum corrosion resistance type i, class 3 coating clear or yellow in appearance type ii, class 3 coating clear rohs compliant conductive coating excellent base or primer for painting. Chemicalconversion rfqs get online quotes from suppliers.
Jan 28, 2008 difference between milc5541 class 1a and mildtl5541 type 2 class 1a january 28, 2008. The chemical conversion coatings are of the following. This kind of film usually looks brown or gold, but can be colorless at times. I struggled with these two classes class 1a and class 3 of type 1 mil dtl 5541f finish. Type i compositions containing hexavalent chromium. Iridite chromate conversion coating finish milc5541.
Supplier shall provide inspection documentation to engineered machining solutions llc. The materials, which form protective coatings by chemical reaction with aluminum and aluminum alloys, are of the following classes. Chemical conversion coating per mildtl5541f, type ii, class 1a, blue. Selected crvi replacement options for aluminum alloys.
Aluminum conversion coating difruscia industries inc. We also offer the more traditional process for gold and yellow mil dtl 5541f class 1a requirements. Aluminum chromate conversion coatings are amorphous in structure with a gellike composition hydrated with. Qualified under specification mildtl81706b, class 1a, form ii, method a,b,c. The resultant coating is dull, clear yellow or grey, and not intended for decorative use. Coatings shall be continuous free from powdery areas, breaks, scratches, etc. Mildtl5541 chemical conversion coatings on aluminum and aluminum alloys this specification covers chemical conversion coatings formed by the reaction of chemical conversion materials with the surfaces of. Chromium content, application method, and supplier for. Klasse 3 dient ebenfalls als korrosionsschutz, jedoch zusatzlich. There are two classes of coating as specified in mildtl81706b and mildtl5541f. The clear iridite 142 finish also qualifies under class 3, form ii, method c of the same specification. Mildtl5541f is a detailed spec for a chemical conversion coating over aluminum. The short answer is you process to pass the class 3 requirements. Mildtl81706b, type i, class 1a, form ii, method c mildtl81706b, type i, class 3, form ii, method c milc5541.
As established by mildtl5541, both class 1a and class 3 refer to coatings that offer increased corrosion resistance and adhesive properties. The military specification referred to as mildtl5541, 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. Class 1a is for maximum corrosion protection, class 3 is for corrosion protection where low electrical resistance is required. Mil dtl 5541f detail specification, chemical conversion coatings on aluminum and aluminum alloys 7. Class 1a for maximum protection against corrosion, painted or unpainted. For maximum protection against corrosion, painted or unpainted. Process specification for the heat treatment of aluminum alloys.