The primer coating that i assume you are referring to is an organic primer, whereas the conversion coating alodine is an aqueousbased chrome oxide solution that is. Chem film, sometimes called alodine or iridite, is a chemical conversion coating that is used to essentially passivate aluminum. The parts are returned to the customer for some assembly. Chromate conversion coatings on an aluminium substrate are known by the following terms. Temperature limit for chromate conversion coating on. Chemical conversion coatings on aluminum and aluminum alloys. Qpl approved chemistries for chromate conversion chemeon. Pins to be used for the chemical conversion materials for coating aluminum and aluminum alloys acquired to this specification are created as follows. These coatings include metal pretreatments and post rinses for light metal pretreatments. Surface treatment can chromate your products using alodine 600, 1200, 1500 and surtec 650. Chromates chromate conversion coatings by metal finisher. Both trivalent clear and hexavalent yellow chromate processes are available. Although mil dtl 5541 has been superseded by more recent specifications, it still remains a specification approved by all agencies and departments in the us department of.
Henkel alodine 5200 is a conversion coating formulated for treating aluminum and its alloys. Aluminum chromate conversion coatings per milc5541 mil dtl 5541 and astm b44993 advanced plating technologies no longer offers chromate services. Chromate conversion coatings are commonly used on aluminum surfaces to improve corrosion protection and to establish a base for paint primers, but the interaction of such coatings with the aluminum substrate is not understood in detail. 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. The chemical conversion coatings are of the following types see 3. Color can vary from colorless to golden iridescent brown. If the conversion coated parts do not require painting for end use, the paint adhesion test may be omitted if specifically. Chromate conversion coatings, or chromates, are chemical coatings that form from the reaction between a base metal and a chromic acid bearing compound. This film typically appears to be gold or brown in color, but in. The composition of chromate conversion solutions varies widely depending on the material to be coated and the desired effect. Our nonchromate conversion coating is an innovative approach of applying a protective oxide coating on aluminum alloys. Mildtl5541 chemical conversion coatings on aluminum and. This coating is compliant with mil c 5541 and has all of the same benefits as our conventional chromate conversion coating.
Mildtl5541f chemical conversion coatings on aluminum and. Please use the below content for reference only the chromate process provides a clear iridescent to slightly golden iridescent film of low contact resistance. Class 3 clear finish what is the difference between gold iridite and clear iridite in terms of process. View 75 suppliers of chromate conversion anodising on including the anodising co. Kaehr coatings is one of the few shops that provides both chromate and painting services. Ppi aerospace a surface engineering solutions company. The mil dtl 5541 specification covers chemical conversion coatings that form protective coatings by chemical reaction with aluminum and aluminum alloy. Chromate conversion coating is a type of conversion coating used to passivate steel, aluminium, zinc, cadmium, copper, silver, magnesium, and tin alloys. Aluminum chromate conversion coatingalodine produces a thin coating in the range of 0. Aluminum chromate conversion coatings per mil c 5541 mil dtl 5541 and astm b44993 advanced plating technologies no longer offers chromate services. Rohs compliant conversion coating we are pleased to now offer a conversion coating which is compliant with both the elv, rohs and weee directives.
Because the two most popular brands of the required chemistry are iridite from macdermid and alodine from henkel, the process is also often called. 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 aluminum and aluminum alloys. Chemfilm chromate conversion coating ams 2473 alodine. The military specification referred to as mildtl5541, military specification, chemical conversion coatings on aluminum and aluminum alloys covers. Being a surface conversion treatment rather than a coating, it will not alter the dimensions of the part. Chromate provides excellent corrosion resistance, is. Chromate conversion is an inexpensive way to impart increased corrosion resistance and provide a good bonding surface for paint and adhesives to parts such as electronic components, heat sinks, electrical cabinet interiors, or any product fabricated from aluminum and aluminum alloys. Hexavalent chromate produces the gold color associated with gold alodine.
Some important standards for chromate conversion coating on aluminum are mil dtl 5541 coma, 2006 and astm b44993 coma, 2004. Often, sodium metasilicate is used as a builder for lightmetal cleaners. The chromate process provides a clear iridescent to slightly golden iridescent film of low contact resistance per milc5541 mildtl5541 and astm b44993. The primer coating that i assume you are referring to is an organic primer, whereas the conversion coating alodine is an aqueousbased chrome oxide solution that is electrochemically applied to the bare aluminum. What is mil dtl 5541f this specification describes chromate conversion coatings and their reactions with aluminum alloys. Alodine chem film chromate conversion equipment tank line best technologys alodine chem film line is flexible and able to be configured for type 1 or type 2 per mildtl5541 s.
Analysis of chromate conversion coatings on aluminum iopscience. This process is also sometimes called chem film, especially in the usa. How to pass mildtl5541f for aluminum products finishing. There are definitely a couple of tricks to passing mil dtl 5541f, type ii, class 1a for al 2024, and they apply to type i, also. Sulfuric anodizing and chromate conversion coating on aluminum.
Aluminum chromate conversion coating advanced plating. This coating is compliant with milc5541 and has all of the same benefits as our conventional chromate conversion coating. Trivalent chromium conversion coating for corrosion protection of aluminum surface harish bhatt metalast international, inc. For boeing spec bac 5719 alodine type liquid chromate. This specification describes chromate conversion coatings and their reactions with aluminum alloys.
It is also commonly used on aluminum alloy parts in the aircraft industry iridite ncp is a nonchromium type of conversion coating for aluminum substrates the most commonly referredto standard for applying chromate conversion. Chromate conversion is an excellent treatment method to prep aluminum prior to paint. Contact ens technology regarding chromate conversion coating mildtl5541 today. Chromate conversion coating advanced surface technologies. 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. It is primarily used as a corrosion inhibitor, primer, decorative finish, or to retain electrical conductivity.
The process is named after the chromate found in chromic acid, also known as hexavalent chromium, 2 the chemical most widely. Nov 29, 2014 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. Haas, henkel corporation chromate conversion coatings are formed on metal surfaces as a result of the chemical attack that occurs when a metal is im mersed in or sprayed with an aqueous solution of chromic acid, chromium salts such as sodium or. Sponsored links speed downloads mil c 5541 trusted download 1500 kbs 10 310 mil c 5541 highspeed download 1200 kbs 5 945 mil c 5541 full download kbs 1 290 68 p misc accy mila8625, type ii, class 2. Of particular interest is the use of chromate conversion. Chromate conversion coating capabilities milc5541e. Best technologys alodine chem film line is flexible and able to be configured for type 1 or type 2 per mildtl5541. 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. The military specification referred to as mildtl5541, military specification, chemical conversion coatings on aluminum and aluminum alloys covers chemical conversion coatings formed by.
Chromate conversion coating on aluminum is most commonly specified to be in accord with milc5541 mildtl5541. It is also commonly used on aluminium alloy parts in the aircraft industry the most commonly referredto standard for applying chromate conversion coating to aluminium is mildtl5541 in. It is possible to apply hexavalent chromate on the 99. Military specification mildtl5541 chemical conversion coatings on aluminum and aluminum alloys applies to chemical conversion coatings formed by the. Sponsored links speed downloads mil c 5541 trusted download 1500 kbs 10 310 mil c 5541 highspeed download 1200 kbs 5 945 mil c 5541 full download kbs 1 290 68 p misc accy mil a8625, type ii, class 2. Some important standards for chromate conversion coating on aluminum are mildtl5541 coma, 2006 and astm b44993 coma, 2004. Chemfilm is also known as chromate conversion coating, alodine and iridite coating.
Chemical conversion coating mildtl5541 type 2, class 1a hexavalentfree chrome entire process of rohscompliant chemical conversion process. It protects aluminum from corrosion and serves as a base for organic paint coatings while leaving the part dimensions unchanged. The processes are sometimes referred to as chemical film. These coating compositions are divided into type i containing hexavalent chromium and type ii containing no hexavalent chromium. For a complete list of services please visit our website or call 586 7727736. Alodine chem film chromate conversion equipment tank line. May 08, 2012 chromate conversion on aluminumalodine. Downloads milc5541 pdf 617kb material chromate conversion coating.
Chromate, iridite, and alodine conversion coatings passivate the aluminum surface and protect the article from corrosion while retaining conductivity. Mil c5541f, chemical films, chromate iridite, aluminum 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. Chromate conversion coating wikimili, the free encyclopedia. Trivalent chromate, however, is only offered in clear. A discussion started in 2000 but continuing through 2019. Iridite chromate conversion coating finish milc5541. Chromate conversion coatings on an aluminum substrate are known by the following terms.
Chromate conversion coating alodine milc81706mildtl81706. Also known as chromate conversion, chem film, iridite and alodine. If you are processing parts and have no obligation to conform to mil dtl 5541 link is to free spec at defense logistics agency, dla. Provides a surface for better adhesion of primers, paints and powder coat. Addresses compositions containing hexavalent chromium. Salt spray, taber abrasion, anodic coating thickness and weight, and paint adhesion. Chromate conversion coating alodine milc81706mildtl. First, we highly recommend using an allpurpose, nonetch lightmetal cleaner. 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.
Pdf corrosion performance of fieldapplied chromate. Registered as a trademark in 1946 as the conversion coating for aluminum substrates, alodine is a series of conversion coatings that improve paint adhesion and provide corrosion protection for light metal substrates. Chromate conversion coating chem film, also widely referred by the brand names alodine or iridite, is the application of a chromate conversion coating on aluminum alloys. Milc5541 link is to free spec at defense logistics agency, dla. Chromating chromate conversion coating surface treatment. The current specification 2009 is mildtl5541f, which superseded milc5541e in july 2006. Milc5541e, mildtl5541f, astm b 44993 2004, ams 2473g, ams 2474d and mildtl. Corrosion performance of fieldapplied chromate conversion coatings article pdf available in corrosion houston tx 583 march 2002 with 1,304 reads how we measure reads. Chemical film treatment for aluminum alloys, general purpose coating. Chromate conversion produces a thin film of chromium compounds on the surface of aluminum parts. Bare aluminum and raw plated zinc and cadmium will rapidly corrode without a supplemental surface. Moreover, it is often prescribed locally for facings or for electrical conductivity. There are definitely a couple of tricks to passing mildtl5541f, type ii, class 1a for al 2024, and they apply to type i, also.
Chromate conversion coating on aluminum is most commonly specified to be in accord with mil c 5541 mil dtl 5541. For a fully rohs compliant solution, trivalent chromate or nonchromate conversion can be performed as well. This finish prevents the aluminum from corroding and enhances the bond surface for paint and lacquer coatings. Aluminum chromate conversion coatingalodine produces a thin coating in the range of. This is created through the chemical conversion substance reaction with aluminum and its alloys. Chromate conversion coating also commonly referred to as chemical film, chem film, alodine or iridite converts the surface properties of the substrate typically aluminum or magnesium as compared to plating which applies a coating onto the surface of the substrate. Chromating is often applied as a coating pretreatment as it provides highquality adhesion and excellent protection against corrosion. Chromates are typically applied to raw aluminum as well as zinc, cadmium, phosphate, and other plating, to passivate and provide a sacrificial barrier, andor a prepaint coating. Chem film chromate conversion coatings electrolurgy. Black oxide finishes, passivation of stainless steel, and titanium etching.
Our hexavalent chemical films are offered in both clear and gold color. Aluminum chromate conversion coatings are amorphous in structure with a gellike composition hydrated with. Chemical conversion coating mildtl5541 aluminum coatings. Click on thumbnail to enlarge modern metal finishing, inc. Alumiplate electroplated aluminum coatings are also enhanced by conversion coatings. Chromate conversion coating chromate conversion coating also commonly referred to as chemical film, chem film, alodine or iridite converts the surface properties of the substrate typically aluminum or magnesium as compared to plating which applies a coating onto the surface of the substrate. Contact ens technology regarding chromate conversion coating mil dtl 5541 today. Kaehr supplies chromate coating to the following specifications. Alodinechem film on aluminum chromate conversion macon. For boeing spec bac 5719 alodine type liquid chromate conversion coating for aluminum. Trivalent chromium conversion coating for corrosion. We are having some paint adhesion issues with one customers parts. Mildtl5541f chemical conversion coatings on aluminum.
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