The phosphate coating is deposited. The topcoat will now have a better substrate profile in which to adhere to. Remember that aluminum does not accept a conversion coat unless phosphate chrome is used. The aluminum will still receive an etch that will accept good adhesion. You need to determine if the job shop is just degreasing the part or actually applying a phosphate coating.
Phosphate cleaners are typically alkaline, phosphate conversion coatings are typically acidic.
I need some know how about metal pre-treatment system. Is there any gentleman who gives me information about alkaline cleaners,pickling solutions,phosphating chemicals. God bless you. Hello, Mr. Saleem, There are entire aisles in technical libraries which attempt to answer your question. It is so very general that nobody can help you except by recommending some books and journals .