T5 = Application of wax. T6 = Application of soap. Supersedes;. BS EN BS AMS Phosphate treatment is defined by reference to a particular. Find the most up-to-date version of BS EN at Engineering BS EN October Phosphate conversion coatings of metals. Method of specifying requirements. Historical Version.
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BS EN – Phosphate conversion coatings of metals. Method of specifying requirements
A comma is used as the decimal marker. The committee decided to retain the specifications of subclause 7. Previous editions DIN EN comprises 12 pages.
The detection of phosphate in a coating shall be taken as proof that it is a phosphate coating cf.
To establish that a coating is a manganese phosphate coating, it is sufficient to establish the presence of manganese for ferrous substrates only cf. To establish that a coating is a zinc phosphate or a zinc calcium phosphate coating, it is sufficient to establish the presence of zinc or zinc and calcium, respectively for zinc-free substrates cf.
If neither manganese nor zinc has been detected in a phosphate coating on a substrate of ferrous material, then the coating is certain to be an iron phosphate coating.
If necessary, scrub the coating off with a rubber wiper. Add 10 ml of the ammonium molybdate solution and 5 g of ammonium nitrate to the acidified filtrate, and leave the mixture to stand for at least 15 minutes.
A yellow precipitate indicates the presence of phosphate. To decompose the excess hydrogen peroxide, boil the resulting solution for a few minutes and sb cool it to ambient temperature.
Using half of the solution, test for manganese by adding 12467 g of bismuth sodium trioxide, thus oxidizing any manganese present to permanganate; a reddish violet colour indicates the presence of manganese. Use the other half of the solution to test for the presence of calcium as described in subclause NA.
A white precipitate, which may have a slight green tinge due to the presence of a small amount of iron, indicates the presence of zinc.
If necessary, adjust the pH to the desired level by adding bx ammonium chloride.
BS EN 12476:2000
Filter this off after 10 minutes of heating and rinse thoroughly with hot distilled water. To identify the purified white precipitate as calcium oxalate, remove it from the filter by spraying with hot distilled water, and then add about 50 ml of distilled water.
Decoloration of the permanganate solution identifies the precipitate as calcium oxalate, thus indicating the presence of calcium in the coating. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Management Centre or to any CEN member.
A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the official versions.