DIN EN ICS A comma is used as the decimal marker. The committee decided to retain the specifications of subclause 7.
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DIN EN ICS A comma is used as the decimal marker. The committee decided to retain the specifications of subclause 7. 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 then cool it to ambient temperature. Using half of the solution, test for manganese by adding 0,5 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 solid ammonium chloride. 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. Table NA. 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.
DIN EN A comma is used as the decimal marker. The committee decided to tetain the specifications of subclause 7. EN comprises 12 pages.
Phosphate coating spec
In practice the presence of corrosive media is no common and the forms of attack so numerous that it is not possible to deal with the entire problem in detail here. It can only be established here that ordinary spring steel must offer no corrosion protection of their own. Therefore, disc springs of these types of steel must be protected again: Phosphating. This is a standard process generally applied to all low alloy steels unless otherwise agreed. A zinc phosphate layer is produced on the surface, which is then impregnated with corrosion-protection oil. The protection achieved in this way is sufficient in the vast majority of all cases.