MIL-STD-1503 Preparation Of Aluminum Alloys For Surface Treatment And Inorganic CoatingThis standard describes the cleaning, activation and under-plating process, and material required for aluminum and aluminum alloys prior to applying inorganic coatings. It is intended that this standard be used in conjunction with other process documents, where the technical requirements are for the application of surface treatments and inorganic coatings on aluminum and aluminum alloys.

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MIL-STD-1503C

Chromic Acid

4.5 - 7.5 g/l (0.7 - l.0 oz/gal)

Sodium Bisulfate

120 - 128 g/l (16 - 17 oz/gal)

Sodium Fluorosilicate

7.5 - 10 g/l (1.0 - 1.25 oz/gal)

Temperature

ambient

Time

10 - 15 minutes

5.2 Surface Preparation for Anodizing/Conversion Coating:

a. Step Number 1: Vapor Degrease.

b. Step Number 2: Alkaline Clean.

c. Step Number 3: Rinse thoroughly in clean water. The rinse water temperature should be ambient.

d. Step Number 4: (Optional) Alkaline Etch.

e. Step Number 5: (Omit if Step 4 was not performed.) Rinse thoroughly in clean water. The rinse water temperature should be ambient.

f. Step Number 6: Remover Smut.

g. Step Number 7: Rinse thoroughly in clean water. The rinse water temperature should be ambient.

h. Step Number 8: Anodize or conversion cost immediately.

5.3 Surface Preparation for Plating.

a. Step Number 1: Parts shall be vapor degreased. No minimum elapsed time shall elapse between this operation and the cleaning operation.

b. Step Number 2: Clean by abrasive blasting per MIL-STD-1504; using 60 - 180 grit aluminum oxide, vapor blast or garnet abrasive blast. Elapsed time between this step and step number 3 should not to exceed sixty (60) minutes.

c. Step Number 3: Alkaline clean.

d. Step Number 4: Rinse thoroughly in clean water. The rinse water temperature should be ambient.

e. Step Number 5: Remove smut.

f. Step Number 6: Rinse thoroughly in clean water. The rinse water temperature should be ambient.