ASTM-B733:2004 pdf free download – Standard Specification for Autocatalytic (Electroless) Nickel-Phosphorus Coatings on Metal.
9.6 Porosity—There is no universally accepted test for porosity. When required, one of the following tests can be used on the plated part or specimen.
9.6.1 iron Base Substrates—Prepare the test solution by dissolving 25 g of potassium ferricyanide and 15 g of sodium chloride in 1 L of distilled water. After cleaning, immerse the part for 30 s in the test solution at 25°C. After rinsing and air drying, examine the part for blue spots, which form at pore sites.
9.6.2 Boiling Water Test for iron-Base Si.i bstrates— Completely immerse the part to be treated in a vessel filled with aerated water at room temperature. Apply heat to the beaker at such a rate that the water begins to boil in not less than 15 mm, nor more than 20 mm after the initial application of heat. Continue to boil the water for 30 mm. Then remove the part, air dry, and examine for rust spots, which indicate pores.
NOTE 19—Aerated water is prepared by bubbling clean compressed air through distilled water by means of a glass diffusion disk at room temperature for 12 h. The pH of the aerated water should be 6.7 + 0.5.
9.6.3 Aerated Water Test for iron-Base Substrates— Immerse the part for 4 h in vigorously aerated Type IV or better water (see Specification Dl 193) at 25 ± 2°C temperature and then examine the part for rust spots.
9.6.4 Aliarin Test frr Aluminum Alloys— Wipe the plated part or specimen with 10 mass % sodium hydroxide solution. After 3 mm contact, rinse, and apply a solution of alizarin sulfonate prepared by dissolving 1 .5 g of methyl cellulose in 90 mL of boiling water to which, after cooling, 0. 1 g sodium alizarin sulfonate, dissolved in 5 mL of ethanol is added. After 4 mm contact, apply glacial acetic acid until the violet color disappears. Any red spots remaining indicate pores.
9.6.5 Porosity Tesifr C’opper Substrates—Wipe the plated part or specimen with glacial acetic acid. After 3 mm, apply a solution of potassium ferrocyanide prepared by dissolving 1 g of potassium ferrocyanide and 1 .5 g methyl cellulose in 90 mL of boiling distilled water. The appearance of brown spots after 2 mm indicate pores.
9.7 Other Test Methods—Test methods which have been developed that are equal to or better than these may be substituted. The precision and bias requirements will vary for each type of test. If an alternate test is specifIed it shall he agreed upon between the producer and the purchaser.
10. Rejection and Rehearing
10.1 Part(s) that fail to conform to the requirements of this standard may be rejected. Rejection shall he reported to the producer promptly in writing. In the case of dissatisfaction occurs with the results of a test, the producer may make a claim for a hearing. Coatings that show imperfections may be rejected.
11. Certification
11.1 When specified in the purchase order or contract, the purchaser shall be furnished certification that the samples representing each lot have been processed, tested and inspected as directed in this specification and the requirements have been met. When specified in the purchase order or contract, a report of the test results shall be furnished.