GB 12305.3-1990 Test methods for metal coatings - Gold and gold alloy electroplated coatings - Part 3: Electrographic test for porosity
Some standard content:
National Standard of the People's Republic of China
Metallic coatings
Test methods for electrodeposltedgold and gold alloy coatings-Part 3: Flectrographic tests for porosityGE12305.390
This standard is equivalent to the international standard IS01521/3-1985 Test methods for electrodeposltedgold and gold alloy coatings-Part 3: Flectrographic tests for porosity. bzxZ.net
1 Subject content and scope of application
This standard specifies the test methods for porosity of gold and gold alloy coatings. This standard is applicable to the determination of porosity of gold alloy coatings for engineering, decoration and protection. 2 Reference Standards
GB4677. Electrical Image Test Method for Porosity of Coatings on Printed Boards 3 Determination Methods
3.1 Cadmium Sulfide Test Paper Test
3.1.1 Applicable Scope
Application of this method 1 Check the gold coating on the steel substrate. 3.1.2 Materials
The reagents used in this test shall be analytically pure reagents, distilled water or deionized water. 3.1.2.1 Cadmium Sulfide Test Paper
Prepare 10% cadmium nitride solution, immerse the filter paper or copy paper fully moistened with distilled water in the newly prepared solution, take it out after 10 minutes, and absorb the excess solution on the paper with absorbent paper. Before the paper is completely dry, immerse it in a newly prepared solution containing 50ε/L of sodium sulfide for 30 seconds. At this time, the paper turns a uniform yellow (indicating that the sulfide deposition is complete). Wash the test paper in running water for about 1 hour, and then hang it to dry. 3.1.2.2 Wetted absorbent paper
Put a piece of high-quality filter paper in water and dry it properly to produce a clear electrical image. 3.1.3 Operation steps
Gently brush off the loose dust and dirt on the plated surface, and then degrease it in ethanol or 1,1,1-trichloroethane vapor or other appropriate solvents.
Put a piece of ionizing radiation test paper (3.1.2.1) on the electroplated sample, and use the sample as the anode. Put a piece of wetted absorbent paper (3.1.2.2) on the test paper, and then put a piece of clean aluminum or stainless steel plate of high purity on it (as the cathode). Use a pressure device to pressurize at a pressure of 1.4 to 1.7 MPa so that the test paper and the sample of the sulfurization pot are evenly stressed. Under pressure, a power supply not exceeding 12V supplies a steady and ripple-free DC current, with an initial anode current density of 7.5mA/cm and a power-on time of 308. Approved by the State Administration of Technical Supervision on April 6, 1990, 1991-0101 implementation
GB12305.3-90
The cadmium sulfide test paper that produces the image is dried, and the pores on the coating show brown spots on the test paper accordingly. 3.2 Cyclohexanedione dioxime test
3.2.1 Scope of application
This method is suitable for checking the gold plating on the bottom of nickel and tin-nickel alloy. 3.2.2 Materials
Analysis-grade reagents, distilled water or deionized water shall be used for the reagents used in this test. YKAONiKAca
Cyclohexanedione dioxime test: Soak the filter paper or copy paper in a solution of 3g/L cyclohexanedione dioxime. Take it out after 10 minutes, absorb the excess solution on the paper and hang it to dry.
3.2 .3 Operation steps
Gently brush away the loose dust and dirt on the coating, and then remove it in anhydrous ethanol or 1.1,1 triethylene glycol vapor or other appropriate solvents.
Wet a piece of cyclohexane paper with water, absorb excess water, and then place it on the electroplated sample (the sample is used as the anode). Place a piece of wetted absorbent paper on it, and place a high-purity clean aluminum or stainless steel plate on the paper (as the cathode). Use a pressurizing device to pressurize the pressure at 1.4-1.7MPa, so that the cyclohexane paper and the sample are evenly stressed. When pressurized, a steady, ripple-free direct current is supplied by a power supply not exceeding 12V, with an initial anodic current density of 7.5mA/cm2, and the power-on time is 30s. The image of cyclohexanedione "paper" is displayed in the ammonia vapor ratio, and then dried. For nickel-plated or tin-nickel-gold-plated on copper, the pores of the gold layer appear as pink spots on the paper, while the pores through the nickel or tin-nickel alloy coating appear as aqua spots on the paper. 3.3 Color-changing paper test 1 can be interchanged with test 3.1. 1 Materials
Reagents used in this test: Use pure reagents, distilled water or deionized water. 3.3.1.1 Color-changing paper: Immerse the color-changing paper in a solution containing 0.01mol/1 of sodium oxide and 0.01mol/1 of sodium carbonate (preparation method: 0.58g of sodium oxide and 1.06g of sodium carbonate dissolved in 1L of water). After 20 minutes, use absorbent paper to absorb excess water. Note: Color-changing paper can be purchased from a photographic material store. 3 3.1.2 Saturated ethanol solution of dithiooxalamide: Dissolve 0.25 g of dithiooxalamide in 100 ml of warm ethanol. If necessary, filter after cooling before use. 3.3.2 Operation steps
Use a soft brush to brush away loose particles and dirt on the bond layer, and then degrease the seed sample in anhydrous ethanol or 1,1,1-triazine vapor or other appropriate solvent.
Wet the color-changing paper (3.3.1 .1, with the latex side facing down, put it on the electroplating sample (sample as anode), then put a high-purity clear pin or stainless plate (as cathode), and use a pressure device to pressurize between 1.1 and 1.7 Mt. Make the color-changing paper and the sample bear the same force: when pressurizing, apply a stable V voltage, take out the color-changing paper after 30s, develop the color in a saturated ethanol solution of dithioethanediamide (rubicinic acid) 305, rinse the resulting image with running cold water, and then dry it: The pores on the coating will appear as dark olive green spots on the paper. Note: ① Rinse the prepared test paper in hot water and dry it carefully. This is the key to completing this test. It is best to use tweezers to dip the paper into the monothiohexamethylenediamine solution, because contact with the paint will leave a large black stain that is difficult to remove: 3.4 Color-changing paper test 2 (interchangeable with test 3.2) is carried out in the same procedure as test 4, but an ethanol solution containing 0.5% of hexamethylenedione "oxime" is used as the color developing solution. The pores on the coating will appear as pink spots on the paper. When nickel or tin-nickel alloy is electroplated on a copper substrate 1, the pores that reach the base metal appear green.
Rinse the prepared test paper in hot water and dry it carefully. This is the key to completing this test. 3.5 Gelatin film electrographic test
3.5.1 Method summary
To determine the porosity of metal coatings on different base metals or substrates, the sample can be placed in an electrolyte containing gelatin and an appropriate indicator for electrolysis. The ions in the electrolyte can form colored reaction products with the base metal. GB 12305.3-90
The electrographic method is usually carried out by immersing paper in a specific test solution. This method can be considered as a derived electrographic method. Compared with the electrographic method, its advantages are: it is suitable for testing curved surfaces, and to some extent, the colored points do not extend outward from the micropores. 3.5.2 Reagents
The reagents used in this test are analytically pure reagents, and the water used is deionized water or deionized water. 3.5.2.1 Gelatin solution
Prepare 10% gelatin solution at 60 °C. Stir carefully during preparation to ensure that no air enters the solution. Store the prepared solution in a cool place.
3.5.2.2 Electrolyte
Mix 20 mL of nitrogen water (density 0.88 g/ml) with 30 mL of water. 3.5.2.3 Methylacetaldehyde oxime indicator solution: Prepare a saturated solution of dimethylglyoxal in ethanol. 3.5.3 Test solution
Add 35 mL of electrolyte (3.5.2.2) and 40 mL of indicator solution (3.5.2.3) to 950 g of gelatin solution (3.5.2.1) at 27-30°C under stirring. Be sure to avoid entraining air. Pour the test solution into the electrolytic cell and cool it to the operating temperature of 22-23°C. 3.5.4 Equipment
3.5.4.1 Water bath. To facilitate the control of the temperature of the test solution, a temperature automatic regulator should be installed in the bath. 3.5.4.2 Stirring device
.3.5.4.3 Electrolytic cell. The electrolytic cell is made of glass or acid-resistant steel. The test solution is placed in the cell. The cathode is made of platinum mesh or gold or. The cathode area is at least the same as the area of the tested part (anode). The cathode should be placed on the side of the cell and insulated from the electrolytic bottle. The distance between the two electrodes is about 50mm. 3.5.4.4 Rectifier or battery.
3.5.5 Operation steps
3.5.5.1 Electrolysis process
Before the test, cover the part of the sample that does not need to be tested, and then immerse the sample in the test solution (3.5.3) as the anode and perform electrolysis treatment, the current density is 100mA/cm, and the electrolysis time is 20s. 3.5.5.2 Drying
Take out the sample from the electrolyte, keep the gelatin on the surface, and keep the sample in the water. Dry it naturally at room temperature for about 30 minl or accelerate drying in air flow for 15min,
3.5.5.3 Evaluation
Check the pores on the surface. The pores in the coating will show colored spots: these spots are usually a clear center point with a diameter of 0.2mm. The color of the spot is related to the base and bottom layer of the gold or gold-containing coating. On the nickel layer, it is a red spot with a dark red center point: on the copper or copper alloy, it is a green spot with a dark green center point. Note: When used as a base layer on copper or copper-gold, if the pores of the plated layer extend to the base gold, green spots with dark green centers will appear. 3.5.6 Expression of porosity
Porosity is expressed as the number of pores per square centimeter, pores/cm24Test report
The test report shall at least include the following: a. The scope of this standard shall include the specific test method used: b. Test results and their expression form:
Abnormal phenomena observed during the test; d. Any operation not included in this standard and its application standards; e: Other relevant information required by the purchaser. Additional remarks:
GB12305.3
This standard is proposed by the Ministry of Machinery and Electronics Industry of the People's Republic of China. 90
This standard is under the jurisdiction of the National Technical Committee for Standardization of Metal and Non-metallic Covers. This standard was drafted by the Technology Research Institute of the Ministry of Machinery and Electronics Industry. The main drafters of this standard are Han Shumei and Zhao Shuying. KAoNKAca
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