1 Range
This standard specifies test methods for electroplating of silver and silver alloys for engineering, decoration and protection purposes against contamination by residual salts.

This standard applies to metal parts; Not applicable to composite parts, such as parts with both plastic and coated metal.

2 Principle
The part was boiled in water with known conductivity for a specified time and the increase in conductivity resulting from precipitation of residual salts and other conductive impurities was measured.

3 Reagents
Water: The conductivity is not more than 100µs/m at 20 ° C ±1 ° C.

4 Instruments
All glass instruments used shall be made of borosilicate glass, shall meet the cleanliness requirements specified in 5.2, and shall be stored separately for this test.

4.1 Round bottom flask: The capacity is 250mL, and the water reflux condenser tube is installed.

4.2 Beaker: Size suitable for the part under test, marked with 100mL scale, equipped with appropriate devices to reduce excessive evaporation loss of water, such as cooling water cover.

4.3 Conductivity meter

ISO 4522-3-1988 “Methods of test for metallic coatings of silver and silver alloys – Part 3: Determination of residual salts”

5 Test methods
5.1 Sample

Take one or more fully coated metal parts with a total surface area of about 30cm2 and test according to the size (see 5.3) as specified in 5.3.1 or 5.3.2.

Be sure to avoid accidental contamination of the sample, and bring clean gloves to the corner of the parts during the inspection.

5.2 Inspection of instrument cleanliness

Before the assay, 100mL of water (see Chapter 3) was added to the test container (see 4.1 or 4.2) and then slowly boiled for 10min under the specified test conditions (see 5.3.1 and 5.3.2). The water was cooled to 20 ° C ±1 ° C and its conductivity was measured with a conductivity meter (see 4.3).

If the measurement exceeded 100µS/m, it was determined again with another 100mL of water. If the measurement value again exceeded 100µS/m, it was changed to a new vessel and tested again.

Qualified glass instruments should be stored separately for this test.

5.3 Measurement

ISO 4522-3-1988 “Methods of test for metallic coatings of silver and silver alloys – Part 3: Determination of residual salts”

5.3.1 Samples with cross section width or diameter less than 15mm and length less than 40mm.

After checking the cleanliness of the instrument (see 5.2), place the sample (see 5.1) into a round-bottom flask and add 100mL of water (see Chapter 3). The electrical conductivity of the water should be determined quickly before the measurement. Completely immerse the test piece in water. The reflow condenser tube was installed on the flask and slowly boiled for 10min. The water was cooled to 20 ° C ±1 ° C, and the conductivity was measured with a conductivity meter (see 4.3). The value added of the conductivity was calculated as the measurement result.

5.3.2 Samples with cross section width or diameter greater than 15mm and length greater than 40mm.

The test was performed as described in 5.3.1. Place the sample (see 5.1) into a beaker (see 4.2) with water to 100mL scale. To PREVENT loss OF WATER from excessive evaporation during the assay, a cooling water hood may be used and, if necessary, additional water (see Chapter 3) may be added to replace the evaporated water.

ISO 4522-3-1988 “Methods of test for metallic coatings of silver and silver alloys – Part 3: Determination of residual salts”

6 Test report
The test report shall include at least the following:

a) Reference to this Standard;

b) Name or number of test sample;

The total surface area of the test sample,cm2; d) the name or model of the instrument used;

Anomalies observed during testing; f) any instructions different from this method;

g) Test results and representation methods;

h) Test date;

i) Name of operator and testing laboratory.