This standard specifies the determination of silver content by silver chloride gravimetric method. This standard is applicable to the determination of silver content in phosphor copper brazing materials, with a determination range of 1.50% to 16.00%. JB/T 7520.2-1994 Chemical analysis method for phosphor copper brazing materials Determination of silver content by silver chloride gravimetric method JB/T7520.2-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical Analysis Method of Phosphor Copper Material
Determination of Silver Content by Silver Chloride Gravimetric Method
Subject Content and Scope of Application
This standard specifies the determination of silver content by silver fluoride gravimetric method. This standard is applicable to the determination of silver content in phosphor copper material, with a determination range of 1.50%~～~16.00%. 2 Method Summary
JB/T 7520.2—94
After the sample is dissolved in nitric acid, hydrochloric acid or sodium chloride is added to generate silver chloride precipitation, which is left overnight, filtered with a glass filter, and weighed after drying.
3 Reagents
3.1 Nitric acid (1+1).
3.2 Nitric acid (1+3).
3.3 Nitric acid (1+100).
3.4 ​​Hydrochloric acid (1+9).
3.5 Sodium chloride solution (10%),
4 Analysis stepswwW.bzxz.Net
4.1 Sample volume
Weigh more than 2.0000 samples.
4.2 Determination
4.2.1 Place the sample (4.1) in a 300ml high-type beaker, add 20mL nitric acid (3.1), cover with a watch glass, slowly heat to dissolve, rinse the cup wall and the surface with water, and continue to heat and evaporate until it is syrupy. 4.2.2 Add 20ml nitric acid (3.2) to dissolve the salts. If saws and other precipitates are precipitated, filter with slow filter paper, wash the precipitate with hot nitric acid (3.3), and discard the precipitate. Dilute the solution with water to a volume of about 150 mL. Add hydrochloric acid (3.4) or sodium chloride solution (3.5) while stirring until no more turbid silver chloride precipitate is produced. Then add a few drops in excess. Boil slowly for 5 minutes and place in a dark place for 12 hours. 4.2.3 Use a constant-weight glass filter (G4) to filter and wash the precipitate with nitric acid (3.3) several times, then wash with water. Dry the precipitate and the glass filter in an oven at 130 ± 1°C to a constant weight, cool in a desiccator, and weigh. 5
Calculation of analysis results
Calculate the percentage of silver according to the following formula:
(mi-mz) X0. 752 6
Ag(%)=
Wherein: m--
-mass of glass filter and precipitate·g;
mass of glass filter, name;
Approved by the Ministry of Machinery Industry of the People's Republic of China on December 9, 1994, 318
Implementation on October 1, 1995!
mo sample volume, g,
silver chloride conversion factor.
0. 752 6—
Allowable difference
JB/T7520.2
The difference in analysis results should not be greater than the allowable difference listed in Table 1. Table 1
Allowance
Additional Notes:
1.50~2.50
This standard was proposed by Harbin Welding Research Institute of the Ministry of Machinery Industry. This standard was drafted by Harbin Welding Research Institute. The main drafters of this standard are Bai Shuyun and Lin Kegong. 94
4. 00-~6. 00
14. 00-16. 00
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