This standard specifies the determination method of tin content in silver cadmium oxide electrical contact materials. This standard is applicable to the determination method of tin content in silver cadmium oxide electrical contact materials. Determination range: 0.10% to 0.50%. JB/T 7776.5-1995 Chemical analysis method for silver cadmium oxide electrical contact materials JB/T7776.5-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical analysis method for silver oxide pick electric contact material Benzene oxide spectrophotometric method for determination of tin content
1 Subject content and scope of application
This standard specifies the method for determination of tin content in silver oxide pick electric contact material. JB/T7776.51995
This standard is applicable to the determination of tin content in silver oxide cadmium electric contact material. Determination range: 0.10%~0.50%. 2 Reference standards
GB7729-—87
General rules for spectrophotometric method for chemical analysis of metallurgical products General rules and general provisions for chemical analysis methods of electric contact materials JB4107.1-85.
3 Principle of the method
The sample is decomposed with sulfuric acid, and tin LV] forms an orange complex with benzophenone in 0.50.6mol/L sulfuric acid medium. The absorbance is measured at a wavelength of 510nm on a spectrophotometer.
4 Reagents
Sulfuric acid (p1.84g/mL).
Sulfuric acid (1+1).
Sodium potassium tartrate solution (100g/L).
Sulfur gland solution (50g/L).
4.5 Gum Arabic solution (10g/L).
4.6 Benzophenone solution (0.3g/L): Weigh 0.15g of benzyl alcohol and dissolve it in 50mL of anhydrous ethanol, add 2mL of sulfuric acid (4.2), dilute to 500mL with anhydrous ethanol, mix well, put into a brown bottle, and place for - days for use. 4.7 Tin standard stock solution: Weigh 0.1000g of pure tin (99.95%) and place it in a 100ml beaker, heat and dissolve it with 10mL of sulfuric acid (4.1), and cool to room temperature. Transfer the solution into a 1000mL volumetric flask with sulfuric acid (1+6) and cool to room temperature. Dilute to scale with sulfuric acid (1+6) and mix. This solution contains 100μg in 1mL.
4.8 Tin standard solution: Transfer 50.00mL of tin standard storage solution (4.7) into a 500mL volumetric flask, dilute to scale and mix. This solution contains 10μg of tin in 1mL.
5 Instruments
Spectrophotometer.
6 Analysis steps
6.1 Sample
Weigh 0.2g of sample, accurate to 0.0001g. 6.2 Blank test
Approved by the Ministry of Machinery Industry on October 9, 1995
Implemented on January 1, 1996
Perform a blank test with the sample.
6.3 Determination
JB/T7776.51995
6.3.1 Place the sample (6.1) in a 100mL beaker, add 6.5mL sulfuric acid (4.1), cover with a watch glass, dissolve in a platform furnace at high temperature for 70min, remove and cool.
6.3.2 Rinse the watch glass and the wall of the beaker with water, and cool to room temperature. Transfer to a 100mL volumetric flask, dilute to scale, and mix. 6.3.3 Take 5.00mL of the sample solution, add 2.6mL sulfuric acid (4.2), 2mL potassium sodium tartrate solution (4.3), 1mL sulfur solution (4.4), 2mL gum arabic solution (4.5), 10mL benzophenone solution (4.6) to a 50mL volumetric flask, dilute to scale with 40~60C hot water, mix, and let stand for 15min.
6.3.4 Transfer part of the solution into a 1cm colorimetric III, use the blank test as a reference, measure the absorbance at a wavelength of 510nm on the spectrophotometer, and find the corresponding tin content from the working curve. 6.4 Drawing of working curve
6.4.1 Transfer 0, 1.00, 2.00, 3.00, 4.00, 5.00mL of tin standard solution (4.8) to a set of 50mL volumetric flasks, add 2.8mL of sulfuric acid (4.2), and the following operations start from 6.3.3, add 2mL of potassium sodium tartrate solution and proceed with 6.3.4. Use the zero concentration solution as a reference to measure the absorbance.
6.4.2 Use the tin content as the horizontal axis and the absorbance as the vertical axis to draw a working curve. 7 Calculation of analysis results
The percentage of tin is calculated according to formula (1):
Sn(%)=m. : V : 10-c
Where: m. Tin amount found from the working curve, ug; V. -Total volume of sample solution, mL;
V,—Volume of sample solution taken, mL;
—Mass of sample, g. wwW.bzxz.Net
8Allowance difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 1. Table 1
0.10~0.30
>0.30~0.50
Additional instructions:
This standard was proposed and managed by the Guilin Electrical Science Research Institute of the Ministry of Machinery Industry. This standard was drafted by the State-owned No. 615 Factory. The main drafters of this standard are Liu Chengjun, Li Bingkuan, Tang YuelinX100
Allowance difference
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