This standard specifies the determination method of zinc content in silver cadmium oxide electrical contact materials. This standard is applicable to the determination method of zinc content in silver cadmium oxide electrical contact materials. Determination range: 0.10% to 1.00%. JB/T 7776.3-1995 Chemical analysis method for silver cadmium oxide electrical contact materials JB/T7776.3-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical analysis method of silver oxide cadmium electric contact material Flame atomic absorption spectrometry to determine the zinc content
1 Subject content and scope of application
This standard specifies the determination method of zinc content in silver oxide cadmium electric contact material. JB/T7776.3—1995
This standard is applicable to the determination of zinc content in silver oxide electric contact material. Determination range: 0.10%～1.00%. 2 Reference standards
GB7728-87
JB4107.185
3 Principle of method
General principles of flame atomic absorption spectrometry for chemical analysis of metallurgical products General principles and general provisions for chemical analysis methods of electric contact materials The sample is decomposed with nitric acid, and the absorbance is measured at a wavelength of 213.9nm on an atomic absorption spectrometer using an air-acetylene flame in a dilute nitric acid medium. Coexisting elements do not interfere with the determination. 4 Reagents
4.1 Nitric acid (1+1).
4.2 Zinc standard stock solution: Weigh 0.1000g pure zinc (99.95%) and place it in a 200mL beaker, add 5mL nitric acid (4.1), cover with blood, heat at low temperature to dissolve, drive off nitrogen oxides, and cool to room temperature. Transfer to a 500mL volumetric flask, dilute to scale, and mix. This solution contains 0.2mg zinc in 1mL.
4.3 Zinc standard solution: Transfer 10.00mL zinc standard stock solution (4.2) to a 200mL volumetric flask, add 2mL nitric acid (4.1), dilute to scale, and mix. This solution contains 10ug zinc in 1mL. 5 Instruments
Atomic absorption spectrometer, with zinc hollow cathode lamp. Under the best working conditions of the instrument, any instrument that can meet the following indicators can be used. Sensitivity: In a solution consistent with the matrix of the sample solution, the concentration of zinc to be characterized should not be greater than 0.01μg/mL. Precision: Measure the absorbance of the highest concentration standard solution 10 times, and calculate its absorbance average and standard deviation. The standard deviation should not exceed 1.0% of the absorbance average.
Measure the absorbance of the lowest concentration standard solution (not the "zero" standard solution) 10 times, and calculate its standard deviation. The standard deviation should not exceed 0.5% of the average absorbance of the highest concentration standard solution. Working curve linearity: Divide the working curve into five sections according to concentration. The ratio of the difference in absorbance of the standard solution in the highest section to the difference in absorbance of the standard solution in the lowest section should not be less than 0.7. See Appendix A (reference) for instrument working conditions. 6 Analysis steps
Approved by the Ministry of Machinery Industry in 19951009
Implemented in 199601-01
6.1 Test materials
Weigh the test materials according to Table 1, accurate to 0.0001g. Zinc
0.10~0.20
>0.20~0.50
>0.50~1.00
6.2 Blank test
Carry out a blank test along with the test materials.
6.3 Determination
JB/T7776.31995
6.3.1 Place the test material (6.1) in a 100mL beaker, add 5mL nitric acid (4.1), cover with table blood, heat at low temperature to dissolve, drive off nitrogen oxides, and cool to room temperature. Transfer to a 100mL volumetric flask, dilute to scale, and mix. 6.3.2 Take 10.00mL of the sample solution, add 1.5mL of nitric acid (4.1) to a 100mL volumetric flask, dilute to scale, and mix. 6.3.3 Use air-acetylene flame to adjust the atomic absorption spectrometer to zero at a wavelength of 213.9nm with water, measure the absorbance in parallel with the working curve solution series, and subtract the blank test absorbance. Find the corresponding zinc concentration from the working curve. 6.4 Drawing of the working curve
6.4.1 Take 0, 2.00, 4.00, 6.00, 8.00, 10.00mL of zinc standard solution (4.3), add 2mL of nitric acid (4.1) to each of the 100mL volumetric flasks, dilute to scale, and mix. 6.4.2 Adjust the absorbance to zero with water under the same conditions as the sample solution measurement. Subtract the absorbance of the zero concentration solution. Draw the working curve with zinc concentration as the horizontal axis and absorbance as the vertical axis. Calculation of analysis results
The percentage of zinc is calculated according to formula (1):
CV. .V,X10-
Zn(%)=
Wherein: C-the zinc concentration μg/mL found from the working curve; V.
-the total volume of the sample solution, mL;
V,——the volume of the solution during the determination, mL; V, the volume of the sample solution taken, mL;
Allowable difference
The mass of the sample, 8.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0.10~0.20
>0.20~0.50
>0.50~1.00
AllowancewwW.bzxz.Net
JB/T 7776.3--1995
Appendix A
Instrument working conditions
(reference)
The reference working conditions of WFX-1F2 atomic absorption spectrometer are shown in Table A1. Table A1
Additional notes:
Lamp current
Burner height
Spectral passband width
This standard was proposed and managed by Guilin Electric Science Research Institute of the Ministry of Machinery Industry. This standard was drafted by State-owned No. 615 Guang. The main drafters of this standard are Zhang Huanwen, Yu Xiaoguang, Wang Enli, Huang Liuqing, Air flow, Acetylene flow
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