This standard specifies the determination method of cadmium content in silver zinc oxide electrical contact materials. This standard is applicable to the determination of cadmium content in silver zinc oxide electrical contact materials. Determination range: 0.30% to 1.00%. JB/T 7774.6-1995 Chemical analysis method for silver zinc oxide electrical contact materials JB/T7774.6-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical analysis method of silver zinc oxide electric contact material Flame atomic absorption spectrometry to determine the amount of silver
1 Subject content and scope of application
This standard specifies the method for determining the amount of silver zinc oxide in electric contact materials. This standard is applicable to the determination of the amount of silver zinc oxide in electric contact materials. Determination range: 0.30%1.00%. 2 Reference standards
GB7728-—87
JB4107.1—85
3 Principle of method
General principles of flame atomic absorption spectrophotometry for chemical analysis of metallurgical products General principles and general provisions for chemical analysis methods of electric contact materials JB/T7774.6—1995
The sample is decomposed with nitric acid, and the absorbance is measured at a wavelength of 228.8nm using an air-acetylene flame on an atomic absorption spectrometer. 4 Reagents
4.1 Nitric acid (1+1).
4.2 Cadmium standard solution: Weigh 0.1000g pure cadmium (99.95%), place in a 250ml beaker, add 10ml nitric acid (4.2), cover with a watch glass, slowly heat until completely dissolved, boil to remove nitrogen oxides, cool to room temperature, transfer to a 1000ml volumetric flask, and dilute to scale. Mix well. This solution contains 0.1mg of cadmium per ml.
5 Instruments
Atomic absorption spectrometer with cadmium 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 measured sample solution, with a burner angle of 90°, the characteristic concentration of cadmium should not be greater than 0.15μg/ml.
Precision: Measure the absorbance of the highest concentration standard solution 10 times, and calculate its absorbance average and standard deviation. Its standard deviation should not exceed 1.5% 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. Its standard deviation should not exceed 0.50% of the average absorbance of the highest concentration standard solution. Linearity of the working curve: 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
6.1 Test material
Weigh about 0.1000g of test material, accurate to 0.0001g. Approved by the Ministry of Machinery Industry on October 9, 1995
Implemented on January 1, 1996
Blank test
Perform a blank test with the test material.
6.3 Determination
JB/T7774.61995
6.3.1 Place the sample (6.1) in a 100ml beaker, add 3ml nitric acid (4.1), heat to dissolve, boil to remove all ammonia oxides, cool to room temperature, transfer to a 100ml volumetric flask, and dilute to scale. Mix well. 6.3.2 Use air-acetylene flame to measure the absorbance at a wavelength of 228.8nm on an atomic absorption spectrometer at the same time as the standard series, adjust to zero with water, subtract the blank absorbance from the measured absorbance, and find the corresponding cadmium concentration from the working curve. 6.4 Working curve drawing
6.4.1 Transfer 0, 2.00, 4.00, 6.00, 8.00, 10.00ml of cadmium standard solution (4.2) to a 100ml volumetric flask, dilute to scale, and mix.
6.4.2 Under the same conditions as the test solution, adjust the concentration to zero with water, measure the absorbance, subtract the absorbance of the zero concentration solution, and draw the working curve with the cadmium concentration as the horizontal axis and the absorbance as the vertical axis. Calculation of analysis results
The percentage of radioactivity is calculated as follows:bzxZ.net
Cd(%) -C. V: 10-*
Where: C is the concentration obtained from the working curve, mg/ml; V is the total volume of the test solution, ml
m—the mass of the test material, g.
Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 1. Table 1
0.30~0.50
>0.50~1.00
JB/T7774.6—1995
Instrument working conditions
(reference)
Use the reference working conditions of the WFX-ID instrument of Beijing Second Optical Instrument Factory as shown in Table A1: Table A1
Additional notes:
Air flow
This standard is proposed and managed by Guilin Electric Science Research Institute of the Ministry of Machinery Industry. This standard is drafted by Shanghai Alloy Material General Factory. This standard is drafted by Shanghai Electric Science Research Institute of the Ministry of Machinery Industry. The main drafters of this standard are Huang Liuqing
Li Yongkang
Ling Xiangqun
Acetylene flow
Burner height
Turn 90°)mm
Monochromator passband
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