This standard specifies the determination method of nickel content in silver zinc oxide electrical contact materials. This standard is applicable to the determination of nickel content in silver zinc oxide electrical contact materials. Determination range: 0.05% to 0.30%. JB/T 7774.4-1995 Chemical analysis method for silver zinc oxide electrical contact materials JB/T7774.4-1995 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 nickel content
1 Subject content and scope of application
This standard specifies the method for determining the nickel content in silver zinc oxide electric contact material. JB/T7774.4—1995
This standard is applicable to the determination of nickel content in silver zinc oxide electric contact material. Determination range: 0.05%~0.30%. 2 Reference standards
GB7728—87
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 JB4107.1—85
3 Principle of the method
The sample is decomposed with nitric acid, and silver is separated with hydrochloric acid. In a dilute hydrochloric acid medium, the absorbance is measured at a wavelength of 232.0nm using an air-acetylene flame on an atomic absorption spectrometer.
4 Reagents
4.1 Nitric acid (1+1).
4.2 Hydrochloric acid (1+1).
4.3 Hydrochloric acid (1+19).
4.4 Nickel standard stock solution: Weigh 0.5000g pure nickel (99.95%) and place it in a 250ml beaker, dissolve it in 20ml nitric acid (4.1) at low temperature, drive out all nitrogen oxides, cool to room temperature, transfer to a 500ml volumetric flask and dilute to the mark, mix well. This solution contains 1mg nickel per ml. 4.5 Nickel standard solution: Transfer 20.00ml nickel standard stock solution (4.4) to a 200ml volumetric flask, dilute to the mark with hydrochloric acid (4.3), mix well. This solution contains 100μg nickel per ml.
5 Instruments
Atomic absorption spectrometer with a nickel hollow cathode lamp. Under the best working conditions, the following performance indicators should be achieved: Sensitivity: In a solution consistent with the test solution, the characteristic concentration of nickel should not exceed 0.125μg/ml. Precision: The standard deviation of the absorbance of the highest concentration standard solution measured 10 times should not exceed 1.0% of the average absorbance, and the standard deviation of the absorbance of the lowest concentration standard solution (not the zero standard solution) measured 10 times should not exceed 0.5% of the average absorbance of the highest concentration standard solution. Working curve linearity: Divide the working curve into five equal sections, and the ratio of the absorbance difference between the standard solution value in the highest section and the standard solution value 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
Approved by the Ministry of Machinery Industry on 199510-09
Implemented on 1996-01--01
Weigh 0.3g of test material, accurate to 0.0001g. 6.2 Blank test
Carry out a blank test with the sample.
6.3 Determination
JB/T7774.4—1995
6.3.1 Place the sample in a 100ml beaker, add 5ml nitric acid (4.1), heat at low temperature to dissolve, remove nitrogen oxides, and cool. 6.3.2 Wash the wall of the beaker with water to make the solution volume about 30ml. Add 1ml hydrochloric acid (4.2) and boil to make the precipitate condense, remove and cool. 6.3.3 Filter the solution into a 100ml beaker with medium-speed filter paper, and wash the precipitate with hot hydrochloric acid (4.3) 3 times. 6.3.4 Evaporate the filtrate to about 2ml at low temperature. Cool to room temperature, transfer the filtrate into a 100ml volumetric flask with hydrochloric acid (4.3), and dilute to the scale. Mix well.
Use air-acetylene flame, adjust the atomic absorption spectrometer to zero with water at a wavelength of 232.0nm, measure the absorbance in parallel with the standard solution, and subtract the absorbance of the blank solution. Find the corresponding nickel concentration from the working curve. 6.4 Drawing of working curve
6.4.1 Transfer 0, 2.00, 4.00, 6.00, 8.00, 10.00ml of nickel standard solution (4.5), place them in 100ml volumetric bottles respectively, and dilute to the scale with hydrochloric acid (4.3). Mix well. 6.4.2 Under the same conditions as the sample determination, measure the absorbance with water, subtract the zero concentration absorbance, and draw the working curve with nickel concentration as the horizontal axis and absorbance as the vertical axis.
Calculation of analysis results
The nickel percentage is calculated as follows:
Ni(%):
CThe nickel concentration found from the working curve, uμg/ml; where:
V.Total volume of the sample, ml,
8Allowable difference
The mass of the sample, g.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 1. Table 1
0.050~0.150
>0.150~0.300
JB/T7774.4-1995
Appendix A
Instrument working conditions
(reference)
The reference working conditions of the PE3100 atomic absorption spectrometer are shown in Table A1. Table A1
Additional Notes:
Spectral Band
Observation Heightbzxz.net
This standard was proposed and managed by Guilin Electric Science Research Institute of the Ministry of Machinery Industry. This standard was drafted by Shanghai Alloy Material General Factory. This standard was drafted by State-owned No. 503 Factory.
Main Drafters of This Standard Yang Xiaodong
Wang Enli
E Fast Flow
Air Flow
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