This standard specifies the determination method of nickel, zinc and indium in silver-indium oxide electrical contact materials. JB/T 7777.5-1995 Silver-tin-indium oxide electrical contact material chemistry JB/T7777.5-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical analysis method for silver oxide, tin oxide, and steel contact materials Flame atomic absorption spectrometry for determination of nickel, zinc, and indium content 1 Subject content and scope of application
This standard specifies the determination method for nickel, zinc, and indium content in silver oxide, tin oxide, and steel contact materials. JB/T7777.5-1995
This standard is applicable to the determination of nickel, zinc, and steel content in silver oxide, tin oxide, and indium oxide contact materials. The determination range is shown in Table 1. Table 1
Content%
Reference standard
GB7728-87
0.03~1.00
0.05~1.00
General rules for chemical analysis of metallurgical products Flame atomic absorption spectrometry General rules and general provisions for chemical analysis of electrical contact materials JB4107.185E
3 Principle of method
1.00~5.00
The sample is decomposed with nitric acid and sulfuric acid, and the silver chloride precipitate is filtered to separate the compounds of silver and silver. In a dilute acid medium, an air-acetylene flame is used for melting, and the absorbance of nickel, zinc and indium is measured by an atomic absorption spectrometer. 4 Reagents
4.1 Sulfuric acid (p1.84g/mL).
4.2 Nitric acid (1+1).
4.3 Hydrochloric acid (1+1).
4.4 Nickel standard solution: Weigh 0.1000g pure nickel (99.95%) and place it in a 250mL beaker, add 5mL nitric acid (4.2), cover with a watch glass, heat to dissolve completely and drive out nitrogen oxides, and cool. Rinse the watch glass and beaker with water, transfer to a 1000mL volumetric flask and dilute to the scale, mix well. This solution contains 0.1mg nickel in 1mL.
4.5 Zinc standard solution: Weigh 0.1000g pure zinc (99.95%) and place it in a 250mL beaker, add acid to dissolve and dilute according to 4.4, and mix well. This solution contains 0.1mg zinc in 1mL.
4.6 Indium standard solution: Weigh 2.0000g pure steel (99.95%) and place it in a 250mL beaker, add 10mL nitric acid (4.2), heat to dissolve and dilute according to 4.4, and mix well. This solution contains 2mg indium in 1mL. 5 Instruments
Atomic absorption spectrometer, with nickel, zinc, indium hollow cathode lamps. 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 characteristic concentrations of nickel, zinc and should not be greater than 0.10μg/mL, 0.20μg/mL and 1.60μg/mL respectively. Approved by the Ministry of Machinery Industry on October 9, 1995
Implementation on January 1, 1996
JB/T7777.5-1995
Precision: When the absorbance is measured 10 times with the highest concentration standard solution, the standard deviation should not exceed 1.0% of the average absorbance; when the absorbance is measured 10 times with the lowest concentration standard solution (not the zero standard solution), the standard deviation should not exceed 0.5% of the average absorbance of the highest concentration standard solution.
Linearity of working curve: Divide the working curve into five sections according to the concentration. The ratio of the absorbance difference of the highest section to the absorbance difference of 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 the test material according to Table 2, accurate to 0.0001g. Table 2
1.00~1.50
>1.50~2.00
>2.00~3.00
>3.00~5.00
6.2 Blank test
Carry out a blank test along with the test material.
6.3 Determination
Sample amount
Nickel content%
>0.10~1.00
>0.10~0.25
>0.25~1.00
>0.20~1.00
>0.40~1.00
Test solution volume dilution factor
Front content%
>0.20~1.00||t t||>0.251.00
>0.40~1.00
>0.80~1.00
Multiple R
6.3.1 Place the sample (6.1) in a 150mL beaker, add 5mL nitric acid (4.2) and 2mL sulfuric acid (4.1), cover the beaker, heat until the sample is completely decomposed, and after the nitrogen oxides are driven off, evaporate to near dryness, cool slightly, add 2mL nitric acid (4.2) and heat for a while. Add about 25mL water and 4mL hydrochloric acid (4.3), heat and boil until the silver chloride precipitate condenses, and cool. Use water to transfer the test solution together with the precipitate into a 50mL volumetric flask, dilute to the scale, and mix well. Let stand for 30min.
6.3.2 Dry filter with two layers of slow qualitative filter paper, and collect the filtrate in a dry beaker. 6.3.3 Using air-acetylene flame, in an atomic absorption spectrophotometer, refer to the working conditions in Appendix A, adjust to zero with water, and measure the absorbance of nickel, zinc and steel in parallel with the series of standard solutions. 6.3.4 For samples with high zinc and nickel content, add 2mL nitric acid (4.2) when diluting the filtrate according to Table 2, and measure the absorbance of nickel and zinc according to 6.3.3.
6.3.5 Subtract the absorbance of the blank test and find the corresponding concentrations of nickel, zinc and indium from the working curve. 6.4 Drawing of the working curve
6.4.1 Weigh 0.2g pure silver (99.95%) and 0.02g tin dioxide (99.95%) in a set of 150mL beakers, add the series of nickel standard solutions (4.4), zinc standard solutions (4.5) and indium standard solutions (4.6) according to Table 3, and proceed as per 6.3.1 to 6.3.3. Table 3
Nickel standard solution (4.4) mL
Zinc standard solution (4.5) mL
Copper standard solution (4.6) mL
Subtract the absorbance of the zero concentration solution, and use the absorbance of nickel, 6.4.2
as the ordinate, and the concentration of zinc and indium as the abscissa, respectively!
Draw the working curve.
7 Calculation of analysis results
The percentage content of nickel, zinc and indium is calculated according to formula (1): JB/T7777.5—1995
CVRX10-
Where: C——the concentration of the element to be measured from the working curve, μg/mL; V-the volume of the test solution, mL,
R--the dilution factor of the test solution (R is 1 when measuring indium, low-content nickel and zinc); the mass of the sample, g. www.bzxz.net
8 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 4. Table 4
0.03~0.10
>0.10~0.50
>0.50~1.00
0.05~0.10
>0.10~0.50
>0.50~1.00
1.00~5.00
.......0
Allowable difference
JB/T7777.5—1995
Appendix A
Instrument working conditions
Reference)
The reference working conditions for measuring nickel, zinc and indium with the 750 atomic absorption spectrometer are shown in Table A1. Table A1
Determination elements
Additional notes:
Lamp current
Monochromator passband
Height mm
This standard is proposed and managed by Guilin Electric Science Research Institute of the Ministry of Machinery Industry. This standard was drafted by Suzhou Alloy Material Factory, and Guilin Electric Science Research Institute participated in the drafting. The main drafters of this standard are Song Lifang and Liu Xuezhen. Jianlan Incense Device
Angle 30°
Angle 5°
Air flow
Acetylene flow
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