JB/T 7777.3-1995 Silver Oxide Tin Oxide Indium Oxide Electrical Contact Material Chemistry JB/T7777.3-1995 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical analysis method of silver oxide, tin oxide, indium contact material-Determination of nickel content by diacetyl spectrophotometry
1 Subject content and scope of application
This standard specifies the method for determining the nickel content in silver oxide, tin oxide, indium contact material. JB/T7777.3—1995
This standard is applicable to the determination of nickel content in silver oxide, tin oxide, indium contact material. Determination range: 0.03% to 1.00%. 2 Reference standards
GB7729—87
JB4107.185
3 Principles
General principles for spectrophotometric methods for chemical analysis of metallurgical products General principles and general provisions for chemical analysis methods of electrical contact materials The sample is decomposed with sulfur-nitric acid mixture, and silver bromide precipitation is filtered to separate silver and tin dioxide. With potassium sodium tartrate as a masking agent, in a strong alkaline medium with ammonium persulfate as an oxidant, nickel (1) and diacetyl form a soluble wine-red complex, and its absorbance is measured at 470nm on a spectrophotometer.
4 Reagents
4.1 Mixed acid: 3 volumes of sulfuric acid (p1.84g/mL) and 2 volumes of nitric acid (p1.42g/mL) are mixed. 4.2 Sodium bromide solution (200g/L).
4.3 Potassium sodium tartrate solution (400g/L). 4.4 Sodium hydroxide solution (100g/L), stored in a plastic bottle. 4.5 Ammonium persulfate solution (60g/L), prepared when needed. 4.6 Diacetyl alkaline solution (50g/L): weigh 5g diacetyl into a plastic cup, add 100mL sodium hydroxide solution (4.4), stir to dissolve, and store in a plastic bottle.
4.7 Disodium ethylenediaminetetraacetic acid (EDTA) solution (100g/L). 4.8 Nickel standard stock solution: weigh 0.2000g pure nickel (99.95%), place in a 250mL beaker, add 10mL nitric acid (1+1), cover with table blood, heat to dissolve and drive off nitrogen oxides, and cool. Transfer to a 200mL volumetric flask, dilute to scale with water, and mix well. This solution contains 1mg nickel in 1mL.
4.9 Nickel standard solution: Pipette 5.00mL of nickel standard stock solution (4.8) into a 200mL volumetric flask, dilute to scale with water, and mix well. This solution contains 25μg nickel in 1mL.
5 Instruments
Spectrophotometer.
6 Analysis steps
6.1 Test materials
Approved by the Ministry of Machinery Industry in 1995-1009
Implemented in 1996-01-01
Weigh the test materials according to Table 1, accurate to 0.0001g. Nickel content %
0.03~0.15
>0.15~0.40
>0.40~1.00
6.2 Determination
JB/T7777.3—1995
6.2.1 Place the sample (6.1) in a 250mL conical beaker, add 20mL of mixed acid (4.1), heat until sulfuric acid smoke rises to the mouth of the beaker, and cool. 6.2.2 Wash the beaker wall with water to make the solution volume about 60mL, add 10mL of sodium bromide solution (4.2) while shaking continuously, heat and boil until the test solution is clear, and let it stand for 30 minutes.
6.2.3 Filter using two layers of slow qualitative filter paper tilting method, wash the precipitate and the cup wall with water 4 times, wash the filter paper 3 times, collect the filtrate and washing liquid in a 250mL volumetric flask, dilute with water to the mark, and mix well. 6.2.4 Take two portions of 25.00mL of the test solution, place them in 100mL volumetric flasks respectively, and proceed as in 6.2.5 to 6.2.6. Color solution: Add 10mL of potassium sodium tartrate solution (4.3) to one portion of the test solution, neutralize with sodium hydroxide solution (4.4) until the test solution is 6.2.5bzxz.net
alkaline (can be tested with pH wide range test paper), excess 3mL. Add 5mL of ammonium persulfate solution (4.5) and 3mL of diacetyl alkaline solution (4.6), mix well. After standing for 10 minutes, add 5mL of LEDTA solution (4.7), dilute with water to the mark, and mix well. Reference solution: Add 5 mL of ETA solution (4.7) to another test solution, and then proceed as per 6.2.5. 6.2.6
6.2.7 Transfer part of the colorimetric solution into 1 cm of colorimetric blood, and measure its absorbance at a wavelength of 470 nm using the reference solution as a reference. Find the corresponding nickel amount from the working curve. 6.3·Drawing of working curve
6.3.1 Transfer 0, 2.00, 4.00, 6.00, 8.00, and 10.00 mL of nickel standard solution (4.9) to a group of 100 mL volumetric flasks, and proceed as per 6.2.5.
6.3.2 Use the zero-concentration nickel standard solution as a reference, measure as per 6.2.7, and draw the working curve using the nickel amount as the abscissa and the absorbance as the ordinate.
7 Calculation of analysis results
The percentage of nickel is calculated according to formula (1):
li(%)=m:VX10-
-the amount of nickel found from the working curve, g;
wherein: m-
V. —total volume of test solution, mL;
V,-volume of test solution taken, mL;
m. --—mass of the sample, g.
8 Allowable difference
The difference in the analysis results between laboratories should not be greater than the allowable difference listed in Table 2 Table 2
0.03~0.10
>0.10~0.50
>0.50~1.00
Additional instructions:
JB/T7777.3—1995
This standard was proposed and managed by the Guilin Electric Science Research Institute of the Ministry of Machinery Industry. This standard was drafted by the Guilin Electric Science Research Institute of the Ministry of Machinery Industry, and Suzhou Alloy Material Factory participated in the drafting. The main drafters of this standard are Jian Lanxiang
Liu Xuezhen
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