This standard is applicable to the determination of molybdenum content in nickel-based alloy powder. Determination range: 0.50% to 5.00%. This standard complies with GB 1437-78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". GB/T 8638.10-1988 Chemical analysis method for nickel-based alloy powder Determination of molybdenum content by thiocyanate spectrophotometry GB/T8638.10-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of nickel-based alloy powder
Determination of molybdenum content- Thiocyanate spectrophotometric method
Nickel base alloy powder-- Determination of melybdenum content- Thiocyanate spectrophotometric method
Nickel base alloy powder-- Determination of melybdenum content- Thiocyanate spectrophotometric method This standard is applicable to the determination of molybdenum content in nickel-based alloy powder. Determination range: 0.50%~~5.00%. UDC669.245-492.2
GB8638.1088
This standard complies with GB1467-78 "General Principles and General Provisions of Chemical Analysis Methods for Metallurgical Products". 1 Method Summary
In sulfuric acid medium, molybdenum is reduced to pentavalent with ascorbic acid, so that molybdenum and thiocyanate form an orange-red complex, and its absorbance is measured at a wavelength of 470nm on a spectrophotometer.
2 Reagents
2.1 Hydrochloric acid (1.19g/mL).
2.2 Nitric acid (p1.42g/mL).
2.3 Hydrofluoric acid (p1.15g/mL).
2.4 Sulfuric acid (1+1).
2.5 Phosphoric acid (1+1).
2.6 Ammonium thiocyanate solution (10%).
2.7 Ascorbic acid solution (10%): Prepare immediately before use. 2.8 Ferrous sulfate solution (0.5%): Weigh 0.5g of ferrous sulfate [Fe(SO.)XH,0] and dissolve it in water, add 10mL of sulfuric acid (2.4), and dilute to 100mL with water.
2.9 Molybdenum standard stock solution: Weigh 0.2000g of pure molybdenum and place it in a 250mL beaker, add 20mL of sulfuric acid (2.1), and while heating, add nitric acid (2.2) dropwise to dissolve it, and continue heating until sulfuric acid smoke appears. Cool, add 20mL of water, and heat to dissolve the salts. Transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 200μg of molybdenum in 1mL. 2.10 Molybdenum standard solution: Transfer 25.00mL of the standard stock solution (2.9) of molybdenum to a 100mL volumetric flask, dilute to scale with water, and mix. This solution contains 50μg of molybdenum in 1mL.
3 Instruments
Spectrophotometer.
4 Analysis steps
4.1 Number of measurements
Measure twice in parallel and take the average value.
4.2 Sample quantity
Weigh 0.1000~0.5000g sample
China Nonferrous Metals Industry Corporation 1988-01-11 approved 392
1989-0101 implementation
:3 Determination
GB 8638.10-88
4.3.1 Place the sample (1.2) in a 250mL beaker, add 15mL hydrochloric acid (2.J) and 2mL nitric acid (2.2), heat to dissolve the insoluble sample, and drop hydrofluoric acid (2.3) to assist dissolution. Add 10mL phosphoric acid (2.5) and 10mL sulfuric acid (2.4), continue heating until sulfuric acid smoke appears for 1~2min, cool, add 30mL water, heat to dissolve the salt, cool to room temperature, transfer to a 100mL volumetric flask, dilute to scale with water, and mix. 4.3.2 Take 5.00 mL of the test solution and place them in two 50 mL volumetric flasks respectively. [If the amount of iron in the test solution is less than 4 mg, add ferric sulfate solution (2.8) until the amount of iron is about 4 ng.] 4.3.3 Colorimetric solution: Add 6 mL of sulfuric acid (2.4), 10 mL of water, 10 mL of ammonium thiocyanate solution (2.6), and 10 mL of ascorbic acid solution (2.7) to one portion of the solution, dilute to the mark with water, and mix. 4.3.4 Reference solution: Add 6 mL of sulfuric acid (2.4), 10 mL of water, and 10 mL of ascorbic acid solution (2.7) to another portion of the solution, dilute to the mark with water, and mix.
4.3.5 Let stand for more than 20 minutes, use a 1-2 cm colorimetric III, and use the reference solution (4.3.4) as a reference to measure its absorbance at a wavelength of 470 nm on a spectrophotometer. Find the corresponding molybdenum content from the working curve. 4.4 Drawing of working curve
4.4.1 Take 0, 1.00, 2.00, 3.00, 4.00, 5.00mL of molybdenum standard solution (2.10) and place them in 50mL volumetric flasks respectively, and add 4mL of ferric sulfate solution (2.8), 1mL of phosphoric acid, and 6mL of sulfuric acid (2.4). The zero concentration solution in the standard series shall be processed according to 4.3.4, and the rest shall be processed according to 4.3.3.
4.4.2 Leave it for more than 20 minutes, use a 1~~2cm colorimetric dish, take the reference solution as the reference, and measure the absorbance at a wavelength of 470nm on a spectrophotometer. Use the molybdenum content as the horizontal axis and the absorbance as the vertical axis to draw a working curve. 5 Calculation of analysis results
Calculate the percentage of molybdenum according to formula (1):
m. .V. 10-*
Mo(%) ±
× 100
Wherein:
Total volume of sample solution, mL;
-volume of sample solution removed, mL;
-amount of molybdenum found from the working curve, g; sample weight, 8.
6 Tolerance
The difference in analysis results between laboratories should not be greater than the tolerable difference listed in Table 1. Table 1
0.50~1.00
>1. 00 ~3. 00
>3. 00～5. 00bzxZ.net
Additional remarks:
This standard was drafted by the Central Iron and Steel Research Institute of the Ministry of Metallurgical Industry. This standard was drafted by the Iron and Steel Research Institute of the Ministry of Metallurgical Industry. The main drafter of this standard is Yang Qiuping.
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