GB/T 15679.3-1995 Chemical analysis method for samarium-cobalt permanent magnet alloy powder Determination of calcium content GB/T15679.3-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method of cobalt permanent magnet alloy powder
Determination of calcium content
Samarium cobalt permanent magnet alloy powder--Determination of calcium content1Subject content and scope of application
This standard specifies the determination method of calcium content in 1-5 type cobalt permanent magnet alloy powder. GB/T 15679.3-1995
This standard is applicable to the determination of calcium content in 1-5 type cobalt water magnet alloy powder, with a determination range of 0.02% to 0.50%. 2 Reference standards
GB1.4 Guidelines for standardization and promotion of chemical analysis methods GB1467 General principles and general provisions for chemical analysis methods of metallurgical products GB7728 General principles for flame atomic absorption spectrometry of chemical analysis of metallurgical products 3 Principle of the method
The sample is decomposed by hydrochloric acid, and the absorbance of calcium is measured at a wavelength of 422.7nm by an atomic absorption spectrophotometer using an air-acetylene flame in a dilute hydrochloric acid medium. The calcium content is calculated using the standard addition method. 4 Reagents
4.1 Hydrochloric acid (1+1). wwW.bzxz.Net
4.2 Calcium standard stock solution: Weigh 2.4972g of calcium carbonate (spectrally pure) dried at 110℃ into a 200mL beaker, and add 40ml of hydrochloric acid (4.1) to dissolve. Boil to remove all carbon dioxide, cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 1mg calcium per mL.
4.3 Calcium standard solution: Pipette 10.00mL of calcium standard storage solution (4.2) into a 200ml volumetric flask, dilute to the mark with water, and mix. This solution contains 50ug calcium in 1mL.
5 Instruments
Atomic absorption spectrophotometer with a calcium 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 that is consistent with the matrix of the sample solution being measured, the characteristic concentration of calcium is not greater than 0.13ug/ml. Precision: The standard deviation of 10 absorbance measurements with the highest concentration standard solution should not exceed 1.0% of the average absorbance. The standard deviation of 10 absorbance measurements with the lowest concentration standard solution (not the zero standard solution) 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 equal sections according to 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.
Approved by the State Administration of Technical Supervision on August 11, 1995 and implemented on April 1, 1996
See Appendix A (reference) for instrument working conditions. 6 Analysis steps
6.1 Determination quantity
GB/T 15679.3—1995
Weigh two samples for parallel determination and take the average value. 6.2 Samples
Weigh the samples according to Table 1, accurate to 0.0001&. Table 1
Calcium content, %
0. 02 ~~0. 06
>0. 06~-0. 20
>0. 20~0. 50
6.3 Blank test
Carry out a blank test together with the sample.
6.4 Determination
Sample g
Dissolve the sample and add hydrochloric acid (4.1) volume, ml12
6.4.1 Place the sample (6.2) in a 100mL beaker, add the volume of hydrochloric acid (4.1) according to Table 1, heat until completely dissolved, evaporate 2~3 mL of the solution, and cool to room temperature.
6.4.2 Transfer the solution (6.4.1) into a 50ml volumetric flask, dilute to the mark with water, and mix. 6.4.3 Take 6 portions of 2.00mL of the test solution (6.4.2) and place them in a set of 10mL volumetric flasks. Add 0, 1.00, 2.00, 4.00, 8.00, and 16.00mL of the calcium standard solution (4.3) to the mark with water and mix. 6.4.4 Use air-acetylene flame to measure the absorbance of the test solution (6.4.3) at a wavelength of 422.7nm on an atomic absorption spectrophotometer with water adjusted to zero. Draw a standard addition curve with calcium concentration as the abscissa and absorbance as the ordinate. Use the extrapolation method to find the calcium concentration of the test solution from the standard addition curve.
Calculation and Expression of Analysis Results
Calculate the percentage of calcium in the diamond 1-5 type permanent magnet alloy powder using the following formula: Ca(%) = (c = co).V: V, × 10-mV
Wherein: c-
-Calcium concentration of the test solution obtained from the standard addition curve, g/mL; co-Calcium concentration of the blank test obtained from the standard addition curve, ug/mL; V-Total volume of the test solution, mL;
V,-—Volume of the test solution taken, mL;
V2—Volume of the tested solution, mL;
m-Mass of the sample, g.
8 Allowable Difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. 246
Calcium content
0.020~0.060
>0. 060~0.200
>0.200～0.500
GB/T 15679. 31995
Tolerance
Instrument model
WFX-1D
Additional instructions:
GB/T15679.3-1995
Appendix A
Instrument working conditions
(reference)
Lamp current
This standard was proposed by the Rare Earth Office of the State Planning Commission. Spectral passband
This standard was drafted by Shanghai Yuelong Nonferrous Metals Co., Ltd. This standard was drafted by Beijing General Research Institute of Nonferrous Metals. The main drafters of this standard are Shuangengle and Zhen Rongqiao. 248
Burner height
Air flow
Acetylene flow
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