GOST 20068.4-88
GOST 20068.4−88 Bronze without tin. X-ray spectral fluorescent method for determination of aluminium
GOST 20068.4−88
Group B59
INTERSTATE STANDARD
BRONZE WITHOUT TIN
Method x-ray
fluorescence determination of aluminum
Tinless bronze.
X-ray spectral fluorescent method for determination of aluminium
AXTU 1709
Date of introduction 1989−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. INTRODUCED FOR THE FIRST TIME
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced | Section number, paragraph, sub-paragraph |
| GOST 15027.2−77 |
5.4.1 |
| GOST 18175−78 |
Chapeau |
| GOST 25086−87 |
1.1 |
5. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
6. REISSUE
This standard specifies a method for x-ray fluorescence determination of aluminum in bronze brand Brazh9−4 according to GOST 18175 standard samples (in mass fraction of aluminum from 7.0% to 12.0%).
X-ray fluorescence method of determination based on the intensity of the characteristic secondary x-ray radiation of the elements from their percentage in the sample irradiated with primary rays of the x-ray tube. Radiation from the sample enters the spectrometer channels of the fixed type, each of which with the crystal-analyzer of the characteristic line is allocated one element, the intensity of which is recorded the electronic computing device on the digital Board and is written tsifropechatayuschee machine.
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 25086.
2. EQUIPMENT AND MATERIALS
The x-ray multichannel spectrometer of the type CPM-18 CPM or-20 or similar.
X-ray devices.
The x-ray tube of the type BHV-9, bkhv-12, bkhv-13 with palladium anode or similar.
Argon-methane mixture according to normative-technical documentation.
Screw-cutting lathe of the type ІП611 for sharpening standard samples and unknown samples.
The set of State standard samples N 126, 1720−79 GSO — GSO 1724−79; allowed to use standard samples of the enterprise and industry standard samples.
3. PREPARATION FOR ASSAY
Sample preparation and standard samples for the analysis consists of identical grinding them on a lathe and wipe the surface of the analyzed technical alcohol. Honed the surface of the sample and the standard sample must be flat, smooth, does not have shrink holes, pores, cracks, slag and non-metallic inclusions.
4. ANALYSIS
4.1. Spectrometric channel for the analysis of aluminium is tuned to the wavelength 8339·10m. the Angle of reflection of the crystal-analyzer ЕДdT is 71°12'. As the x-ray detector uses a gas flow proportional counter BJP-3−05 with argon-methane filling. The intensity of the analytical lines of aluminum measured by a Timer in
series.
4.2. The mode of operation of the x-ray tube and the electronic computing device is selected in the range:
25−50 kV — voltage on the tube;
15−100 mA anode current;
40−250 — gain;
0−9,5 — lower threshold;
0,5−9,0 V — window width;
4.0 to 6.0 volts — max amplitude distribution;
15−200 — exposure.
4.3. Analyze a sample placed in the cuvette set in the loading chamber of a spectrometer head, paying particular attention to the absence of distortions, and close the lid. Further, the measurement cycle is automatic. The measurement results are output to tsifropechatayuschee typewriter or on a computer. Check the intensity of the analytical lines of aluminum from the sample and carried out at least twice.
5. PROCESSING OF THE RESULTS
5.1. The calibration graphs are built in coordinates 
— mass fraction of the element in the standard sample, %.
Mass fraction of aluminium in the sample find for the calibration graphics, built according to the averaged results of at least two parallel measurements of the intensity of the analytical line.
5.2. Control the convergence of the results of the analysis
5.2.1. The convergence of the results of the analysis is characterized by the difference between the results of parallel measurements of mass fraction of aluminium in the analyzed sample. The absolute discrepancy between the results of parallel measurements (the rate of convergence) must not exceed 0.15% at the confidence probability
=0,95.
5.2.2. The final result of the analysis taking the arithmetic mean of two parallel definitions.
5.2.3. In case of exceeding of permissible values of analysis again.
5.3. Control the reproducibility of the results of the analysis
5.3.1. The reproducibility of the results is characterized by the absolute discrepancy between the results of the analysis (the measure of reproducibility) obtained in two different laboratories or in one laboratory, but under different conditions.
5.3.2. The absolute discrepancy between the results of the two tests should not exceed 0.20%.
5.3.3. If the discrepancy between the results of the initial and re-analyses (or analyses obtained in two different laboratories) does not exceed the permissible values, the repeatability is considered satisfactory.
5.4. Control of accuracy of analysis results
5.4.1. Control the accuracy of the results of the analysis of aluminium in bronze brand Brazh9−4 check of State standard samples (set No. 126), held through the entire course of the analysis.
The sample analysis results are considered accurate if the absolute difference between the found and the certified mass fraction of aluminium in bronze brand Brazh9−4 does not exceed 2/3 of the allowable absolute discrepancies in the results of the two tests.
The differences in the assessment of the quality of the brand of bronze Brazh9−4 determination of aluminium is carried out according to GOST 15027.2.
