X-ray spectral analysis is an important research and quality control method in producing precision alloys. It is based on studying spectra of characteristic X-ray radiation arising when material atoms are excited. In alloy production it ensures precise control of material chemical composition at all production stages, from incoming raw material control to release of finished products.
Operating principle of X-ray spectral analysis
The main idea of X-ray spectral analysis is exciting material atoms with electrons, which leads to emission of characteristic X-ray radiation. Energy must be sufficient to tear electrons from atom shells. The characteristic radiation spectrum consists of a set of spectral lines, each corresponding to a certain element. The operating principle is based on measuring these lines to identify elements in the sample.
Application in producing precision alloys
X-ray spectral analysis gives both qualitative and quantitative results. The former help determine elemental composition of the sample under study, the latter — concentration of chemical elements in it.
Main components of X-ray spectral analysis instruments
Conducting X-ray spectral analysis provides for use of specialized instruments consisting of several main components:
- Excitation source — an electron probe used to bombard with fast electrons and initiate the process of X-ray emission by sample atoms.
- Spectrum analyzer — intended for separating X-ray spectra by wavelengths and measuring intensity of each line. Usually analyzer crystals separating X-rays by wavelength and a detector registering radiation intensity are used.
- Detector — registers intensities of characteristic X-ray radiation and converts them into electrical signals, providing data for subsequent analysis.
- Data processing system — includes software that processes the obtained information, conducts quantitative or qualitative analysis of sample elemental composition, and issues final results.
Overall the instrument operation process looks as follows:
- Sample bombardment: the excitation source bombards the sample with electrons.
- X-ray emission: sample atoms emit characteristic X-ray radiation.
- Separation and registration: the spectrum analyzer separates X-ray spectra, and the detector registers their intensities.
- Data processing: the data processing system analyzes the obtained information to determine sample chemical composition.
- Calibration: comparison of measured data with known element concentrations in calibration samples, which ensures accuracy and reliability of results.
Joint work of main instrument components ensures high effectiveness of material quality control at all production stages, which is important for maintaining high standards and achieving uniformity of precision alloy properties.
Calibration method in X-ray spectral analysis of precision alloys
Calibration is the process of establishing correspondence between measured data (intensity of analytical lines of the sample) and known chemical concentrations of elements in samples. This method is often used to control composition of steels, alloys, and charge.
The calibration method includes the following stages:
- Preparation of standard samples — multi-element samples with known concentrations of chemical elements (analogous to those present in precision alloys under study) are analyzed to obtain their X-ray spectra.
- Measuring spectra of standard samples — used to obtain X-ray spectra containing characteristic peaks corresponding to various elements in the sample.
- Peak identification — characteristic peaks are recognized on the obtained spectra, each corresponding to a certain element. Peaks may be separated by their energy, shape, or intensity.
- Energy scale correction — based on measured characteristic peaks and known element concentrations in standard samples, correction of the spectrometer energy scale is performed. This includes corrections for shift, nonlinearity, or temperature drift needed for precise correspondence of measured data to actual concentrations.
- Eliminating spectral overlaps — sometimes spectral overlaps arise on spectra when two or more peaks overlay each other. This hinders identification and precise determination of element concentrations. Various methods are applied to eliminate overlaps, including use of spectral databases and approximation of peak shape.
Data obtained after calibration are used to determine element concentrations in unknown samples, which ensures precise control of alloy chemical composition.
PZPS X-ray spectral laboratory
The X-ray spectral laboratory at PZPS plays an important role in ensuring high quality and stability of precision alloy production. Systematic control of chemical composition of raw materials, intermediate products, and finished alloys using X-ray spectral analysis methods is conducted in the laboratory. Such an approach ensures not only conformity of plant products to quality standards but also gives the opportunity to promptly react to changes in production processes, ensuring stability and reliability of alloys.
