The paper describes the growth features of thin Ti-Zr-Ni films prepared by the method of magnetron sputtering of the targets with compositions Ti53Zr30Ni18 and Ti41Zr38.3Ni20.7 on the substrates at 300 K with subsequent annealing in vacuum. The formation peculiarities of phase composition, structure and thermal stability of quasicrystalline thin films were studied. It was established that in initial state the films were X-ray-amorphous or nanocrystalline with coherence lengths (according to Scherrer) near 1.6-1.8 nm independently on the element composition of the sputtered target. This structure is relatively stable up to the temperature 673 K when the formation of the quasi-crystalline phase begins. In the films with composition of Ti53Zr30Ni18, the largest quantity of the quasicrystalline phase with a characteristic parameter aq 0.517 nm is observed at the annealing temperature of 673 K. It is added with an admixture of the 1/1 W-crystal approximant phase. In the films with Ti41Zr38.3Ni20.7 composition, an optimal annealing temperature is between 823 K and 873 K. The quasicrystalline phase is characterized by the quasicrystallinity parameter aq 0.5205 nm. Additionally, for the first time, the data on the formation of 2/1 approximant crystal as an admixture phase in this system were obtained. Under annealing at the temperatures higher than 873 K, the decomposition of the quasi-crystalline and approximant phases into crystalline phases stable at higher temperatures according to the equilibrium phase diagram was established.
Compton to Rayleigh scattering intensity ratios (IC/IR) have been measured using X‐rays with energy 17.44 keV for single‐component materials with atomic number Z from 4 (Be) to 31 (Ga) and binary compounds of stoichiometric composition. The measurements have been performed using two optical schemes: an energy‐dispersive X‐ray fluorescence scheme with a molybdenum secondary target and wavelength‐dispersive X‐ray fluorescence one. The processing of the spectra was carried out by fitting with Pearson VII functions. For single‐component and binary standards, the experimental dependence of the scattering intensity ratio on the atomic number was found to be the same. This confirms the additivity of the contribution of different atoms to the scattering. The dependence has a complex shape but is well described by the theoretical relationship for IC/IR with correction on the difference between Compton and Rayleigh radiation absorption coefficients. Two ranges of atomic number values are defined, in which the effective atomic number Zeff can be determined by the calibration method using this dependence: for Z from 4 to 7 with low error of ΔZeff =±0.15 and for Zeff from 10 to 18 with low error of ΔZeff =±0.69. A change in the shape of the Compton peak and an overestimated value of the of the Compton and Rayleigh peak intensity ratio when passing from a single‐component scatterer (Al or Si) to their oxides Al2O3 or SiO2, respectively, have been revealed.
A generalization of the Compton method for determining elements with a low atomic number Z from 1 (H) to 9 (F) by the ratio trueICIR of the intensities of incoherent (Compton) and coherent (Rayleigh) scattering is proposed. The generalization takes into account not only the dependence of this ratio on the effective atomic number of the scatterer material but also the momentum transfer variable x = sin0.5emθλ. The new method is based on the application of calibration function of trueICIR=g()Z,x obtained by measuring scattering spectra at two values of x1= 0.831 Å−1 and x2= 1.297 Å−1 with a WDXRF spectrometer. The elemental atomic numbers and their concentrations of binary compounds with unknown compositions are determined by the solution of a system of linear equations. Coefficients of the equations are calculated from the measured trueICIR ratios for the test sample and the regularization solution for the corresponding calibration. The experiments have been carried out for standard samples of single‐component, binary and triple stoichiometric compounds based on H, Li, Be, B, C, O and F. The identification of these elements was found to be possible in the absence of a relationship between the positions of scattering peaks and the composition of the sample, and a qualitative and quantitative analysis of the composition of the material was carried out as part of the solution of a single inverse problem.
Using the methods of X-ray diffraction, transmission and scanning microscopy, the features of the initial stage of the formation of the quasicrystalline phase in thin films of Ti-Zr-Ni are studied. The films were obtained by magnetron sputtering of a target of the composition Ti41Zr38.3Ni20.7 (at. %) with deposition on substrates at T 300 K and further vacuum annealing. It was established that immediately after deposition, the films are X-ray amorphous, nanostructured. An analysis of the radial distribution functions shows that immediately after deposition, the structural state of a disordered cluster, which is topologically close to icosahedral, prevails in the near atomic medium. It is concluded that the atoms are not arranged randomly, but form a "transitional" structure with an imperfect order like three shells of the Bergman cluster stacking using icosahedrons and dodecahedrons. Such a structure is a "prepared" nucleus for the further formation of the icosahedral phase upon heating. An analysis of the annealing results suggests that the qualitative nature of the transition from the pseudo-amorphous to the quasicrystalline phase and the scale of the transformations are determined by the annealing time and temperature, as well as by the film thickness. The smaller the thickness, the more the annealing processes are inhibited. It was shown that by annealing the films of a thickness of 6 μm or more at 500 C for more than 28 h, single-phase quasicrystalline coatings with a quasicrystallinity parameter aq of about 0.5245 nm can be obtained.
An alternative method is proposed for the determination of the inorganic constituent mass fraction (ash) in solid fuel by the ratio of Compton and Rayleigh X-ray scattering peaks I/I subject to the iron fluorescence intensity. An original X-ray optical scheme with a Ti/Mo (or Sc/Cu) double-layer secondary radiator allows registration of the combined fluorescence-and-scattering spectrum at the specified scattering angle. An algorithm for linear calibration of the Compton-to-Rayleigh I/I ratio is proposed which uses standard samples with two certified characteristics: mass fractions of ash (A) and iron oxide (W ). Ash mass fractions have been determined for coals of different deposits in the wide range of A from 9.4% to 52.7% mass and W from 0.3% to 4.95% mass. Due to the high penetrability of the probing radiation with energy E > 17 keV, the sample preparation procedure is rather simplified in comparison with the traditional method of A determination by the sum of fluorescence intensities of all constituent elements.
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