SU1696616A1 - Method of growing single crystal of complex oxide - Google Patents

Abstract

The invention relates to the synthesis of single crystals and can be used in electronic engineering. The purpose of the invention is to obtain a SrAteO / i single crystal with high oxygen ion conductivity. The method includes a crucibleless zone melting with optical heating of a polycrystalline vertical rod, sintered from a stoichiometric charge mixture, in an air atmosphere with a speed corresponding to the growth rate of a single crystal, equal to 3-10 mm / h. SrO and are used as the charge. 2 tab.

Description

The invention relates to the synthesis of single crystals, namely the single crystal of the compound SrAl204, which has high oxygen-ionic conductivity at elevated temperatures, and can be used to produce an oxygen-exchangeable material, such as a solid electrolyte in high-temperature cells, it is also possible to use single crystals in radio electronic and jewelry technology.

The purpose of the invention is to obtain a single crystal SrAiaO with high oxygen-ionic conductivity.

Example. The initial components of the ZgSO3 composition of the grade of 29.52 g and the grade of the secondary grade 20.39 g are mixed in a ball mill for 1.0 h, the mixture is calcined at 900 ° C for 8 h. The calcined product is homogenized in a ball mill for 2 h and molded from it the rods in a special mold. Molded rods are sintered at 1400 ° C for 8 hours. Part of the cooled rod

goes to make a seed, the rest of the part (the rod is ground to the required dimensions and used as a feeding rod.

The growth of single crystals was carried out in an air atmosphere by zone recrystallization of cylindrical rods with a diameter of 4-12 mm and a length of 10-90 mm.

The feed rod is fastened to the upper rod of the URN-2-ZP installation with a collet clamp. A seed of the required shape, made from a part of a rod of the same composition, is installed in the collet clamp of the lower stem of the installation. The installation is switched on and, gradually increasing the power, the free ends of the rod and the seed are melted. By gradually moving the rod and seed, a stable floating zone of the melt is formed. Rotational speed of rods is 60-100 rpm. Next, set the speed of the vertical movement of the rod (and seed) down. equal to 33 mm / h and after forming 1-2 peretz set

rod movement speed (crystal growth rate) of 5 mm / h. Dz /, it establishes the diameter of the growing crystal to the desired size and continue to peer in the specified mode until consumed 5/6 of the size of the supply rod. Gradually reducing the diameter of the zone and the heating power, break the melt zone. The crystal is removed from the heating zone at a rate of 33 mm / h.

In a cooled single crystal, the upper and lower portions (both ends) are disconnected, and the flat in slice is determined. i o /; scientific single-crystal boules have a diameter up to 10 mm and a length, g, about 30 mm. The monocrystals are transparent, the cells, show the cleavage of the surface of the gay (100).

The chemical composition of the single crystal, determined on the spectrometer CAMEVACH-301, corresponds to the formula

SrAl204.

The orientation of the obtained single crystal slices was determined by an x-ray diffraction method using a DRON-3 diffractometer (orientation accuracy is no worse than 1 °). To determine the unit cell of a single crystal, the powder X-ray diffraction method 1 is used:; fr: DRON-3 kg meter: Cu Ca - radiation; i, / fine single crystals, dotted (. C OZMmie) with the use of fc. The first is the induction program implemented on the ЁС-1045 computer.

Monocrystalch is characterized by a monoclinic elementary cell, the space group Р2- with parameters а-8.4388 (3),, 8127 (17), с 5.1561 (7} .h., 43 (1) °, High-temperature rents, --- Neva studies allow us to establish an SrAlaCKi single crystal fzzzyg transition in the region of (6 0-680) ° С with a change in the symmetry of P2i - Р8з22, which is associated with the appearance of ferroelectric ordering, which is also indicated by the results of electrophysical and non-optical measurements .

The results of powder indexing are given in Table 1, where the hKi-mdax of the reflection, Onep and dBw4 are the observed and calculated values of the interplanar distances (A), respectively. and observable and calculated angle

0

five

0

diffraction (hail), 1Nib and 1Hych - respectively observable and calculated Izhys.k; diffraction reflection (relative units).

Electrical measurements were performed on single-crystal plates oriented along the GLEEIU; crystallographic directions from the period; - 8.4; 8.8 and 5.15 A. are applied by firing at 900 ° С Zop, cho. The largest conductor was found along the b direction with a period of 0.8 A. A SOBPZDZ-shshm with a polar axis of the crystal.

The measurements were carried out iia constant (Oka using the instrument: V7-23, at a frequency of 1 kHz using moslp / -10 and on 1G-1Hz with iO-, ia L7-12 change in ii T ipt (ie temperatures -: U-1CC / 0 C. Wm of a torsion f in a w o A o ic re p i x d c (np and 6 ° C) along the axis with tif.-iCoi m, then gyurschenn-e electrical conductivity with: out of .- its activation (О, бЗВ). characteristic п - ОО for /. 1: hydrogen – ion; –– for wires (сars) T: / I g, phagite. This is carried out and confirmed by i c and m -phenyls in a constant mode, a concomitant hypocrosis with frequencies of 1 kHz and 1 k c (.mg. -) lawsuit /; yucha et re / .acclusion gphosodimosg ,, /, l: 1.,; oroGnos- e. - Lie about reverse si "O7: oio; ieii. j salvation

EVIL TO I rOGFO WITH DNSI. J. pC lip. WATER in monocrystals SrAl204 ru-ieof r --- k; , in the manner of purely domestic /; l and and; -: Shs. | - | The zonal transition (at) ps / to its se- 5 personage m small (ab 1.2) slips avimy with npOBorsM oOTtir pg to and; l with the kind of n solid electrolytes on the og. my I HH Ch R O 8 L N O G O D I O K G, A D, 0 LI I O O I and G.

  Understanding other rc.nii.v ,. xpme:. / s- 0 lore and in the three-year SrA i jO / j structure, excluded kg / isllowyim –ec.

Ph o o m l l i l invented

The method of obtaining mono-crg 3 composite oxide by the method of b &

melting on the optical path ne); gristallmzac chi vergik lcho ne ne "ch.u-G. UI. of my kepuskim core 5, ...

shilgy stekh |, chometer | /: chgskogo; osggs.a, g tl ich a ksch i and so. "That, cnse / ibi:} gk Yau -. Ei .-,

0 monocrystal ЗГА ЗО - 1 with PUCOKOV: to ch. NORMAL PRINODLMOS i olO,; KachKLZW YHYhts take SrO and, zedug process on the air with a speed of 3-10 mm / 5.

0

Table 1

table 2

Claims (1)

For r m ul z o o breteiiz A method of producing a single crystal of a complex oxide by the bestigey method. zone melting with optical ice by recrystallization of a vertically moving ceramic rod, a sintered mixture of stoichiometric composition. t lich a y-sch and y s. I am the one. what, g; testg; method of obtaining a single crystal SrAI-iC ’· -! with high knellerodno-ionic conductivity, with the quality of the charge take $ rO and AFOz, the process I lead r in air>: about a speed of'3-10 mm / *.