The method of growing crystals of zinc

 

(57) Abstract:

The invention relates to the production of synthetic crystals, in particular to methods of obtaining crystals of zinc, which is good piezoelectric materials with high Electromechanical coupling coefficient, and can be used used in piezoelectric engineering, acoustoelectronics and other areas of science and technology. The inventive method includes the crystal growth of zinc under hydrothermal conditions from a solution of KOH with the addition of ions Li+on oriented parallel monoideism face (0001) of the bare plate cut from pre-grown hydrothermal crystals of zinc in a sealed vessel made of corrosion-resistant material, the bare plate cut from a crystal of zinc, pre-grown on the seed, the surface of which is oriented parallel to the faces of the hexagonal prism and the process is carried out in the linings of titanium alloy or Nickel with a thickness of 10-20 mm or in autoclaves of the same material. Receive high-quality crystals of zinc for technical use in the simplification and cheapening of their growth process.

A method of obtaining crystals of zinc oxide, including hydrothermal crystal growth from alkaline solutions with the addition of ions Li+on the bare plate with slices (0001) and pre-grown from small crystal grains, a silver cylinder placed inside the vessel, designed for high-pressure Hydrothermal growing single crystals of zinc oxide" magazine article "Uli", 1976, 1, T. 5, S. 6-10, 64, China). However, the thus grown crystals of zinc oxide have numerous dislocations, reducing their quality and use in the process of growth of the silver cylinder does not provide stabilization of the growth process due to the low mechanical properties of noble metals, as well as significantly increase the costs of obtaining such crystals.

The closest technical solution to the proposed method is a hydrothermal process for growing crystals of zinc from alkaline solution in pH pre hydrothermal crystals of zinc, in autoclaves lined silver lining "floating" type, with subsequent cooling (Lobachev, A. N., Kuzmina, I. P., Saldin Y. C., Lazarevskoye O. A. zinc Oxide. Growing and some physical properties. In Proc. of the crystal Growth from high-temperature aqueous solutions. - M. : Nauka, 1977). The disadvantage of this method is that when multiple extensions of the crystal in the pyramid growth monetra (0001), with an optimal rate of growth, accumulation growth defects that reduce the quality of the business of crystals and pyramid growth prism having the most perfect material because of the low growth rate has a small volume for practical use. The process of synthesis of crystals in thin-walled (wall thickness 0.5-1 mm) silver liners (liners) because of the low mechanical strength of noble metals causes problems such sealing linings and the formation of a large number of crystals of spontaneous nucleation, and hence the impossibility of obtaining high-quality crystals. In addition, noble metals are too expensive, which creates additional costs for synthesis.

The technical task of the invention is the p process of their cultivation.

The technical problem is solved due to the fact that in the known method, including the crystal growth of zinc under hydrothermal conditions from a solution of KOH with the addition of ions Li+on oriented parallel monoideism face (0001) of the bare plate cut from pre-grown hydrothermal crystals of zinc in a sealed vessel made of corrosion-resistant material, the bare plate cut from a crystal of zinc, pre-grown on the seed, the surface of which is oriented parallel to the faces of the hexagonal prism and the process is carried out in the linings of titanium alloy or Nickel with a thickness of 10-20 mm or in autoclaves of the same material.

Comparative analysis of the proposed solutions with the prototype shows that the inventive method differs from the known fact that manaakitanga bare plate used in the method for increasing the crystal of zinc used in the technique, the cut of the crystals of zinc, pre-grown on the seed plate, the surface of which is oriented parallel to the faces of the hexagonal prism and the process of synthesis of the crystals is carried out in the foot the way, the claimed method meets the criteria of the invention of "novelty."

Using the method monadicity plates cut from crystals, pre-grown on the seed, oriented parallel to the faces of the hexagonal prism accrued layer which does not inherit linear defects, because they are oriented in the plane of the seed, and also due to the fact that the sector growth prism captures fewer impurities Fe, Al, si, causes an additional decrease in the number of linear defects appearing on the surface Mandrichenko seed (0001) used for growing the business of the crystals, and thereby provides a growing multilocation high-quality crystals of zinc. The process of synthesis in corrosion-resistant liners made of titanium alloy or Nickel due to their physico-mechanical properties, ensuring the reliability and stability of the process parameters during the whole cycle, and thereby provides a high quality of the crystals. The optimum thickness of the wall lining 10-20 mm ensures the tightness of the reaction volume during heating and cooling of the autoclave without additional compensationis pressure of 2-3 MPa inside and outside of the lining, develop during heating and cooling of the autoclave. Lining with wall thickness less than 10 mm do not provide a reliable seal, and with a thickness exceeding 20 mm cause economic inexpediency of their use. In addition, the process of synthesis autoclave made of titanium alloy or Nickel additionally simplifies and cheapens the process of growing crystals of zinc.

An example of a specific implementation.

In the lower part (zone dissolution) of the liner (liner) made of titanium alloy or Nickel with a capacity of 2 liters was placed a mixture of zinc oxide brand "OFS". In the upper part (the crystallization zone) suspend the seed crystals in the form of plates oriented parallel to monoideism faces (0001), which are cut out from hydrothermal crystals of zinc, pre-grown on the seed, the surface of which is oriented parallel to the faces of the hexagonal prism In the lining poured an aqueous solution of 4 mol KOH+0.5 mol LiOH. The lining is sealed and placed in an autoclave with a capacity of 24 litres, which is filled with distilled water. The autoclave is sealed and heated. Mode set temperature crystallization zone 340oWith, the zone of dissolution 3502.

The use of the proposed method of growing single crystals of zinc compared to the existing produces high quality crystals of zinc in reducing the cost and simplifying the synthesis method.

The method of growing crystals of zinc under hydrothermal conditions from a solution of KOH with the addition of ions Li+on oriented parallel monoideism face (0001) of the bare plate cut from pre-grown hydrothermal crystals of zinc in a sealed vessel made of corrosion-resistant material, characterized in that the bare plate cut from a crystal of zinc, pre-grown on the seed, the surface of which is oriented parallel to the faces of the hexagonal prism and the process is carried out in the linings of titanium alloy or Nickel with a thickness of 10-20 mm or in autoclaves of the same material.

 

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FIELD: jewelry industry; optics.

SUBSTANCE: proposed method is used for coloring fianites (man-made diamonds) in green, blue and brownish-yellow colors; proposed method may be also used in optics for production of colored light filters withstanding temperatures above 1000°C. Proposed method includes preliminary application of cobalt on fianite surface to be colored and at least one metal whose oxide is liable to spinelle-forming with oxide of bivalent cobalt, iron and/or aluminum, for example. Then material is subjected to heat treatment in oxygen-containing atmosphere at temperature above 1000°C but not exceeding the fianite melting point. The procedure is continued for no less than 3 h. Coat is applied by thermal spraying of metals in vacuum. Said metals may be applied in turn and simultaneously. For obtaining bluish-green color of fianite, cobalt and aluminum are applied at atomic ratio of 1:1 to 1:2. For obtaining yellowish-green color, cobalt, aluminum and iron are applied at atomic ratio of 1:1 :0.1-0.2. For obtaining yellowish-brown color, cobalt and iron are applied at ratio of 1:1 to 1:2.

EFFECT: enhanced resistance to high temperature and chemical action.

7 cl, 11 ex

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