SU650274A1 - Charge for producing single crystals - Google Patents

Description

one

This invention relates to the field of producing colored corundum single crystals grown by the Verneil method and widely used in the jewelry and watch industry.

A known method for producing orange-yellow and red corundum crystals grown according to Verneil 1.

Orange-yellow corundum crystals are obtained by introducing impurities of chromium, nickel, magnesium, barium, and calcium as coloring additives. Corundum crystals turn red when chromium, titanium, barium and calashium impurities are added to the aluminum oxide mixture.

However, the known method is distinguished by the difficulty of preparing the mixture due to the large (isla of the input components.

The closest to the invention in technical essence and the effect achieved is a mixture for obtaining single crystals of Corundum according to Verneil, containing alumina and chromium oxide 2.

However, this method is characterized by an uneven distribution of the introduced impurities during growth throughout the entire volume of the crystal.

and the impossibility of producing orange-yellow and red monocrystals of different colors.

The purpose of the invention is to expand the range of corundum shades of a yellow-red gamut with a uniform distribution of color.

This is achieved by the fact that the mixture additionally contains beryllium oxide in the following ratio of components, wt.%:

Chromium oxide 0.05-4.0

Beryllium oxide 0.005-0.05

Alumina Rest

Example 1. A mixture for growing orange-yellow corundum consists of two com ponents.

 The first component is prepared as follows.

Claims (2)

Ammonium dichromate in the amount of 2 g per 10 kg of alum is introduced into alumoammonium alum. The resulting mixture is subjected to thermal decomposition at 1080 ° C for 1.5 hours. The mass formed after thermal decomposition is sieved. 36 For the preparation of the second component, beryllium sulphate is introduced into ammonium alum in the form of an aqueous solution at the rate of 15, 712 g per 10 kg of alum. The resulting mixture is subjected to thermal decomposition in a gas oven for 1.5 hours. The mass formed after thermal decomposition is sieved. 75% of the primary GHS component and 25% of the second component are mixed and crystals are grown from the resulting mixture at a rate of 18 g / h. The resulting crystals are evenly distributed throughout the volume orange-yellow color. Example 2. A mixture for growing orange corundum consists of two components. Preparation of the first component. Ammonium dichromate in the amount of 4 g per 10 kg of alum is introduced into the ammonium alum. The resulting mixture is subjected to thermal decomposition at 1080 ° C for 1.5 hours. The mass formed after thermal decomposition is sieved. The second component is prepared as in example 1. 80% of the first component and 20% of the second component are mixed and the crystals are grown at a rate of 1.8 g / h from the resulting mixture. The crystals obtained have an orange color uniformly distributed throughout the volume. After annealing in oxygen or air, the color intensity increases. The use of the proposed mixture significantly simplifies the process of preparation of ishkhta and allows you to expand the range of high-quality synthetic synthetic corundum. Claims for obtaining single crystals of corundum according to Verneuil, containing alumina and chromium oxide, characterized in that, in order to expand the range of corundum shades of yellow-red gamma with a uniform distribution of color, the mixture further contains beryllium oxide in the following ratio of components, %: Chromium oxide 0.05-4.0 Beryllium oxide 0.005-0.05 Alumina Rest Sources of information taken into account when examining 1. Contract of the Swiss company Jeva No. 46 / 89648-136. 2. Kt Wilke. Crystal growing methods. Science, L., 1968, p. 226.