RU2253706C2 - Jewelry material-synthetic polycrystal corundum and method of manufacture of articles from such material - Google Patents

Abstract

FIELD: jewelry technology; manufacture of jewelry colored inserts.

SUBSTANCE: synthetic corundum contains alumina, color-forming additives and binder-paraffin. Required color is obtained as follows: for obtaining black color molybdenum oxide is added to alumina in the amount of 0.03%; for obtaining gray color, tungsten oxide is added to alumina in the amount of 0.01%; for obtaining blue color, neodymium oxide is added in the amount of 0.01%; for obtaining pink color, erbium oxide is added to alumina in the amount of 0.01%; for obtaining red color, chromium oxide is added in the amount of 0.05%. Proposed method of manufacture of jewelry articles includes molding in casting machines at a pressure of 4 atm and roasting; first roasting cycle is performed in continuous furnaces for burning-out the binder and is continued for 90 h at temperature of 1150 C; second roasting cycle is performed in batch furnaces at temperature of 1750 C and is continued for 170 h for forming and sintering of microcrystals making translucent crock at density of 4 g/cu cm and hardness of 9 according to Mohs hardness scale; then polishing is performed with the aid of diamond materials. Articles thus made have high-quality miniature texture at hardness which is disadvantage in relation to diamond only.

EFFECT: high quality of articles; enhanced hardness of articles.

7 cl

Description

The invention relates to technology for jewelry production, more specifically to methods for producing colored jewelry inserts, as well as inserts using jewelry enamels, and is intended for use in the jewelry industry in circulation.

Currently, the Verneuil method is the main one in the production of synthetic single-crystal corundums.

For the jewelry industry, about 150 mm is currently being grown; ⌀35 mm, which is suitable for cutting in the shape commonly accepted for jewelry stones, although the cutting loss reaches 98%. The boulevard grown in the furnace is a material in the form of crystals arranged in a regular order along the crystallographic axis, intersecting at an angle of 60 °, having a grid formed by the smallest planes - lateral curved growth lines of corundum rhombohedrons, which are closely adjacent to each other, creating transparency of the material.

However, for industrial purposes, the Verneuil method is very little improved.

Known single-crystal corundum and a method for its production from alumina and color-forming additives, followed by heat treatment of the crystal at 1600-1850 ° C and 1100-1150 ° C (US 3897529, IPC F 27 D 71/00, 07.29.1975), but also it does not allow to obtain ready-made products, since it requires subsequent processing by sawing, grinding, lapping, grinding, polishing, drilling, cutting, tumbling, engraving to bring the material to the product.

The technical result consists in the creation of industrial production of jewelry material with the possibility of obtaining in circulation industrial production of finished products in the form of jewelry inserts with a high-quality miniature relief of colored polycrystalline corundum, which is inferior only to diamond in hardness.

The technical result is achieved by jewelry material - a synthetic polycrystalline corundum, consisting of alumina, color-forming additives and a paraffin binder.

Moreover, as a color-forming additive, molybdenum oxide is used in an amount of 0.03% to obtain a black color; tungsten oxide in an amount of 0.01% to obtain a gray color; neodymium oxide in an amount of 0.01% to obtain a blue color; erbium oxide in an amount of 0.01% to obtain a pink color; chromium oxide in an amount of 0.05% to obtain a red color.

The technical result is also achieved by the method of obtaining products from jewelry material - synthetic polycrystalline corundum from alumina, color-forming additives and paraffin binder by molding on injection machines at a pressure of 4 atm and firing, and the first firing is carried out in continuous furnaces to burn the binder for 90 hours at a temperature of T-1150 ° C, and the second - in batch furnaces for 170 hours at a temperature of T-1750 ° C for the formation and sintering of microcrystals that make up a translucent color turnip products with a density of 4 g / cm ³ and a hardness of 9 units. on the Mohs scale, which is then polished with diamond materials.

Jewelry material is obtained as follows:

- alumina A 1203 of the VK-100-1 grade (2) is used as a starting material;

- grind it in ball mills;

- sift, after which

- enter the target color-forming additive and a bunch of paraffin in an amount of 1.5%.

To obtain the desired color, molybdenum, tungsten, neodymium, erbium, or chromium oxides are added to alumina in appropriate amounts.

Polycrystalline corundum products are obtained by molding it on injection machines at a pressure of 4 atm at a temperature of 80 ° C and two-stage annealing.

A molded polycrystalline corundum with a double firing mode for 10 days to create and sinter microcrystals makes it possible to obtain a READY PRODUCT, creating less transparent, due to the disordered arrangement of microcrystals, but translucent, translucent and opaque products with a hardness of 9 units. on the Mohs scale without further machining, except polishing.

Thus, the invention allows to obtain high-quality molded FINISHED PRODUCTS with complex miniature relief, which cannot be performed in the material of monocorund without carving on stone and engraving on hard stones in the manufacture of cameos, gems, mini-sculptures, mini-reliefs.

Also, the invention allows to obtain a product - an insert with a complex miniature relief of a chemically neutral substrate, consisting of microscopic polycorundum crystals, ensuring the adhesion of jewelry enamels to the substrate during repeated firing of enamels of local colors and enamels with brightly saturated halftone colors, without the use of precious metals used for the manufacture of substrates emulsion enamels.

Claims (7)

1. Jewelry material - a synthetic polycrystalline corundum, consisting of alumina, color-forming additives and a paraffin binder. 2. The jewelry material according to claim 1, in which molybdenum oxide in an amount of 0.03% is used as a color-forming additive to produce black. 3. The jewelry material according to claim 1, in which tungsten oxide is used in an amount of 0.01% as a color-forming additive to obtain gray color. 4. The jewelry material according to claim 1, in which neodymium oxide in an amount of 0.01% is used as a color-forming additive to obtain a blue color. 5. The jewelry material according to claim 1, in which erbium oxide in an amount of 0.01% is used as a color-forming additive to obtain a pink color. 6. The jewelry material according to claim 1, in which chromium oxide in an amount of 0.05% is used as a color-forming additive to obtain a red color. 7. A method of obtaining products from jewelry material — synthetic polycrystalline corundum from alumina, color-forming additives and a binder — paraffin — by molding on injection machines at a pressure of 4 atm and firing, the first firing being carried out in continuous furnaces to burn the binder for 90 hours at temperature T-1150 ° C, and the second - in a batch furnace for 170 hours at a temperature of T-1750 ° C for sintering and formation of microcrystals constituting the colored translucent crock product density 4 g / ^cm3 and hardness 9 units. on the Mohs scale, which is then polished with diamond materials.