RU2452612C2 - Ceramic binder - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a ceramic binder for making a corundum polishing tool. The binder contains the following, wt %: silicon dioxide from 40.00 to 70.00, aluminium oxide from 16.00 to 30.00, calcium oxide from 0.40 to 3.00, magnesium oxide from 0.10 to 7.00, potassium oxide from 0.30 to 7.00, sodium oxide from 1.00 to 12.00, boron oxide from 4.00 to 15.00, iron oxide from 0.10 to 1.00, titanium dioxide from 0.05 to 2.00, lithium oxide from 0.20 to 5.00, and additionally at least one additive from a group comprising: zinc oxide from 0.01 to 15.00, barium oxide from 0.05 to 15.00, zirconium dioxide from 0.05 to 6.00, chromium oxide from 0.01 to 3.00, alkaline hexafluoroaluminate from 0.20 to 10.00.

EFFECT: possibility of reducing burning of the polishing tool made from artificial corundum, silicon carbide or boron nitride.

2 ex

Description

Technical field

The invention relates to a ceramic bond for the manufacture of a corundum grinding tool, the composition of which makes it possible to lower the firing temperature of a grinding tool made of artificial corundum, silicon carbide or boron nitride.

The current state of the art

Ceramic ligaments are currently used for the manufacture of grinding tools with firing temperatures in excess of 1200 ° C. The disadvantages of firing at high temperatures so far used are that such ligaments cannot be used for the manufacture of grinding tools based on cubic boron nitride, since boron nitride at high temperatures passes from the cubic to hexagonal modification. The minuses also include an increase in production costs in view of the high energy resource consumption.

The closest analogue (prototype) can be the invention according to the patent of the Russian Federation No. 1390004 "Mass for the manufacture of abrasive tools" related to the production of abrasive tools, in particular grinding wheels with a ceramic bond. The purpose of the invention is to reduce the heat treatment temperature, increase the mechanical strength of the tool and eliminate the swelling of the mass. The mass as a binder contains chromochlorophosphate binder in the following ratio of components, wt.%: Abrasive 75-80 chromochlorophosphate binder 5-20; water, the rest.

The essence of the invention

The above disadvantages are eliminated by the ceramic bond for the manufacture of corundum or carbide grinding tools, the essence of which according to the invention is that it contains in wt.% The following substances:

silica from 40.00 to 70.00 alumina from 16.00 to 30.00 calcium oxide from 0.40 to 3.00 magnesium oxide from 0.10 to 3.00 potassium oxide from 0.30 to 7.00 sodium oxide from 1.00 to 12.00 boron oxide from 4.00 to 15.00 iron oxide from 0.10 to 1.00 titanium dioxide from 0.05 to 2.00 lithium oxide from 0.20 to 5.00

and at least one additive from the group including:

zinc oxide from 0.01 to 15.00 barium oxide from 0.05 to 15.00 zirconium dioxide from 0.05 to 6.00 chromium oxide from 0.01 to 3.00 tin dioxide from 0.20 to 2.00 alkaline hexafluoroaluminate from 0.20 to 10

In accordance with the invention, in the ceramic bond described above, the chemical composition comprises from 10 to 90% by weight of borosilicate glass and up to 30% by weight of plastic ceramic raw materials. This composition of the ligament ensures a reduction in the firing temperature of grinding wheels based on corundum to over 900 ° C. The optimal viscosity of the glass phase, which reacts in the outermost layer of corundum without its increased dissolution, provides optimal exposure to the ligament. In this way, a high-quality combination of grinding grains and ceramic ligaments is ensured during firing of grinding wheels. Their preparation consists in grinding glass frits and other ceramic raw materials to a size of 60 μm. Raw materials and frits are mixed in ratios at which their chemical composition is in the proposed range. After homogenization of the crushed binder with grinding grain, the mass is ready for pressing. At the end of drying, the press products of various sizes are fired at temperatures above 900 ° C. The main advantage of the grinding wheels made in this way on the basis of the claimed bond is their higher grinding efficiency and higher relative abrasion G compared to the circles obtained by firing at temperatures above 1200 ° C.

Execution examples

Example 1

A ceramic binder was made by melting and fritting glass with the following composition in wt.%:

silica 57.03 alumina 18.56 iron oxide 0.34 titanium dioxide 0.27 calcium oxide 1.83 magnesium oxide 1.25 potassium oxide 1.89 sodium oxide 6.36 boron oxide 12.03 lithium oxide 0.22 zinc oxide 0.02 zirconium dioxide 0.05 barium oxide 0.15

Ceramic bond and grinding grains of corundum with a grain size of No. 60 were mixed in a weight ratio of 12:88. The mixture was moistened with a solution of dextrin in an amount of 3.5 wt.% And thoroughly homogenized. From the mass prepared in this way, the circles were pressed. After drying at a temperature of 100 to 120 ° C, firing was performed in an electric or gas furnace with increasing temperature in increments of 55 ° C / h to a temperature above 960 ° C and holding for 9 hours. The circles were machined to their final size after cooling to a temperature of 50 ° C. The parameters were in accordance with the technological requirements.

Example 2

A ceramic binder was made by melting and fritting glass with the following composition in wt.%:

silica 63.36 alumina 20.17 iron oxide 0.28 titanium dioxide 0.11 calcium oxide 0.60 magnesium oxide 0.12 potassium oxide 5.18 sodium oxide 2.15 boron oxide 7.18 lithium oxide 0.2 zinc oxide 0,07 zirconium dioxide 0.08 barium oxide 0.50

The glass frit was crushed to the required fineness and mixed with grinding grains of silicon carbide with a grain size of No. 54 in a weight ratio of 16:84. The mixture was moistened with a solution of dextrin in an amount of 3.5 wt.% And thoroughly homogenized. From the mass prepared in this way, the circles were pressed. After drying at a temperature of 100 to 120 ° C, firing was performed in an electric or gas furnace with a temperature increase in increments of 55 ° C / hr to a temperature above 960 ° C and holding for 9 hours. The circles were processed to a final size after cooling to a temperature of 50 ° C. The parameters were in accordance with the technological requirements.

Industrial applicability

When grinding external cylindrical surfaces of steel according to GOST 801 SchCH15 (ШХ15), a grinding tool made of a bond according to the invention achieves a hardness of 60 to 62 HRC and a relative abrasion G of 24% more in comparison with similar wheels fired to a temperature of 1200 ° C.

Claims (1)

Ceramic binder for the manufacture of corundum and carbide grinding tools, characterized in that it contains, wt.%:
silica from 40.00 to 70.00 alumina from 16.00 to 30.00 calcium oxide from 0.40 to 3.00 magnesium oxide from 0.10 to 7.00 potassium oxide from 0.30 to 7.00 sodium oxide from 1.00 to 12.00 boron oxide from 4.00 to 15.00 iron oxide from 0.10 to 1.00 titanium dioxide from 0.05 to 2.00 lithium oxide from 0.20 to 5.0
and additionally at least one additive from the group including:
zinc oxide from 0.01 to 15.00 barium oxide from 0.05 to 15.00 zirconium dioxide from 0.05 to 6.00 chromium oxide from 0.01 to 3.00 alkaline hexafluoroaluminate from 0.20 to 10.00