Method of production of electroinsulating glass enamel

FIELD: metallurgy.

SUBSTANCE: frit of the following composition, wt % is melted: SiO₂- 20.0-25.0; CaO- 4.5-12.0; SrO-1.0-2.0; CdO- 2.0-3.0; MnO- 0.1-0.5; K₂O - 3.0-4.0; Na₂O-1.0-1.5; B₂O₃- 5.0-5.5; CaF₂-4.0-5.0; MoO₃ - 0.5-0.8; Cr₂O₃ -0.5-0.8; Co₂O₃ -0.1-0.5; NiO - 0.1-1.0; Na₃AlF₆ - 0.1-0.5; BaO is the rest. Melting is carried out at 1150-1200 °C. The obtained product is crushed, and then injected 5-10% SrTiO₃ of the frit weight.

EFFECT: increased dielectric permeability.

1 ex, 3 tbl

The invention relates to the field of silicates, in particular to a method for insulating stellamara, which are used as the dielectric barrier electrodes ozonation equipment operating under conditions of barrier discharge.

To create a high-performance installations ozone type you need to use a dielectric barrier having a high dielectric constant and low dielectric loss. According to published data, the performance of the installation depends on the form you receive in her barrier discharge, which in turn is connected with the dielectric constant used in the ozone generator of the barrier. Also stekloemali must have good covering power, dilatometric characteristics similar to the metal substrate, and a high adhesion to metal.

Known composition of the insulating enamel for the electrodes of the ozone generator of low carbon steel, wt.% contents: SiO₂37,6-40; Na₂O of 7.1-8.2; B₂O₃1,2-3,6; K₂O 0,7-3,3; CaO 2-2,3; Li₂O 2,9-3,3; SrO 2,0-3,6; Zr₂O 1,8-4,9; Na₂SiF₆0,6-3,6; CoO 0,6-1,1; SrTiO₃28,6-41,2 [RF Patent №2081070, class C03C 8/06, 1997].

The closest in technical essence and the achieved result is a composition, wt.% contents: SiO₂25-35; HLW 35-45; CaO 4-7; SrO 3-; CdO 4.5 to 6; MnO 0.2 to 1; K₂O 3-5; Na₂O 1-4; B₂O₃3-75; NGO₃0,5-1; Cr₂O₃0,5-1; CoO of 0.5-1; NiO 0,5-1 [RF Patent №2209786, class C03C 8/02, 2003]. This composition has a dielectric constant of 11.3-13,0; TCLE (142-154)·10^-71/°C, the tangent of dielectric loss angle (2,7-4,1)·10^-3temperature cooking enamel 1250°C, the firing temperature of the enamel 700-720°C. the Disadvantage of this composition are reduced dielectric characteristics, particularly low dielectric constant.

The technical result of the invention is the increase in the values of dielectric constant while maintaining other physical-chemical parameters.

This technical result is achieved in that the method of obtaining the insulating stekloemali includes melting Frit composition: SiO₂, BaO, CaO, SrO, CdO, MnO, K₂O, Na₂O, B₂O₃Moo₃, Cr₂O₃, Co₂O₃, NiO, characterized in that the composition additionally contains Na₃AlF₆and CaF₂in the following ratio of components, wt.%: SiO₂- 20.0-25.0, CaO - 4.5-12.0, SrO - 1.0-2,0, CdO, - 2.,0-3 .0, MnO - 0.1-0.5, K₂O - 3.0-4.0. Na₂O - 1.0-1.5, B₂O₃- 5.0-5.5, CaF₂- 4.0-5.0, MoO₃- 0.5-0.8, Cr₂O₃- 0.5-0.8, Co₂O₃- 0.1-0.5, NiO - 0.1-1.0, Na₃AlF₆- 0.1-0.5, BaO - rest and the fact that the cooking is carried out at 1150-1200°C; grinding obtained what about the product and the introduction of 5-10% SrTiO ₃by weight of the Frit.

Metatitanate strontium is introduced in an amount of 5; 7.5 and 10 wt.% of the total weight of the Frit.

As raw materials were used: quartz sand;

boric acid; carbonates of barium, calcium, strontium, cadmium, potassium, sodium oxides: manganese, Nickel, molybdenum, chromium, cobalt; cryolite, fluorite and metatitanate strontium.

Example 1. For the preparation of glass-Frit raw materials were weighed on a technical scale accurate to 0.01 g according to the chemical composition shown below, and thoroughly stirred to obtain a homogeneous mixture.

The composition of the glass Frit contains the following components, wt.%: SiO₂- 25,0; CaO - 4,5; SrO - 1,0; CdO - 2,0; MnO - 0,1; K₂O - 3,0; Na₂O - 1,0; BrO₃- 5,5; CaF₂- 4,0; MoO₃to 0.5; Cr₂O₃- 0,5; Co₂O₃- 0,1; NiO - 0,1; Na₃AlF₆- 0,1; BaO - 52,6.

Melting glass was carried out in corundum crucibles in an electric laboratory furnace with silicafume heaters. Cooking temperature is 1150°C, holding at the maximum temperature is 60 minutes. The production of glass was carried out by granulation of the molten glass in the water. The granulate is milled in a ball mill. The resulting powder was weighed on a technical scale accurate to 0.01, the Hanging glass Frit in an amount of 500 g was mixed until smooth with pre is varicella weighted additive metatitanate strontium in amounts of 50 g (10% by weight of glass Frit). Before applying, the surface of the metal substrate is subjected to pre-treatment: sand blasting and degreasing. The application is carried out by electrostatic deposition. The coating is applied in layers to a thickness of 0.3 to 0.5 mm, the Firing of each layer is carried out at a temperature of 840°C.

In the following data were obtained: dielectric 22; the tangent of dielectric loss angle of 0.005, the strength of the enamel coating on the cob is 2.3, J.

The synthesis of other compounds, as well as the application of enamel coatings carried out similarly to the above example (see Tables 1 and 2).

The specified technical result is the cumulative effect of additives metatitanate strontium as material belonging to the ferroelectric and high dielectric permittivity, and components that are additionally introduced into the composition of Frits that improve melting properties, provide good flowability and strong adhesion of the enamel to the metal substrate. Thus, the comparative analysis showed that the proposed method for insulating stekloemali differs from the known higher values of dielectric permittivity, as well as a sufficient degree of adhesion of the enamel coating with metal vile who ICOI. This demonstrates the advantage of the proposed enamel compared to the prototype.

The method of obtaining the insulating stekloemali by melting the Frit composition of SiO₂, BaO, CaO, SrO, CdO, MnO, K₂O, Na₂O, B₂O₃, MoO₃, Cr₂O 3, Co₂O₃, NiO, characterized in that the composition additionally contains Na₃AlF₆and CaF₂in the following ratio, wt.%: SiO₂- 20,0-25,0, CaO - 4,5-12,0, SrO - 1,0-2,0, CdO - 2,0-3,0, MnO - 0,1-0,5, K₂O - 3,0-4,0, Na₂O - 1,0-1,5, B₂O₃- 5,0-5,5, CaF₂- 4,0-5,0, MoO₃is 0.5 - 0.8, Cr₂O₃- 0.5 to 0.8, Co₂O₃- 0,1-0,5, NiO - 0,1-1,0, Na₃AlF₆- 0,1-0,5, BaO - rest, and the cooking is carried out at 1150-1200°C, the resulting product is ground, then enter the 5-10% SrTiO₃by weight of the Frit.