SU681021A1 - Charge for the preparation of diopside ceramic - Google Patents

Description

(54) CHARGE FOR MAKING DIOPSID CERAMICS

The invention relates to the production of high-frequency (radio engineering) materials with a dielectric constant below 9 and can be used to produce high-voltage high-frequency dielectrics in the electrical and radio engineering industry. Known mixture for the manufacture of diopside ceramics, including a mixture of lime or lime, magnesite or oxide magnesium and sand 1. The closest to the invention to the technical essence and the achieved result is the mixture for the manufacture of diopside ceramics, in Key, wt.%: Tremolite. Calcium carbonate 1–20 Barium carbonate 10–12 Clay 2–15 Quartz sand 1–15 2. The disadvantage of products made from these masses is the relatively low mechanical strength and heat resistance. The purpose of the invention is to increase the mechanical strength and heat resistance. This is achieved by the fact that the mixture for making diopside ceramics, including treMOL1GG, calcium carbonate, barium carbonate, clay and quartz sand, additionally contains beryllium oxide or strontium in the following ratio of components, May. %: Calcium carbonate 1–20 Barium carbonate 10–12 Clay 6–15 Quartz sand 1–15 Beryllium oxide or strontium 0.25–1 Tremolite Ostal The product is prepared as follows. Before making the mixture, a mixture of tremolite with a dispersion of 0.5 mm and calcium carbonate is treated with an aqueous solution of strontium or beryllium salts, stirred for 30 minutes in a paddle mixer or a ball mill. After this, the mixture is dried and granulated. Burning of the granulated mixture is carried out in fireclay caps x at 1200-1250 ° С

3

aged at a final temperature of 1.5-2 hours. To the obtained product, the required amount of barium carbonate, clay and quartz sand is added, the resulting mixture is subjected to joint grinding in a ball mill before passing through sieve No. 0060, After grinding the mixture they are dehydrated to a moisture content of 25–30% and granulated, pressed into fireclay caps x at 1240–1260 ° C for 8–9 h with an exposure at a final temperature of 1.5–2 h. The burnt granules are ground by a dry method in a ball mill active additive (oleic acid

Compone) (you

Tremolite Calcium Carbonate Barium Carbonate Clay

Quartz sand Strontium oxide Beryllium oxide

Properties of products obtained from ...

Sintering temperature, ° С

Water absorption,%

Bulk weight, kg / m

Strength at static

bending, MPa

Thermal expansion coefficient

(a.10gr at 20-800 ° С)

Tangent of dielectric loss angle

tgS-lO at 1 MHz and at 20 ° C

Dielectric constant ()

at 1 MHz and fi200 ° C

four

in the amount of 0.3-0.4%). The products are molded by the method of hot injection under pressure from a thermoplastic slip obtained by mixing the obtained powder with 12-20% binder, including paraffin and wax. The firing of the products is carried out in two stages: preliminary firing in the alumina filling at 960-970 ° C for 10-13 h, the final calcination at 12301250 ° С with a lifting speed of 150-200 ° C / h with an exposure at a final temperature of 1.5 h.

The specific composition of the mixture shown in the table.

Composition, May. %

.:

80

0.5

0.5 charge

200 ° C

400 ° C

300 ° C

400 ° G

Specific volumetric resistivity (R ..), ohm-cm, at 200С

Claims (2)

Compressive strength as a percentage of the baseline after thermal shocks in the range of 300-20 ° C (air-water) after cycle 1 Formula of the Invention A mixture for the manufacture of daopside ceramics, including tremolite, calcium carbonate, barium carbonate, clay and quartz sand, characterized in that In order to increase mechanical strength and heat resistance, it additionally contains beryllium oxide or strontium in the following ratio of components, wt.%: Calcium carbonate 1-20 Barium carbonate 10-12 (2-2,2) -10 1,5-10  (1.9-4). ten 400 ° C 10 cycles Clay6-15 Quartz sand1-15 Beryllium oxide or strontium 0,25-1 TremoliteOstalal Sources of information taken into account during the examination of l.Kurezrjk HQ- S nlbetiscVier DopsidnCNwer-Rotistoff urd-ie keramik Ke.ram.i / 1975, 27, no. 5, 233-235. 2. USSR author's certificate N 501051, L. С 04 В 35/00, 1974.