ALUMINA PORCELAIN FOR ELECTRICAL ENGINEERING AND PROCEDURE OF ITS MANUFACTURE

The subject of invention is alumina porcelain for electrical engineering and the procedure for its manufacture. Technical porcelain according to the invention belongs to the group of high mechanical strength alkaline alumosilicate porcelains. The alumina porcelain according to the invention has the following chemical composition (mass %): from 58 to 62 % aluminium oxide, from 0,3 to 0,6 % iron oxide, from 0,1 to 0,3 % sodium oxide, from 1,5 to 2,5 % potassium oxide and from 0,8 to 1,2 % lithium oxide. The total content of iron oxide is lower than 0,5 %. Ceramic material is fired in the temperature range from 1280 to 1320 degrees Celsius for 1 to 4 fours. Ceramic material with the said composition and prepared according to the procedure described exhibits a higher flexural strength than 200 MPa. Surface glazed ceramic material prepared according to the procedure described exhibits a higher flexural strength than 240 MPa. Predmet izuma je glinični porcelan za elektrotehniko in postopek njegove izdelave. Tehnični porcelan po izumu spada v skupino alkalijskih alumosilikatnih porcelanov z visoko mehansko trdnostjo. Glinični porcelan po izumu ima sledečo kemijsko sestavo (masni %): od 58 do 62 % aluminijevega oksida, od 0,3 do 0,6 % železovega oksida, od 0,1 do 0,3 % natrijevega oksida, od 1,5 do 2,5 % kalijevegaoksida ter od 0,8 do 1,2 % litijevega oksida. Celotna vsebnost železovega oksida je nižja od 0,5 %. Keramični material se žge v temperaturnem območju od 1280 do 1320 stopinj celzija od 1 do 4 ure. Keramični material z navedeno sestavo in pripravljen po opisanem postopku ima upogibno trdnost višjo kot 200 MPa. Površinsko glaziran keramičnimaterial in žgan po opisanem postopku ima upogibno trdnost višjo kot 240 MPa.