1450 u00b0 c for 1 hour the molten glass was pressed between a pair of rollers to form a thin plate having a thickness of about 0 5 mm the thin plate glass was crushed for more than 24 hours in a pot mill made of alumina so as to form a glass powder having maximum diameter less than 20 u03bc and average diameter 3 5 u03bc the electrically insulating coating glass of the invention is applied as follows a vehicle consisting of 92 percent by weight of u03b2 terpineol and 8 by weight of ethylcellulose was mixed with the glass powder prepared above in a ratio of 25 75 by weight to form a paste the paste was printed through a 200 mesh screen after a paste of electroconductive powder was printed and dried on an alumina substrate the insulating paste was dried at 150 u00b0 c for 1 hour the printed alumina substrate was heated at a rate of 50 u00b0 c min to 750 u00b0 850 u00b0 c was kept at the same temperature for about 10 minutes and was cooled at a rate of 50 u00b0 c min the properties of the electrically insulating coating glass which thus crystallized are shown in table 2 table 1__________________________________________________________________________sample no component 1 2 3 4 5 6 7 8 9 10 11 12 13__________________________________________________________________________sio sub 2 34 1 28 6 44 1 29 3 31 3 38 6 31 5 38 6 31 1 38 6 39 5 41 5 41 5al sub 2 o sub 3 19 3 19.