| abstract |
Ceramic compsn. (I) contains 55-70 vol.% borosilicate glass (II), 5-30 vol.% Al2O3 as filler (III), 5-35 vol.% cordierite (IV) and 0-20 vol.% quartz glass (V). (I) contains 55-65 vol.% (II), 10-25 vol.% Al2O3, 15-25 vol.% (IV) and 0-10 vol.% (V). (II) consists of 65-88 wt.% SiO2, 5-25 wt.% B2O3, 1-5 wt.% Li2O, K2O, and/or Na2O and 0-5 wt.% Al2O3 and has a softening point of 750-880 deg.C and coefft. of thermal expansion of 1.0 x 3.8 x 10 power (-6) deg.C. USE/ADVANTAGE - (I) is used as the ceramic layer of a ceramic circuit board, which is used in an electronic device (claimed). The laminated circuit board is esp. useful in electronic computers. (I) has the properties required for efficiency and reliability, i.e. low sintering temp. (below 1000 deg.C), relatively low dielectric constant (4.5-5.3), coefft. of thermal expansion about the same as that of Si (2.4-4.0 x 10 power (-6) deg.C cf. (3.1 +/- 1.0) x 10 power (-6) deg.C for Si) and high flexural strength (17-26 kg/mm2). |