Dielectric compositions

A dielectric composition formed by firing a composition comprising:

• (a) from about 60% to about 95% by weight of a mixture of two glass compositions, one of said glass compositions having a glass transition temperature in the range of about 585.degree. C. to about 620.degree. C. and comprising from about 45% to about 60% by weight SiO.sub.2, from about 2% to about 7% by weight B.sub.2 O.sub.3, from about 14% to about 20% by weight PbO, from about 5% to about 12% by weight Al.sub.2 O.sub.3, up to about 3% by weight MgO, from about 4% to about 12% by weight CaO, up to about 3% by weight K.sub.2 O, and up to about 3% by weight Na.sub.2 O;
• and the other of said glass compositions having a transition temperature in the range of about 765.degree. C. to about 815.degree. C. and comprising from about 43% to about 56% by weight SiO.sub.2, from about 20% to about 31% by weight Al.sub.2 O.sub.3, from about 20% to about 27% by weight MgO, and up to about 2% by weight CaO;
• (b) about 2% to about 30% by weight of at least one expansion modifier;
• and
• (c) about 2% to about 40% by weight of at least one refractory oxide.

A composition which upon firing forms a dielectric composition, said composition comprising:

• (a) about 30% to about 100% by weight of a mixture of two glass compositions wherein the first of said glass compositions has a glass transition temperature in the range of about 585.degree. C. to about 620.degree. C. and the second of said glass compositions has a glass transition temperature in the range of about 765.degree. C. to about 815.degree. C.;
• (b) up to about 30% by weight of an expansion modifying component;
• and
• (c) up to about 40% by weight of a refractory oxide;
• said first of said glass compositions comprising from about 45% to about 60% by weight SiO.sub.2, from about 2% to about 7% by weight B.sub.2 O.sub.3, from about 14% to about 20% by weight PbO, from about 5% to about 12% by weight Al.sub.2 O.sub.3, from about 0% to about 3% by weight MgO, from about 4% to about 12% by weight CaO, from about 0% to about 3% by weight K.sub.2 O, and from about 0% to about 3% by weight Na.sub.2 O;
• and
• said second of said glass compositions comprising from about 43% to about 56% by weight SiO.sub.2, from about 20% to about 31% by weight Al.sub.2 O.sub.3, from about 20% to about 27% by weight MgO, and from about 0% to about 2% by weight CaO.

A dielectric paste composition which comprises an admixture of finely divided solids and an organic binder wherein the finely divided solids are present in an amount ranging from about 60% to about 80% by weight of the total composition with said binder being present in an amount ranging from about 20% to about 40% by weight, wherein the finely divided solids include (i) about 25% to about 75% by weight of a mixture of two glass compositions wherein the first glass has a glass transition temperature in the range of about 585.degree. C. to about 620.degree. C. and the second glass has a glass transition temperature in the range of about 765.degree. C. to about 815.degree. C., (ii) up to about 30% by weight of an expansion modifying component, (iii) up to about 40% by weight of refractory oxide, and wherein the binder includes an organic resinous material and a suitable solvent therefor;

• said first glass comprising from about 45% to about 60% by weight SiO.sub.2, from about 2% to about 7% by weight B.sub.2 O.sub.3, from about 14% to about 20% by weight PbO, from about 5% to about 12% by weight Al.sub.2 O.sub.3, up to about 3% by weight MgO, from about 4% to about 12% by weight CaO, up to about 3% by weight K.sub.2 O, and up to about 3% by weight Na.sub.2 O;
• and said second glass comprising from about 43% to about 56% by weight SiO.sub.2, from about 20% to about 31% by weight Al.sub.2 O.sub.3, from about 20% to about 27% by weight MgO, and up to about 2% by weight CaO.