Dielectric glasses for low dielectric loss, low temperature cofired ceramics with medium dielectric constants

摘要

Dielectric glass compositions which can be used to produce glass ceramics having medium dielectric constants ( ELEMENT r 15 to 100), and being formed from: (a) a major proportion of a glass composition comprising 14 to 30 % by weight SiO2, 5 to 11 % by weight Al2O3, 20 to 35 % by weight SrO, and 8 to 28 % by weight TiO2; and (b) a minor proportion of one or more additives selected from the group consisting of 0 to 7 % by weight MgO, 0 to 20 % by weight La2O3, 0 to 20 % by weight PbO, 0 to 20 % by weight Nb2O5, 0 to 8 % by weight CdO, and 0 to 10 % by weight B2O3. Also provided are mixtures of host glass powders with partially crystallized glass powders of substantially the same composition, the partially crystallized glass having crystalline and amorphous phases in a volume ratio between 5:95 and 95:5, and having been crystallized at a temperature between T1 and T2, wherein T1 is a temperature which is not more than 40 DEG C below a first exothermic peak on a differential thermal analysis curve for the glass, and T2 is a temperature at least 20 DEG C below a temperature which causes complete crystallization of the glass. The partially crystallized glass provides improved dimensional stability to sintered glass ceramics formed from such mixtures, along with the ability to tailor the properties of the glass ceramic to the required needs or application. Methods to produce the partially crystallized glass powder, and methods of forming dense glass ceramic bodies with or without the partially crystallized glass, are also provided.