Use of zeolites in preparing low temperature ceramics
AssigneeUop LLC
InventorRobert L. Bedard
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Abstract
A dielectric ceramic article precursor and a process for preparing a dielectric ceramic article are presented. The ceramic article precursor comprises a crystalline aluminosilicate zeolite or an amorphous aluminosilicate, a zinc oxide additive and a glass phase. The ceramic article precursor can optionally contain at least one forming aid selected from binders, plasticizers and surfactants. The process for preparing a dielectric ceramic article involves forming a mixture from the above components into a shaped article such as a tape and then calcining the shaped article at a temperature of about 700° C. to about 1000° C. for a time of about 0.5 to about 24 hours.
Claims25
A dielectric ceramic article precursor comprising from about 1 wt. % to about 99 wt. % of a crystalline aluminosilicate zeolite or an amorphous aluminosilicate derived from the zeolite, from about 99 wt. % to about 1 wt. % of a glass phase, and from about 1 to about 10 wt. % of ZnO, the zeolite having a composition on an anhydrous basis represented by an empirical formula of:
- Al/nSixAlOy
- where A is an exchangeable cation selected from the group consisting of alkali metals, alkaline earth metals, transition metals, zinc, rare earth metals and mixtures thereof, “n” is the valance of A and varies from about 1 to about 3, “x” has a value from about 1 to about 10 and “y” has a value which balances the sum of the valences of (A+Si+Al).
A process for preparing a dielectric ceramic article comprising forming a mixture of a crystalline aluminosilicate zeolite or an amorphous aluminosilicate derived from the zeolite, a zinc oxide (ZnO) additive and a glass phase into a shaped article and calcining the shaped article at a temperature of about 700° to about 1000° C. for a time of about 0.25 to about 1 hrs, the crystalline aluminosilicate zeolite having a composition on an anhydrous basis represented by an empirical formula of:
- Al/nSixAlOy
- where A is an exchangeable cation selected from the group consisting of alkali metals, alkaline earth metals, transition metals, zinc, rare earth metals and mixtures thereof, “n” is the valence of A and varies from about 1 to about 3, “x” has a value from about 1 to about 10 and “y” has a value which balances the sum of the valences of (A+Si+Al) and where the zeolite or amorphous aluminosilicate is present in an amount from about 1 wt. % to about 99 wt. %, the zinc oxide is present in an amount from about 1 to about 10 wt. % and the glass phase is present in an amount from about 99 wt. % to about 1 wt. %.
Dependencies are inferred from the claim text.