US 6,447,712 B1 · Method for sintering ceramic tapes

Abstract

Flexible setter powder deposition sheets containing setter powders were developed for sintering of ceramic articles including tapes by an economical, fast and simple method. The sheets provide for deposition of a thin and uniform layer of setter powders on a green ceramic article after burnout of a binder in the sheet. Because of high strength and low burnout temperature, hydroxypropyl methylcellulose binder is preferred for production of these sheets. Tape cast sheets with low solids loading can be obtained by optimizing the wetting behavior of aqueous slurries on tape carrier. Setter, powder deposition sheets are of particular benefit in processing of thin ceramic tapes, particularly for processing of piezoelectric ceramic tapes. Tapes can be processed in a sandwich formed by layering setter powder deposition sheets between tapes and cover plates employed to maintain tape flatness and to reduce evaporation of volatile components of the ceramic.

Claims19

Dependent claims

A method for sintering a green ceramic tape having a thickness less than or equal to about 100 microns prior to sintering which comprises the steps of:

(a) prior to sintering, applying at least one top and at least one bottom setter powder deposition sheet to the top and bottom surfaces of the tape, respectively, wherein the setter powder deposition sheet comprises a carrier having a binder layer impregnated with setter powder or particles, wherein the setter powder or particles are ceramic powder or particles which constitute between about 1% and about 15% by weight of the binder layer;
(b) prior to sintering, placing a bottom cover plate such that the bottom setter powder deposition sheet is positioned between the bottom surface of the tape and the bottom cover plate;
(c) prior to sintering, placing a top cover plate such that the top setter powder deposition sheet is positioned between the top surface of the tape and the top cover plate, wherein the force applied by the top cover plate to the top and bottom sheets and the tape is selected so that the tape remains flat during sintering and so that shrinkage of the tape in a plane parallel to the cover plate can occur during sintering, said shrinkage causing movement of the setter particles;
and
(d) sintering the green ceramic tape.

2 more elements

A method for sintering a green ceramic tape subject to loss of a volatile inorganic component during sintering which comprises the steps of:

(a) prior to sintering, applying at least one top and at least one bottom setter powder deposition sheet to the top and bottom surfaces of the tape, respectively, wherein the setter powder deposition sheet comprises a carrier having a binder layer impregnated with setter powder or particles, wherein the setter powder or particles are ceramic powder or particles which constitute between about 1% and about 15% by weight of binder layer;
(b) prior to sintering, placing a bottom cover plate such that the bottom setter powder deposition sheet is positioned between the bottom surface of the tape and the bottom cover plate, wherein the bottom cover plate is dense and chemically compatible with the green tape;
(c) prior to sintering, placing a top cover plate such that the top setter powder deposition sheet is positioned between the top surface of the tape and the top cover plate, wherein the force applied by the top cover plate to the top and bottom sheets and the tape is selected so that the tape remains flat during sintering and so that shrinkage of the tape in a plane parallel to the cover plate can occur during sintering, said shrinkage causing movement of the setter particles, and wherein the top cover plate is dense and chemically compatible with the green tape;
and
(d) sintering the green ceramic tape, wherein the green tape provides the only source of the volatile component during the sintering process;
whereby the loss of the volatile inorganic component is minimized.

3 more elements

Dependencies are inferred from the claim text.

Method for sintering ceramic tapes

Life of this patent

Method for sintering ceramic tapes

Life of this patent

Abstract

Claims19