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Making Green Sheet Ceramic Parts

IP.com Disclosure Number: IPCOM000081604D
Original Publication Date: 1974-Jul-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Cullen, FM: AUTHOR

Abstract

Parts made from green sheet ceramic tend to become dimensionally distorted in shape when fired, if placed directly on fire brick or the like in a furnace. This is particularly true of parts which have cut-cut designs such as a picture frame shape.

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Making Green Sheet Ceramic Parts

Parts made from green sheet ceramic tend to become dimensionally distorted in shape when fired, if placed directly on fire brick or the like in a furnace. This is particularly true of parts which have cut-cut designs such as a picture frame shape.

The problem of dimensional distortion is overcome by placing the shaped part on a substrate made of the same green sheet material that is at least as large as the outer dimensions of the green sheet part. The part and the green sheet layer are then placed on fire brick or a sintering tray or the like and heat treated the desired amount.

In the course of heat treatment both part and substrate shrink and become hardened; but since both are of the same material, shrinking occurs in both at the same rate. In this manner, the shaped part retains its true shape although dimensionally smaller due to shrinkage on curing.

A suitable material for this process is commonly referred to as alumina green tape comprising 94-96% alumina, 3-4% SiO(2), 1/2-1 CaO, and 1/2-1% MgO bonded in green state with an organic binder such as PVA. The parts can be made from the green tape by cutting, punching or other processes to the desired shape prior to firing.

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