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US 5,254,191 AGranted
Method for reducing shrinkage during firing of ceramic bodies
AssigneeE. I. Du Pont de Nemours and Company
InventorsKurt R. Mikeska, Daniel T. Schaefer
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Abstract
A method for reducing X-Y shrinkage during firing of ceramic bodies in which a flexible constraining layer, which becomes porous during firing, is applied to the ceramic body such that the flexible constraining layer conforms closely to the surface of the unfired ceramic body as the assemblage is fired.
Claims28
A method for reducing X-Y shrinkage during firing of a ceramic body comprising the sequential steps of
- a. providing an unfired ceramic body comprising an admisture of finely divided particles of ceramic solids and sinterable inorganic binder dispersed in a voltalizable solid polymeric binder;
- b. applying to a surface of the unfired ceramic body a flexible constraining layer such that the constraining layer conforms closely to the unfired ceramic body to form an assemblage, the constraining layer comprising finely divided particles of non-metallic inorganic solids dispersed in a voltilizable polymeric binder, penetration of the sinterable inorganic binder of the ceramic body into the constraining layer being no more than 50 .mu.m whereby said constraining layer is applied such that X-Y shrinkage upon firing of the ceramic body is reduced;
- c. firing the assemblage at a temperature and for a time sufficient to effect volatilization of the polymeric binders from both the ceramic body and the constraining layer, forming interconnected porosity in the constraining layer and sintering of the inorganic binder in the ceramic body;
- d. cooling the fired assemblage;
- and
- e. removing the constraining layer having interconnected porosity from the surface of the sintered ceramic body.
3 more elements
A method for reducing X-Y shrinkage during firing of a ceramic body comprising the sequential steps of:
- a. providing a monolith comprising n unfired ceramic bodies alternated with n+1 flexible constraining layers wherein n is a positive integer, each unfired ceramic body comprising one or more layers of ceramic tape comprising an admixture of finely divided particles of ceramic solids and sinterable inorganic binder dispersed in a volatizable solid polymeric binder, each constraining layer comprising finely divided particles of non-metallic inorganic solids dispersed in a volatilizable polymeric binder, and each constraining layer conforming closely to a surface of each adjacent ceramic body, penetration of the sinterable inorganic binder of the ceramic body into the constraining layer being no more than 50 .mu.m;
- b. firing the monolith at a temperature and for a time sufficient to effect volatilization of the polymeric binders from the ceramic body or bodies and the constraining layers, form interconnected porosity in the constraining layers and sinter the inorganic binder in the ceramic body or bodies;
- c. cooling the fired monolith, and
- d. removing the constraining layers having interconnected priority from the surfaces of the sintered ceramic body or bodies.
1 more element
Dependencies are inferred from the claim text.