US 4,305,756 AGranted

Method and means for removing binder from a green body

AssigneeWitec Cayman Patents, Ltd.

InventorRaymond E. Wiech, Jr.

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Abstract

The disclosure relates to a method of binder removal from a green body before sintering or the like wherein the green body is placed in a pressure chamber wherein the pressure is raised to a level above the vapor pressure of the binder in the green body at the ambient temperature within the pressure chamber. Where several binders are utilized simultaneously, the pressure within the chamber is maintained higher than the vapor pressure of the lowest of the binders then in the green body at the temperature within the green body. Under these conditions, the binder or binders will turn to a vapor, will follow the normal laws of evaporation and diffusion and diffuse out from the green body into the surrounding environment within the chamber. The binder can subsequently be removed from the chamber in conventional manner.

Claims37

Dependent claims

A method of producing an article in the form of a fired particulate configuration, whereby binder material is removed from the particulate configuration prior to firing without swelling the particulate configuration and consequent imparting of sheer tensile forces to the particulate configuration prior to the firing thereof, comprising the steps of:

(1) mixing together predetermined amounts of particulate material and binder whereby the binder covers substantially all of the surfaces of the particles of said particulate material;
(2) forming said mixture from (1) into the desired configuration;
(3) placing said configuration in a pressure chamber and raising the temperature and total pressure throughout said chamber such that the total pressure in said chamber is above the vapor pressure at the ambient temperature within said chamber at the location of said configuration in the chamber of at least a portion of said binder material while maintaining nonequilibrium partial pressure conditions in said chamber with respect to the said portion of said binder, wherein said nonequilibrium conditions comprise maintaining the partial pressure of the binder less than the vapor pressure of the binder at said temperature, to remove said binder material from said configuration;
and
(4) sintering said stripped and formed mixture from (3).

2 more elements

Dependencies are inferred from the claim text.