摘要 |
A method for heat processing of multilayered ceramic articles containing internal conductive metal patterns that have been formed from multiple ceramic green sheets individually coated with inks or pastes containing conductor metal/metal oxide material, and thereafter assembled in registry with each other and laminated. The heat treating method to convert the laminate to the final ceramic article comprises a first heating stage under conditions to promote burn-out of the organic polymeric binder present, a second stage performed under conditions to reduce the metallic conductor, and a third stage to sinter the multilayered composite to form the final ceramic article. The invention is characterized by the presence of moisture in an amount of from about 0.5% to about 3% of the gaseous atmosphere in at least the sintering stage, and preferably at both the binder burnout stage and the sintering stage. Multilayered articles heat treated under these conditions exhibit a combination of improved properties, including little or no staining in combination with improved conductivity and dielectric properties. In a preferred embodiment, the present method may be performed as a continuous process without the need for cool-down and heat-up of the laminate, in a continuous furnace with an atmosphere that is microprocessor-controlled. Optional catalytic generation of the moisture containing heating atmosphere may be utilized to further reduce cost and processing time while increasing process efficiency and productivity.
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