Abstract: Compound preforms are provided having a first region, including a porous ceramic and a second region including a porous or solid ceramic in which the two regions differ in composition. The compound preform is infiltrated with a liquid metal which is then solidified to form a metal matrix composite.

Abstract: Dense metal vias in pure alumina substrates are derived from a metallization composition having 80-97% refractory metal, 2-15% alumina, 0.05-5% sintering aid, and 0-5% bonding additive; it has been found that for alumina contents greater than about 12%, a bonding additive is not required. The same compositions, absent the sintering aid, can be used to form bimetallic vias; these vias include a porous metal network where the pores are infiltrated with another metal, for example, porous tungsten infiltrated with copper.

Abstract: An improved method and system are provided for centrifugally separating a suspended colloidal phase. The method in accordance with a preferred embodiment of the invention involves filling a spinning centrifuge bowl with a fluid medium distinct from the suspension, so that a static zone of liquid forms in the bowl, and then introducing the suspension into the bowl in a feed location concentrically inside of the static zone.

Abstract: Slurries or suspensions for forming sintered ceramic or metallic articles are described as having a high volume fraction of sinterable particles, at least 55% by volume. while the slurries maintain a pourable viscosity, such as not more that 2000 cPs at 100 s.sup.-1 ; the slurries can be dilatant and/or pseudoplastic. The slurries are prepared by using specific families of dispersants; namely acrylic acid-based polymeric polyelectrolytes, polyethylene imine-based polyelectrolytes, and coupling agents from the subfamilies of oxy-silane esters and phosphate esters. Fabrication of the compositions includes milling under high energy and the addition of at least a portion of the particles in a step-wise manner.

Abstract: Bonding additives for refractory metallization compositions allow for circuit traces having good resistivities and adhesion values in excess of 6 kpsi, generally between about 10 and 20 kpsi. The inks are provided in formulations devoid of a glass component, and are suitable for co-sintering circuit traces and vias with 96% alumina substrates, and especially for 99% alumina substrates. Suitable bonding additives are the oxides of molybdenum, tungsten, niobium, manganese, yttrium, and titanium, or mixtures of such oxides.

Abstract: Removal of classified particles from the classifier apparatus is simplified by the addition of a polymeric dispersant in the slurry, added in an amount substantially in excess of that needed to disperse the particles.

Abstract: A highly loaded, uniform ceramic composite can be made by first preparing a highly loaded suspension. Due to the particle-particle interactions of a highly concentrated system, virtually any dopant can be added, including other suspensions, fibers, and whiskers. The process is particularly useful for making composites of materials which coagulate when mixed at low concentration.

Abstract: Glass-ceramic packages for integrated circuits containing multi-layer, interconnected thick film wiring patterns are obtained by co-sintering a glass-ceramic composite and copper, silver, palladium, gold, based conductors at temperatures not exceeding about 1000.degree. C. The dielectric systems include composites of borosilicate glasses and crystalline fillers which are fabricated by either mixing glass frit and the filler or by a sol-gel coating process. The package is fabricated using a tape specifically designed for clean binder burnout in a reducing atmosphere at low temperatures and also for superior mechanical and thermal properties. Metallization, applied by the thick film screening technique, utilized herein has glass-ceramic bonding agents designed to promote adhesion yet maintain the desired electrical properties and post-processing characteristics.

Abstract: Substrates consisting of at least 98% narrow size distribution ceramic particles are co-sinterable with metallized paste to which selected compositions of glass have been added. Substrates produced in accordance with the present invention exhibit superior thermal conductivity, low shrinkage variability, and smoother and more homogeneous surface finish.