Abstract: A method of forming substantially spherical ceramic beads that includes conveying an aqueous ceramic slurry to a nozzle tip that is immersed in an inert water-immiscible fluid layer. The nozzle tip is spaced a predetermined distance away from a rotating disk that is also immersed in the immiscible fluid layer. The rotating disk creates a shear force that at the nozzle tip that dislodges droplets of the aqueous ceramic slurry from the nozzle tip into the immiscible fluid layer. Once dislodged, the droplets assume a substantially spherical shape and a substantially mono-modal size distribution. The droplets are permitted to pass from the immiscible fluid layer into an aqueous gelling solution wherein the droplets are converted into rigid beads. In a preferred embodiment of the invention, the rigid beads are recovered from the gelling solution, washed, and then sintered to obtain a density of greater than about 98% of theoretical density and a sphericity of greater than about 0.95.

Abstract: A method of forming substantially spherical ceramic beads that includes conveying an aqueous ceramic slurry to a nozzle tip that is immersed in an inert water-immiscible fluid layer. The nozzle tip is spaced a predetermined distance away from a rotating disk that is also immersed in the immiscible fluid layer. The rotating disk creates a shear force that at the nozzle tip that dislodges droplets of the aqueous ceramic slurry from the nozzle tip into the immiscible fluid layer. Once dislodged, the droplets assume a substantially spherical shape and a substantially mono-modal size distribution. The droplets are permitted to pass from the immiscible fluid layer into an aqueous gelling solution wherein the droplets are converted into rigid beads. In a preferred embodiment of the invention, the rigid beads are recovered from the gelling solution, washed, and then sintered to obtain a density of greater than about 98% of theoretical density and a sphericity of greater than about 0.95.

Abstract: A porous refractory product suitable for use in filtering high temperature combustion products. The product includes a matrix of recrystallized silicon carbide formed by heating a cast preform containing relatively coarse silicon carbide crystals selected to produce the desired permeability, and relatively fine silicon carbide crystals to a temperature of at least 2320° C. At this temperature, the relatively fine silicon carbide crystals sublime and condense on the relatively large crystals. This results in recrystallization of the cast preform to form the porous matrix with the desired permeability.

Abstract: A low dielectric, low temperature fired glass ceramic produced by firing at about 800.degree.-900.degree. C. a mixture comprising at least one glass consisting of, by weight percent, 0 to 50% B.sub.2 O.sub.3, 35 to 65% CaO, and 10 to 65% SiO.sub.2, and selected from the glasses of CaO-B.sub.2 O.sub.3 -SiO.sub.2 glass system. The glass ceramic is light weight, exhibits a dielectric constant of less than about 7.9, has adequate mechanical strength and thermal conductivity, and is compatible with precious metal conductors. The glass ceramic is useful in the manufacture of integrated circuits and any other electronic or mechanical components where a glass ceramic exhibiting this particular combination of characteristics is suitable.

Abstract: A low dielectric, low temperature fired glass ceramic produced by firing at about 800.degree.-950.degree. C. a mixture comprising at least one glass consisting of, by weight percent, 0 to 50% B.sub.2 O.sub.3, 35 to 65% CaO, and 10 to 65% SiO.sub.2 l , and selected from the glasses of CaO-B.sub.2 O.sub.3 -SiO.sub.2 glass system. The glass ceramic is light weight, exhibits a dielectric constant of less than about 5.2, has adequate mechanical strength and thermal conductivity, and is compatible with precious metal conductors. The glass ceramic is useful in the manufacture of integrated circuits and any other electronic or mechanical components where a glass ceramic exhibiting this particular combination of characteristics is suitable.