Abstract: The invention provides a method for improving the effectiveness of colloidal silica. The method involves removing enough charged impurities from the colloid to prevent the charged particles from causing the colloid to become a viscous gel. The method however also involves not removing too many charged particles so the silica material doesn't gel by cross-linking with itself. This method is quite effective because it recognizes that materials that have accumulated during the formation of the colloid do perform an important function, but they can perform better at a lower concentration.

Abstract: The invention provides a method for improving the effectiveness of colloidal silica. The method involves removing enough charged impurities from the colloid to prevent the charged particles from causing the colloid to become a viscous gel. The method however also involves not removing too many charged particles so the silica material doesn't gel by cross-linking with itself. This method is quite effective because it recognizes that materials that have accumulated during the formation of the colloid do perform an important function, but they can perform better at a lower concentration.

Abstract: A filler component for making an investment casting slurry, which comprises: a major portion of finely divided silica, aluminum silicate, alumina, zircon, or mixtures thereof; and a minor portion of one or more finely divided materials having particles in which, on average, at least one dimension of the particle is at least about four times greater than at least one other dimension of the particle. Typically, the particles are of generally plate-like or needle-like shape.

Abstract: Metal oxide particle agglomerates prepared by adding an aluminum phosphate agglomerating agent with mixing to an aqueous dispersion of metal oxide nanoparticles to form an aqueous homogeneous dispersion of nanoparticles and agglomerating agent and then adjusting the pH of the dispersion with mixing to about 3.5 to about 6.5 to produce the particle agglomerates and use of the particle agglomerates to prepare ink receptive coatings, as catalysts, as reinforcing fillers, as polishing abrasives and as flattening agents.

Abstract: Investment casting binders containing a mixture of colloidal silicas having average particle size diameters of 4, 8 and 13 nanometers yield molds having high green strength and low fired strength.

Abstract: Investment casting binders containing a mixture of colloidal silicas having average particle size diameters of 4, 8 and 13 nanometers yield molds having high green strength and low fired strength.

Abstract: The strength and solids level of an investment casting shell is increased by incorporating at least one microsilica into the shell.

Abstract: Emissive compositions are described that can be applied as a coating to the surface of an investment casting mold to increase or decrease the rate of cooling of a casting within the mold. A coating that decreases the rate of cooling of an investment casting within an investment casting mold may comprise a compound having an emissivity less than the emissivity of the mold; a high temperature glass-forming material and a solvent to make a slurry. Similarly, a coating that increases the rate of cooling may comprise a compound having an emissivity greater than the emissivity of the mold; a low temperature glass-forming material and a solvent to make a slurry. Also disclosed in a method of investment casting wherein an emissive composition is applied to the investment casting mold.

Abstract: A water-based paste which is curable to a flowing glass which is made generally from boric acid, silica flour, or diatomite silica. Generally, silica flour is added for pipe sealer or diatomite-type silica for cap sealers. Optional additives are latex and Kelzan for modifying rheology and trisodium phosphate to fine control the softening point. These compositions may be utilized in standpipes and collecting mains in coke ovens. The softening point of the composition is selected so that it is compatible with the operation of the coke oven. Softening temperatures for these compositions range from about 400.degree. C. to about 750.degree. C. and the boric acid and silica components were selected with a particle size ranging from about 44-210 microns.