Abstract: A process for forming a silicon nitride-bonded silicon carbide honeycomb monolith by a) forming a plasticizable mixture which includes (1) about 60% to 85% by weight, powdered silicon carbide with a median particle size of about 10-40 micrometers; (2) about 15% to 40% by weight, powdered silicon metal with a median particle size of about 5-20 micrometers; and, (3) organic components; b) extruding the plasticizable mixture to form a green honeycomb monolith; c) drying the green honeycomb monolith; and, d) heating the honeycomb monolith to 1450° C. with a hold of 1 hour in an atmosphere of argon; and, e) nitriding the honeycomb monolith between 1450° C. to 1600° C. for a time sufficient to obtain a silicon nitride-bonded silicon carbide body.

Abstract: A process for forming a silicon nitride-bonded silicon carbide honeycomb monolith by a) forming a plasticizable mixture which includes (1) about 60% to 85% by weight, powdered silicon carbide with a median particle size of about 10-40 micrometers; (2) about 15% to 40% by weight, powdered silicon metal with a median particle size of about 5-20 micrometers; and, (3) organic components; b) extruding the plasticizable mixture to form a green honeycomb monolith; c) drying the green honeycomb monolith; and, d) heating the honeycomb monolith to 1450° C. with a hold of 1 hour in an atmosphere of argon; and, e) nitriding the honeycomb monolith between 1450° C. to 1600° C. for a time sufficient to obtain a silicon nitride-bonded silicon carbide body.

Abstract: Refractory materials are provided which contain P2O5/R2O3 constituents, where R is Y, Sc, Er, Lu, Yb, Tm, Ho, Dy, Tb, Gd, or a combination thereof, and/or V2O5/R?2O3 constituents where R? is Y, Sc, one or more rare earth elements, or a combination thereof. In certain embodiments, the refractory materials are xenotime-type materials and/or xenotime-stabilized zircon-type materials. The refractory materials can be used in the manufacture of glass and glass-ceramics. For example, the refractory materials, especially those that contain P2O5/R2O3 constituents, can be used as forming structures (“isopipes”) in the fusion process for making flat sheets of glass such as the glass sheets used as substrates in the manufacture of flat panel displays.