Abstract: Silicon carbide sintered bodies having controlled porosity in the range of about 2 to 12 vol %. in which the pores are generally spherical and about 50 to 500 microns in diameter, are prepared from raw batches containing a polymer fugitive. Sintered bodies in the form of mechanical seal members exhibit lower power consumption at low PV and, in addition, lower wear rates at high PV in comparison to commercially available silicon carbide seal members.

Abstract: A silicon nitride ceramic comprising:a) inclusions no greater than 25 microns in length,b) agglomerates no greater than 20 microns in diameter, andc) a surface finish of less than about 8 microinches, said ceramic having a four-point flexural strength of at least about 900 MPa.

Abstract: A ceramic igniter comprising: a) a lead wire, b) a ceramic substrate, and c) a braze pad having a thickness of less than about 150 microns, wherein the lead wire and ceramic substrate are placed in electrical connection by the braze pad.

Abstract: There is provided a sidewall lining for use in an electrolytic reduction cell for the production of aluminum by reduction of alumina in a molten fluroide electrolyte, the lining consisting essentially of a ceramic material having a density of at least 95% of theoretical density and at least closed porosity, the ceramic material selected from the group consisting of silicon carbide, silicon nitride and boron carbide.

Abstract: A sintered silicon nitride ceramic comprising between about 0.6 mol % and about 3.2 mol % rare earth as rare earth oxide, and between about 85 w/o and about 95 w/o beta silicon nitride grains, wherein at least about 20% of the beta silicon nitride grains have a thickness of greater than about 1 micron.

Abstract: A hydrogen torch comprising concentric inner and outer fluid delivery tubes wherein the outer tube comprises silica and the inner tube comprises silicon carbide. One end of the inner tube is connected to a third tube comprised of silica which has an inlet in fluid connection with a hydrogen supply line. The outer tube is in fluid connection with an oxygen supply line. A reverse ball joint connection is used to join the tubes and defines an annulus between the inner and outer tubes through which the oxygen can flow and be isolated from the hydrogen flowing within the inner tube.

Abstract: This invention relates a high density green bodies, particularly high density silicon nitride spherical green bodies having substantially no radial density gradients.

Abstract: A sintered silicon nitride ceramic comprising between about 0.6 mol % and about 3.2 mol % rare earth as rare earth oxide, and between about 85 w/o and about 95 w/o beta silicon nitride grains, wherein at least about 20% of the beta silicon nitride grains have a thickness of greater than about 1 micron.

Abstract: An annular seal for use in a heat exchanger connection comprising a tube and at least one annular seal, wherein the annular seal is compression seated upon the outside diameter of the tube.

Abstract: A ceramic material comprising:(a) between about 50 and about 80 v/o of an electrically insulating ceramic having a resistivity of at least about 10 E+10 ohm-cm;(b) between about 10 and about 45 v/o of a semiconductive material having a resistivity of between about 1 and about 10 E+8 ohm-cm;(c) between about 5 and about 25 v/o of a metallic conductor having a resistivity of less than about 10 E-2 ohm-cm; and(d) between about 0.5 and about 20 v/o of a resistivity-enhancing compound selected from the group consisting of metallic oxides, metallic oxynitrides, rare earth oxides, rare earth oxynitrides, and mixtures thereof.

Abstract: This invention relates to a sintered silicon nitride ceramic comprising samaria and ytterbia for enhanced toughness.

Abstract: A ceramic comprising:a) between 20 w/o and 90 w/o unnecked composite grains comprising:i) between 5 w/o and 100 w/o silicon nitride, andii)between 0 w/o and 95 w/o free silicon,said composite grains having lengths of at least 50 microns and widths of at least 10 microns, andb) between 10 w/o and 80 w/o matrix grains having lengths of less than 20 microns.

Abstract: A sintered silicon nitride ceramic having an L10 value of at least 50 million stress cycles in ASTM test STP 771 under 6.9 GPa applied contact stress.

Abstract: A glass embedded, sintered ceramic comprising a total sintering aid concentration of between about 1 and about 5 w/o, said ceramic having a reaction layer of less than about 750 microns, where the reaction layer is defined as the depth at which the sintering aid concentration is 80% of that of the bulk of the ceramic, and the ceramic is selected from the group consisting of silicon nitride, silicon carbide, boron carbide, titanium diboride, and aluminum nitride.

Abstract: This invention relates to a refractory lining for use in a coreless induction furnace having a refractory crucible, wherein the refractory lining lines the inner surface of the refractory crucible and has a porosity of between 0.2% and 1%.

Abstract: This invention is directed to a novel borosilicate glass for use in glass hipping consisting essentially of:a) boron oxide,b) silica,c) between about 2 w/o and about 6 w/o K.sub.2 O,d) less than about 1 w/o Na.sub.2 O, ande) between about 3.6 w/o and about 5.4 w/o magnesia.

Abstract: A process for drip casting silicon nitride slurries.

Abstract: A method of making shaped, gelled bodies, comprising: (1) producing a mixture comprising a first liquid, a granular substance or precursor thereof, and a gelation compound which quickly gels at a gelation temperature, and (2) introducing portions of the mixture into a first fluid in which the first liquid is immiscible, said first fluid having a temperature of about the gelation temperature, thereby causing the portions to take on a shape and then gel to form shaped, gelled bodies.

Abstract: Components for semiconductor diffusion furnaces are constructed of a high purity impervious silicon carbide or silicon nitride matrix deposited onto and within a pre-shaped fibrous matrix of silicon carbide or silicon nitride which contains sufficient nucleation aids to produce a structure having a density greater than about 85% of theoretical density. The impregnation of the matrix material into the fibrous reinforcement prevents undesired gaseous components from contaminating the atmosphere of the furnace, and the fibrous reinforcement provides strength combined with light weight.

Abstract: A sheet transporting apparatus, for transporting a sheet from a sheet supplying device to a sheet supplied device, includes a transporting path, through which the sheet is transported, and a plurality of driving rollers disposed along the transporting path. The plurality of driving rollers are adapted to independently rotate so as to transport the sheet through the transporting path by sequentially rotating in a prescribed manner based on a position of the transported sheet. The sheet transporting apparatus also includes a coupling device for selectively coupling and decoupling the driving rollers to each other. The sheet transporting apparatus further includes a device, such as a knob, for rotating one of the driving rollers.