Abstract: This disclosure relates to an electrically insulating filler for sheathed heaters. The filler includes globular and nonglobular particles containing at least 95 wt. % MgO, and the percentage of globular particles being at least 5 wt. %. The globular magnesia includes at least one single magnesia or a combination of magnesias selected from groups of sintered magnesias and electro-fused magnesias.

Abstract: Flame spraying compositions exhibiting improved adherence to a variety of substrates are disclosed, as well as articles coated with such compositions. The spraying compositions comprise a granulated mixture of two components: (1) a powdery material selected from the group consisting of powdered metals, heat resistant ceramics, cermets, and resins; and, (2) a ceramic needle fiber such as whisker crystals of SiC or Si.sub.3 N.sub.4. Articles coated with thin films of these coatings exhibit increased thermal and corrosion resistance.

Abstract: A method of manufacturing silicon carbide crystals in which a rice husk raw material is pretreated with an acid solution (e.g., 5N to 6N H.sub.2 SO.sub.4, HCl or HNO.sub.3) prior to being heated in a furnace of non-oxidizing atmosphere. Pretreatment of the rice husks in this manner results in silicon carbide crystals of high purity.

Abstract: A method of manufacturing silicon nitride whiskers in which a carbon and silicon containing material having a thin configuration and sufficient porosity to permit both the passage of a gas therethrough and to provide spaces for growing whiskers therein is charged on a gas-permeable tray, and heated in a furnace of non-oxidizing atmosphere. The tray is moved intermittently through a series of temperature zones, increasing stage-by-stage from about 400.degree. C. to 1,300.degree. C., while a non-oxidizing gas is circulated through the porous material to remove any impurities. Thereafter, the heated tray is intermittently moved through a series of increasing temperature stages from about 1,350.degree. C. to 1,450.degree. C. in the presence of a flow of nitrogen gas to effect whisker growth. The heat-treated silicon nitride-containing material is dispersed in a two-phase mixture of a hydrophobic organic liquid and water. The desired silicon nitride whiskers can be isolated from the aqueous phase.

Abstract: A method of manufacturing silicon carbide whiskers in which a carbon and silicon containing material having a thin configuration and sufficient porosity to permit both the passage of a gas therethrough and to provide spaces for growing whiskers therein is charged on a gas-permeable tray, and heated in a furnace of non-oxidizing atmosphere. The tray is moved intermittently through a series of temperature zones, increasing stage-by-stage from about 400.degree. C. to 1,300.degree. C., while a non-oxidizing gas is circulated through the porous material to remove any impurities. Thereafter, the heated tray is intermittently moved through a series of increasing temperature stages from about 1,350.degree. C. to 1,450.degree. C. to effect whisker growth. The treated silicon carbide-containing material is dispersed in a two-phase mixture of a hydrophobic organic liquid and water. The desired silicon carbide whiskers can be isolated from the aqueous phase.