摘要:
The process comprises forming a mixture comprised of aluminum nitride powder and free carbon wherein the aluminum nitride has a predetermined oxygen content higher than about 0.8% by weight and wherein the amount of free carbon reacts with such oxygen content to produce a deoxidized powder or compact having an oxygen content ranging from greater than about 0.35% by weight to about 1.1% by weight and which is at least 20% by weight lower than the predetermined oxygen content, heating the mixture or a compact thereof to react the carbon and oxygen producing the deoxidized aluminum nitride, and sintering a compact of the deoxidized aluminum nitride producing a ceramic body having a density greater than 85% of theoretical and a thermal conductivity greater than 0.5 W/cm.multidot.K. at 22.degree. C.
摘要:
A ceramic useful as an electrically insulating material is produced by calcinating wollastonite powder, admixing the calcined powder with phosphoric acid of certain P.sub.2 O.sub.5 concentration range, die-pressing the resulting mixture, and firing the resulting pressed piece. The ceramic is employed within arc circuit breakers as a substitute for asbestos liners, dividers and arc splitters.
摘要:
A method for minimizing the formation of a reaction layer at the metal-ceramic interface comprises doping a superalloy material with the rare earth metal whose metal cation is in the ceramic material comprising the mold and/or core used in casting and directionally solidifying the superalloy material.
摘要:
A weakly acid solution of either NH.sub.4 NO.sub.3, NH.sub.4 Cl, NH.sub.4 HSO.sub.4, CH.sub.3 COOH or equimolar CH.sub.3 COOH -- CH.sub.3 COONa is employed to remove cores of either Y.sub.2 O.sub.3 or Sm.sub.2 O.sub.3 from castings of advanced superalloy materials. A molten salt bath may be used thereafter to remove reaction products formed by the reaction of the materials of the core and the metal casting.
摘要:
A magnesium-boron composite is made by mechanically mixing magnesium powders with boron powders. An alternative embodiment includes mixing a small amount of lithium powder with the magnesium boron composite to improve the ductility. The mixed powders are processed by cold pressing, hot pressing, sintering, extruding, rolling and re-extruding.