Publications by Year: 1986

1986
Gallagher, D. ; Cesarano, J. ; Aksay, I. A. SURFACTANT-SOLVENT EFFECTS IN DISPERSED CERAMIC SYSTEMS. Abstracts of Papers of the American Chemical SocietyAbstracts of Papers of the American Chemical Society 1986, 191, 223-COLL.
Halverson, D. C. ; Pyzik, A. J. ; Aksay, I. A. Boron-carbide-aluminum and boron-carbide-reactive metal cermets, 1986.Abstract
Cermets based on a ternary system with B, C, and a reactive metal are manufd. with controlled structures having ≥1 ceramic phases distributed in an alloy matrix. A starting compn. as well as reaction temp., time, and atm. are selected for controlling the manufg. process and final structures, with emphasis on initial powder consolidation, early melt wetting, and final sintering. Surfactant selection is considered for obtaining a uniform blend of initial feed powders having particle size of ≤5 μ. Thus, powd. B4C (av. size 5 μ) 80 and Al 20 vol.% were mixed in EtOH by using an ultrasonic probe, and slip cast in a mold from plaster of Paris for dewatering. The powder mixt. removed from the mold was pressed at 10,000 psi and room temp. Pellet preforms were heated in 10 min to 1050° in a furnace, and then sintered at 800° for 24 h. The final composite contained an unknown Al-rich phase 34, B4C 32, AlB2 23, Al 5, α-AlB12 3, Al4C3 2, and AlB12C2 1 vol.%. The unknown phase showed crystallog. structure intermediate between hexagonal and rhombohedral. Cermet products of this type showed bend strength >110 kpsi and fracture toughness 12 kpsi-in.0.5, with the latter exceeding the value of ∼4 for conventional Al2O3-B4C composites. [on SciFinder(R)]