title: Fabrication and characterization of aluminum nitride/boron nitride nanocomposites by carbothermal reduction and nitridation of aluminum borate powders.
abstract: In order to fabricate aluminum nitride/boron nitride (AIN/BN) nanocomposites by pressureless sintering, the present study investigated the synthesis of AIN-BN nanocomposite powders by carbothermal reduction and nitridation of aluminum borate powders. Homogeneous mixtures of alumina (Al2O3), boric acid (H3BO3), and carbon powder were used to synthesize AIN/BN nanocomposite powders containing 10 and 20 vol% BN. Aluminum borate was produced by reacting Al2O3 and B2O3 above 800 degrees C, and AIN and turbostratic BN (t-BN) were produced by reacting aluminum borate with carbon powder and nitrogen gas at 1500 degrees C. Carbothermal reduction followed by nitridation yielded an AIN/BN nanocomposite powder composed of nanosized AIN and t-BN. By pressureless sintering nanocomposite AIN/BN powders containing 5 wt% Y22O3, AIN/BN nanocomposites were obtained without compromising the high thermal conductivity and high hardness.
authors.affiliation: The Institute of Scientific and Industrial Research, Osaka University, Ibaraki, Osaka 567-0047, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Kusunose
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Sakayanagi
authors.forename: Tohru
authors.initials: T
authors.lastname: Sekino
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Ando
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry*; D001896:Boron Compounds / Q000737:chemistry*; D002244:Carbon / Q000737:chemistry; D003460:Crystallization / Q000379:methods*; D006244:Hardness; D006358:Hot Temperature; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010084:Oxidation-Reduction; D010316:Particle Size; D011208:Powders; D013499:Surface Properties; D013814:Thermal Conductivity
chemical_list: D017607:Aluminum Compounds; D001896:Boron Compounds; D046911:Macromolecular Substances; D011208:Powders; C405266:aluminum boride; C017282:boron nitride; D002244:Carbon; C052045:aluminum nitride