Stability of alumina ceramics bonded with nanoscaled alumina powder

Nanoscaled alumina particles were employed for bonding of commerical coarse -grained corundum ceramics. The nanopowder was generated by ablation of sol id corundum samples with the pulsed radiation of a Nd:YAG-laser and subsequ ent condensation of the vapor in a controlled atmosphere. Some of the nanop owder was sandwiched between corundum discs followed by uniaxially hot pres sing of the assembly in vacuum at various pressures up to 80 MPa and temper atures up to 1300 degrees C. Some of these specimens were additionally sint ered in air at 1500 degrees C without load In order to determine the struct ure and the strength of the sample joints HR-SEM investigations and four-po int bending tests were carried our. (C) 1999 Acta Metallurgica Inc.