Effect of whisker surface treatment on the mechanical properties of 20vol%SiCw/BAS glass-ceramic composites

20vol%SiCw/BAS (barium aluminosilicate) composites with as-received, acid-l eached and heat-treated whiskers were fabricated by a hot-pressing techniqu e and their mechanical properties were evaluated. The whiskers used in thes e composites were characterized using Auger electron spectrometry (AES) and scanning electron microscopy (SEM), and the observations were correlated w ith the mechanical properties. The results show that the oxygen content of the whisker surfaces was reduced by the hydrogen fluoride (HF) acid-leachin g treatment and the surface geometry of whiskers was smoothed by the heat-t reatment in an inert gas atmosphere. The corresponding composites show an o bvious increase (18% and 31%, respectively) in toughness compared with the composites reinforced with as-received whiskers. Fracture surfaces revealed evidence of toughening by the mechanisms of crack deflection, crack bridgi ng and whisker pullout for the composites with surface treated whiskers. (C ) 2001 Kluwer Academic Publishers.