Co-Al2O3 nanocomposites powder prepared by electroless plating

In this paper, a new type of Co-Al2O3 nanocomposites powder prepared by electroless plating technique will be introduced. The raw Al2O3 nanoparticles are 10-20 urn in diameter. The Co plating was carried out at middle temperature (45-50 degreesC) with application of ultrasonic radiation. Plating rate was determined by measuring the weight gain of powder after plating. High-resolution transmission electron microscopy (HRTEM) reveals that Co-Al2O3 nanocomposites particles is of nearly sphere-like shape and is about 50-60 mn in diameter. Xray diffraction (XRD) indicates that the chemical composition of plating layer is Co-P alloy. The phase structure is different when the reductant content changed. Co-P alloy was found to be amorphous in as-plating Co-Al2O3 powder and was transformed into a crystalline phase after sintering. Differential scanning calorimeter (DSC) analysis proves that such a phase transformation occurs at 203-253 degreesC. Different Co-P content was obtained by changing the Al2O3 load. (C) 2003 Elsevier B.V. All rights reserved.