| Abstract Scope |
Low pressure/high temperature (LPHT) methods such as reaction bonding are attractive for fabricating large lower-cost diamond-ceramic composites for structural, wear, and thermal management applications. As further exploration of LPHT methods, an initial study on the effects of diamond content and modality on the densification of diamond-SiB6 powder mixtures by hot-pressing are reported. Guided by a particulate percolation threshold model, for a given diamond content, diamond powders of two-to-three different particle sizes in several relative proportions were acoustically wet mixed with SiB6 powder. After drying, powders were hot-pressed at 1600oC for 60-120 mins under flowing high-purity Ar and 48 MPa. An LVDT recorded ram displacement from which densification history was determined. The resulting densities, phases, microstructures were determined. As expected, for complete densification, the maximum diamond content was higher for multi-modal particulate size distributions but strongly dependent on relative proportions. Further findings and experimental procedures will be discussed. |