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Thirty biporous slugs with 3 different cluster diameters and 5 different particle diameters (15 combinations with 2 repetitions) and 12 monoporous slugs with 6 different particle diameters were sintered from spherical copper powder, and thermophysical properties were measured. The neck size ratio for all the particles was approximately 0.4. The porosity of monoporous samples was found to be independent of particle diameter and was equal to 0.28, and the porosity of biporous samples was found to be independent of cluster and particle diameters, and was equal to 0.64. The liquid permeability and maximum capillary pressure of small pores were found to be a linear function of the particle diameter. Similarly, vapor permeability was found to be a linear function of the cluster diameter. The thermal conductivity of monoporous samples was measured to be 142±3W∕mK at 42±2°C, and it was independent of particle diameter. The thermal conductivity of biporous samples was found to be a function of cluster to particle diameter ratio.

Thermophysical properties of monodispersed-sintered copper are measured. An apparatus to measure effective thermal conductivity of dry and wet samples is built. It is calibrated using bulk samples with known thermal conductivity. Permeability is measured based on flow resistance though the porous samples. Velocity at different pressure drops is measured and the permeability calculated using Darcy’s law. The experiment is performed using water and silicone oil as working liquids. The error of the measurement is less then five percent. Capillary pressure for all samples is measured based on amount of liquid that is held by the porous sample. The Young-Laplace relationship is used to relate capillary pressure to effective pore radius. Porosity of the samples is calculated by measuring the dimension of samples and weighing the amount of liquid in fully saturated samples. Thermal conductivity and capillary pressure are found to decrease as powder diameter increases; permeability and porosity increases with powder diameter.

High‐energy shaker milling of hexagonal boron nitride (hBN) powders was used to produce powders rich in sp3 bonding. The powders contained up to 68% sp3 bonding and were found to nucleate nanosize cBN grains during consolidation at 5.5 GPa and 1400°C. The effect of hBN starting particle size, milling time, and powder‐to‐milling ball ratio were studied. The amount of sp3 bonding for milled hBN powders was determined, using 11B solid‐state NMR. The milled material was also analyzed by XRD, Raman spectroscopy, and HRTEM. The results indicate that the material has a nanosized microstructure comprised of a disordered hBN matrix and cBN nuclei in the form of sp3‐rich domains. Eight different milled powders were produced and consolidated at pressures of either 5.5 or 6.5 GPa and temperatures of either 1400°C or 1450°C into 12 mm diameter and 5 mm thick pellets. Consolidated pellets formed from milled hBN with 68% sp3 bonding had Vickers hardness of 42 ± 1 GPa and fracture toughness 3.8 ± 0.1 MPa.m1/2. Vickers hardness of 49 ± 1 GPa and fracture toughness of 4.6 ± 0.1 MPa.m1/2 was achieved with a precursor that contained milled hBN and 50 vol. % of 0.5 μm diameter cBN crystals.