Stoichiometric hydroxyapatite (HAp) nanoparticles were prepared by the solution-precipitation method at 37 °C. During the 72-h maturation period, the Ca/P molar ratio first rapidly increased to >1.6, and then reached 1.67 relatively slowly. The crystallite sizes of the stoichiometric HAp nanoparticles were estimated to be 11.0(3) and 25.7(3) nm from 300 and 002 diffractions, respectively. The crystallite size in the [001] direction continued to increase after the 72-h maturation period at a constant Ca/P molar ratio of 1.67. The obtained stoichiometric HAp nanoparticles also exhibited higher thermal stability than commercially available HAP-100 and prevented grain growth during sintering. This material is suitable for use in various sintering methods.

A dual-phase membrane composed of an oxide ionic conducting ceramic phase [8 mol % yttria-stabilized zirconia (8YSZ)] and electronic conducting metal phase [316L stainless steel (SS)] was fabricated for an oxygen separation application. A sintering process called spark plasma sintering (SPS) or pulsed electric current sintering (PECS) was chosen as the means to densify the 8YSZ phase below the melting point of the SS phase. The SS content was varied from 15 vol % to 55 vol % to achieve a percolation structure for obtain the oxygen transport activity. Silver paste was applied to both sides of the membrane to act as a catalyst to improve the oxygen exchange rate. In this research study, a free-standing dense 8YSZ-SS dual-phase membrane with a thickness of 0.5 mm was fabricated by SPS at 1200 °C and the applied pressure of 80 MPa in 10 min. The 8YSZ-SS45 vol % dual-phase membrane achieved a good percolation structure of the 8YSZ and SS phases. By applying silver paste, 8YSZ-SS45 vol % dual-phase membrane exhibited the reasonably good oxygen permeation flux of 1.38 ml (STP)/min·cm² at 900 °C.

Usually, the synthetic process of tantalum carbide (TaC) by using tantalum dioxide as tantalum source require high reaction temperature (above 1300 °C). In this study, TaC nanoparticles have been synthesized in large scale through a one-step autoclave route by the reaction of tantalum pentoxide, tin oxalate and metallic lithium at 700 °C. The X-ray powder diffraction pattern reveals the obtained product was cubic TaC with lattice constant of a = 4.439 Å. Scanning electron microscope images show the obtained TaC product are composed of particles with an average size of about 50 nm. Furthermore, the oxidation resistance of the obtained TaC has been investigated.