Atomistic Green-Kubo simulations are performed to evaluate the lattice thermal conductivity for single crystals of the ultra high temperature ceramics ZrB2 and HfB2 for a range of temperatures. Recently developed interatomic potentials are used for these simulations. Heat current correlation functions show rapid oscillations which can be identified with mixed metal-Boron optical phonon modes. A...

A powder metallurgy route combining high-energy ball-milling (HEBM) of elemental powders and reactive spark-plasma sintering (SPS) is proposed for the controlled fabrication novel composites based on a Zr–Al intermetallic matrix hardened with ceramic second-phase. As proof-of-concept, its suitability demonstrated ZrB2–hardened Zr3Al2. Specifically, commercially available ZrH2, Al, B were first ...

The focus of the present work is investigation influence polymer-derived ceramics, used as sintering aids for preparing ZrB2-based monoliths, on their high-temperature oxidation behavior. For preparation ZrB2 powder was coated with SiCN, SiZrCN, or SiZrBCN and subsequently densified via hot-pressing at temperatures low 1800°C. To investigate kinetics, thermogravimetric analysis (TGA) performed ...

The incorporation of 1 wt% hexagonal BN (hBN) into ZrB2–30 vol% SiC could noticeably better the fracture toughness, hardness, and consolidation behavior this composite. This research intended to scrutinize effects various amounts hBN (0–5 wt%) on different characteristics ZrB2–SiC materials. hot-pressing method under 10 MPa at 1900 °C for 120 min was employed sinter all designed specimens. Afte...

The effect of SiC content, additives, and process parameters on densification and microstructural properties of pressureless sintered ZrB2– (1–10 wt %) SiC particulate composites have been studied. The ZrB2–SiC composite powders mixed by Spex mixer with 1-2wt% C (added as graphite powder) and CMC have been cold-compacted and sintered in argon environment in the temperature range of 1800–2100ºC ...

storage of hydrogen is one of the key challenges in developing hydrogen economy. magnesium hydride (mgh2) is an attractive candidate for solid-state hydrogen storage for on-board applications. in this study, 10 wt.% zrb2 was co-milled with magnesium hydride at different milling times to produce nanocrystalline composite powder. the effect of milling time and additive on the hydrogen desorption ...