High-temperature friction and wear of eutectic carboboride alloys of group V metals

Fabrication, microstructure and properties of in situ synthesized B4C^|^ndash;NbB2 eutectic composites by spark plasma sintering

“…Quasibinary alloys of B 4 C with Me IVV B 2 diborides are one of examples of such ceramic composite systems being widely investigated for structural applications. 7)11) Eutectic inclusions with a rodlike structure ensure an improved balance between the hardness, fracture toughness and strength of such bulk ceramic composites as compared with individual bulk ceramics.…”

“…Furthermore recent research on eutectic (B 4 CTiB 2 )B 4 C composites underlines the possibility designing multihierarchal eutectic composites using the directional solidification (DS) and sparkplasma sintering (SPS) 15), 16) . A twostep method for the production of B 4 CTiB 2 eutectic composites consisted of DS followed by milling, etching and finally consolidation by SPS.…”

“…7), 10) These findings also indicate that a proper selection of SPS parameters (Tsps, pressure, Td) allows tailoring microstructure in a composite with multilevel hierarchy. We anticipate that in situ fabrication of eutectic rods during spark-plasma sintering in other B 4 CMe IVV B 2 systems will result in additional toughening of traditionally brittle boron carbide ceramics.…”

Consolidation of B4C-TaB2 eutectic composites by spark plasma sintering

“…The differences between the observed hardness values with that reported in the literature (∼24 GPa) can be explained by the diffusion of carbon into the ceramic specimen during SPS [19,20]. Namely, carbon diffusion in TaB 2 , as suggested by Ordan'yan [5] (e.g. by means of TaC dissolving into TaB 2 lattice), is limited to a few percent, but it causes decrease in the diboride lattice (r B = 0.91Å, r C = 0.77Å) resulting in the formation of tantalum carboborides [20].…”

“…Transition-metal diborides embedded in a boron carbide matrix exhibiting good mechanical properties are considered as attractive materials for high-temperature applications [1][2][3][4][5][6][7][8]. Among such systems, B 4 C-Me V B 2 eutectic composites have not been studied as extensively as boron carbide eutectic composites of other transition-metal diborides such as B 4 C-TiB 2 and B 4 C-ZrB 2 [1][2][3][4][5]. In particular, B 4 C-TaB 2 remains largely unexplored among the B 4 C-Me IV−V B 2 composites owing to its high eutectic temperature (∼2640 K), which is only slightly lower than that for the HfB 2 eutectic with boron carbide (∼2650 K) [8].…”