2024-03-19T10:18:19Zhttp://digital.csic.es/dspace-oai/requestoai:digital.csic.es:10261/1009452021-07-21T12:24:12Zcom_10261_98com_10261_3col_10261_351
2014-08-21T06:54:36Z
urn:hdl:10261/100945
Additive-free superhard B4C with ultrafine-grained dense microstructures
Moshtaghioun, Bibi Malmal
Cumbrera, F. L.
Ortiz, A.L.
Castillo-Rodríguez, Miguel
Gómez-García, D.
A unique combination of high-energy ball-milling, annealing, and spark-plasma sintering has been used to process superhard B4C ceramics with ultrafine-grained, dense microstructures from commercially available powders, without sintering additives. It was found that the ultrafine powder prepared by high-energy ball-milling is hardly at all sinterable, but that B2O3 removal by gentle annealing in Ar provides the desired sinterability. A parametric study was also conducted to elucidate the role of the temperature (1600-1800°C), time (1-9min), and heating ramp (100 or 200°C/min) in the densification and grain growth, and thus to identify optimal spark-plasma sintering conditions (i.e., 1700°C for 3min with 100°C/min) to densify completely (>98.5%) the B4C ceramics with retention of ultrafine grains (~370nm). Super-high hardness of ~38GPa without relevant loss of toughness (~3MPam1/2) was thus achieved, attributable to the smaller grain size and to the transgranular fracture mode of the B4C ceramics. © 2013 Elsevier Ltd.
2014-08-21T06:54:36Z
2014-08-21T06:54:36Z
2014
2014-08-21T06:54:36Z
artículo
Journal of the European Ceramic Society 34: 841- 848 (2014)
http://hdl.handle.net/10261/100945
10.1016/j.jeurceramsoc.2013.10.006
eng
closedAccess
Elsevier