Influence of processing conditions in TEOS/PDMS derived silicon oxycarbide materials. Part 1: Microstructure and properties

Thermal stability and electrical conductivity of carbon-enriched silicon oxycarbide

“…28 Lower pyrolysis temperatures lead to lower weight changes, at less than 0.2 wt% at 1200 1C and 1300 1C pyrolysis temperatures; at 1400 1C, the weight loss is up to 0.5 wt%. This means that higher pyrolysis temperature leads to less stable SiOC microstructures because of phase separation and thus more oxidation.…”

Effect of starting particle size and barium addition on flexural strength of polysiloxane-derived SiOC ceramics

“…Mazo et al 23) reported a maximal flexural strength of 153 MPa by 3-point bending in bulk SiOC ceramics processed by the conventional ceramic processing route. This is comparable to the value (142 MPa) obtained in the 48-h-milled SiOC and lower than the value (220 MPa) obtained in the 48-h-milled SiOC-Ba.…”

“…The flexural strength values of the bulk SiOC samples were 173 222 MPa when measured by the ball-on-three-balls testing methods. Recently, Mazo et al 23) successfully fabricated fully dense bulk SiOC ceramics by a conventional ceramic processing route consisting of (1) pyrolysis of tetraethylortosilicate/polydimethylsiloxane (TEOS/PDMS) hybrids, (2) attrition milling of the pyrolyzed powders, (3) mixing of the SiOC powders with 6 wt % binders (isobutyl methacrylate or PDMS), (4) uniaxial pressing of the mixed powders, (5) cold isostatic pressing of the formed body, and finally (6) sintering at 1550°C for 412 h in nitrogen atmosphere. A maximum flexural strength of 153 « 15 MPa was obtained by a 3-point bending test (a span of 20 mm) in the bulk SiOC ceramics.…”

“…However, the starting SiOC powders in the conventional ceramic processing route were as-pyrolyzed powders 22) or micron-sized powders (4.51¯m after 2-h attrition-milling). 23) There is no report on the effects of starting particle size on the flexural strength of bulk SiOC ceramics prepared by the conventional ceramic processing route. Furthermore, there is no report on the flexural strength of SiOC ceramics fabricated from submicron-size SiOC powders.…”

Structure properties relationship in silicon oxycarbide glasses obtained by spark plasma sintering

“…The weight loss associated to the ceramic conversion, partial shrinkage and the appearance of cracks and voids can be listed as some of the most common disadvantages in the fabrication of large monoliths of polymer-derived ceramics [1,2]. Several strategies have been carried out to obtain dense ceramic materials such as the incorporation of fillers [3], modification of the crosslinking conditions [4] or hot pressing techniques [5,6]. The addition of active or passive fillers are, by far, the easiest and most recurring approach to obtain pore-free ceramics but still, in many of the cases, the procedure requires high temperature and long annealing times with the subsequent risk of partial crystallization of the contained phases [2,7].…”