Electrical, thermal and mechanical properties of silicon carbide–silicon nitride composites sintered with yttria and scandia

Tribological Behavior of Silicon Carbide Ceramics - A Review

“…Hardness and fracture toughness of SiC ceramics are reported to generally range from 16 GPa to 27 GPa, and 2.3 MPa.m ½ to 8.3 MPa.m ½ , respectively based on types of sintering/additives, microstructure etc. 49,51,[77][78][79][80] Particularly, the influence of hardness and fracture toughness on friction and wear behavior was debated in most of the reports.…”

Mechanical properties of silicon carbide—in situ zirconium carbonitride composites

“…For example, the strength of 647 MPa for monolithic SiC was improved to 1020 MPa for SiC–35 wt% Si 3 N 4 upon sintering with a 10 wt% Y–Mg–Si–Al–ON glass . Similarly, Shaoming et al and Yeom et al reported high strength values of 810 and 720 MPa for SiC–25 vol% Si 3 N 4 with 3 wt% Y 2 O 3 –La 2 O 3 and SiC–35 vol% Si 3 N 4 with 2 vol% equimolar Y 2 O 3 –Sc 2 O 3 , respectively, which were attributed to grain refinement, reduction in flaw size, and increase in fracture toughness upon Si 3 N 4 addition. Among the group‐13 nitrides, BN addition (≤5 vol%) leads to improved strengths of in situ SiC–BN composites, whereas for the powder‐processed SiC–BN composites, a monotonic decrease in strength is observed with the BN addition owing to the intrinsic weakness of BN grains .…”

“…Silicon carbide (SiC) is an essential material for various industrial applications owing to its high thermal conductivity, high mechanical strength, and superior wear, oxidation, and corrosion resistances . In order to expand the applicability of SiC, extensive studies have been performed on the development of SiC‐based composites.…”

“…For example, the monolithic strengths increased from 620 to 750 and 616 to 921 MPa for SiC–30 wt% TiC and SiC–40 vol% TiN, respectively. Generally, particulate addition improves the fracture toughness owing to favorable residual thermal stresses, crack bridging, crack deflection, etc In particular, in the case of a β‐Si 3 N 4 ‐reinforced SiC composite, the acicular morphology of β‐Si 3 N 4 grains contributes favorably to the increase in fracture toughness by crack deflection and crack bridging. For example, an improved fracture toughness of ~7 MPa·m 1/2 was obtained for SiC–35 vol% Si 3 N 4 , whereas the toughness value of monolithic SiC was ~4 MPa·m 1/2 .…”

“…Generally, particulate addition improves the fracture toughness owing to favorable residual thermal stresses, crack bridging, crack deflection, etc In particular, in the case of a β‐Si 3 N 4 ‐reinforced SiC composite, the acicular morphology of β‐Si 3 N 4 grains contributes favorably to the increase in fracture toughness by crack deflection and crack bridging. For example, an improved fracture toughness of ~7 MPa·m 1/2 was obtained for SiC–35 vol% Si 3 N 4 , whereas the toughness value of monolithic SiC was ~4 MPa·m 1/2 . In case of nonacicular particulate phases, the major factor for the increased toughness is the residual thermal stresses emerging owing to the mismatch in coefficient of thermal expansion (CTE) between SiC and particulate phases, leading to an enhanced crack deflection …”