Microstructure and mechanical properties of ZrB2-SiC composites

Significance of hot pressing parameters and reinforcement size on sinterability and mechanical properties of ZrB2–25vol% SiC UHTCs

“…The optimal qualifications of the processing variables based on the main effects plots and ANOVA are 1850 1C temperature, 90 min holding time, 16 MPa applied pressure and 200 nm particle size of SiC. The predicted value of the bulk density for the optimum processing conditions and contribution contents of variables are listed in Table 3.…”

“…In another paper, ZrB 2 -SiC ceramic composites, which were fabricated by ZrB 2 powder (2 μm) containing 20 vol% nanosized β-SiC particles (30 nm), were densified at 1900 1 C for 30 min under a pressure of 30 MPa by hot pressing. It was indicated that the grain growth of ZrB 2 matrix was impressively graveled by adding submicron SiC particles, and the mechanical properties were strongly improved by incorporating the nanosized SiC particles as a fracture toughness of 6.4 MPa m 1/2 was obtained [16].…”

Toward Oxidation-Resistant ZrB2-SiC Ultra High Temperature Ceramics

“…Hot Pressing Hot pressing is the conventional method for fabricating UHTCs and has been used extensively, [8][9][10]12,16,17,20,22,27,33,35,39,47,48,[50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65] with typical temperatures of~2173 K (1900°C) and applied pressures between 30 and 50 MPa. It allows full densification without the use of sintering aids, although most research employs modest amounts of sintering aids such as silicides, borides, metals (e.g., Ni), or C to reduce processing times and temperatures, thus reducing the costs associated with the production technique.…”

“…It has long been known that the addition of SiC improves the properties of ZrB 2 UHTCs significantly, [4,[8][9][10][11][12] and it is concluded generally that the optimum amount of SiC is between 15 and 20 vol pct. The addition of SiC increases the sinterability of the starting powders by facilitating liquid phase sintering via formation of a borosilicate liquid.…”

Effect of SiC whiskers and graphene nanosheets on the mechanical properties of ZrB2-SiCw-Graphene ceramic composites

“…Generally, the densification of ZrB 2 powder requires a high temperature above 2000°C at high pressure [5]. To improve the sintering properties of ZrB 2 , many different kinds of sintering aids are employed to fabricate composites, such as carbon [6], MoSi 2 [7], SiC [8,9], et al Moreover, ZrB 2 will be oxidized to ZrO 2 and B 2 O 3 under oxidizing conditions over 800°C [10]. In the high temperature application environment, it is proved that silicide will be oxidized to form a glassy phase which improves the oxidation resistance of ZrB 2 based ceramic composites [11,12].…”