Effect of hot pressing time and temperature on the microstructure and mechanical properties of ZrB2–SiC

Effect of Yb2O3 Addition on Hot‐Pressed ZrB2‐SiC Ceramics

“…[11][12] Grain refinement could markedly increase the flexural strength of ZrB 2 -SiC ceramics. [17][18] However, compared to ZS-1900, the ZrB 2 and SiC grain sizes of ZSYb3 sample had no obvious reduction ( Fig. 2(a) and (c)).…”

“…Previous studies have reported that the grain coarsening would induce the reduction of flexural strength of ZrB 2 -SiC ceramics. [17][18] So, the decrease of flexural strength from 566±33 MPa for ZS-1900 to 468 ± 25 MPa for ZS-1950 may be due to the coarsening of ZrB 2 grains (Fig. 2(b)).…”

Microstructures and Mechanical Properties of Hot‐Pressed ZrB2‐Based Ceramics from Synthesized ZrB2 and ZrB2‐ZrC Powders

“…[15] In ZrB 2 -SiC ceramics, the mismatch of thermal expansion (coefficient of thermal expansion (CTE) of ZrB 2 : 6-7 8C À1 ; CTE of SiC: 3-4 8C À1 ) also exists. [16] So, microcracking was observed in ZS ceramics. Earlier investigations showed that the development of residual stresses was closely connected with the grain size.…”

“…Previous studies have shown that grain size was the critical factor determining the strength of ZrB 2 -SiC, and grain growth would lead to the strength reduction, especially the grain growth of SiC. [16,21] Zhu et al reported that the fracture strength of ZrB 2 -SiC was a strong function of SiC grain size, decreasing from around 909 MPa with SiC grain size of about 1 mm to approximately 389 MPa with SiC grain size of about 6 mm. [21] Therefore, the relatively low strength of ZS could be a result of larger average grain size of ZrB 2 and SiC, especially SiC.…”

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.…”