ChemInform Abstract: KRIECHEN BEI DER KOMPRESSION VON ZRC‐NBC‐MISCHKRISTALLEN IM TEMPERATURBEREICH 2600‐3150 GRAD K

Deformation‐resistant Ta0.2Hf0.8C solid‐solution ceramic with superior flexural strength at 2000°C

“…Preceramic polycarbosilane polymers are commonly used as precursors to make ceramic fibers 10,39 and ceramic matrix. [7][8][9]40,41 The chemical and volume changes that accompany ceramization of the polymer during pyrolysis have been documented in several studies.…”

“…Assuming the lattice parameter from the XRD measurements as a = 4.5719 Å, one can expect that such a volume is proportional to ~40b 3 (b is a a/2). [1][2][3][4][5][6][7][8][9][10] For clarity, the tantalum carbide values of 50b 3 to 55b 3 been reported, 31 while the yielded ~30b 3 . 24 For 1900°C and 1950°C, the activation volume can be evaluated as 490 Å 3 .…”

“…Another factor contributing to the resistance to deformation is the grain size [7][8][9][10] because the grains coarser than 15 μm in [7][8][9][10] would mean that the bulk (lattice) diffusion mechanisms will be dominant and the contribution of the grain-boundary diffusion would be minimal. Andrievskii et al 34 suggested that based on the diffusion profiles of 14 C in carbides, the contribution of the grain-boundary diffusion was at the detection limit during the creep tests above 2200°C.…”

“…Considering good high-temperature compressive creep, 7 one may expect that the properties, such as high-temperature toughness or flexural strength for the TaC-HfC system, will also be superior to the monolithic HfC or TaC bulks, as it is expected that solid-solution strengthening will play a role in determining the strength at elevated temperatures. [8][9][10] In this study, we focused on the consolidation and high-temperature strength and toughness of the…”

“…29,30 The physics of resin under pressure is similar to the seepage pr lar approaches have been used also to mod into a mold containing fiber mats. 23,[31][32][33][34][35][36][37][38] T in these cases to determine the resin flow ing times corresponding to different infilt Preceramic polycarbosilane polymers as precursors to make ceramic fibers 10,3 trix. [7][8][9]40,41 The chemical and volume ch pany ceramization of the polymer during documented in several studies.…”