Oxidation behavior of ZrB2/SiC laminates: Effect of composition on microstructure and mechanical strength

Evaluation of rare‐earth element dopants (Sm and Er) on ablation resistance of ZrB2/SiC‐sintered billets

“…The liquid boria-rich oxidation product is transported through the overlying layer of SiO 2 liquid by convection, forming convection cells aligned like the petals of a flower. 14,[18][19][20] Brenner et al 17 also noted these convection cells during the oxidation of Sm-doped ZrB 2 /SiC coatings at ~1700°C. Even though the convection cells mechanism during the ablation process in the present study was very similar compared to both Brenner et al 17 Studies have shown that the B 2 O 3 glass present on the surface of a Sm-doped ZrB 2 /SiC coating after heating to 900°C contains Sm 3+ atoms.…”

“…The rising B 2 O 3 ‐rich liquid contains dissolved ZrO 2 , which deposits in the center of the flower‐like structure when the B 2 O 3 evaporates. The liquid boria‐rich oxidation product is transported through the overlying layer of SiO 2 liquid by convection, forming convection cells aligned like the petals of a flower …”

“…Spray‐dried powders were prepared using the same method employed by Tan et al and the Brenner et al studies. Briefly, a laboratory spray dryer (APV Anhydro Model S1, Anhydro Inc, Soeborg, Denmark) was used to produce powder agglomerate from a liquid suspension feed (Aero‐Instant Spraying Service, Brunswick, USA) that consisted of 80 vol% ZrB 2 (3‐5 μm, Grade A, HC Starck, Munich, Germany), 20 vol% α‐SiC (1.4 m, Grade UF‐05, HC Starck, Munich, Germany), 0.4 wt% dispersant (Darvan 821A, RT Vanderbilt Company, Inc, Norwalk, USA), 2 wt% PVA binder (Celvol 203, Celanese Corporation, Dallas, USA), and deionized water.…”

Thermophysical and radiative properties of pressureless sintered SiC and ZrB2-SiC laminates

“…the difference between the average experimental curves for the two materials is constant (around 1.8 ´10 -6 K -1 ) at temperatures higher than 700 K. This mismatch can cause the formation of stresses and the consequent development of cracks. There is a small number of works regarding the joint use of HTCs and UHTCs materials in a multifunctional component: our previous paper [39] shows preliminary results regarding the processing of hybrid laminates integrating ZrB 2 -SiC composite layers in between SiC ones. The integration of the two materials was successfully achieved, but the properties of the hybrid laminate should be improved.…”

Oxidation Resistance and Residual Strength of Laminated ZrB2-SiC-G Ceramics at 1300℃

“…无 机 材 料 学 报 第 32 卷 Hwang 等 [8] 研究了 SiC 颗粒大小对 ZrB 2 基复合材料 的影响, 发现加入 SiC 能够提升 ZrB 2 的致密度, 且 随着 SiC 颗粒尺寸的减小, ZrB 2 的致密度不断提高, 从而使抗氧化性能得到提高。Guo 等 [9] 实验发现, ZrB 2 -SiC 陶瓷在 1500℃氧化 0.5 h 后的室温弯曲强 度较未氧化前有大幅度的提高。Sciti 等 [10] 制备并研 究了 ZrB 2 -MoSi 2 陶瓷的抗氧化性, 发现在高温下 MoSi 2 可以发生氧化, 并在表面形成 SiO 2 保护层, 该材料在 1200℃氧化后的弯曲强度为 370MPa。 近年来, 通过模仿生物结构而制备的层状陶瓷 成为研究的焦点, 层状陶瓷是根据贝壳珍珠层的结 构设计的 [11][12] 。研究表明层状结构能够使裂纹在材 料断裂过程中发生偏转, 从而延长裂纹长度, 断裂 功增加, 并由原来的脆性断裂变为二次或多次断裂, 从而提高断裂韧性 [13] 。Li 等 [14] 制备了层状和块状 [15] :…”