共查询到19条相似文献,搜索用时 109 毫秒
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水基冷冻干燥工艺制备层状结构多孔SiC陶瓷 总被引:1,自引:0,他引:1
以微米级SiC粉体为原料,利用冷冻干燥和原位反应烧结制备了具有层状孔道结构的SiC多孔陶瓷.XRD分析表明多孔陶瓷的主相是α-SiC,结合相是方石英;SEM观察到多孔陶瓷具有相互连通的开孔结构;多孔SiC陶瓷的总孔隙率和开孔隙率随固相含量和烧结温度的增加而下降.多孔陶瓷的孔径分布呈现双峰分布特点,大孔孔径峰值介于20~80 μm,小孔孔径峰值为0.5~0.9 μm.在原位反应烧结过程中,在1100℃以上SiC开始发生氧化形成SiO2结合的多孔SiC陶瓷,显著提高了陶瓷的压缩强度.随着烧结温度从1000℃提高到1500℃,固相含量为30vol%的多孔SiC陶瓷开孔率从68.9%下降到61.8%,压缩强度由5.5 MPa升至25.5 MPa. 相似文献
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电子烟多孔陶瓷雾化芯,是以氧化铝,硅藻土和石英砂等为主体,通过高温烧结而制成.为进一步提高样品性能,通过注射成型,烧结助剂和造孔剂的配方改进,使得多孔陶瓷气孔率达到56%~58%,弯曲强度为20~30MPa,也就同时兼顾了高气孔率和高强度.更进一步,在多孔陶瓷和发热组件之间增加了导热层,比多孔陶瓷的导热系数高出近10倍... 相似文献
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《Journal of the European Ceramic Society》2021,41(15):7412-7422
Joining is crucial for ultra-high temperature ceramics (UHTCs) to be used in demanding environments due to the difficulty in manufacturing large and complex ceramic components. In this study, ZrB2-SiC composite UHTCs parts were joined via Ni foil as filler, and the mechanical properties and oxidation behaviour of the fabricated ZrB2-SiC/Ni/ZrB2-SiC (ZS/Ni/ZS) joint were investigated. Firstly, dense ZrB2-SiC composites were prepared from nano-sized powders by spark plasma sintering (SPS). The ZrB2-SiC parts were then joined using SPS. Furthermore, the elastic modulus, hardness, shear strength and high temperature oxidation behaviour of the ZS/Ni/ZS joint were examined to evaluate its properties and performance. The experimental results showed that the ZrB2-SiC parts were effectively joined via Ni foil using SPS and the resultant microstructures were free from any marked defects or residual metallic layers in the joint. Although the elastic modulus and hardness in the joining zone were lower than those in the base ZrB2-SiC ceramics, the shear strength of the joint reached ∼161 MPa, demonstrating satisfactory mechanical properties. Oxidation tests revealed that the ZS/Ni/ZS joint possesses good oxidation resistance for a wide range of elevated temperatures (800–1600 oC), paving the way for its employment in extreme environments. 相似文献
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Jin-Seong Kim Ngoc-Huan Nguyen Myung-Eun Song Jong-Bong Lim Dong-Soo Paik Sahn Nahm Jong-Hoo Paik Byung-Hyun Choi Soon-Jae Yu 《International Journal of Applied Ceramic Technology》2009,6(5):581-586
Bi2 O3 was added to a nominal composition of Zn1.8 SiO3.8 (ZS) ceramics to decrease their sintering temperature. When the Bi2 O3 content was <8.0 mol%, a porous microstructure with Bi4 (SiO4 )3 and SiO2 second phases was developed in the specimen sintered at 885°C. However, when the Bi2 O3 content exceeded 8.0 mol%, a liquid phase, which formed during sintering at temperatures below 900°C, assisted the densification of the ZS ceramics. Good microwave dielectric properties of Q × f =12,600 GHz, ɛr =7.6, and τf =−22 ppm/°C were obtained from the specimen with 8.0 mol% Bi2 O3 sintered at 885°C for 2 h. 相似文献
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Ying Lang Chang‐An Wang Shengnian Tie 《International Journal of Applied Ceramic Technology》2014,11(5):824-831
Porous YSZ ceramics reinforced by different fibers were prepared by gel‐casting with 15% solid content and pressureless sintering. The four kinds of fibers (mullite, aluminosilicate, Al2O3, and YSZ fibers) were added into the YSZ ceramics with the same 10% vol content. After sintered at 1500°C for 2 h, aluminosilicate and mullite fibers could not be found in the samples of porous YSZ ceramics, which showed they reacted with YSZ ceramics at high temperature, while YSZ and Al2O3 fibers still kept perfect after sintering. Furthermore, the influences of fiber content, sintering temperature, porosity of matrix materials on compressive strength and porosity of the porous YSZ ceramics were studied. The results showed that Al2O3 fiber showed more obvious reinforcing effect than YSZ fiber on porous YSZ ceramics. The fiber‐reinforcing effects depend on fiber content, sintering temperature, and porosity of matrix materials. The fiber addition can improve the shrinkage behavior of porous ceramics during sintering and strengthen the skeleton of porous ceramics. 相似文献
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Geng-fu Xu Tayo Olorunyolemi Yuval Carmel Isabel K. Lloyd Otto C. Wilson 《Journal of the American Ceramic Society》2003,86(12):2082-2086
A multilayer insulation configuration suitable for microwave sintering of ceramics up to 2100°C was designed and tested successfully. The configuration is based on porous, granular BN/ZrO2 fiber composite powder for packed beds and spacer cylinders. This insulation allows stable, controlled microwave sintering and can be modified to microwave process materials with different thermal, dielectric properties with improved properties. 相似文献
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Yue Hu Zhen Xiao Huanping Wang Can Ye Yuqian Wu Shiqing Xu 《Ceramics International》2019,45(3):3710-3714
Porous CaSiO3 ceramics were prepared via a solid-state reaction method using CaCO3 and SiO2 as raw materials and active carbon as a pore-forming agent. The results indicated that porous CaSiO3 ceramics could be obtained under a low sintering temperature of 1320?°C. The addition of active carbon significantly affected the volume density, microstructure, pore size distribution and mechanical strength of porous CaSiO3 ceramics. With the increase of active carbon content, the volume density decreased, meanwhile the pore size and porosity increased gradually. Besides, the three-point bending tests demonstrated that the mechanical strength was decreased with increasing active carbon content. However, all the porous ceramics still exhibited high mechanical strength. These results implied that the increase of active carbon content not only enlarged the pore size and enhanced the porosity, but also kept a remarkable mechanical strength of porous CaSiO3 ceramics. Therefore, these rationally designed CaSiO3 porous ceramics will be a highly potential material in various applications due to its high mechanical strength, low sintering temperature and narrow pore size distribution. 相似文献
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Zhangzhao Weng Zhengyu Han Fen Xiao Hao Xue Dongliang Peng 《Ceramics International》2018,44(12):14145-14150
The Zn1.8SiO3.8 (ZS) ceramics with BaCu(B2O5) (BCB) additive were synthesized by the conventional solid-state reaction route and the effect of BCB additive on the microwave dielectric properties of the ceramics was investigated. The results demonstrate that BCB could effectively decrease the sintering temperature from 1300?°C to 930?°C and does not induce obviously degradation of the microwave dielectric properties. The 6.wt% BCB added ZS ceramics exhibited a low sintering temperature (~ 930?°C) and excellent dielectric properties of εr =?6.79, Q×f =?33,648?GHz, and τf =??30?ppm/°C. To compensate the negative τf value of this system, TiO2 powders were introduced. Particularly when 10.wt% TiO2 was added, good microwave dielectric properties of εr=?8.175, Q×f=?21,252?GHz, and τf =?1.2?ppm/°C were obtained for the 6.wt% BCB added ZS ceramic sintered at 930?°C for 3?h. Moreover, BCB added ZS-TiO2 ceramics have a chemical compatibility with silver, which indicate that the BCB added ZS ceramics are promising candidate for LTCC applications. 相似文献