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以共沉淀法制备的钛和铬的摩尔比为4:6的TiO2/Cr2O3纳米复合粉体为前驱体,氨气为氮化剂,制备了钛铬双金属氧氮化物纳米粉体。采用Auger电子能谱、X射线衍射、透射电子显微镜、BET比表面积、电子探针等技术对氧化物复合粉体和合成氧氮化物粉体进行了表征。结果表明:前驱体组成均匀、比表面积大、反应活性高,800℃氮化8h可以合成X射线衍射纯立方相钛铬双金属氧氮化物纳米粉体e粉体呈球形,晶粒尺寸在20~35nm,比表面积达35.62m^2/g,基本无团聚。氮化前后粉体的氧含量和氮含量发生了明显变化,粉体的组成可以用Ti0.4Cr0.6OxNy表示。 相似文献
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金属-氮化物结合滑板的研制与应用 总被引:6,自引:5,他引:6
以刚玉为骨料,金属铝为主要基质,利用粉末冶金工艺,氮化烧成,制成了具有金属陶瓷性能的金属-氮化物结合滑板.金属铝以细粉、颗粒和铝纤维三种形式引入,加入量为10%~20%,同时在配料中引入一种氨盐作添加剂,确定氮化温度低于1100℃.研制的滑板具有优良的抗氧化性、抗侵蚀性和高温结构强度,尤其适合于高氧钢及钙处理钢的浇铸,其理化指标为w(Al2O3)96.6%,w(T.C)3.23%,常温耐压强度147~224 MPa,常温抗折强度51.6~59.4 MPa,体积密度3.15~3.26g@cm-3,显气孔率8%~10%,线膨胀率1.2%(1200℃). 相似文献
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采用陶瓷注射成型技术制备了氧化锆(ZrO2)固体电解质基体,在烧成的ZrO2基体上涂制铂(Pt)电极浆料,将电极在不同温度下烧结.用扫描电镜表征所制备的Pt电极和进行时效实验电极表面的微观形貌,结果表明:电极烧结温度和时效时间对电极微观形貌影响很大.用电化学阻抗谱研究了Pt电极的电化学性能,结果显示:所制备的Pt电极显示出优良的电化学催化性能. 相似文献
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水热合成镧掺杂钛酸铋粉体的初步研究 总被引:1,自引:0,他引:1
初步研究了镧掺杂钛酸铋粉体的水热合成工艺,借助XRD及TEM对粉体的组成、结构、晶粒度及粉体形貌进行了研究。结果表明:合成该粉体的最佳工艺条件为240℃保温6h;粉体的微观形貌呈片状;镧的掺杂抑制了钛酸铋晶体的生长。 相似文献
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磷酸锂粉体的制备与表征 总被引:1,自引:0,他引:1
以LiOH·H2O和NH4H2PO4为原料,采用微波水热法在200℃下合成磷酸锂。研究了微波水热反应对磷酸锂颗粒形貌的影响,并对其物相组成、形貌以及晶体结构进行了分析。结果表明,利用微波和水热合成的优势制备的磷酸锂物相较纯、形状较规则,结晶性较好。 相似文献
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本研究利用溶胶-凝胶技术制备Y-La-Si-O-N氧氮玻璃配合料,在1大气压N2气氛中1600℃左右温度熔制,制备出表观呈灰黑色透明的Y-La-Si-O-N系统氧氮玻璃。实验结果表明氧氮玻璃含氮量为6.7-10.9at%;显微硬度Hv为3.5-6.47GPa;断裂韧性为0.64-1.38MPam^1/2,Tg在1000℃以上,膨胀系数为1.05×10^-6℃^-1. 相似文献
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Raja Wusirika 《Journal of the American Ceramic Society》1991,74(2):454-456
Oxynitride glass fibers were drawn from the melt in N2 atmospheres. The fibers were tested for their alkali durability in 10% NaOH at 96°C for 6 h. The durability is reported as weight loss in mg/cm2 . The photomicrographs of the fibers before and after testing are presented. Calcium silicate oxynitride fibers have good durability because of a protective surface layer of Ca(OH)2 . Yttria-containing glasses have the best durability among the compositions reported here. 相似文献
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Highly transparent Aluminum oxynitride (AlON) body has been produced using aqueous slip casting technique. High‐purity alumina and AlN were used as raw materials for the synthesis of single‐phase AlON powder. As‐synthesized AlON powder was surface modified to enable the AlON powders resistant to hydrolysis in water during aqueous slip casting. High solid loaded aqueous AlON slip was prepared for casting followed by drying and sintering to produce transparent AlON. Phase formation and stability was characterized by XRD, pH, and viscosity measurements. AlON powders before and after surface treatments were characterized. Sintered transparent AlON samples were characterized for their mechanical, microstructural, and optical properties. Sintered and polished AlON produced in this study has shown inline transparency up to 80% between 0.22 and 6 μm wavelength region. 相似文献
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Rong-Jun Xie Mamoru Mitomo Guo-Dong Zhan Hideyuki Emoto 《Journal of the American Ceramic Society》2000,83(10):2529-2535
Starting with a mixture of ultrafine β-Si3 N4 and a SiO2 -containing additive, a superplastic Si3 N4 -based composite was developed, using the concept of a transient liquid phase. Significant deformation-induced phase and microstructure evolutions occurred in the nonequilibrium, fine-grained Si3 N4 material, which led to the in situ development of a Si3 N4 –22-vol%-Si2 N2 O composite and strong texture formation. The unusual ductility of the composites with elongated Si2 N2 O grains was attributed to the fine-grained microstructure, the presence of a transient liquid phase, and the alignment of the elongated Si2 N2 O grains. The mechanical properties of the resultant composite were enhanced rather than impaired by superplastic deformation and subsequent heat treatment; the resultant composite exhibited both high strength (957 MPa) and high fracture toughness (4.8 MPa·m1/2 ). 相似文献
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Reaction and Formation of Crystalline Silicon Oxynitride in Si–O–N Systems under Solid High Pressure
Ya-Li Li Fen Zheng Yong Liang Xian-Feng Ma Suo-Jing Cui Takamasa Ishigaki 《Journal of the American Ceramic Society》2001,84(4):875-877
Oxidized amorphous Si3 N4 and SiO2 powders were pressed alone or as a mixture under high pressure (1.0–5.0 GPa) at high temperatures (800–1700°C). Formation of crystalline silicon oxynitride (Si2 ON2 ) was observed from amorphous silicon nitride (Si3 N4 ) powders containing 5.8 wt% oxygen at 1.0 GPa and 1400°C. The Si2 ON2 coexisted with β-Si3 N4 with a weight fraction of 40 wt%, suggesting that all oxygen in the powders participated in the reaction to form Si2 ON2 . Pressing a mixture of amorphous Si3 N4 of lower oxygen (1.5 wt%) and SiO2 under 1.0–5.0 GPa between 1000° and 1350°C did not give Si2 ON2 phase, but yielded a mixture of α,β-Si3 N4 , quartz, and coesite (a high-pressure form of SiO2 ). The formation of Si2 ON2 from oxidized amorphous Si3 N4 seemed to be assisted by formation of a Si–O–N melt in the system that was enhanced under the high pressure. 相似文献
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Processing, Mechanical Properties, and Oxidation Behavior of Silicon Oxynitride Ceramics 总被引:2,自引:0,他引:2
Masayoshi Ohashi Shuzo Kanzaki Hideyo Tabata 《Journal of the American Ceramic Society》1991,74(1):109-114
Silicon oxynitride ceramics were prepared by hot-pressing an equimolar Si3 N4 + SiO2 mixture with 3 mol% CeO2 . The Ce2 O3 /SiO2 ratio of intergranular phase (liquid phase) increased as the formation of Si2 N2 O proceeded. The intergranular liquid remained as a glass on cooling until the Ce2 O3 /SiO2 ratio exceeded a certain value, at which point the liquid crystallized. There were great differences in thermal and mechanical properties and oxideation behavior between the specimen containing intergranular glassy phase and the one containing intergranular crystalline phase (Ce5 (SiO4 )3 N–Ce4.67 (SiO4 )3 O). The specimen containing the intergranular glassy phase showed excellent hightemperature strength and oxidation resistance. 相似文献
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Rong-Jun Xie Mamoru Mitomo Wonjoong Kim Young-Wook Kim 《Journal of the American Ceramic Society》2000,83(12):3147-3152
Silicon nitride–silicon oxynitride (Si3 N4 –Si2 N2 O) in situ composites have been fabricated via either the annealing or the superplastic deformation of sintered Si3 N4 that has been doped with a silica-containing additive. In this study, quantitative texture measurements, including pole figures and X-ray diffraction patterns, are used in conjunction with scanning electron microscopy and transmission electron microscopy techniques to examine the degree of preferred orientation and texture-development mechanisms in these materials. The results indicate that (i) only superplastic deformation can produce strong textures in the β-Si3 N4 matrix, as well as Si2 N2 O grains that are formed in situ ; (ii) texture development in the β-Si3 N4 matrix mainly results from grain rotation via grain-boundary sliding; and (iii) for Si2 N2 O, a very strong strain-dependent texture occurs in two stages, namely, preferred nucleation and anisotropic grain growth. 相似文献
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Reaction Sintering and Properties of Silicon Oxynitride Densified by Hot Isostatic Pressing 总被引:4,自引:0,他引:4
Richard Larker 《Journal of the American Ceramic Society》1992,75(1):62-66
Silicon oxynitride ceramics were reaction sintered and fully densified by hot isostatic pressing in the temperature range 1700°C to 1950°C from an equimolar mixture of silicon nitride and silica powders without additives. Conversion to Si2 N2 O increases steeply from a level around 5% of the crystalline phases at 1700°C to 80% at 1800°C, and increases a few percent further at higher temperatures. α -Si3 N4 is the major residual crystalline phase below 1900°C. The hardness level for materials containing 85% Si2 N2 O is approximately 19 GPa, comparable with the hardness of Si3 N4 hot isostatically pressed with 2.5 wt% Y2 O3 , while the fracture toughness level is around 3.1 MPa. m1/2 , being approximately 0.8 MPa.m1/2 lower. The three-point bending strength increased with HIP temperature from approximately 300 to 500 MPa. 相似文献