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用不同粘土矿物合成Sialon粉末的研究 总被引:5,自引:0,他引:5
本文以高岭土、蒙脱石、叶腊石为原料,将粘土矿物与碳混合,加入适量的添加剂,在N2气氛1400°C下,经4h碳热还原氮化合成Sialon,产物经XRD、XPS、EPMA等分析,结果表明:用不同粘土矿物合成Sialon,矿物的Al/Si比与碳的含量直接影响最终的合成产物,但主晶相仍为Z=3的β′-Sialon。 相似文献
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本文研究了Al2O3、Y2O3、La2O3、Y2O3+SiO2几种类型的添加剂对AIN陶瓷力学性能和高温抗氧化性能的影响。结果表明:Y2O3+SiO2为一种较好的AIN陶瓷添加剂,材料在烧结过程中由于2H^5Sialon及8H-Sialon等纤维状的Sialon相形成,对材料起到一种自补强作用,SiO2的存在使用AIN陶瓷在氧化工程中形成Mullite保护层,故使AIN陶瓷肯有良好的力学性能及高温 相似文献
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研究了热处理对AlN/SiCw(Y2O3+SiO2)复合材料机械性能的影响。结果表明,该材料经热处理后的强度提高,当添加剂Y2O3/SiO2=1/2.5摩尔比时,提高幅度最大。经XRD,SEM,TEM/EDAX和HREM分析,热处理增强的机理主要是粒界玻璃相在高温氧化气氛中和AlN颗粒表层作用,生成的纤维2H^δSialon相和SiCw形成空间交错结构。 相似文献
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采用比较研究的方法,探讨了AA·HPA,AA·AES、MA·AA及PAA四种聚电解质在不同浓度,PH值、Ca^2+浓度、PO4^3-浓度、温度及恒温时间对聚电聚质阻垢率的影响。研究结果表明,AA·HPA和AA·AES共聚物具有良好的的阻磷酸钙垢性能、增加聚电解质中羟基含量将降低阻磷酸钙垢的效果。 相似文献
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高效液膜分离富集镍基合金镀层中稀土总量 总被引:2,自引:0,他引:2
用TBP-TTA(协同流动载体)、SPAN80和煤油高效液膜体系,研究∑RE^3+迁移行为。在适宜条件下,10min内,∑RE^3+的迁移率达99.5%以上。在同样条件下,常见共存金属离子如Fe^3+、Al^3+、Ni^2+、Cr^3+、Mo^6+、Cu^2+、Co^2+、Zn^2+、Cd^2+等均不被迁移;大量碱金属、碱土金属、Cl、NO3、ClO4、F、SiO3^2-、SO4^2-等离子也不影 相似文献
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用^27Al、^29Si和^31P核磁共振和XRD了铝硅酸胶-MgSiF6-H3PO4系统的物相组成及Al、Si、P在其中所处的结构状态。结果表明,在铝硅酸溶胶中加入MgSiFt会导致Al^+5离子从溶胶胶粒中溶出,溶胶胶粒结构的破坏,从而引起胶胶粒中Al/Si比和Al、Si所处结构状态的变化。MgSiF6与从溶胶胶粒溶出的Al^3+、Na^+离子作用形成水溶性很低的NaMgAlF6从而使得铝硅酸 相似文献
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Fe^3+,Al^3+,Mg^2+对石膏结晶习性影响的研究 总被引:3,自引:0,他引:3
本文在MSMPR结晶器中研究了无F存在下,Fe^3+、Al^3+、Mg^2+三咱离子共存时对石膏结晶习性的影响,结果发现,无论硫酸根过量2.4%还是过量4.8%,Fe^3+、Al^3+、Mg^2+共存得到的石膏晶体几乎都是针状晶体;当硫酸另两种相应的离子浓度保持一定水平时,增大Fe^3+含量,石膏晶体变长;增长Mg^2+含量,石膏晶体变小;增长Al^3+含量,石膏晶体长大,F与Al^3+同时存在 相似文献
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Preparation and Performance Study of Sialon‐Si3N4‐SiC Composite Ceramics for Concentrated Solar Power 下载免费PDF全文
Xiaohong Xu Xinbin Lao Jianfeng Wu Zhenggang Rao Yang Zhou Dezhi He Yi Liu 《International Journal of Applied Ceramic Technology》2015,12(5):949-956
For lowering the sintering temperature of silicon carbide ceramics used for solar thermal energy storage technology, O'‐Sialon and silicon nitride were employed as composite phases to construct Sialon‐Si3N4‐SiC composite ceramics. The composite ceramics were synthesized using SiC, Si3N4, quartz, and different alumina sources as starting materials with noncontact graphite‐buried sintering method. Influences of alumina sources on the physical properties and thermal shock resistance of the composites were studied. The results revealed that the employment of O'‐Sialon and silicon nitride could decrease the sintering temperature greatly to 1540°C. The optimum formula G2 prepared from mullite as alumina source achieved the best performances: 66.7 MPa of bending strength, 10.0 W/(m·K) of thermal conductivity. The composition parameter x = 0.4 of O'‐Sialon decreased to 0.04 after 30 cycles thermal shock, and the bending strength increased with a rate of 11.0% due to the increase of O'‐Sialon grain size, and the optimization of microstructure caused by the transformation of O'‐Sialon grains and densification within the samples. The good thermal shock resistance makes the composites suitable for the use as thermal storage materials of concentrated solar power generation. 相似文献
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Shaojie Sun Long Xia Tao Zhang Hua Yang Chunlin Qin Bo Zhong Li Xiong Xin Wu Guangwu Wen 《Journal of the American Ceramic Society》2021,104(10):5354-5364
Dense Sialon fibers/barium aluminosilicate (BAS) matrix self-reinforced composite was synthesized by one-step method without applying pressure before or during sintering process. In this work, BAS matrix and internal Sialon fibers were synthesized successfully by directly sintering precursor powders at 1400°C for 4 h. The BAS is not only introduced as a structural matrix material, but also as an effective liquid phase sintering aid to attain full densification bulk sample. The results show that the diameter of fibers is about 100–200 nm, and the quantity of the fibers can be changed with different temperatures. The obtained Sialon fibers/BAS matrix composites exhibit better toughness due to fiber bridging, crack deflection, and pullout. The sample with 3.5 wt% carbon content has maximum value of flexural strength (74.5 ± 3.5 MPa) and fracture toughness (3.2 ± 0.20 MPa·m1/2). The growth of the Sialon fibers follows a vapor-liquid-solid (V-L-S) mechanism. These findings featured with a green and simple preparation process provide a facile strategy to design and fabricate the bulk ceramic matrix composites in complex shapes and different sizes. 相似文献
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Effect of hBN addition on the fabrication,mechanical and tribological properties of Sialon materials
《Ceramics International》2022,48(6):7715-7722
This work aims to investigate the effect of hBN on the friction and wear resistance of Sialon composite. Sialon and its composite with 10 wt% hBN were fabricated by SPS sintering. The effect of hBN additive on the phase composition, microstructure, densification behavior, mechanical and dry sliding tribological properties of Sialon material was studied. Being sintered at 1600 °C for 10 min, compared to monolithic Sialon, Sialon-hBN composite has more refined β-Sialon grains with smaller aspect ratios and slightly declined relative density. The hardness of the Sialon-hBN composite was reduced due to the weak bonding between Sialon and hBN grains. Nevertheless, its fracture toughness increased ascribing to the toughening mechanisms, including crack deflection and crack bridging. hBN had an essential impact on the tribological performances of the composite due to its lower friction coefficient and good lubrication action. Under the same densification level (i.e., with a relative density of around 97.5%), the friction and wear resistance of Sialon-hBN composite were much better than monolithic Sialon. The main wear mechanisms were tribolayer formation, oxidized wear, and abrasive wear. 相似文献
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Sialon结合SiC耐火材料的化学稳定性 总被引:4,自引:1,他引:3
采用高岭土、炭黑为主要结合相原料,合成了Sialon结合SiC耐火材料。考察了Sialon结合SiC耐火材料的氧化行为、高温碱侵蚀行为和冰晶石熔体的侵蚀行为。结果显示,合成Sialon结合SiC耐火材料具有高的机械强度和化学稳定性。 相似文献
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Xixi Hu Shenglin Zhong Jing Geng Peicheng Mo Jiuyang Li Peixun Wang Luyu Yang Yi Wu 《International Journal of Applied Ceramic Technology》2023,20(4):2183-2193
Polycrystalline cubic boron nitride (PcBN) composites were synthesized in situ with TiB2, TiN, and Sialon as binders under ultrahigh temperature (1550°C) and high pressure (5.5 GPa). X-ray diffractometry, universal testing machine, field emission scanning electron microscopy, and transmission electron microscopy were used to study the effect of Sialon content (0%, 20%, 40%, 60%, and 80% by mass of binder) on the phase composition, microstructure, and mechanical properties of PcBN composites. The results show that the main phases in the system are lamellar TiN, needle-rodlike TiB2, and irregular long-rodlike Sialon. Some TiB2 grows along the (1 0 −1 0) face, and Sialon grows along the (0 0 0 1) face. The density and mechanical properties of the sintered product are significantly improved due to the formation of Sialon. When the content of Sialon is 60%, the binder is uniformly distributed, the cBN interface is well bonded, and the density is the highest. At this time, the strength reaches the maximum 34.57 GPa, the fracture toughness is 6.82 MPa m1/2, and the flexural strength reaches the maximum 870.79 MPa. On the whole, cBN composites have excellent prospects for future applications in cutting inserts due to their excellent mechanical properties. 相似文献
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Sialon/SiC复相材料研究进展 总被引:11,自引:0,他引:11
根据相图,合成Sialon相的技术途径包括采用Si3N4粉末和其它反应添加物以无压或热压工艺高温合成,或以Si粉与其它金属及其氧化物为原料无压反应烧成而成,ialon粉末也可通过粘土类矿物的碳热还原反应来合成,但前两种技术作乱在原料及合成工艺上的高成本使其难于在耐火材料领域大规模开发应用,后一种工艺目前仅见到合成Sialon粉末的试验报道,本研究在对粘土类矿物合成Silaon粉末的研究基础上,由廉 相似文献