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《硅酸盐学报》2016,(12)
以高钙粉煤灰为主要原料,通过添加造孔剂,采用高温固相烧结法合成出钙长石多孔陶瓷。考察了烧成制度和造孔剂含量对多孔陶瓷显气孔率及抗折强度的影响。利用X射线衍射仪和扫描电子显微镜表征了多孔陶瓷的物相组成和微观结构。结果表明:提高烧成温度和延长保温时间会降低多孔陶瓷的显气孔率,增强其抗折强度;增加造孔剂含量会导致显气孔率升高,但过量添加反而造成显气孔率下降。当烧成温度为1 140℃、保温时间为90 min、造孔剂含量为35%(质量分数)时,多孔陶瓷具有较高的显气孔率和抗折强度(分别达到58.05%和9.41 MPa)。多孔陶瓷的主晶相为钙长石,孔径分布为数微米到150μm。 相似文献
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以镁渣,粉煤灰为原料,添加造孔剂(电石渣、碳粉)和增强剂(高岭土、膨润土)制备多孔陶瓷,并研究造孔剂和增强剂种类和含量对多孔陶瓷性能的影响.结果表明,添加造孔剂后,多孔陶瓷的烧失率、吸水率和气孔率升高,体积密度和强度降低.同等含量时,碳粉具有较好的造孔效果;多孔陶瓷的烧失率、吸水率和气孔率最高可分别达到30%,38%和53%,体积密度最小达到1.4 g/cm3;添加增强剂后,多孔陶瓷的强度大为提高,但其吸水率、气孔率降低,体积密度增加.高岭土的含量不大于10%时,其粘结增强效果明显优于同等含量膨润土的;多孔陶瓷的压缩强度可至28 MPa. 相似文献
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采用碳化硅、烧高岭土、氢氧化铝、滑石为主要原料,石墨为造孔剂制备了碳化硅/堇青石复相多孔陶瓷.研究了烧结温度和烧结助剂二氧化铈对碳化硅/堇青石复相多孔陶瓷气孔率和强度的影响,并分别用XRD和SEM分析晶相组成和断面显微结构表明:制备出的SiC多孔陶瓷的主相是SiC,结合相是堇青石与方石英,多孔陶瓷具有相互连通的开孔结构;在1350℃烧结,并保温3h,当造孔剂含量为15%时,碳化硅/堇青石复合多孔陶瓷性能最佳,其气孔率31.80%,相应的弯曲强度为63.74 MPa.在1200℃下,添加不同含量的CeO2,对烧结样品的相组成有影响,能够降低生成堇青石的温度,在CeO2含量为3%的样品中,堇青石的峰最明显,但是过量的氧化铈会抑制了堇青石的生成;随着CeO2加入量的增加,其气孔率和弯曲强度也会随之变化,1200℃下,在CeO2加入量为4%时其弯曲强度最优.但随着CeO2的含量的增加,其气孔率逐渐下降. 相似文献
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以碳化硅、氮化铝、层析氧化铝、氢氧化铝、氟化铝、滑石为主要原料,石墨为造孔剂通过原位反应烧结技术制备碳化硅/堇青石复相多孔陶瓷.研究了含铝化合物种类、烧结温度、石墨含量对SiC/堇青石复相多孔陶瓷相组成、微观结构、气孔率和抗折强度的影响,同时对S0组在1200℃烧结温度下制得的SiC/堇青石复合多孔陶瓷的孔径分布进行了测试分析.结果表明:以AlN为铝源在1200℃下烧结,石墨含量在15%时,堇青石结合SiC多孔陶瓷的抗弯强度和气孔率两项综合性能达到最优,气孔率为31.99%,相应的弯曲强度86.20 MPa.S0组的平均孔径大小在3.0191 μm. 相似文献
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以低品位岩浆土为原料,以碳粉和锯末作为造孔剂制备多孔吸声陶瓷.结合岩浆土、碳粉和锯末的热分析结果,研究了单一碳粉或锯末和两者复配作为造孔剂对陶瓷结构和性能的影响,并采用Voronina经验模型对材料的吸声系数进行了理论计算.采用传递函数法和超景深显微系统测试材料的吸声性能并对其形貌进行表征.结果 表明:与单一碳粉或锯末作造孔剂相比,两者复配分别将样品的吸声系数提高了27%和45%;当碳粉与锯末的用量分别为1.5%和1.5%时,样品性能最优.此条件下,样品在500 ~ 6300 Hz下的平均吸声系数为0.61,第一吸收峰频率在2000 Hz出现,峰值为0.95,Voronina模型可较好的拟合具有高显气孔率样品的吸声系数. 相似文献
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加速量热仪在锂离子电池热安全性研究领域的应用 总被引:2,自引:0,他引:2
加速量热仪(Accelerating RateCalorimeter,简称ARC)是用于危险品评估的新型热分析仪器,可以提供绝热条件下化学反应的时间、温度、温升速率和压力数据。本文着重介绍了加速量热仪应用在锂离子二次电池热安全性研究方面的研究成果,总结了锂离子二次电池的正负极材料、电解液和粘结剂等对锂离子二次电池热安全性的影响,并对ARC在离子电池热安全性研究发展方向的应用进行了展望。 相似文献
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综述了导热胶粘剂的导热机理、导热模型以及提高胶粘剂导热性能的途径;详细介绍了非绝缘导热胶粘剂和绝缘导热胶粘剂的技术研究与应用,最后对导热胶粘剂的发展前景作了展望。 相似文献
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为了适应测量热老化橡胶的导热率,改进了传统的稳态法测定导热率的测量方法.用该方法测量了热老化橡胶的导热率,并对热老化橡胶的导热率的变化机理进行了初步探讨. 相似文献
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Synthesis and thermophysical properties of RETa3O9 (RE = Ce,Nd, Sm,Eu, Gd,Dy, Er) as promising thermal barrier coatings 下载免费PDF全文
Lin Chen YeHua Jiang XiaoYu Chong Jing Feng 《Journal of the American Ceramic Society》2018,101(3):1266-1278
Thermal barrier coatings (TBCs) are one of the most important materials in gas turbine to protect the high temperature components. RETa3O9 compounds have a defect‐perovskite structure, indicating that they have low thermal conductivity, which is the critical property of TBCs. Herein, dense RETa3O9 bulk ceramics were fabricated via solid‐state reaction. The crystal structure was characterized by X‐ray diffraction (XRD) and Raman Spectroscope. Scanning electron microscope (SEM) was used to observe the microstructure. The thermophysical properties of RETa3O9 were studied systematically, including specific heat, thermal diffusivity, thermal conductivity, thermal expansion coefficients, and high‐temperature phase stability. The thermal conductivities of RETa3O9 are very low (1.33‐2.37 W/m·K, 373‐1073 K), which are much lower than YSZ and La2Zr2O7; and the thermal expansion coefficients range from 4.0 × 10?6 K?1 to 10.2×10?6 K?1 (1273 K), which is close to La2Zr2O7 and YSZ. According to the differential scanning calorimetry (DSC) curve there is not phase transition at the test temperature. Due to the high melting point and excellent high‐temperature phase stability with these oxides, RETa3O9 ceramics were promising candidate materials for TBCs. 相似文献
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PA66导热绝缘塑料的制备与性能 总被引:3,自引:0,他引:3
通过尼龙66(PA66)与大粒径MgO共混经双螺杆挤出机挤出制备了导热绝缘塑料。研究了热导率与MgO填充量的关系。该导热绝缘塑料的热扩散系数和热导率随MgO填充量的增加而增大。在MgO填充量达到70%时,热导率达到1.9 W/(m.K),同时仍保持较好的力学性能和一定的电绝缘性能。热失重分析表明,该导热绝缘塑料的热分解温度受MgO填充量的影响,有约10℃的变化,低填充量(40%和50%)时,因MgO具有良好的导热性能,试样中的PA66几乎完全被分解汽化。 相似文献
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Changzeng Yan Tianhang Yu Chao Ji Xiaoliang Zeng Jibao Lu Rong Sun Ching-Ping Wong 《应用聚合物科学杂志》2019,136(6):47054
Heat removal via thermal management materials is attracting more and more attention in the electronic industry. Conventional particle/polymer thermal conductive composites require a high filler loading ratio (>30 vol %), which cause severe thermal interfacial resistance and mechanical issue. In this work, we fabricate tellurium nanowires (NWs)/epoxy nanocomposites via a facile bar coating method. According to Agari model and Maxwell–Eucken model, the as-synthesized ultra-long NWs with high aspect ratio (>100) construct the 3D interconnected thermal conductive network better in resin matrix to facilitate the heat transfer process. The results show that at a low loading ratio of 2.4 vol %, this nanocomposite exhibits the out-of-plane and in-plane thermal conductivity of 0.378 and 1.63 W m−1 K−1, respectively, which is 189 and 715% higher than that of pure epoxy resin. Importantly, good stability, and flexibility of nanocomposites are well maintained. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47054. 相似文献
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J. Chojnowski J. Kurjata S. Rubinsztajn M. Scibiorek M. Zeldin 《Journal of Inorganic and Organometallic Polymers》1992,2(4):387-404
Thermal decomposition of poly[oxybis(dimethylsilylene)] having chains terminated with trimethylsiloxy groups was studied by thermogravimetry, pyrolysis-mass spectrometry, and infrared spectroscopy. The polymer is thermally less stable than poly(dimethylsiloxane). Depolymerization occurs at temperatures of 250–350°C, although this process also takes place at lower temperatures. The depolymerization produces cyclic oligomers of general formula [(Me2Si)2O]
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, with predominant formation of the oligomern=2. The depolymerization is accompanied by processes which are referred to as restructurization because they change the structure of the polymer backbone. Decomposition may lead also to the formation of branching points. The shape of the thermograms taken under isothermal conditions is in agreement with an unzipping mechanism for depolymerization involving random initiation. Excluding the short initial period of the process, the unzipping is terminated at a restructurization point. A low activation energy points to initiation induced by electron transfer, presumably involving traces of contaminant. At higher temperatures, 350–600°C, loss of organic parts of the polymer takes place along with further restructurization. At higher temperatures the polymer was also found to undergo easily oxygenation of its backbone with atmospheric oxygen, which leads to the formation of siloxane groups. 相似文献