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氧化铝基纳米复合陶瓷显微结构的研究 总被引:18,自引:2,他引:16
考察了Al2O3-SiC和Al2O3-ZrO2(3Y)-SiC纳米复合陶瓷的断裂方式。由于SiC的加入,材料以穿晶断裂为主。通过透射电镜观察,研究了纳米复合陶瓷中材料SiC颗粒的分布,证明所制备的材料为晶内型纳米复合陶瓷。在Al2O3-ZrO3(3Y)-SiC纳米复合陶瓷中,小的ZrO2颗粒分布于Al2O3晶粒内,大的ZrO2晶粒位于Al2O3晶粒间,ZrO2的分布影响Al2O3晶粒的形状。通过高分辨透射电镜,观察了Al2O3-SiC和Al2O3-ZrO2(3Y)-SiC纳米复合陶瓷中Al2O3/Al2O3,Al2O3/SiC,Al2O3/ZrO2的界面。在两颗晶粒间的晶界几乎没有玻璃相的存在,证明纳米复合材料中晶界得到了加强,有利于力学性能的提高。 相似文献
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以TiCl4,ZnSO4溶液为原料,采用液相沉淀法制备了不同ZnO/TiO2摩尔比的纳米复合粉体.对合成的纳米复合晶的相变、晶粒生长过程以及紫外-可见光吸收性能进行了研究.结果表明:纳米TiO2经ZnO复合后,其晶型转变和晶粒生长均受到抑制.当ZnO为30%(摩尔分数)时,且采用氨水滴入TiCl4和ZnSO4溶液中的沉淀方式制备的ZnO/TiO2纳米复合晶的晶型转变和晶粒生长最缓慢.紫外-可见光吸收测试表明:800℃煅烧的ZnO/TiO2复合粉体的吸收强度比纯TiO2的高;900~1 050℃煅烧的复合粉体,虽然紫外区的吸收强度有所下降,但其光吸收带边比纯TiO2纳米晶的有显著红移. 相似文献
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将纳米SiO2颗粒添加到磷化液中,在建筑结构钢表面制备出锌系复合磷化膜,并与纯锌系磷化膜进行了比对.结果表明:两种磷化膜都完全覆盖了基体,且都呈断层状形貌,锌系复合磷化膜的晶粒空隙被纳米SiO2颗粒填补,其含量约为7.54%.两种磷化膜的耐蚀性都好于建筑结构钢,且锌系复合磷化膜的耐蚀性最好.纳米SiO2颗粒在一定程度上填补了晶粒空隙,有效阻碍了腐蚀介质通过晶粒空隙渗透和扩散,从而保证锌系复合磷化膜具有较好的耐蚀性,使建筑钢构件能更好的满足防腐蚀要求. 相似文献
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抑制剂对纳米WC-10Co复合粉末烧结性能的影响 总被引:1,自引:0,他引:1
以液相复合-连续还原碳化方法制备的纳米WC-10Co(以质量计)复合粉末为原料,选择VC和Cr3C2作为超细WC-10Co硬质合金晶粒生长抑制剂,研究晶粒生长抑制剂加入量对超细WC-10Co硬质合金组织、晶粒和性能的影响。实验结果表明:超细WC-10Co硬质合金中WC晶粒度随着晶粒生长抑制剂加入量的增加而减小,纳米WC-10Co复合粉中加入0.4%VC和0.4%Cr3C2(以质量计)晶粒生长抑制剂,经1380℃真空烧结60min,1320℃低压处理30min后,可以得到平均晶粒度380nm、断裂强度3.55 GPa和Rockwell A硬度92.6综合性能较好的超细WC-10Co硬质合金。过多添加晶粒生长抑制剂反而降低了超细WC-10Co硬质合金的性能。 相似文献
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Zhenying Liu Chongmei Wu Nan Xie Jinbo Zhu Yin Liu Shouwu Huang Xiulin Shen Zhongde Yang Xin Lin Lingbing Kong 《International Journal of Applied Ceramic Technology》2022,19(3):1659-1668
Needle-like nanocrystalline mullite powders were prepared through the molten salt process at the temperature of 900°C using coal gangue as raw material. Then, mullite-based composite ceramics were prepared by a conventional solid-state reaction between in situ synthesized mullite and Al2O3 powders. Effects of Al2O3 content and sintering temperatures on phase compositions, microstructure, and mechanical properties of the mullite-based composite ceramics were also studied. The results show that mullite content productivity increase from 72% to 95%, as the sintering temperature increased from 1480°C to 1580°C, which led to the improvement in the bulk density and flexural strength of the samples. The three-dimensional interlocking structure for mullite-based composite ceramics was obtained by the in situ solid-state reaction process. The maximum bulk density, flexural strength, and fracture toughness for the sample with 15 wt% Al2O3 content are 2.48 g/cm3, 139.79 MPa, and 5.62 MPa··m1/2, respectively, as it was sintered at the temperature of 1560°C for 3 h. The improved mechanical properties of mullite-based composite ceramics maybe ascribed to good densification and increased mullite phase content, as well as to the in situ three-dimensional network structure. Therefore, the results would provide new ideas for high-value utilization of coal gangue. 相似文献
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Juan Wang Wensheng Liu Xiaolei Song Yunzhu Ma Yufeng Huang 《Ceramics International》2018,44(13):15418-15427
In this study, mullite nanofibers with smooth surface and dense structure were successfully fabricated with various amounts of polyvinyl pyrrolidone (PVP) as polymer template using electrospinning. To optimize properties of mullite nanofibers, effects of PVP content on the morphology and microstructure of the nanofibers were investigated. Results show that the nanofibers were composed of multiple phases (including nanocrystalline mullite, Al-Si spinel, and amorphous phase), and all had good flexibility. When PVP content increased, diameters of the fibers decreased. Meanwhile, mullite grain size and phase content increased, which led to changes in mechanical properties. Also, it was revealed that removal of PVP polymers (which helps atom diffusion and promotes nucleation-growth of mullite) was the acceleration mechanism of the additives. From analysis of crystallization activation energy and chemical structure, clear picture of the acceleration mechanism is gained, and this can provide a guideline for future optimization of electrospinning processes for high-temperature ceramics nanofibers. 相似文献
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2014年9月22日-26日,意大利博罗尼亚(Bologna)举办了一年一度的陶瓷砖CERSAIE,展示了许多用数字装饰技术与设备生产的各类瓷砖。与此同时,在意大利里米尼(Rimini)举办了两年一度的陶瓷机械设备展(Tecnargilla),中国广东东莞琅菱企业的超细研磨设备、广东佛山康立泰(国瓷)的陶瓷墨水、广东佛山新景泰陶瓷的喷墨设备,代表中国在瓷砖数字装饰领域的一股新兴力量参加了本次展会。本文对瓷砖产品不进行讨论,对国内企业的情况也不作展开,仅从宏观角度上介绍国外一些企业在瓷砖数字装饰技术与设备领域的新进展,供国内瓷砖行业同行参考,不对之处,敬请批评指正。 相似文献
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利用添加剂改善结构陶瓷材料的性能是一种较佳的方法,复合陶瓷mullite/ZrO_2/Al_2O_3具有较高的力学性能。试验证明:加入不同的添加剂对复合陶瓷有不同的影响,TiO_2会使材料的力学性能大幅度降低;Cr_2O_3会使材料的硬度显著提高。 相似文献
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Hiroaki Katsuki Sachiko Furuta Sridhar Komarneni 《Journal of the American Ceramic Society》2000,83(5):1093-1097
The formation and properties of continuous ZSM-5 film on a porous mullite honeycomb have been investigated. The porous mullite honeycomb coated with ZSM-5 film provides a novel microporous (0.5 nm in diameter)–macroporous (0.5–0.6 μm in diameter) composite. Amorphous silica-glass in the kaolin honeycomb sintered at 1650°C is used as a source for ZSM-5 formation. The honeycomb is hydrothermally treated in NaOH, tetrapropylammonium bromide, and water to prepare a novel honeycomb–zeolite composite by in situ crystallization of ZSM-5 film. This paper describes the effects of hydrothermal conditions—such as reaction temperature, time, and concentration of NaOH solution—on the formation of ZSM-5 film on the honeycomb, and on the mechanical strength and porous properties of the honeycomb composite. 相似文献
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Hiroaki Katsuki Sachiko Furuta Atsunori Shiraishi Sridhar Komarneni 《Journal of Porous Materials》1995,2(4):299-305
A conventional hydrothermal treatment with various concentrations of NaOH was used at 150° and 190°C to dissolve excess silica glass and thus make porous mullite ceramics from a fired New Zealand kaolin body. The effect of hydrothermal treatment time on the dissolution of the glass was examined. At 150°C, the dissolution of glass was almost complete after treatment for 8 hrs in 5N-NaOH solution and about 40–43 wt% of the glass was removed from the fired kaolin body leading to porous mullite. However, when the fired kaolin body was treated for more than 5 hrs in 5N-NaOH at 190°C, a composite of mullite and a nonporous crystalline phase of unknown symmetry resulted. These crystals formed from the dissolution and recrystallization of the glass. After the dissolution of glass in 2N-NaOH solution at 190°C for 5 hrs, a porous mullite body of 52.8% porosity with an average pore diameter of 0.57 m could be obtained, and this was only composed of mullite whiskers. Growth of unidentified nonporous crystals in the body which was treated in 5N-NaOH solution at 190°C led to a decrease in specific surface area and therefore, these crystals should be avoided. 相似文献
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Yaqun Wu Yuming Tian Ming Feng Mei Qing Yaqiao Wu 《International Journal of Applied Ceramic Technology》2022,19(3):1300-1308
In this paper, spodumene/mullite ceramics with good thermal shock resistance were prepared from spodumene, quartz, talc, and clay when the sintering temperature was 1270℃. In the sintering process, the effect of holding time on densification, mechanical properties, phase transformation, microstructure, and thermal shock resistance of the composite ceramics were investigated. The phase transition and microstructures of the ceramics were identified via X-ray diffraction (XRD) and scanning electron microscopy (SEM). The interaction between holding time and bulk density was studied by response surface methodology. The result show that an appropriate holding time can improve the mechanical properties of spodumene/mullite ceramics. When the holding time was kept 90 min, the spodumene/mullite ceramics with the apparent porosity was .47%, the bulk density was 2.28 g/cm3, and bending strength was 63.46 MPa. Furthermore, since no cracks formed after 20 thermal shock cycles for the composite ceramics with a bending strength decreasing rate of 12.66%, it is revealed that spodumene/mullite ceramics exhibit good thermal shock resistance. Therefore, this study can provide beneficial guidance for both industrial production and energy conservation. 相似文献
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Elizabeth Withey Christopher Petorak Rodney Trice Graeme Dickinson Thomas Taylor 《Journal of the European Ceramic Society》2007,27(16):4675-4683
Plasma-sprayed stand-alone coatings of 7 wt.% Y2O3–ZrO2 (YSZ), nominally 74 wt.% Al2O3–26 wt.% SiO2 mullite, and a 46:54 volume ratio composite of YSZ to mullite were examined using X-ray diffraction, dilatometry, and compression creep. X-ray diffraction and dilatometer results showed that the as-sprayed predominantly amorphous mullite crystallized at 970 °C. Creep tests were conducted on all three coating types in the as-sprayed condition at stresses from 40 to 80 MPa and temperatures of 1000–1200 °C. The primary deformation mechanism in coatings made from all three materials was stress-assisted densification of the porous coating. While the creep behavior of YSZ/mullite composite specimens was between that of pure YSZ and pure mullite specimens for all combinations of temperature and stress tested, the creep response of the composite was more similar to that of pure mullite for all cases tested, consistent with mullite being the continuous phase in the composite. 相似文献