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以ZrO2 为基本组成相的层状材料 ,采用干法成型工艺 ,通过对表面层不同组分Al2 O3+ZrO2 和表面厚度的系统研究和设计 ,提出设计三层结构复合陶瓷层裂参数λ ,当λ小于 1.5时 ,表面层不会出现层裂 ,整体材料性能较好 .研究表明 ,表面残余压应力的存在 ,使得三层结构复合陶瓷较单层结构陶瓷表现出更高的强度、硬度、断裂韧性和其他性质 .45 %Al2 O3/ZrO2 / 45 %Al2 O3层状复合陶瓷的弯曲强度达 682MPa,断裂韧性达 16.2MPa·m1 /2 ;而单层ZrO2 陶瓷的弯曲强度和断裂韧性分别仅为 45 0MPa和 8.8MPa·m1 相似文献
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微米级多孔Al2O3陶瓷的研制 总被引:1,自引:0,他引:1
本课题以a-Al3O3为骨料,通过调整骨料颗粒度颗粒级配、烧成温度、粘结剂量,研究了平均孔径在2-10μm范围内,具有狭窄的孔径分布,气孔率在40%以上,HRA超过60的陶瓷多孔体。 相似文献
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运用回归技术并结合SEM的测试结果,对影响ZnO-Al2O3系陶瓷电阻及电阻温度特性的线性化机制进行了探讨。研究表明,Al2O3、MgO的掺杂及烧成工艺均对材料的电阻率和电阻温度系数有较为明显的影响,镁掺杂对材料的电子激活能有较大的影响。当材料的电子能值较低时,通过回归发现其阻温特性具有较好的线怀,符合麦克荣林公式近似。 相似文献
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采用无压烧结法制备Al2O3–15%(质量分数)ZrO2(简称ZTA)复相陶瓷,研究了ZTA复相陶瓷在293~77K的力学性能以及300~5K的热学性能,分析了ZTA复相陶瓷在不同温度断裂时断面上ZrO2发生的相变量和相变区宽度。结果表明:ZTA复相陶瓷的抗弯强度、断裂韧性和Vickers硬度均随温度下降而逐渐提高;77K时抗弯强度、断裂韧性和Vickers硬度比293K时分别提高了10.8%、19.7%和10.4%;ZTA复相陶瓷的热导率随温度下降先增大,在97K时达到最大值,然后随温度下降而降低。低温环境增强了ZTA复相陶瓷中应力诱导t-ZrO2→m-ZrO2的相变增韧效应,提高了ZTA复相陶瓷的低温力学性能。ZTA复相陶瓷具有良好的低温力学性能和较小的低温热导率,是一种有广阔应用前景的低温结构陶瓷材料。 相似文献
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ZrO2 对堇青石多孔陶瓷性能和显微结构的影响 总被引:1,自引:0,他引:1
以高岭土、滑石和αAl2O3微粉为主要原料,按堇青石的理论组成配料后,外加10%的化学纯活性炭为造孔剂,同时分别外加0、0.25%、0.5%、0.75%和1.0%的分析纯ZrO2,经湿混、干燥、造粒、成型和1340℃保温5h烧成后,制成不同ZrO2含量的堇青石多孔陶瓷,并研究了ZrO2外加量对试样热膨胀系数、显气孔率、吸水率及烧成收缩率的影响,并用XRD和SEM分析了试样的物相组成和断面形貌。结果表明:与未加ZrO2的相比,外加0.25%ZrO2时,试样的热膨胀系数显著降低,但超过0.25%时,热膨胀系数随ZrO2外加量的增加而略有升高;随ZrO2外加量的增加,试样的显气孔率和吸水率逐渐增大,而烧成收缩率降低;与未加ZrO2的试样相比,外加1.0%ZrO的试样内扁平状气孔的数量较多,且气孔在试样内分布较均匀。 相似文献
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为了以较低成本制备较高性能的ZrN(ZrON)-SiAlON复合陶瓷材料,先以粉煤灰、锆英石和活性炭为主要原料,经碳热还原氮化法合成ZrN-SiAlON复合粉;然后在ZrN-SiAlON复合粉中添加不同量(质量分数分别为0、5%、10%)的Y2O3,在1500℃保温1 h埋碳烧结制备了ZrN(ZrON)-SiAlON复合陶瓷材料,并研究了ZrN(ZrON)-SiAlON复合陶瓷材料的相组成、烧结性能和力学性能等。结果表明:Y2O3可促进ZrN和β-SiAlON等主晶相的形成,同时促进材料的烧结致密化。添加5%(w)的Y2O3制得的ZrN(ZrON)-SiAlON复合陶瓷材料的显气孔率为5.3%,体积密度为3.47 g·cm-3,常温耐压强度为29.4 MPa,性能较优。 相似文献
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Pengcheng Zhao Kehui Hu Haoyuan Wang Xinyi Li Zhigang Lu 《Ceramics International》2021,47(16):23144-23152
Porous ceramics based on additive manufacturing have great application potential in many industries, including filtration, catalysis, and heat insulation. In this research, we propose a method for manufacturing porous ceramics with connected channels structure through ceramic digital light processing (DLP) and organic fiber decomposition. The crossed fibers in the green body, working as a pore-forming agent, were decomposed and removed to form connected channels in ceramic. It was confirmed that ball milling changed the fiber morphology during slurry preparation, which was beneficial to promote fibers crossing. Besides, we focused on the influence of the “Sponge Compression effect” during the DLP process, which affected the fibers distribution. The existence of fibers in the green body resulted in uneven pressure distribution during the debinding process, providing a potential source of cracks. Results show that this method can produce channels with a diameter of 100 μm and high connectivity, providing great potential in fabricating high connectivity porous ceramics with complex shapes and structures. 相似文献
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Zhiwei Chen Guogang Xu Hongzhi Cui Xueying Zhang Xiaoyuan Zhan 《International Journal of Applied Ceramic Technology》2018,15(6):1550-1558
Porous alumina ceramics were fabricated by starch consolidation casting using corn starch as a curing agent while their microstructure, mechanical properties, pore size distribution, and corrosion resistance were examined. Results showed that the porous alumina ceramics with the flexural strength of about 44.31MPa, apparent porosity of about 47.67% and pore size distribution in the range of 1‐4 μm could be obtained with 3wt% SiO2 and 3wt% MgO additives. Corrosion resistance results showed mass losses: hot H2SO4 solution and NaOH solution for 10 hours were 0.77% and 2.19%, which showed that these porous alumina ceramics may offer better corrosion resistance in acidic conditions. 相似文献
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以溶胶-凝胶加浸渍法制备了CuO/Al2O3-ZrO2催化剂,对催化剂结构与催化性能进行了表征。结果表明以Al2O3稳定的ZrO2做载体制得的CuO/Al2O3-ZrO2催化剂具有较好的NO转化性能和较低的反应温度。 相似文献
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《Journal of the European Ceramic Society》2022,42(8):3463-3472
Soft LiZnMn ferrites with low coercive force values and small grain sizes were developed by the solution combustion synthesis and low temperature sintering technique for microwave applications at a high frequencies. Bismuth oxide was used as an additive to lower the sintering temperature. The examination covered the influence of Bi2O3 on the crystal structure, microstructure, primary magnetic and dielectric characteristics of lithium-zinc-manganese ferrites. The most promising sample designed for using in microwave devices was produced by sintering at 1075 ℃ temperature for 8 h with added 1.5 wt% Bi2O3. These production conditions have yielded 2.98 µm average grain size in a ceramic product, the density is 4.84 cu cm/g, and the coercive force, residual induction, and saturation induction are 58 A/m, 2078.4 G, and 3439.1 G, respectively. In addition, this sample demonstrates a high initial magnetic permeability (μi = 168), Curie temperature (Tc = 437.5 ℃), high values of the dielectric loss tangent (tan δ? = 6.32?10?3), ferromagnetic resonance line width (ΔH = 280 Oe) and the resonance line of spin waves (ΔHk = 1.87 Oe). Further increase in the bismuth oxide content allows observing a change in the ceramics microstructure, accompanied by a deterioration in the magnetic and electromagnetic characteristics. Here, the discussion covers the mechanism of change in the functional properties of lithium-zinc-manganese ferrites produced in the conditions of solution combustion with added bismuth oxide. Thus, synthesizing of initial pre-ceramic powder by glycine-nitrate combustion and subsequent low-temperature sintering with added bismuth oxide is a novel efficient technique of producing advanced soft high-frequency LiZnMn ferrites. 相似文献
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首先将质量分数为5%的ZrO2溶胶、7%的Al2O3溶胶、3%的SiO2溶胶作为浸渍试剂对核桃壳粉(WSP)浸渍处理。然后以α-Al2O3微粉为主原料,以处理后的WSP为造孔剂,制备了Al2O3多孔材料。研究了溶胶浸渍处理后WSP对多孔材料孔结构、热导率和力学性能的影响。结果表明,在Al2O3多孔材料的孔中可以清楚地观察到WSP的形变,这是优化陶瓷孔结构的重要因素。通过使用质量分数为3%的SiO2溶胶浸渍处理的WSP,可以获得低热导率(200℃,0.297 W·m-1·K-1)和高耐压强度(43.5 MPa)的Al2O3多孔材料,并在孔中发现了莫来石的交叉网络结构。 相似文献
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Kezhuo Li Shengtao Ge Gaoqian Yuan Haijun Zhang Jun Zhang Jiangfeng He Quanli Jia Shaowei Zhang 《Ceramics International》2021,47(8):11240-11248
Spearhead columnar mullite was synthesized by in-situ reaction with V2O5 as additive. When the content of V2O5 was 7 wt%, the length of the spearhead columnar mullite was the longest with an aspect ratio of about 3.5. Furthermore, columnar self-reinforced mullite porous ceramics were prepared by a foam-gelcasting method, and the effects of V2O5 content on the rheological and gelling properties of mullite slurries as well as the microstructure, physical property and thermal insulation property of the prepared mullite porous ceramics were studied. The results showed that the flexural strength and compressive strength of the porous ceramics with 63% porosity prepared by using 2 wt% V2O5 additive were respectively as high as 13.9 and 41.3 MPa, and the thermal conductivity was about 1.04 W m?1 K?1. 相似文献
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A new approach for preparing of microcellular ceramic materials is the reproduction of wood morphologies by biotemplating, where the structural features of the native wood are maintained in the ceramic product. Biomorphic Al2O3-ceramics were manufactured via the sol-gel route by repeated infiltration of low viscous alumina sols into wood preforms and subsequently sintered in air at 1550°C. The microstructure and phase formation during processing were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), density and porosimetry measurements. In contrast to conventional processed, highly-porous Al2O3-ceramics, the microstructure of the biomorphic Al2O3-ceramics is characterized by an uniaxial pore morphology with pore diameters in the micrometer range, depending on the initially used wood template. 相似文献