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流延法制备低温烧结的高热导率AlN基片 总被引:6,自引:2,他引:4
本文研究了流延法制备低温烧结的高热导率AlN基片过程中影响流延浆料粘度的主要因素,结果表明,溶剂比例的增加会导致浆料粘度下降。增塑剂的减少则使粘度上升,本文还研究了添加剂对AlN陶瓷烧结及热导性能的影响,实验表明B2O3能以过渡液相的形式促进烧结,而Dy2o3在低温下人较好的去除AlN晶格氧的能力,通过添加Dy2O3、B2O3等组成的混合助烧结剂。在1650℃下烧结4h,获得了热导率高达130W/ 相似文献
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研究了有机物对CLST陶瓷流延浆料性能的影响.结果表明:体积比为1∶3的乙醇与氮-氮二甲基甲酰胺为混合溶剂对粉料的湿润性能最好,以聚乙烯醇缩丁醛( PVB)为粘结剂,邻苯二甲酸二丁酯为增塑剂,蓖麻油为分散剂配制了CLST陶瓷流延浆料.当w(分散剂)为0.8%,w(粘结剂)为8%,固相体积分数为50%,R(增塑剂:粘结剂... 相似文献
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采用乳化机将MAS(MgO-Al2O3-SiO2)系微晶玻璃粉与有机组分均匀混合制成浆料,流延出生带。研究了流延工艺中多种因素对生带厚度、浆料干燥成膜过程及规律的影响。结果表明:乳化机混料的效果与传统的球磨方式相同。生带厚度主要由刮刀间隙控制,流延速度对其影响很小;温度越高,浆料干燥速率越快。较佳的流延工艺参数为:刮刀间隙300μm,流延速度6mm/s,干燥温度25℃。 相似文献
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以BaCO3和TiO2粉末为原料,采用固相反应法合成Ba2Ti9O20的粉体,并以此粉体为主要原料添加适量的分散剂、粘结剂及塑性剂,采用流延法制备Ba2Ti9O20陶瓷膜片。研究了不同种类和配比的溶剂、不同种类和含量的分散剂对Ba2Ti9O20流延浆料的流变特性的影响。结果表明,当选用异丙醇和甲苯(体积比为75:25)为溶剂,固含量Ba2Ti9O2054wt%,分散剂蓖麻油0.5wt%,粘结剂聚乙烯醇缩丁醛5wt%,塑性剂聚乙二醇5wt%时,流延浆料的流变性能较好,浆料的粘度为9.1Pa.s。 相似文献
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高固相、低粘度浆料的获得是凝胶注模成型工艺实现的关键,而分散剂在浆料制备中作用至关重要,采用柠檬酸三胺(TAC)和聚甲基丙烯酸胺(PMAA-NH4)作为压电陶瓷PMN-PZT浆料的分散剂,讨论了两种分散剂对浆料稳定性和流变性的影响。对加入分散剂前后的PMN-PZT浆料进行粒度测定和扫描电镜分析,结果表明:两种分散剂均能减少陶瓷浆料中的颗粒团聚,使颗粒分散更均匀,PMAA-NH4的分散效果优于TAC。 相似文献
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本研究采用一种快速凝胶的氮化铝凝胶通过在氮气气氛下烧结制备AlN陶瓷。将AlN粉体、少量的Y2O3粉体(烧结助剂)和去离子水以一定比例混合制得AlN浆料, 在浆料中加入一种新型的水溶性共聚物Isobam(由异丁烯和马来酸酐形成的共聚物)作为交联剂, 所得浆料在室温空气中自发凝胶成型。研究了Isobam和AlN、Y2O3粉体表面的有机包裹剂聚亚氨酯对浆料流变性能和凝胶性能的影响。结果表明, 加入0.3wt% Isobam可制备出固含量达52vol%的低粘度(0.2 Pa·s)AlN浆料。将凝胶干燥并脱粘, 获得的AlN素坯在氮气气氛下1800 ℃烧结4 h, 可制备出鳍状AlN陶瓷, 所得陶瓷的密度为3.33 g/cm3, 热导率为204 W/(m·K)。 相似文献
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Tape casting of AlN/glass composites for LTCC substrate 总被引:1,自引:0,他引:1
Qingxue Zhang Xiaojun Luo Wenlan Li Hanrui Zhuang Dongsheng Yan 《Journal of Materials Science》2003,38(8):1781-1785
AlN/glass composite is low-fired substrate material for microelectronic packaging material. In this work, AlN/glass sheets were prepared by tape casting process. The dispersion, stabilization and the rheological properties of the slurry were studied. The optimum drying condition and mechanisms of debinding were also investigated. The results showed that powder size influenced the optimum content of dispersant and the viscosity of slurry. The slurry for tape casting exhibited a typical shear-thinning behavior. Smooth green tape without cracking was acquired after it was dried at solvent atmosphere. The binder was fully burned out at 600°C at low heating speed. The lamination with uniform microstructure was achieved by hot-pressed at 900°C. 相似文献
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采用基于密度泛函理论(DFT)的第一原理方法,研究了外加电场对单层AlN薄片储氢性能的影响。通过几何优化得到AlN薄片最稳定的吸氢位置为N原子顶位。研究结果表明:在一定范围内,随着外加电场强度的增加,H2分子在AlN薄片上的吸附能逐渐增大,N—H键长越来越小,H—H键长越来越大。态密度分析表明,加上外电场之后,H-1s轨道与N-2p轨道杂化导致N与H间的交互作用增强。说明电场极化使AlN薄片与H2分子结合得更加紧密,大大提高了AlN薄片的储氢稳定性。而一旦撤销外加电场,H2分子又能恢复到在AlN薄片上的物理吸附状态,使得吸放氢可逆。研究还发现在电场作用下,可同时在AlN薄片的上下表面各吸附一层H2分子,储氢容量显著提高。 相似文献
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Elmazria O El Hakiki M Mortet V Assouar BM Nesládek M Vanecek M Bergonzo P Alnot P 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》2004,51(12):1704-1709
In this work, the effect of a diamond nucleation process on freestanding aluminium nitride (AlN)/diamond surface acoustic wave (SAW) device performances was studied. Before diamond deposition, silicon (Si) substrates have been mechanically nucleated, using an ultrasonic vibration table with submicron diamond slurry, and bias-enhanced nucleated (BEN). Freestanding diamond layers obtained on mechanically scratched Si substrates exhibit a surface roughness of R(MS) = 13 nm, whereas very low surface roughness (as low as R(MS) < or = 1 nm) can be achieved on a freestanding BEN diamond layer. Propagation losses have been measured as a function of the operating frequency for the two nucleation techniques. Dispersion curves of phase velocities and electromechanical coupling coefficient (K2) were determined experimentally and by calculation as a function of normalized thickness AlN film (kh(AlN) = 2pi h(AlN)/lambda). Experimental results show that the propagation losses strongly depend on the nucleation technique, and that these losses are weakly increased with frequency when the BEN technique is used. 相似文献
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Shichao Liu Feng Ye Limeng Liu Quang Liu Junyi Li 《Materials and Manufacturing Processes》2015,30(5):605-610
High compacted aluminum nitride (AlN) substrates were prepared by aqueous tape casting. Aluminium dihydrogen phosphate was used to modify AlN particle surface from hydrolysis during casting process. The absolute value of zeta potential for the AlN particle treated by Al(H2PO4)2 was 60mv at pH = 9. The slurry suitable for tape casting was prepared which possessed shear-thinning behavior and appropriate viscosity. The results showed that the green tapes own excellent properties including high bulk density, uniform pore distribution and low porosity. The samples were fired at 1700°C (lower than melting point of Pt) with pressureless sintering process which can be used to fabricate complex device. 相似文献
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Aluminium nitride (AlN) one-dimensional (1D) nanostructures, including crystalline nanowires, faceted nanotubes and conventional single-walled nanotubes, were investigated by means of density functional theory (DFT) using the generalized gradient approximation (GGA). While the larger diameter crystalline nanowires are the most favoured energetically of all these 1D nanostructures, the thick faceted nanotubes have comparable binding energies and can be obtained experimentally. The single-walled nanotubes have the lowest binding energies, and are less feasible experimentally. Due to the surface states at the band edges, the band gaps of all the AlN 1D nanostructures are much smaller than that of bulk AlN. The band structures of AlN nanowires can be modified by NH(3) adsorption. Consequently AlN nanowires have potential applications as gas sensors, since their electronic structures are very sensitive to NH(3) adsorption. 相似文献
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本工作研究了焙烧Mg-Al水滑石(LDO)水泥浆涂层对钢筋氯离子腐蚀的缓蚀性能。将焙烧Mg-Al水滑石材料添加到水泥浆中制备了复合水泥浆涂层,并涂覆在钢筋表面。由等温吸附实验、线性极化测试(LP)、电化学阻抗谱测试(EIS)研究了在混凝土模拟孔溶液中复合水泥浆涂层对钢筋氯离子腐蚀的缓蚀性能;此外,采用X射线衍射仪(XRD)和傅里叶变换红外光谱(FT-IR)检测了吸附实验前后水泥浆的物相变化,探讨了焙烧Mg-Al水滑石水泥浆涂层对钢筋氯离子腐蚀的缓蚀机理。结果表明,LDO的掺入能显著提高水泥浆体对氯离子的饱和吸附量,且随着LDO掺量的增加,复合水泥浆涂层的综合阻锈效果增强。复合LDO涂层缓释机理归因于层状结构的复原使其能有效地吸附氯离子并释放氢氧根离子,从而能有效阻止氯离子的侵蚀。 相似文献
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In order to form ice slurry in ice storage, W/O emulsion was made from water–oil mixture with a small amount of surfactant. And, it was proved that ice slurry could be formed even in a metal vessel, which is expected to improve ice formation rate, without ice adhesion to a cooling vessel wall because of a structural feature of the emulsion. In this paper, authors proposed application of ice slurry to cold storage of foods. In order to apply ice slurry to cold storage of foods, a new harmless ice slurry to human being was formed by cooling a new W/O emulsion made from tap water–edible oil mixture with a small amount of edible emulsifier. And, the fundamental characteristics and availability of new W/O emulsion-ice slurry formed were clarified. Finally, it was concluded that new harmless ice slurry to human being could be fully applied to cold storage of foods. 相似文献
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常规砂浆无法满足反倾斜裂隙和缺陷的工程填充要求,在注浆压力驱使下会引入大量气泡,浆液密实度得不到保障。针对此,研发了一种新型磁性环氧树脂水泥(MEC)浆液,可实现反重力式注浆锚固、导向式流动、增大浆体密实度、浆液黏度实时调控。采用SEM、XRD、N2吸附测试方法,对MEC浆液在不同磁场作用下的微观形貌、水化产物和孔径进行了分析。结果表明:MEC浆液主要分为环氧树脂固化、水泥水化两个硬化过程。固化产物对水化产物进行包裹,与钙矾石(Ettringite,AFt)和Ca(OH)2中的Ca2+发生离子作用,形成络合物包裹磁粉,对浆液中存在的微小孔隙进行填充;磁场强度由400 GS增大到6 000 GS时,孔隙面积减小率达77.6%,孔隙数量减小率达76.8%。N2吸附试验表明:附加磁场会降低介孔和大孔的数量,显著减小比表面积,磁性浆液符合H4型滞回线,主要表现为墨水瓶孔;基于磁偶极子理论,数值模拟了磁颗粒受力,分析结果表明在磁场强度为2 000~6 000 GS可高效减小孔隙面积。 相似文献