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碳酸钙晶须的制备与应用研究进展 总被引:6,自引:2,他引:4
文石相碳酸钙是一种新型环保晶须材料,由于造价低廉,使其具有很强的市场竞争力.综述了国内外在文石相碳酸钙晶须的制备和应用方面的研究进展,特别是国内碳酸钙晶须的开发现状和性能特点,分析了其市场前景. 相似文献
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碳化法制备均一文石晶须的研究及机理探讨 总被引:9,自引:0,他引:9
利用改进的碳化法制备了文石型碳酸钙晶须 ,讨论了温度、MgCl2 浓度、初始 pH值、CO2 的流速、搅拌速度对文石晶须制备的影响 ,探讨了其影响机理。采用高倍显微镜—计算机联用技术和X射线衍射技术进行产品形貌观察和晶型分析。实验表明在一定温度下的稳定反应体系中 ,维持较低的过饱和度 ,保证成核与生长的分离可制备出均一的文石晶须。实现这一条件的工艺参数为pH值维持在 9左右 ,反应温度为 70℃ ,CO2 流速为 4 .5mL/min( 1gCaO) ,搅拌速度为 2 0 0r/min。 相似文献
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碳酸钙晶须可以有效改善水泥基复合材料在常温下的压缩性能,但是高温作用后碳酸钙晶须对材料压缩性能的影响尚不清楚。研究了不同体积掺量(0%、0.5%、1%、2%)的碳酸钙晶须增强水泥基复合材料分别在常温以及200,400,600和800℃高温作用后的压缩性能。试验结果表明,常温下随着晶须掺量的提高,试件的抗压强度和压缩韧性呈先上升后下降的趋势,其中掺入1%碳酸钙晶须的材料压缩性能最好。200℃条件下材料的抗压强度和压缩韧性较常温均有明显提高,而当目标温度超过200℃后,高温对材料的压缩性能劣化作用明显,其抗压强度和压缩韧性持续衰减,800℃作用后各组的压缩性能已没有明显差距,但在每个目标温度作用下,碳酸钙晶须均可以提高高温作用后的抗压强度值和压缩韧性值,说明碳酸钙晶须的掺入对提高材料在高温作用后的压缩性能有积极作用。 相似文献
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为了探究碳酸钙晶须对钢纤维/PVA混杂纤维增强高延性水泥基复合材料(HyFRHDCC)力学性能的影响,利用2%体积掺量的廉价碳酸钙晶须替代部分纤维,研究了不同纤维掺量HyFRHDCC的压缩性能和拉伸性能,利用扫描电子显微镜观察了HyFRHDCC的微观结构。研究结果表明,引入碳酸钙晶须能够提高HyFRHDCC的初裂拉伸应变和峰前压缩韧性;在1.5%PVA+0.25%钢纤维HyFRHDCC中掺入2%碳酸钙晶须可以改善材料的拉伸性能;当PVA纤维减少至1%时,HyFRHDCC出现了明显的应变软化行为。微观形貌分析发现,碳酸钙晶须能够通过裂纹偏转、晶须拔出以及裂缝桥联等微观机制改善HyFRHDCC的应变硬化行为。 相似文献
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淡水珍珠的生物矿化机理研究进展 总被引:2,自引:0,他引:2
碳酸钙广泛存在于生物矿物中, 是地球上最普遍的生物矿物之一。贝壳和珍珠的主要组成部分为碳酸钙无机相。我国淡水养殖珍珠多数品质优异, 具有良好的珍珠光泽。该种珍珠以文石晶型碳酸钙为无机相, 称为文石珍珠。近年来, 在我国淡水养殖珍珠中发现了球文石的存在, 球文石的出现是导致珍珠失去光泽、降低质量的主要原因。本文对比阐述了淡水文石珍珠和球文石珍珠的微观结构与性能, 总结了与珍珠层有关的体外模拟碳酸钙生物矿化的实验结果, 提出了珍珠层生物矿化机理未来的研究方向。 相似文献
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固相原料反应生成碳化硅晶须的实验研究 总被引:3,自引:0,他引:3
实验研究了三种碳原料和七种硅原料反应生成SiC晶须工艺过程,结果表明,反应生成碳化硅晶须的固相原料中,除稻壳外,白炭黑作为硅源,喷雾炭墨作为碳源,加入适当催化剂也可以得到高品位碳化硅晶须,纯度在95%以上,生成率在25%以上。 相似文献
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提出一种自石灰石矿粉中直接提取CaCO_3晶须的碳化-分解方法。该方法能够以天然石灰石矿粉为原料,通过水溶性碳酸的作用溶解出Ca(HCO_3)_2,进而在升温条件下通过Ca(HCO_3)_2的分解反应得到形貌规整的棱锥状CaCO_3晶须。扫描电镜观测与X射线衍射分析显示,Ca(HCO_3)_2分解温度对CaCO_3晶须微观形貌的影响显著,晶须长度与长径比随分解温度的升高均呈上升趋势,但分解温度超过80℃会导致文石晶相向方解石晶相转化。实验结果表明,80℃、2h条件下,Ca(HCO_3)_2分解产物中文石晶相含量较高,晶须几何形貌更为合理,其平均长度为14.61 μm、长径比为8.10。 相似文献
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Outstanding mechanical properties of biological multilayered materials are strongly influenced by nanoscale features in their structure. In this study, mechanical behaviour and toughening mechanisms of abalone nacre-inspired multilayered materials are explored. In nacre''s structure, the organic matrix, pillars and the roughness of the aragonite platelets play important roles in its overall mechanical performance. A micromechanical model for multilayered biological materials is proposed to simulate their mechanical deformation and toughening mechanisms. The fundamental hypothesis of the model is the inclusion of nanoscale pillars with near theoretical strength (σth ~ E/30). It is also assumed that pillars and asperities confine the organic matrix to the proximity of the platelets, and, hence, increase their stiffness, since it has been previously shown that the organic matrix behaves more stiffly in the proximity of mineral platelets. The modelling results are in excellent agreement with the available experimental data for abalone nacre. The results demonstrate that the aragonite platelets, pillars and organic matrix synergistically affect the stiffness of nacre, and the pillars significantly contribute to the mechanical performance of nacre. It is also shown that the roughness induced interactions between the organic matrix and aragonite platelet, represented in the model by asperity elements, play a key role in strength and toughness of abalone nacre. The highly nonlinear behaviour of the proposed multilayered material is the result of distributed deformation in the nacre-like structure due to the existence of nano-asperities and nanopillars with near theoretical strength. Finally, tensile toughness is studied as a function of the components in the microstructure of nacre. 相似文献
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目的 将来源于自然的细菌纤维素作为包装材料应用于包装领域,以取代传统的塑料包装材料.方法 综述近几年细菌纤维素在包装领域的研究与应用现状,介绍细菌纤维素的基本培育过程、改性技术和制备方法,阐述细菌纤维素在包装领域的研究与应用.结果 细菌纤维素通过层层组装、聚合、联接等方式,可与多种聚合物高效复合,形成不同微观尺寸和结构特性的纤维素基多孔复合材料,从而改善其力学性能和物理性能,并可调控其阻隔性能和抗菌灭菌性能.常用细菌纤维模式为纳米细菌纤维和纳米细菌晶须.结论 细菌纤维素材料及其复合材料完全可以替代塑料用于包装领域,在食品包装和智能包装上的研究和应用前景较大. 相似文献
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F. Monchau Ph. Hivart B. Genestie F. Chai M. Descamps H.F. Hildebrand 《Materials science & engineering. C, Materials for biological applications》2013,33(1):490-498
Close to the bone mineral phase, the calcic bioceramics, such as hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP), are commonly used as substitutes or filling materials in bone surgery. Besides, calcium carbonate (CaCO3) is also used for their excellent biocompatibility and bioactivity. However, the problem with the animal-origin aragonite demands the new technique to synthesize pure calcite capable of forming 3D bone implant. This study aims to manufacture and evaluate a highly-pure synthetic crystalline calcite with good cytocompatibility regarding to the osteoblasts, comparing to that of HA and β-TCP. After the manufacture of macroporous bioceramic scaffolds with the identical internal architecture, their cytocompatibility is studied through MC3T3-E1 osteoblasts with the tests of cell viability, proliferation, vitality, etc. The results confirmed that the studied process is able to form a macroporous material with a controlled internal architecture, and this synthesized calcite is non-cytotoxic and facilitate the cell proliferation. Indeed requiring further improvement, the studied calcite is definitely an interesting alternative not only to coralline aragonite but also to calcium phosphate ceramics, particularly in bone sites with the large bone remodelling. 相似文献
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《Materials Science & Technology》2013,29(12):1438-1443
AbstractThis research is concerned with thermodynamic control of inorganic whisker synthesis in existence of some additives. The polymorphism and morphology control of calcium carbonate (CC) is an active research area because of wide applications of CC. Magnesium chloride has been used to improve the formation of aragonite whisker synthesised from Ca(OH)2 and CO2. However, the reaction kinetics and the purity of final products affected by MgCl2 have not been theoretically studied. In the present research quantitative thermodynamic calculation showed that MgCl2 can decrease relative supersaturation by several orders of magnitude and so is favourable to the formation of aragonite. High reactant ratio of MgCl2/Ca(OH)2 will give a marked decrease in pH within the transformation of Ca(OH)2 into Mg(OH)2, but a small decrease in pH in the following CaCO3 formation, which is disadvantageous to the control of the synthesis with pH. Both solid Mg(OH)2 and MgCO3 may exist in aragonite product, but can be avoided by pH control. Maximum MgCO3 content in aragonite product is <1·00 wt-% and MgCO3 can be removed by slightly decreasing pH using excessive CO2 adsorption, which will result in a negligible decrease in Ca2+ conversion and an increase in carbonate ion concentration. High carbonate ion concentration, unfortunately, is disadvantageous to the reuse of MgCl2 solution. The present study gives a guidance of synthesising aragonite in the presence of inorganic salts such as MgCl2. 相似文献