共查询到20条相似文献,搜索用时 171 毫秒
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用水溶液挤压法制备了24个CaCl2/ENG成型混合吸附剂样品,利用目前闪光扩散法测量导热系数最先进的仪器——LFA447激光导热仪对样品进行了导热系数的测试。研究表明:挤压法制备的样品垂直于压力方向上的导热系数高于平行于压力方向上的,大约是其1.1~1.2倍,具有各向异性;在一定范围内,随着固化密度的增加导热系数不断增加,随着氯化钙和膨胀石墨质量比的减小导热系数也不断增大;在氯化钙和ENG的质量比为2∶1,固化密度从600kg/m3增加到700kg/m3的过程中导热系数增加得最为明显,固化密度和膨胀石墨的含量对成型吸附剂样品的导热系数的影响有耦合作用。 相似文献
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以无涂层、C+SiC复合涂层处理的炭布/网胎预制体,分别经过化学气相渗透、树脂浸渍/炭化制备了3种C/C坯体,熔融渗硅后获得不同的C/SiC复合材料,对其组织结构和导热性能进行了研究。结果表明:热解炭坯体的C/SiC复合材料存在集中分布的Si,混合基体炭的C/SiC中可见较多微裂纹,C+SiC涂层的材料中残留Si含量少,基体组织均匀;热解炭坯体的C/SiC复合材料热扩散率和导热系数最大;混合基体炭的坯体,纤维经过C+SiC涂层,可明显提高材料的热扩散率和导热系数,且随温度的升高,导热系数的下降速率增大。 相似文献
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采用廉价原料和简单工艺制备了具有高强度和低导热系数的硬硅钙石板复合材料,重点研究了成型压力、玻璃纤维添加量等因素对硬硅钙石板的隔热性能和力学性能的影响.结果表明:随着成型压力的增大,硬硅钙石板样品的密度、导热系数、抗压强度及抗折强度都逐渐增大;随着短切玻璃纤维添加量的增加,硬硅钙石板样品的密度和导热系数基本保持不变,抗压强度及抗折强度则呈现先增大后减小的变化趋势.当成型压力和短切玻璃纤维添加量分别为30 MPa和5%(wt)时,硬硅钙石板的导热系数为0.114 W·m-1·K-1,抗压强度和抗折强度分别达到20.17 MPa和7.22 MPa. 相似文献
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The composition of a stiff molding mixture has been developed for making concrete ceramic solid brick by press molding or vibrocompression. The brick has a standard size, beige or light red color, and meets the requirements of GOST 530–95. The production cost of this brick is 30–35% lower than that of analogous ceramic bricks because the firing operation is excluded from the production cycle. 相似文献
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Yu Kuo-Tsen 《Refractories and Industrial Ceramics》1960,1(1-2):69-74
Conclusions With increased pressure the effects of the grain distribution on the porosity of the green compact gradually decreases.The higher the amount of fine fractions in the mixture the lower the porosity of the green compact at similar pressure. As the molding pressure increases the effect of the fineness of the ground batch on the porosity of the green compact decreases.By the introduction of grains with a maximum size of 4, 6 and 8 mm into the mixture and a simultaneous increase in the molding pressure the porosity of brick is reduced. The spalling resistance of the brick is superior to that of brick prepared from 0.0 to 2 mm fractions. Lowest spalling resistance was observed in brick made from a mass with 0.0 to 1.0 mm grains.In order to increase refractoriness-under-load by decreasing the amount of fused substances at elevated temperatures the mixture should be ground finer and the sintering temperature raised during the manufacturing of magnesite powder or brick; increased molding pressures fail to affect refractoriness-under-load.In using high-density magnesite for the production of magnesite brick which contains an insignificant amount of fused inclusions at elevated temperatures regular grinding may be applied (for small fractions) to coarse-grained mixtures and higher pressure as well as regular sintering temperatures. Brick with a low density (6.2%), a rather high spalling resistance (39 air heating — cooling cycles) and a high refractoriness-under-load (1680° C) is produced.Fon T'ienjung, Liu Kung fu, Ch'ang Ai ch'ihn, Hai Ch'eng, Sun shu sheng and Li Yu cheng participated in the study. 相似文献
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许建文;刘斌;顾永华 《中国塑料》2009,23(11):69-74
采用田口实验设计方法与BP(Back Propagation)神经网络技术,选取模具温度、模压时间、注射压力和模压压力四因素四水平安排正交实验,分析了工艺参数对EVA塑料发泡倍率的影响程度。结果发现,模具温度对发泡倍率的影响较为显著,模压时间次之,注射压力与模压压力的影响较小。最后选取对倍率影响较大的模具温度、模压时间与注射压力工艺参数,对不同形状与尺寸的标准试样模具安排正交实验,以实验结果作为神经网络的样本数据,经过训练后的神经网络能够较为准确地预测EVA塑料的发泡倍率。 相似文献
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《应用陶瓷进展》2013,112(2):72-76
AbstractA study of the effect of cement in the formation of efflorescence on the surface of ceramic building materials was conducted. Wicking tests were performed with bricks covered with cement, and a test procedure, where temperature and water pressure applied to the samples could be controlled, has been developed. Salts formed at brick surfaces consist of arcanite (K2 SO4 ). Results show that salt deposition kinetics are enhanced by higher test temperature and particularly by imposing water pressure around the brick. A method to quantify efflorescence was developed in order to avoid any subjectivity in the assessment of the test results. Image analysis offers an alternative for quantification of this phenomenon. Study of efflorescence digital images lead to the definition of an efflorescence coefficient. A set of samples with low to high levels of efflorescence was used and the results show a clear distinction between different degrees of efflorescence. It is concluded that this process is a valid one for quantifying the efflorescence phenomenon. 相似文献
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冲击参数对氧化铝基耐火材料常温耐磨性的影响 总被引:4,自引:2,他引:2
参照GB/T18301《耐火材料常温耐磨性试验方法》,分别以标准碳化硅砂(36#)、电熔白刚玉砂(36#)和石油支撑剂用陶粒为磨损介质,采用不同压力(300kPa、448kPa和600kPa)的压缩空气和不同量(1kg、2kg)的磨损介质对普通高铝砖(LZ-65和LZ-75)、高炉用高铝砖、磷酸盐结合高铝砖、高纯刚玉砖、刚玉莫来石砖、铬刚玉砖、赛隆结合刚玉砖、微孔刚玉砖和塑性相复合刚玉砖等10种氧化铝基耐火材料进行了磨损实验。结果表明:(1)随着冲击气体压力的增大,10种材料的磨损量都增加,但由于这些材料在组成和结构上的差异,其磨损量增加的幅度存在明显差异。(2)由于磨损介质的颗粒形状和体积密度不同,在相同的冲击气体压力下,磨损介质的流动速度不同,对材料的磨损量也不同,其中,采用碳化硅时磨损量最大,采用白刚玉时次之,采用陶粒时最小。(3)当磨损介质碳化硅砂用量增加1倍时,材料的磨损量增加,但不同材料的磨损量增加幅度不同,其中微孔刚玉砖和磷酸盐结合高铝砖分别增加了1.84倍和1.26倍,而高纯刚玉砖和高炉用高铝砖增加的不足0.4倍。(4)耐火材料的常温耐磨性能取决于其强度和结构的致密性,强度和致密度较高的材料耐磨性能较好。 相似文献