共查询到18条相似文献,搜索用时 62 毫秒
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低温烧成高纯Al_2O_3多孔陶瓷膜支撑体的制备 总被引:2,自引:0,他引:2
为了降低高纯Al2O3(α-Al2O3质量含量≥99%)多孔陶瓷膜支撑体烧成温度,以粒径为30μm的α-Al2O3为原料,分别添加TiO2和TiO2/Cu(NO3)2为烧结助剂,通过干压成型和挤出成型制备片状和管式多孔支撑体。Al2O3-TiO2和Al2O3-TiO2-CuO体系分别在高温下出现的液相低共熔物促进了多孔支撑体的烧结。当氧化铝支撑体中添加0.5%(摩尔分数,下同)TiO2+0.5%Cu(NO3)2后,在1600℃的烧成即可获得机械性能高、渗透性能好和耐酸碱腐蚀性能优异的管式支撑体。在压力为0.1MPa时,支撑体的水渗透通量为12.1m3/(m2·h),弯曲强度为44.5MPa。经过80℃,含10%(质量分数,下同)HNO3的溶液腐蚀800h及80℃,含10%NaOH的溶液1200h后,支撑体的质量损失率分别为1%和0.35%。 相似文献
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以粒径为0.5μm的超细氧化铝粉为原料,加入成孔剂和粘接剂,经干压成型及高温烧结制备出多孔氧化铝陶瓷膜支撑体。制备过程中,以纯水通量为实验指标进行正交试验,分别研究烧结温度、粘结剂含量、成型压力以及聚乙烯醇(PVA)浓度对膜性能的影响程度,并确定制备氧化铝支撑体的最佳工艺条件。使用扫描电镜(SEM)和聚乙二醇(PEG)截留实验对支撑体的微观结构和性能进行表征。实验结果表明:烧结温度和粘接剂含量对支撑体的纯水通量影响高度显著,成型压力和PVA浓度几乎无影响;加入1.75%(w)的粘接剂,80mg/mlPVA溶液2ml,采用9MPa的成型压力和1535℃的烧结温度制备的氧化铝超滤膜支撑体的纯水通量为60kg/(m2h),截留分子量(MWCO)为8 500。 相似文献
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包覆型Al_2O_3粉体制备低温烧成多孔陶瓷膜支撑体 总被引:3,自引:0,他引:3
采用22μmα-Al2O3为骨料,0.5μmα-Al2O3为烧结助剂,一是采用简单机械混合得到上述2种氧化铝的混合粉体,二是通过粉体表面修饰的方法,将0.5μmα-Al2O3包覆在22μmα-Al2O3表面得到包覆型氧化铝粉体。采用上述2种原料,通过干压成型法制备出片状多孔支撑体,考察了不同烧成温度下2种粉体路线制备出的多孔支撑体的弯曲强度、平均孔径、孔隙率和纯水通量。结果表明:在获得相同支撑体性能的前提下,以包覆型氧化铝粉体为原料制备出的支撑体的烧成温度大大低于采用简单机械混合后粉体制备支撑体的。在1550℃的烧成温度下,包覆型氧化铝粉体制备的支撑体的机械强度为34.2MPa,孔隙率为34%,平均孔径为2.34μm,纯水通量为205m3/(m2·h·MPa)。 相似文献
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以平均粒径为4μm的a-Al2O3为起始原料、活性炭为成孔剂,通过干压成型法制备片状多孔Al2O3支撑体。研究了活性炭含量对多孔氧化铝支撑体结构和性能的影响。结果表明:活性炭在高温烧成过程中的氧化可显著提高支撑体的孔隙率,进而提高其渗透性能。当活性炭添加量为17%(质量分数)、烧成温度为1450℃时,支撑体的孔隙率、平均孔径、三点抗弯强度和纯水渗透通量分别达到45.8%,2.1μm,44.6MPa和88m3/(m^2·h·MPa)。经过80℃、10%NaOH溶液腐蚀20d后,支撑体的三点抗弯强度仍可以维持在23.4MPa,表明支撑体具有较好的耐碱腐蚀性能。 相似文献
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以粉煤灰为原料,采用挤压成型和固态粒子烧结法制备管状粉煤灰基多孔陶瓷膜支撑体.采用TG-DSC技术对粉煤灰进行了热分析,采用SEM和XRD技术对样品的微观结构及物相组成进行了分析,并测定了样品的开孔率、抗压强度及空气渗透速率等性能指标.研究了烧结温度、保温时间和造孔剂添加量对支撑体性能的影响.结果表明:支撑体晶相组成主要为赤铁矿、红柱石和石英;烧结温度为1000 ℃,保温2 h,仅添加1%的粘结剂,不添加造孔剂的条件下制备出的管状支撑体综合性能最优,此时的支撑体孔隙率为44.95%,抗压强度为8.92 MPa,空气渗透速率为2.57×104 m3·h-1·m-2·MPa-1. 相似文献
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成孔剂的量对多孔氧化铝支撑体孔结构的影响 总被引:1,自引:0,他引:1
以氧化铝为骨料,淀粉及其它有机粘结剂为成孔剂制备出管状多孔氧化铝支撑体。系统地考察了成孔剂对多孔氧化铝支撑体孔结构的影响。研究表明:当支撑体中成孔剂的质量分数 <10%时,支撑体的孔隙率稳定在35%左右。当成孔剂的质量分数在 10% ~25%之间时,支撑体的孔隙率随成孔剂量的增大而显著增加。当成孔剂的质量分数>25%时,在保证支撑体完整性的前提下,支撑体的孔隙率随成孔剂量的增大变化不大,稳定在 45%左右。成孔剂质量分数的增加会使支撑体的平均孔径增大,孔径分布变宽,平均孔径与最可几孔径的差值增大。 相似文献
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The pore size distribution(PSD)measured by the gas bubble point(GBP)method ofceramic microfiltration(MF)membranes prepared by suspension technique was found to be signifi-cantly influenced by the membrane thickness.A culm-like model for pore structure was introduced tocharacterize the membrane pores instead of the conventional model which does not reflect the radiusvariation along the pore passages and is unable to explain the thickness effect on the membrane PSD.A laminate structure,taking the culm-like model for pore structure into consideration,was hypoth-esized for ceramic MF membranes.A mathematical model was then established to quantitativelydescribe the relationship between the membrane number PSD and the membrane thickness.Goodresults were obtained for the correlation of mean pore size and simulation of the PSD for ceramicMF membranes. 相似文献
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Sintering Effects on the Porous Characteristics of Functionally Gradient Ceramic Membrane Structures 总被引:1,自引:0,他引:1
A method to drain cast porous ceramics has been conceived and established, where samples were shown to have a functionally gradient cross-section with a continuously increasing mean particle size between the two principal surfaces.Ceramic discs approximately 45 mm in diameter, and 3.3 mm thick were cast by sedimentation. These green bodies were dried prior to sintering. Maximum sintering temperature and the length of the sintering soak time were varied for samples made from suspensions of both 5 and 10 volume percent solids. Mercury porosimetry was used to obtain the porosity and pore size distribution in each sample. Additionally, a number of atomic force microscopy (AFM) measurements were made on some samples in order to correlate bulk porous properties with those on the outside surfaces.The results showed that as the sintering temperature increased, the densification of the bodies proceeded more rapidly. In general, the longer the sintering soak time, the denser the samples became as well. For the samples prepared at the lower temperatures however, the porosity showed less of a soak time dependence. The green body had a clustered and asymmetric microstructure, which contributed to differing degrees of localized densification and coarsening effects depending on the sintering temperature. Densification effects were more pronounced with the samples made from the more concentrated suspenisions.There was an inverse correlation between the bulk and surface pore dimensions, attributable to the different size scales of particles in the two regions. The much finer surface layer particles were able to undergo some amount of densification while surface diffusion sintering mechanisms were primarily at work elsewhere in the structure. 相似文献
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