Influence of coatings on microstructure and mechanical properties of preceramic paper-derived porous alumina substrates
Influence of coatings on microstructure and mechanical properties of preceramic paper-derived porous alumina substrates
复制标题
DOI：
10.1016/j.jmatprotec.2012.09.005
复制
发表时间：
2013-02
影响因子：
6.3
通讯作者：
J. Junkes;B. Dermeik;Björn Gutbrod;D. Hotza;P. Greil;N. Travitzky
中科院分区：
文献类型：
--
作者：
J. Junkes;B. Dermeik;Björn Gutbrod;D. Hotza;P. Greil;N. Travitzky
载无机填料的预陶瓷纸可作为预制体，用于制备轻质陶瓷结构。为了减少纤维素纤维和有机物燃烧造成的孔隙度，采用二氧化硅悬浮液或甲基苯基乙烯基聚硅氧烷两种不同的涂层路线对多孔预陶瓷纸衍生氧化铝衬底进行后处理。铝填充预陶瓷纸在1600℃空气中烧结2h，气孔率分布不均匀，范围为23% ~ 26%。在涂层和渗透后，所有样品都被额外热处理至1500°C 2h。采用热分析法（DTA/TG）测定聚硅氧烷的热解温度。采用扫描电镜（SEM）和x射线衍射（XRD）对其进行微观结构和物相分析。烧结后测定试样的吸水率、表观密度和开孔率，并对涂层前后基体的力学性能进行评价。对于包覆二氧化硅悬浮液的样品，机械强度保持在与未包覆样品相同的范围内，而对于包覆聚硅氧烷的样品，经过多次浸渍步骤后，机械强度稳步增加，达到~ 350MPa。
Preceramic papers loaded with inorganic fillers may be used as preforms in a novel manufacturing technique to fabricate lightweight ceramic structures. In order to reduce the porosity caused by burning out cellulosic fibers and organics, porous preceramic paper-derived alumina substrates were post-treated via two different coating routes using silica suspension or methylphenylvinylhydrogen polysiloxane. Sintering of the alumina-filled preceramic papers in air at 1600°C for 2h resulted in a non-uniform distributed open porosity ranging from 23 to 26%. After coating and infiltration, all samples were additionally heat treated up to at 1500°C for 2h. Thermal analysis (DTA/TG) was applied to determine the pyrolysis temperature of polysiloxane. Microstructure and phase analysis were performed respectively by SEM and XRD. After sintering, water absorption, apparent density and open porosity of test pieces were determined, and mechanical properties of the substrates were evaluated before and after coating. For the samples coated with silica suspension, the mechanical strength remained in the same range of those for uncoated samples, while for the polysiloxane coated samples the mechanical strength steadily increases after repeated impregnation steps, reaching ∼350MPa.