以尿素催化硅酸乙酯水解制得SiO2溶胶。采用29Si NMR、27 Al NMR、FT-IR、TEM、DTA、XRD和SEM等对SiO2溶胶、Al2O3凝胶纤维化学结构和微观结构研究结果表明,该SiO2溶胶稳定性好,含有大量的单硅酸Si(OH)4,能和Al2O3表面的Al—OH反应生成A...以尿素催化硅酸乙酯水解制得SiO2溶胶。采用29Si NMR、27 Al NMR、FT-IR、TEM、DTA、XRD和SEM等对SiO2溶胶、Al2O3凝胶纤维化学结构和微观结构研究结果表明,该SiO2溶胶稳定性好,含有大量的单硅酸Si(OH)4,能和Al2O3表面的Al—OH反应生成Al—O—Si键而有效地将其包裹,从而阻止了过渡态Al2O3微晶的相互接触,抑制了α-Al2O3的成核和生长。展开更多
The precursor sol of alumina was prepared by sol-gel method with aluminum nitrate and malic acid as raw materials.The effects of content of malic acid and polyvinylpyrrolidone （PVP） on sol spinnability were explored...The precursor sol of alumina was prepared by sol-gel method with aluminum nitrate and malic acid as raw materials.The effects of content of malic acid and polyvinylpyrrolidone （PVP） on sol spinnability were explored.The gel fibers with above 80 cm in length were obtained by mixing aluminum nitrate,malic acid and PVP on mass ratio of 10 3 1.5.Thermogravimetry-differential scanning calorimetry （TG-DSC）,Fourier transform infrared （FTIR） spectrum,X-ray diffractometry （XRD）,and scanning electron microscopy （SEM） were used to characterize the properties of the gel and ceramic fibers.The alumina fibers with a smooth surface and about 20μm in diameter were obtained by sintering at 1 200℃,and their main phase was indentified to be α-Al2O3.展开更多
针对硬质碳毡在高温下由于辐射传热严重存在导热系数偏高的问题,以氧化铝纤维为主要原料,以石墨箔为辐射屏蔽层,以酚醛树脂为粘接剂和浸渍剂,采用真空压滤和浸渍炭化工艺制备出了层状复合氧化铝纤维硬质隔热毡。对其微观结构、力学性能...针对硬质碳毡在高温下由于辐射传热严重存在导热系数偏高的问题,以氧化铝纤维为主要原料,以石墨箔为辐射屏蔽层,以酚醛树脂为粘接剂和浸渍剂,采用真空压滤和浸渍炭化工艺制备出了层状复合氧化铝纤维硬质隔热毡。对其微观结构、力学性能和隔热性能进行了测试和分析,结果表明:酚醛树脂炭化后对材料基体产生的"铠装"和"锚固"作用使材料具备了一定刚性;采用酚醛树脂浓度35%浸渍的样品层间抗拉强度达70 k Pa,1000℃导热系数为0.18W/(m·K);在热面1000℃的隔热效果测试中,10 mm样品冷面平衡温度为640℃,比市售碳毡低200℃,隔热性能优异。展开更多
文摘以尿素催化硅酸乙酯水解制得SiO2溶胶。采用29Si NMR、27 Al NMR、FT-IR、TEM、DTA、XRD和SEM等对SiO2溶胶、Al2O3凝胶纤维化学结构和微观结构研究结果表明,该SiO2溶胶稳定性好,含有大量的单硅酸Si(OH)4,能和Al2O3表面的Al—OH反应生成Al—O—Si键而有效地将其包裹,从而阻止了过渡态Al2O3微晶的相互接触,抑制了α-Al2O3的成核和生长。
基金Project(2010K10-21) supported by the Natural Science Foundation of Shaanxi Province,China
文摘The precursor sol of alumina was prepared by sol-gel method with aluminum nitrate and malic acid as raw materials.The effects of content of malic acid and polyvinylpyrrolidone （PVP） on sol spinnability were explored.The gel fibers with above 80 cm in length were obtained by mixing aluminum nitrate,malic acid and PVP on mass ratio of 10 3 1.5.Thermogravimetry-differential scanning calorimetry （TG-DSC）,Fourier transform infrared （FTIR） spectrum,X-ray diffractometry （XRD）,and scanning electron microscopy （SEM） were used to characterize the properties of the gel and ceramic fibers.The alumina fibers with a smooth surface and about 20μm in diameter were obtained by sintering at 1 200℃,and their main phase was indentified to be α-Al2O3.
文摘针对硬质碳毡在高温下由于辐射传热严重存在导热系数偏高的问题,以氧化铝纤维为主要原料,以石墨箔为辐射屏蔽层,以酚醛树脂为粘接剂和浸渍剂,采用真空压滤和浸渍炭化工艺制备出了层状复合氧化铝纤维硬质隔热毡。对其微观结构、力学性能和隔热性能进行了测试和分析,结果表明:酚醛树脂炭化后对材料基体产生的"铠装"和"锚固"作用使材料具备了一定刚性;采用酚醛树脂浓度35%浸渍的样品层间抗拉强度达70 k Pa,1000℃导热系数为0.18W/(m·K);在热面1000℃的隔热效果测试中,10 mm样品冷面平衡温度为640℃,比市售碳毡低200℃,隔热性能优异。
