YSZ多孔隔热材料的制备与性能研究
发布时间：2019-01-30 16:10
【摘要】：本文创新性地采用二氧化硅气凝胶作为成孔剂制备轻质氧化锆多孔隔热材料,借助XRD、FT-IR、FE-SEM、TEM、万能材料试验机和导热系数仪等测试手段系统研究了Si O2气凝胶加入量、甘油用量、料浆p H值以及热处理温度对隔热材料导热系数、抗压强度、密度等性能的影响。为进一步提高隔热材料的综合性能,本文应用碳模板法成功制备出氧化锆空心球,研究了碳模板表面改性时间对氧化锆空心球制备的影响,为今后以氧化锆空心球替代氧化锆粉体制备高性能的多孔隔热材料奠定了坚实的基础。通过系统研究得出如下结论:(1)当添加30wt%的Si O2气凝胶时,料浆粘度适中,样品孔径小而均匀,导热系数达到最低值,隔热性能最佳;气凝胶加入量过少或过多会使料浆粘度过小或过大,造成孔分布不均,从而影响隔热性能。(2)加入适量甘油可以有效防止纳米粉制备料浆在干燥中的团聚,形成均匀的纳米孔,从而提高样品的隔热性能;甘油加入量过少或过多,均不利于孔的均匀分布,因此会影响样品的隔热性能。(3)当p H=4~12时,隔热材料的导热系数呈“W”型变化。p H=10时,料浆ζ-电位的绝对值达到最大值,有利于促进YSZ粉体和气凝胶均匀分散,形成均匀的纳米孔,从而使得样品的导热系数最小。(4)温度过低(≤400℃)时,由于样品中还残余着大量C,导热系数较高;温度超过600℃,材料中的孔径增大,即由均匀的纳米孔变成亚微米孔甚至微米孔,致使其导热系数增加。(5)应用优化的工艺参数(Si O2气凝胶加入量为30 wt%,甘油用量为50 wt%,料浆p H值为10,热处理温度为600℃),制备出综合性能优于相关文献值的材料,其指标为:导热系数为0.043 W/(m?k),抗压强度为35.6 MPa,密度为1.51g/cm3,气孔率为60.9%。(6)采用碳模板法制备氧化锆空心球时,空心球产物由四方相Zr O2组成。通过碱处理能有效地增加碳球模板表面的官能团数目,改善碳球表面的荷电状态和亲水性,从而调控核-壳结构中壳层的厚度;随着碳球表面改性时间从0 h增加到6 h时,空心球的壁厚逐渐增大,比表面积从104.7 m2/g逐渐减少到47.9 m2/g。
[Abstract]:In this paper, silica aerogel was used as pore forming agent to prepare light zirconia porous heat insulation material, and XRD,FT-IR,FE-SEM,TEM, was used to prepare the porous thermal insulation material. The effects of the amount of Si O2 aerogel, glycerol dosage, slurry pH value and heat treatment temperature on the thermal conductivity, compressive strength and density of heat insulating materials were studied systematically by means of universal material testing machine and thermal conductivity meter. In order to improve the comprehensive properties of insulating materials, zirconia hollow spheres were successfully prepared by carbon template method. The influence of surface modification time of carbon template on the preparation of zirconia hollow spheres was studied. It has laid a solid foundation for the preparation of high performance porous insulating materials with zirconia hollow spheres instead of zirconia powders. The conclusions are as follows: (1) when 30 wt% Si O 2 aerogel is added, the slurry viscosity is moderate, the pore size of the sample is small and uniform, the thermal conductivity reaches the lowest value, and the thermal insulation property is the best; Too little or too much aerogel will make the slurry viscosity too small or too large, resulting in uneven distribution of pores, thus affecting the heat insulation. (2) the addition of appropriate amount of glycerol can effectively prevent the agglomeration of the slurry prepared by nano-powder during drying. A uniform nano-pore is formed to improve the thermal insulation performance of the sample; Too little or too much glycerin is not conducive to the uniform distribution of the pores, so it will affect the thermal insulation properties of the samples. (3) the thermal conductivity of the insulating materials varies in the "W" shape when the amount of p-H ~ (2 +) is 4 ~ 12:00, and the thermal conductivity of the insulating materials varies in the form of "W" when pH = 10:00, The absolute value of Zeta potential of slurry reaches the maximum value, which is helpful to promote the uniform dispersion of YSZ powder and aerogel and to form a uniform nano-pore, so that the thermal conductivity of the sample is minimized. (4) when the temperature is too low (鈮，
本文编号：2418295
[Abstract]:In this paper, silica aerogel was used as pore forming agent to prepare light zirconia porous heat insulation material, and XRD,FT-IR,FE-SEM,TEM, was used to prepare the porous thermal insulation material. The effects of the amount of Si O2 aerogel, glycerol dosage, slurry pH value and heat treatment temperature on the thermal conductivity, compressive strength and density of heat insulating materials were studied systematically by means of universal material testing machine and thermal conductivity meter. In order to improve the comprehensive properties of insulating materials, zirconia hollow spheres were successfully prepared by carbon template method. The influence of surface modification time of carbon template on the preparation of zirconia hollow spheres was studied. It has laid a solid foundation for the preparation of high performance porous insulating materials with zirconia hollow spheres instead of zirconia powders. The conclusions are as follows: (1) when 30 wt% Si O 2 aerogel is added, the slurry viscosity is moderate, the pore size of the sample is small and uniform, the thermal conductivity reaches the lowest value, and the thermal insulation property is the best; Too little or too much aerogel will make the slurry viscosity too small or too large, resulting in uneven distribution of pores, thus affecting the heat insulation. (2) the addition of appropriate amount of glycerol can effectively prevent the agglomeration of the slurry prepared by nano-powder during drying. A uniform nano-pore is formed to improve the thermal insulation performance of the sample; Too little or too much glycerin is not conducive to the uniform distribution of the pores, so it will affect the thermal insulation properties of the samples. (3) the thermal conductivity of the insulating materials varies in the "W" shape when the amount of p-H ~ (2 +) is 4 ~ 12:00, and the thermal conductivity of the insulating materials varies in the form of "W" when pH = 10:00, The absolute value of Zeta potential of slurry reaches the maximum value, which is helpful to promote the uniform dispersion of YSZ powder and aerogel and to form a uniform nano-pore, so that the thermal conductivity of the sample is minimized. (4) when the temperature is too low (鈮，
本文编号：2418295
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