【摘要】：本文創(chuàng)新性地采用二氧化硅氣凝膠作為成孔劑制備輕質(zhì)氧化鋯多孔隔熱材料,借助XRD、FT-IR、FE-SEM、TEM、萬能材料試驗機和導(dǎo)熱系數(shù)儀等測試手段系統(tǒng)研究了Si O2氣凝膠加入量、甘油用量、料漿p H值以及熱處理溫度對隔熱材料導(dǎo)熱系數(shù)、抗壓強度、密度等性能的影響。為進一步提高隔熱材料的綜合性能,本文應(yīng)用碳模板法成功制備出氧化鋯空心球,研究了碳模板表面改性時間對氧化鋯空心球制備的影響,為今后以氧化鋯空心球替代氧化鋯粉體制備高性能的多孔隔熱材料奠定了堅實的基礎(chǔ)。通過系統(tǒng)研究得出如下結(jié)論:(1)當(dāng)添加30wt%的Si O2氣凝膠時,料漿粘度適中,樣品孔徑小而均勻,導(dǎo)熱系數(shù)達(dá)到最低值,隔熱性能最佳;氣凝膠加入量過少或過多會使料漿粘度過小或過大,造成孔分布不均,從而影響隔熱性能。(2)加入適量甘油可以有效防止納米粉制備料漿在干燥中的團聚,形成均勻的納米孔,從而提高樣品的隔熱性能;甘油加入量過少或過多,均不利于孔的均勻分布,因此會影響樣品的隔熱性能。(3)當(dāng)p H=4~12時,隔熱材料的導(dǎo)熱系數(shù)呈“W”型變化。p H=10時,料漿ζ-電位的絕對值達(dá)到最大值,有利于促進YSZ粉體和氣凝膠均勻分散,形成均勻的納米孔,從而使得樣品的導(dǎo)熱系數(shù)最小。(4)溫度過低(≤400℃)時,由于樣品中還殘余著大量C,導(dǎo)熱系數(shù)較高;溫度超過600℃,材料中的孔徑增大,即由均勻的納米孔變成亞微米孔甚至微米孔,致使其導(dǎo)熱系數(shù)增加。(5)應(yīng)用優(yōu)化的工藝參數(shù)(Si O2氣凝膠加入量為30 wt%,甘油用量為50 wt%,料漿p H值為10,熱處理溫度為600℃),制備出綜合性能優(yōu)于相關(guān)文獻值的材料,其指標(biāo)為:導(dǎo)熱系數(shù)為0.043 W/(m?k),抗壓強度為35.6 MPa,密度為1.51g/cm3,氣孔率為60.9%。(6)采用碳模板法制備氧化鋯空心球時,空心球產(chǎn)物由四方相Zr O2組成。通過堿處理能有效地增加碳球模板表面的官能團數(shù)目,改善碳球表面的荷電狀態(tài)和親水性,從而調(diào)控核-殼結(jié)構(gòu)中殼層的厚度;隨著碳球表面改性時間從0 h增加到6 h時,空心球的壁厚逐漸增大,比表面積從104.7 m2/g逐漸減少到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，

本文編號：2418295