【摘要】：多孔陶瓷不僅具有普通陶瓷化學穩(wěn)定性好、剛度高、耐高溫、耐腐蝕等優(yōu)良特性,還具有低導熱性、對液體和氣體的選擇透過性,以及能量吸收或阻尼等性能,已經(jīng)在隔熱、換熱、分離過濾、催化劑載體、儲能、電極、隔音吸聲、生物植入等許多方面發(fā)揮了重要作用。 本文結(jié)合了顆粒堆積工藝和添加造孔劑工藝,利用噴霧干燥工藝將亞微米級的氧化鋁粉體制備成近似球形的含有凹陷孔洞結(jié)構(gòu)的二次顆粒,同時使造孔劑與氧化鋁粉體分散均勻,然后經(jīng)過模壓成型、燒結(jié)制備成多孔氧化鋁陶瓷,具有較高的孔隙率及強度,可用作剛性隔熱材料。 本文詳細研究了制備過程中的各種工藝參數(shù),測試了其氣孔率及壓縮強度,并用激光共聚焦顯微鏡觀察了粉體及多孔陶瓷的形貌。實驗結(jié)果表明,pH值為3,粘結(jié)劑含量為1%時,漿料的粘度在20mPa·s以下,適合于噴霧干燥。增加漿料的固含量,制備的粉體的粒徑增大,顆粒間孔隙尺寸增大,有利于增大氣孔率,降低材料的強度,但固含量增大至40%后,顆粒逐漸趨近于球形,內(nèi)部凹陷減少,氣孔率降低,強度增加。增加造孔劑加入量及降低燒結(jié)溫度,都會增加多孔陶瓷的氣孔率,降低其強度。 正交試驗證明燒結(jié)溫度對多孔陶瓷的性能影響最大,其次固含量對氣孔率的影響較造孔劑高,對強度的影響較造孔劑低。綜合考慮多孔陶瓷的氣孔率及強度,本文最終確定的最優(yōu)方案為固含量40%、粘結(jié)劑含量10%、燒結(jié)溫度1400℃,該條件下制備的多孔氧化鋁陶瓷氣孔率為60.8%,壓縮強度81.0MPa。
[Abstract]:Porous ceramics not only have good chemical stability, high stiffness, high temperature resistance, corrosion resistance and other excellent properties, but also have low thermal conductivity, liquid and gas penetration, as well as energy absorption or damping and other properties, which are already in thermal insulation. Heat transfer, separation and filtration, catalyst support, energy storage, electrode, sound insulation and sound absorption, biological implantation and many other aspects play an important role. In this paper, the submicron alumina powder was prepared into a spherical secondary particle with concave pore structure by spray drying process combined with the process of particle stacking and adding pore-making agent. At the same time, porous alumina ceramics were prepared by molding and sintering, which has high porosity and strength and can be used as rigid thermal insulation material. In this paper, various technological parameters in the preparation process were studied in detail, and their porosity and compression strength were measured. The morphology of the powder and porous ceramics was observed by laser confocal microscope. The experimental results show that when the pH value is 3 and the binder content is 1%, the viscosity of the slurry is below 20mPa 路s, which is suitable for spray drying. With the increase of solid content of slurry, the particle size of the prepared powder increases and the pore size between particles increases, which is beneficial to increase the porosity and reduce the strength of the material. However, when the solid content increases to 40%, the particles gradually approach the sphere and the internal depression decreases. The porosity decreases and the strength increases. The porosity and strength of porous ceramics will be increased and the strength will be reduced by increasing the amount of pore-making agent and decreasing the sintering temperature. Orthogonal test shows that sintering temperature has the greatest influence on the properties of porous ceramics, and secondly, the effect of solid content on porosity is higher than that of pore-making agent, and the effect on strength is lower than that of pore-making agent. Considering the porosity and strength of porous ceramics, the optimum scheme determined in this paper is solid content 40%, binder content 10%, sintering temperature 1400 鈩，

本文編號：2497118