以冰为模板制备超轻多孔氧化锆块材

Preparation and formation mechanism of porous ultralightweight zirconia by ice templating

以冰为模板,经真空冷冻干燥过程制备轻质ZrO_2多孔材料和水玻璃为粘结剂的超轻多孔ZrO_2块材,研究了其微观结构、形成机理和隔热耐火性能.结果表明,冰是一种理想的制作多孔材料的模板,可同时获得多种尺度的孔结构,还可获得多孔和层状两种结构复合的微观结构.ZrO_2多孔材料的微观结构为奇特的周期性层状结构.添加水玻璃作为粘结剂,制备出多孔和层状两种微结构复合的ZrO_2多孔块材,在400℃煅烧6h后仍良好地保持原有的微观结构,孔隙率达87%,表观密度仅为0.50 g·cm^(-3),超轻且机械强度有较大提高,在1300℃丁烷气火焰灼烧下表现出较好的隔热耐火性能.

Porous lightweight ZrO2 and porous ultralightweight ZrO2 monolith were prepared via a freeze-drying process using ice as template. The microstructures, formation mechanisms and performances of thermal insulation and fire-resistant were studied. The results indicated that ice is an ideal template for fabrication of porous materials. The obtained porous ZrO2 with periodical layered microstructures were lightweight, but with poor strength. After adding sodium silicate as binder, the obtained ZrO2 monolith has porous and layered hybrid microstructures, which were still kept after calcination at 400 ℃ for 6 h. The calcined ZrO2 monolith has a porosity of 87%, an apparent density of 0.50 g·cm^-3 and high strength. The ZrO2 monolith showed good thermal insulating and fire-resistant properties with 1300 ℃ butane gas flame.