图1 冷冻干燥法制备多孔陶瓷近13年来论文发表数量(截止到2013年9月)

Fig. 1 Annually published papers on freeze casting of porous ceramics from Jan. 2001 to Sep. 2013 based on Web of ISI

图2 冷冻干燥法四个基本步骤: 浆料的制备、冷冻、升华和烧结[19]

Fig. 2 The four processing steps of freeze-casting: slurry preparation, solidification, sublimation and sintering[19]

图3 典型的冷冻装置示意图[21]

Fig. 3 Schematic diagram of a typical cooling setup for freeze casting[21]

图4 冷冻过程原理示意图[18]

Fig. 4 Schematic diagram of the basic principle during freezing[18]

图5 单个颗粒界面处受力示意图[27]

Fig. 5 Schematic diagram of the particle-solidification front interactions[27]

图6 莰烯升华过程质量变化图[29]

Fig. 6 Weight loss of green body during sublimation of the camphene (30vol% solid loading)[29]

图7 冰晶结构(a)、各向异性(b)和获得的多孔结构(c) [19]

Fig. 7 Ice crystal structure (a), anisotropy of ice crystal growth (b) and resulting porous structure (c)[19]

图8 典型的以水为溶剂获得的多孔氧化铝SEM照片[21]

Fig. 8 Typical cross-section SEM images of porous alumina obtained by water-based freeze casting[21] (a) Ice growth direction perpendicular to the page; (b) Ice growth direction from bottom to top

图9 固化中的莰烯形成的树枝状结构(a)及以此为溶剂获得的多孔氧化铝(b)

Fig. 9 Dentritic structure during solidification of camphene]43] (a) and typical SEM images of porous alumina obtained by camphene-based freeze casting (b)[20]

图10 多孔氧化铝-氧化锆复合物扫描电镜截面照片, 固相含量分别为40wt% (a)、50wt% (b)、60wt% (c)、70wt% (d)和80wt% (e)[23]

Fig. 10 Cross-sectional SEM images of the Al2O3-ZrO2 composite ceramics obtained from slurries with different initial solids loading[23] (a) 40wt%; (b) 50wt%; (c) 60wt%; (d) 70wt%; (e) 80wt%. Solidification direction is perpendicular to the page

图11 多孔氧化铝陶瓷扫描电镜照片[44]

Fig. 11 SEM images of the porous alumina ceramics sintered at 1400℃ for 5 h with initial solid loadings of 20vol%(a), 15vol%(b), 10vol%(c), and 5vol% (d), showing porous structures at low magnification[44]

图12 冷冻干燥法获得的多孔陶瓷气孔率随浆料固相含量变化图

Fig. 12 Porosity vs solids loading forwater- (a) and camphene- (b) based freeze-cast porous ceramics

图13 薄片状结构(水系浆料冷冻)波长定义示意图(a)及薄片状结构波长随冷却速率变化图(b)[21]

Fig. 13 Pattern formation and particle segregation during freeze casting of ceramic slurries (a) and the wavelength of the <br/>structure is defined. (b) Variation of structure wavelength vs ice front velocity[21]

图14 多孔二氧化钛陶瓷截面扫描电镜照片[52]

Fig. 14 SEM images of porous TiO2 with cross-section parallel and perpendicular to the ice growth direction[52] (a) 3wt% PVA, parallel; (b) 3wt% PVA, perpendicular; (c) 6wt% PVA, parallel; (d) 6wt% PVA, perpendicular

图15 多孔氧化铝陶瓷扫描电镜照片[55]

Fig. 15 SEM images of porous alumina ceramics, which are prepared by using (a) 20vol% slurry without glycerol, (b) 20vol% slurry with glycerol, (c) 30vol% slurry without glycerol and (d) 30vol% slurry with glycerol[55] The direction of fracture parallels to the ice front

图16 烧结温度对抗压强度(a)和总气孔率(b)的影响[58]

Fig. 16 Influence of sintering temperature (2 h at dwell temperature) on compressive strength (a) and total porosity(b)[58]

图17 不同制备技术获得的多孔羟基磷灰石抗压强度对比图

Fig. 17 Comparison of compressive strength of porous hydroxyapatite obtained by different techniques according to literature data

图18 冷冻干燥法获得的多孔陶瓷抗压强度随气孔率变化图

Fig. 18 Compressive strength versus porosity for water-based (a) and camphene-based (b) freeze-cast porous ceramics

图19 测量或估计的冷冻干燥法获得的多孔陶瓷的孔径大小分布图[68]

Fig. 19 Measured or estimated pore channels size of freeze- cast ceramics[68]

图20 典型的梯度孔结构[29]

Fig. 20 Graded porosity with three distinct regions[29]

图21 典型的冻结流延成型装置图[68]

Fig. 21 Typical freeze-tape-casting apparatus[68]

图22 双面冷却装置示意图[73]

 Fig. 22 Schematic illustration of double-side cooling apparatus[73]

图23 不同方法获得的多孔氧化铝抗压强度对比(a)和不同方法获得的多孔氧化铝气孔率对比(b)图[24]

Fig. 23 Compressive strengths of freeze cast and freeze gelcast samples versus solids loading (a) and porosities of the sintered samples versus solids loading (b)[24]