推荐人:刘静静

文献信息1Xiangong Deng, Songlin Ran, Lei Han, Haijun Zhang, Shengtao Ge, Shaowei Zhang, Foam-gelcasting preparation of high-strength self-reinforced porous mullite ceramics, Journal of the European Ceramic Society, 2017, 37, 4059-4066.

推荐理由:莫来石多孔陶瓷由于气孔率高、比表面大和抗热震性优良,被广泛应用于隔热保温、催化和过滤等领域。本文作者利用莫来石粉为主要原料,AlF3·3H2O为助烧剂、Isobam-104为分散剂和发泡剂,采用凝胶注模工艺制备了晶须自增强莫来石多孔陶瓷。系统研究了AlF3·3H2O含量 (0-8 wt%) 对陶瓷浆料粘度、凝胶行为及多孔陶瓷力学性能的影响。通过优化工艺参数,所制备的多孔陶瓷气孔率为67.0%、抗折强度为13.9 MPa,耐压强度高达41.3 MPa,可应用于高温工业窑炉保温层,拓宽了其应用范围。作者在大量既有数据上做了深入的分析,在文章撰写上值得大家学习。特别是前言部分的撰写非常精彩,介绍了多孔莫来石材料的研究现状并指出其现存不足,是一篇窑炉保温研究工作者必读的文章。

下载地址:https://www.sciencedirect.com/science/article/pii/S0955221917303412

AbstractHigh-strength self-reinforced porous mullite ceramics were prepared via foam-gelcasting using mullite powder as a main raw material, AlF3·3H2O (0-8 wt%) as an additive, Isobam-104 as a dispersing and gelling agent, sodium carboxymethyl cellulose as a foam stabilizing agent, and triethanolamine laurylsulfate as a foaming agent. The effects of AlF3·3H2O content on rheological and gelling behaviors of the slurries, and porosity and mechanical properties of self-reinforced porous mullite samples were examined. Addition of AlF3·3H2O promoted the in-situ formation of elongated mullite in the fired porous samples, which improved considerably their mechanical properties. Compressive strength and flexural strength of 67.0% porous mullite ceramics prepared with addition of 6 wt% AlF3·3H2O was as high as 41.3 and 13.9 MPa, respectively. Its hot modulus rupture (HMOR) increased initially with the testing temperature, and peaked (with a maximum value of 16.6 MPa) at 800°C above which it started to decrease with the testing temperature. Nevertheless, it was still retained as high as 6.7 and 2.8 MPa at 1200 and 1400°C, respectively.

Fig. 1-1. XRD patterns of starting mixture with 6 wt% AlF3·3H2O before sintering (a) and porous mullite samples prepared with various contents of AlF3·3H2O (b) (f).

Fig. 1-2. SEM image of porous mullite ceramics synthesized with 6 wt% AlF3·3H2O at 1600◦C for 5 h under a flowing atmosphere.

Fig. 1-3. Effect of AlF3·3H2O content on mechanical properties of porous mullite ceramics. 

文献信息2Lei Han, Junkai Wang, Faliang Li, Huifang Wang, Xiangong Deng, Haijun Zhang, Shaowei Zhang, Low-temperature preparation of Si3N4 whiskers bonded/reinforced SiC porous ceramics via foam-gelcasting combined with catalytic nitridation, Journal of the European Ceramic Society, 38 (2018) 1210-1218.

推荐理由:碳化硅多孔陶瓷由于气孔率高、比表面大和高温力学性能优良,被广泛应用于隔热保温、催化和过滤领域。由于SiC属于共价键化合物,膨胀系数较低,导致碳化硅多孔陶瓷烧结温度较高。作者利用工业SiCSi粉体为原料,利用Fe为催化剂,在1200℃低温氮化制备了力学性能优异的晶须结合Si3N4(w)/SiC多孔陶瓷。其中,作者对硅粉氮化机理和α-Si3N4晶须生成机理进行了深入的研究和分析,所制备样品的气孔率为71.53%、抗折强度为5.60 ± 0.69 MPa和耐压强度为12.37 ± 1.05 MPa。作者在大量既有数据上做了深入的分析。在文章撰写上值得大家学习,特别是前言部分的撰写非常精彩,层层深入介绍了多孔SiC材料的研究现状,思路非常清晰,在文章写作方面具有较大的借鉴意义。

下载地址:https://www.sciencedirect.com/science/article/pii/S0955221917307239

AbstractPorous α-Si3N4 whiskers bonded/reinforced SiC (Si3N4(w)/SiC) ceramics were successfully prepared at as low as 1473 K for 2 h, via a combined foam-gelcasting and catalytic nitridation route using commercial Si and SiC powders containing some Fe impurity as the main raw materials. Small pores (0.03-5 μm) left by the packing of raw material particles and interlocking of in-situ formed Si3N4 whiskers coexisted with large ones (8-400 μm) resultant mainly from the foaming process. The impurity Fe from the raw materials Si and SiC acted as an internal catalyst, accelerating the nitridation of Si by increasing the bond length and weakening the bond strength in the N2 molecules adsorbed on it. As-prepared Si3N4(w)/SiC porous ceramics contained 71.53% porosity and had flexural and compressive strengths of 5.60 ± 0.69 MPa and 12.37 ± 1.05 MPa, respectively.

Fig. 2-1. DFT calculation on electronic structure of Si43Fe12 (a), N2 molecule adsorbed on (100) surface of Si43Fe12 (b), and N2 molecule adsorbed on (111) surface of Si43Fe12 (c) (Dark blue balls: Fe atoms; yellow balls: Si atoms).

Fig. 2-2. Schematic illustration of the growth process of α-Si3N4 whiskers.


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