高温泡沫陶瓷的制备及性能研究
文献类型：学位论文
| 作者 | 张智 |
| 学位类别 | 硕士 |
| 答辩日期 | 2010-05-26 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 卢旭晨 |
| 关键词 | 碳化硅 泡沫陶瓷 有机泡沫浸渍工艺 |
| 其他题名 | Preparation and properties of high temperature ceramic foams |
| 学位专业 | 化学工程 |
| 中文摘要 | 本论文利用聚氨酯海绵的三维网状结构作为模板、采用有机泡沫浸渍法制备碳化硅质泡沫陶瓷。从聚氨酯海绵的表面预处理、陶瓷浆料的流变学行为、组成配比、浸渍成型及烧成工艺等方面研究了碳化硅质泡沫陶瓷制备工艺的影响因素。本工作采用无机硅溶胶作为分散剂，研究了高岭土在硅溶胶中的分散行为，通过带负电荷的纳米级硅溶胶胶粒吸附在高岭土颗粒的表面，改变了颗粒的表面电荷状态，使高岭土的等电点向酸性方向漂移，其Zeta电位的绝对值增大，有利于高岭土的分散；高岭土在硅溶胶中良好分散的pH值为11.5左右，硅溶胶浓度为5 wt%。碳化硅粉体的酸洗、碱洗预处理能降低碳化硅浆料的粘度，改善其分散行为，结果表明：碳化硅在碱性溶液中处理后经过适当烧结处理其效果最好。通过Zeta电位和浆料流变学研究，碳化硅、氧化铝、高岭土的混合陶瓷粉体在硅溶胶中最佳分散的pH值约为11，硅溶胶浓度为10 wt%。对海绵进行碱洗、CMC浸泡和硅溶胶浸泡预处理能增加其孔筋表面的粗糙程度和对陶瓷浆料的粘附性，增加陶瓷浆料在海绵孔筋上的浸浆厚度。结果表明：海绵在碱性溶液中浸泡之后经过硅溶胶溶液处理，陶瓷浆料浸浆量的增加程度最大。聚氨酯海绵的热分解主要发生350~450℃之间，在700℃左右时，海绵基本分解完全。通过对坯体预烧结体的二次挂浆，泡沫陶瓷表面的裂纹明显减少、增加了孔筋的厚度、提高了孔筋的强度，从而能够改善泡沫陶瓷制品的强度。 实验表明：固含量为77 wt%、碳化硅与氧化铝的质量比约为2、坯体的烧结温度为1410℃、烧结时间为2 h时，浆料浸渍最均匀、堵孔最少、泡沫陶瓷制品的物相中莫来石的成分相对较高、氧化铝和方石英的含量较低、制品的强度最高。 |
| 英文摘要 | Silicon carbide ceramic foam was prepared by polymeric sponge replica method using polyurethane sponge with a three dimensional network as template. The effects of surface pretreatment of polyurethane sponge, rheological properties of ceramic slurry, ratio of ceramic powders, coating procedure and sintering system on the preparation of ceramic foam were studied. The dispersion behavior of kaolin powders in silica sol was studied with the inorganic silica sol as dispersant.. Silica sol changed the dispersion behavior of kaolin powders by adsorption of colloidal silica onto the surface of kaolin powders. When the pH value was 11.5 and the concentration of silica sol was 5 wt%, the dispersion of kaolin powders in silica sol was the best. The pretreatment of SiC powders could reduce the viscosity of SiC slurry and the amelioration was the best when the SiC powders were washed in alkaline solution followed by moderate sintering. The viscosity of the mixed ceramic powders of silicon carbide, alumina and kaolin was the lowest when the pH value was 11 and silica sol concentration was 10 wt%. The effect of pretreatment on the surface of sponge was studied. It was proved that the pretreatment could improve the roughness of the sponge and increase the adhesion between sponge and ceramic slurry. The main decomposition process of sponge was taken place in the temperature range of 350~450℃ and decomposed completely when the temperature reached 700℃. The recoating of presintered ceramic green body with ceramic slurry of lower viscosity and same composition could effectively reduce the cracks of ceramic foam. This increased the thickness of the struts and improved the strength of the struts, therefore ameliorate the properties of the ceramic foams. According to the experiments, when the solid content was 77 wt% the coating result was the best with few closed cell. The ceramic foam sintered at 1410℃ with 3 hour holding time obtained not only the maximum in flexural strength ,but also the maximum in content of mullite as well as the minimum in content of alumina and cristobalite. |
| 公开日期 | 2013-09-17 |
| 页码 | 77 |
| 源URL | [http://ir.ipe.ac.cn/handle/122111/1535]  |
| 专题 | 过程工程研究所_研究所（批量导入） |
| 推荐引用方式 GB/T 7714 | 张智. 高温泡沫陶瓷的制备及性能研究[D]. 北京. 中国科学院研究生院. 2010. |
入库方式： OAI收割
来源：过程工程研究所
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