共查询到19条相似文献,搜索用时 328 毫秒
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采用凝胶注模工艺成型氧化铝陶瓷,讨论了凝胶注模工艺成型工艺条件及影响因素,通过FESEM等现代测试手段研究了坯体的显微结构与其性能之间的关系。
在凝胶注模成型的工艺过程中,主要研究了如何制得高固相体积含量、低粘度的浆料,讨论了分散剂的选用、含量、pH值、球磨时间及固相含量等对浆料流动性能的影响,研究得出浆料中固相含量为55%时,以聚甲基丙烯酸铵为分散剂,在pH=10时,可获得985mPa·s的低粘度浓悬浮液。分别选择低毒的有机单体N-羟甲基丙烯酰胺和2-甲基丙烯酸羟乙酯,研究了有机单体与交联剂的比例与含量对生坯抗弯强度的影响,引发剂与催化剂的加入量对固化速率的影响。 相似文献
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钛酸铝陶瓷凝胶注模成型工艺的研究 总被引:1,自引:1,他引:1
通过凝胶注模工艺成型了钛酸铝坯体。研究了分散剂和固相含量对钛酸铝浆料流变性的影响,并探讨了单体和交联剂用量对钛酸铝坯体性能的影响规律。结果表明,聚甲基丙烯酸铵(PMAA-NH4)比柠檬酸铵(TAC)的分散效果更佳。加入0.5vol%的PMAA-NH4可制备出固相体积含量达52vol%的低粘度钛酸铝浆料。单体丙烯酰胺(AM)加入量应控制在1.0wt% ̄1.5wt%,交联剂N,N'-亚甲基双丙烯酰胺(MBAM)的最佳用量为0.1 5wt%。凝胶注模成型的钛酸铝烧成试样晶粒细小,其强度相比于干压成型或注浆成型的试样提高了一倍。 相似文献
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Stable YAG (Y3Al5O12) aqueous slurry with ammonium polyacrylate (NH4PAA) polyelectrolytes as dispersant was prepared by ball mill method. The effects of polyelectrolyte concentration and pH value on the stability of the suspension is described here, and the stability maps are constructed at different pH value and polymer concentration. The rheological behavior of YAG slips of different solid loading (60–70%) has been studied by measuring their viscosity and shear stress as a function of shear rate and pH of the slurry. An optimal amount of dispersant and pH value for the suspension was found. YAG suspension displays a maximum in zeta potential values and a minimum viscosity in pH range of 9–11. Slips behaved as near Newtonian at the pH value up to a solid loading of 60 wt% and as non-Newtonian with thixotropic behaviors above this solid loading value. The density and the green as well as sintered microstructure of the cast products bear a direct relationship to the state of this slips induced by the alternation in the pH and the concentration of the dispersant as well as solid loading. 相似文献
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Shuang Yin Limei Pan Lin Guo Yun Liu Yongbao Feng Tai Qiu Jian Yang 《Ceramics International》2018,44(7):7569-7579
A low-toxic and water-soluble monomer N, N-dimethylacrylamide (DMAA) was employed as a gelling agent in the gelcasting of porous Si3N4 ceramics. The process conditions and composition for slurry preparation (with a solid loading of 36?vol%), the consolidation and sintering of green bodies were investigated and optimized. The effects of various factors such as zeta potential, pH value of the premix solution, dispersant dosage and ball milling time on the rheological properties of the slurries were investigated. The results suggest that the best rheological properties (66.5 mPa.s at a shear rate of 96.3?s?1) of the slurries were obtained when pH value ranged between 9 and 11, dispersant dosage reached 1?wt%, and ball milling time was 6?h. All the as-prepared green bodies showed a homogeneous microstructure and high flexural strength ≥ 26?MPa with a maximum up to 46.3?MPa when the ratio of DMAA to MBAM, initiator dosage, polymerization temperature and time were 14, 1?wt%, 70?°C and 90?min, respectively. The sintered bodies had a homogeneous microstructure, excellent and regulatable properties, a flexural strength of 216.3–327.3?MPa, and a porosity of 39.6–29.1% by varying the sintering temperature from 1710?°C to 1810?°C and the holding time from 1?h to 3?h. The superior comprehensive effect makes DMAA a promising candidate for an environmentally friendly gelling agent in gelcasting of porous Si3N4 ceramics. 相似文献
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Han Chen Shunzo Shimai Jin Zhao Xiaojian Mao Jian Zhang Zhengjuan Wang Jian Yang Guohong Zhou Shiwei Wang 《Journal of the American Ceramic Society》2021,104(1):284-293
This study reports a new wet forming method by hydrophobic modification of short-chain anionic dispersants. The influence of the content and type of hydrophobic chains on the rheology of alumina slurries, the drying shrinkage rates of wet bodies, the density and strength of the green bodies, and the density and microstructure of the resultant ceramics were intensively investigated. It is revealed that hydrophobic modification can endow short-chain dispersants with coagulation ability, when 0.3 wt% short-chain PIBM (a copolymer of isobutylene and maleic anhydride) was combined with 0.1 wt% TMAC (tetramethylammonium chloride), solid loading of the slurry was increased to 58 vol% and the slurry can coagulate to a wet green body in a short time. The resultant green body showed a uniform microstructure and was successfully sintered into translucent ceramics. 相似文献
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陶瓷凝胶注模成型工艺是一种新颖的成型工艺,它将高分子化学单体聚合的思路引入到陶瓷的成型工艺中。通过加入分散剂制备了流动性较好的Al2O3浆料,用改性淀粉原位凝胶注模成型技术制备了具有较高强度和均匀性良好的氧化铝陶瓷坯体。研究了不同分散剂在制备低粘度高固相体积分数Al2O3浓悬浮体中的分散作用,并重点考察了添加不同分散剂的Al2O3浆料的粘度随pH值变化的趋势,对比了不同分散剂对Al2O3浆料的分散效果。 相似文献
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Improved Strength of Alumina Ceramic Gel and Green Body Based on Addition‐Esterification Reaction 下载免费PDF全文
Yi Sun Xiang Peng Shunzo Shimai Guohong Zhou Shiwei Wang 《International Journal of Applied Ceramic Technology》2016,13(6):1159-1163
Ethylene glycol diglycidyl ether (EGDGE), a water‐soluble epoxy resin, was used as a complementary gelling agent to improve the strength of alumina green bodies gelcast using PIBM (a copolymer of isobutylene and maleic anhydride acting as both dispersant and gelling agent) gelling system. The effects of EGDGE on the gelling behavior of PIBM‐EGDGE aqueous solutions and alumina slurries, mechanical properties of the resultant alumina gels, green bodies, and sintered ceramics were evaluated. Gelation of both the solutions and the slurries was accelerated with the addition of EGDGE. The changes in storage modulus (G′) of the slurries during gelation were quite different from those of the solutions. With the addition of 0.6 wt% EGDGE, G′ of the gel from a slurry with 50 wt% solid loading and 0.3 wt% PIBM increased 63% (100 min of testing), and flexural strength of the resultant green body increased 167%. Such gels and green bodies are strong enough for subsequent processing. They resulted in presintered bodies with low porosity and sintered ceramics with high relative density and flexural strength. 相似文献
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《Ceramics International》2020,46(6):7609-7614
β-TCP has excellent biodegradability and bioabsorption properties, and is regarded as an ideal hard tissue repair material. In the present study, 3D printing β-TCP green bodies was realized using the stereo lithography apparatus (SLA) technology. The effects of the KH-560 dispersant and solid loading on the slurry properties were investigated systematically. The optimized KH-560 addition amount and the solid loading of the slurry were 2.0 wt% and 48 wt%, respectively, and the corresponding slurry for the subsequent SLA 3D printing exhibited good fluidity, uniform dispersion and good stability. The sintering schedule of the printed β-TCP green bodies was optimized by the DSC-TG analysis. By sintering the green bodies at 1050 °C for 8 h, high quality β-TCP bioceramics without crack or deformation were fabricated. It was found that increasing the solid loading of the slurry would decrease the porosity while reducing the shrinkage degree of the β-TCP ceramics. However, the slurry could hardly be printed when its solid loading was higher than 50 wt%. 相似文献
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Preparation of alumina by aqueous gelcasting 总被引:6,自引:0,他引:6
The alumina ceramic was prepared by aqueous gelcasting. The effects of zeta potentials, solid loading, dispersant content and milling time on the alumina suspension were studied systematically. The dispersant content has remarkable effects on the viscosity of the suspension. The appropriate dispersant concentration for alumina aqueous slurry with the solid loading of 55 vol.% is 0.6 wt.%. It can be seen that all suspensions (50–56 vol.% solid loading) exhibited a shear-thinning behavior and relatively low viscosity, which was suitable for casting. The degree of shear thinning and the viscosity at high shear rates increased with increasing volume fraction of solid. As the milling time prolongs, viscosity of the suspension decreases first, then the plateau appears and the average diameter keeps changeless. When the milling time was shorter than 20 h, the viscosity of slurries decreased gradually as the time of milling increased. After 20 h milling, the viscosity of the slurry tended to be consistent. Therefore, the ball milling time should be equal to or more than 20 h to obtain a stable suspension at equilibrium. The time available for casting the slurry (idle time) can be controlled by the amounts of initiator and catalyst added to the slurry as well as by the processing temperature. Micrograph of the gelcast green body was homogeneous. 相似文献