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陶瓷原位凝胶注模成形技术的发展 总被引:4,自引:0,他引:4
对凝胶注模成形技术的各种凝胶体系进行了系统介绍,并对这些新凝胶体系的凝胶化原理、工艺过程及应用特点进行了较全面的分析和比较。指出了目前存在的问题及发展趋势。 相似文献
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研究了Al2O3凝胶注模成形中浆料的流变性,素坯的强度、密度等随有机单体丙烯酰胺和Al2O3固含量的变化特性。实验采用L8(27)正交试验,并对各分散剂对屈服应力有显著影响,球磨时间主要影响流变指数。在120℃干燥后,凝胶注模后的素坯的强度可达到28—45MPa。随着有机单体丙烯酰胺的含量的增加,素坯强度上升,而随着Al2O3固含量的增加,素坯强度下降。在600℃热处理后,坯体相对密度为57—60%。随着有机单体含量和Al2O3固含量的增加,坯体密度表现为先上升后下降的趋势。 相似文献
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SiC陶瓷凝胶注模成形研究 总被引:3,自引:0,他引:3
采用丙烯酰胺单体及合适的外加剂,可较好地实现SiC陶瓷的凝胶注模成型,SiC浆料注模成形合适的pH值为10,热固化温度为60℃,脱模时间为6小时。每100克SiC中加入8克丙烯酰胺时,坯体强度可达7.42MPa。 相似文献
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研究了分散剂的种类、用量、料浆pH值、球磨时间、有机单体含量等因素对氧化硅料浆性能的影响,制备出固相体积分数达42vol%,流变性能够满足凝胶注模工艺要求的二氧化硅料浆,并成功制备了复杂形状的二氧化硅坯体。对凝胶注模成形二氧化硅坯体低温烧结技术进行了研究,提出了素烧、浸渍工艺,有效地降低了二氧化硅坯体的烧成温度。实验表明:二氧化硅凝胶注模成形坯体在1200℃素烧,冷却后浸渍硅溶液,可在1300℃烧结。 相似文献
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凝胶注模成型技术是一种近净尺寸陶瓷成型技术,它为解决陶瓷材料的加工成型问题提供了一条十分有效的的工艺途径。介绍了陶瓷凝胶注模成型技术的基本原理和工艺过程,着重介绍了目前凝胶注模成型技术的应用研究。 相似文献
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陶瓷凝胶注模成型技术及其应用研究 总被引:1,自引:0,他引:1
凝胶注模成型技术是一种近净尺寸陶瓷成型技术,它为解决陶瓷材料的加工成型问题提供了一条十分有效的工艺途径。介绍了陶瓷凝胶注模成型技术的基本原理和工艺过程,着重介绍了目前凝胶注模成型技术的应用研究。 相似文献
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本文以氧化铝陶瓷为例,研究探讨了凝胶注模成形工艺中制备低粘度、高固相含量浓悬浮体的关键技术,讨论了分散剂因素对粘度的影响和不同固相含量对坯体强度的影响。 相似文献
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《Ceramics International》2016,42(7):8066-8071
A non-aqueous gel casting process based on the mixed solvent (ethanol and polyethylene glycol) and low-toxicity N,N-dimethylacrylamide (DMAA) was developed for an aluminum nitride (AlN) ceramic. In the present work, rheological properties of non-aqueous concentrated AlN suspensions were investigated in the presence of mixed solvent, dispersant, milling time, monomer and solid loading, in order to screen for the most suitable experimental conditions to obtain a good rheological behavior for gel casting. The results showed that the 50 vol% slurry with 0.2 wt% dispersant concentration, 2 h milling time, 6 wt% -monomer content, and a solvent ratio of 3:1, can meet the requirements for the casting process of AlN ceramic slurries. After being dried at 100 °C for 1 h, the optimum bulk density and maximum flexural strength of the AlN green bodies were as high as 1.97 g/cm3 and 18.68 MPa, respectively. SEM photographs revealed that the green body had a relative uniform microstructure when the solid loading was 50 vol%. The shrinkage and deformation of shaped sintered bodies prepared through gel casting were small after sintering. The sintering shrinkage, apparent porosity, bulk density and flexural strength were 14.8%, 0.22%, 3.21 g/cm3 and 310 MPa, respectively. 相似文献
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Han Chen Shunzo Shimai Jin Zhao Zhengxian Di Xiaojian Mao Jian Zhang Juan Liu Guohong Zhou Shiwei Wang 《Ceramics International》2018,44(14):16572-16576
High density and homogeneous green body is important for fabricating transparent ceramics. Inspired by the improved samples’ homogeneity in slip casting, we introduced low pressure filtration to gel casting to further increase the relative density and homogeneity of the green body and to shorten the drying time. The effect of pressure filtration on drying characteristics, bulk density and porosity of the pre-sintered bodies, and the microstructure and optical transmittance of the resultant ceramics were intensively investigated. The results showed that pressure filtration can reduce the drying time by 27.3%, improve the density of the pre-sintered bodies and reduce the residual pores of the sintered ceramics. The in-line transmittance of the translucent alumina prepared by the pressure filtration assisted gel casting was 32.7% at 600?nm with a thickness of 1?mm, which is about 6% higher than that without pressure filtration. In principle, this process can be applied to fabricate any other high-performance ceramic. 相似文献
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《Ceramics International》2016,42(4):5036-5044
In this study an easy-to-use ceramic processing technique based on temperature-controlled ionotropic gelation of alginate is presented. This method is the breakthrough for simultaneously large scale tape casting and high quality patterning of thin ceramic tapes. Alumina powder (d50= 205 nm) is used to cast flexible and on demand shapeable tapes. Compared to conventional ceramic micropatterning, ionotropic gelation combines complexity of the patterned structure over large-scale areas, a high pattern resolution down to sub-µm regime (~400 nm) and tape thickness below 300 µm. Obtained green and sintered (1350 °C) micro- and sub-micropatterns are characterized by SEM and quantitative 3D-profilometry focusing on both, pattern quality and pattern aspect ratio. The results show that reproducible thin ceramic tapes featuring positive and negative patterns maintain their aspect ratios after demolding, drying and sintering. This processing route represents a versatile tool for designing tailored ceramics for e.g. microelectromechanical engineered systems, biomaterial or microfluidic applications. 相似文献
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Slip casting of MgOY2O3 suspensions has been investigated in this research. For this purpose relatively pure commercial raw materials were used. The Taguchi experiment method was used for design of experiments and selection of suitable solvents and dispersants and theirs optimum values. Preparation of suspensions was done in two stages, according to particle size distributions of powders after different milling time and Taguchi results. The best suspensions were selected based on viscosity and solid load of suspensions. Green bodies were slip casted using the optimized suspensions in order to obtain the green bodies with maximum density and a homogeneous structure in term of porosity size distribution. Results showed that using from ethanol as solvent, an optimum dispersant level of 3%wt. TEA +1%wt. DEA with a constant TEA/DEA ratio of 3/1 and mean particle size of 155 nm (milling time of 48 h) was the best choice for preparing of optimum suspensions. The highest relative green density of 65.91% was obtained for a suspension containing 35 vol % of solid particles casted under 3MPa. The dense Y2O3MgO submicron composite samples were sintered by SPS technique at 1250?°C under 70MPa for 6?min with a density about 99.5%. 相似文献
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《Journal of the European Ceramic Society》2014,34(5):1457-1463
A simple, effective method for fabricating zirconia green bodies is described that utilizes phenolic resin as a binder in the gel casting process. Both the zeta potential of zirconia particles and the rheological behavior of the slurries were measured. To prepare stable, homogeneous, fluidic zirconia slurry with high solid loading, the zeta potential was adjusted by varying the phenolic resin content of the premixed solution. This represented a departure from normally adjusting the slurry pH by using an acids, alkali or dispersants. To promote gelation of the slurry, a curing agent was added. Gel casting a mixture of a 42 vol.% zirconia slurry containing 13 wt.% phenolic resin yielded an easily sintered, very homogeneous green body with the desired strength. The gelation time of the slurries and the mechanical strength of the green bodies were controlled by adjusting the quantity of the curing agent in the slurries. 相似文献
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《Ceramics International》2022,48(5):6488-6496
In view of technical difficulties in preparing ceramics with complex shapes, gel casting combined with 3D printing was here adopted to prepare silicon carbide ceramic green body, and gaseous silicon infiltration sintering was used to prepare 3D lattice-structured ceramics. The preparation of the slurry, gel curing, and ceramic molding was investigated. Results demonstrate that the ratio of components affects the fluidity and stability of slurry. However, when volume fraction of the solid phase of the slurry reaches 56%, the viscosity of slurry is only 300 mPa s, and drying shrinkage rate of green body is 6.6%; these characteristics make slurry suitable for 3D complex model injection molding. Furthermore, both the temperature and the initiator affect gel curing speed. As the temperature and initiator content increase, the induction and gel time are rapidly shortened. When demolding at 300 °C and when gaseous silicon infiltration sintering is carried out at 1550 °C, a 3D lattice-structured ceramic with relative density of 87% and average compressive strength of 433 MPa can be obtained. 相似文献
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A new technique of combining the gel casting and indirect rapid prototyping methods was utilized to fabricate macroporous
β-tricalcium phosphate (β-TCP) scaffolds, which provided an excellent control over the internal architecture of scaffolds
and enhanced their mechanical properties. A stereolithography apparatus was used to produce resin molds for ceramic gel casting.
These molds were filled with a water based thermosetting ceramic slurry which solidifies inside the mold. After burning the
resin mold and sintering, the β-TCP scaffolds with designed pore architecture were obtained. The pore morphology, size, and
distribution of the resulting scaffolds were characterized using a scanning electron microscope. X-ray diffraction was used
to determine the crystal structure and chemical composition of scaffolds. The mechanical measurements showed that the average
compressive strength was 16.1 ± 0.8 MPa. 相似文献
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影响凝胶注模成型SiAlON-SiC复相材料坯体性能的因素 总被引:2,自引:0,他引:2
选用Al粉、Si粉、SiO2 等活性原料与较大颗粒的SiC ,采用凝胶注模成型工艺制备了SiAlON-SiC复相耐火材料的坯体 ,并研究了有机单体、分散剂和引发剂的加入量以及催化剂、胶凝温度等因素对坯体性能的影响。最终 ,在有机单体AM加入量为 1.8% (质量分数 ,下同 ) ,交联剂MBAM加入量为 0 .6‰ ,引发剂过硫酸铵溶液的最佳加入量为 0 .9% (体积分数 ) ,胶凝温度在 6 0℃左右 ,不加催化剂的条件下 ,制备出了抗折强度达到 32MPa ,密度为 2 .5g·cm- 3的均匀致密的SiAlON -SiC复相材料坯体。 相似文献
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水平连铸用分离环的研究现状 总被引:4,自引:1,他引:3
介绍了水平连铸用分离环的材质、合成工艺、结构与特性的研究及其应用情况,指出了目前水平连铸用分离环存在的问题,并探讨了今后的发展方向。 相似文献