Controllable Forming Technology in Gelcasting

Yang, Jin Long; Dai, Chun Lei; Huang, Yong

doi:10.4028/www.scientific.net/msf.475-479.1325

Cited by 6 publications

(5 citation statements)

References 2 publications

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“…This process does not need the extra force and can realize an in-situ polymerization, which is beneficial for preparing the samples with high-quality, uniformity, and complex-shape. What is more, its polymerization time can be controlled by adjusting the amount of initiator and catalyst and the gelled green body has high strength so that the cost of machining is low [13][14][15][16]. Our preliminary research showed that the degree of texture could reach to 0.84 in SiC ceramics prepared in a low magnetic field of 6 T compared with other textured SiC prepared in 10 T or 12 T [8][9][10]17].…”

Section: Introductionmentioning

confidence: 77%

Effect of sintering aids on microstructure and properties of textured SiC ceramics prepared in 6 T

Yang

Zhu

Zhao

et al. 2020

Journal of Asian Ceramic Societies

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C-axis textured α-SiC ceramics were prepared by gel-casting in a strong magnetic field of 6 T and subsequent sintering at 1950 °C for 2 h. The effects of sintering aids on the microstructure and properties of textured SiC ceramics were discussed. Results showed that highly textured α-SiC green bodies were obtained by gel-casting in a strong magnetic field of 6 T. The sintering process slightly suppressed the texture development of α-SiC ceramic. The degree of texture in the α-SiC green bodies and sintered bodies both showed a decreasing trend with the increase of sintering aids content. And the increase of the sintering aids content promoted the densification and improved the bending strength of α-SiC ceramics. Besides, the bending strength of textured SiC ceramics showed an anisotropy based on the grain orientation.

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Section: Introductionmentioning

confidence: 77%

Effect of sintering aids on microstructure and properties of textured SiC ceramics prepared in 6 T

Yang

Zhu

Zhao

et al. 2020

Journal of Asian Ceramic Societies

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“…Before drying green gelcast bodies, the dipping pretreatment was applied, in which green gelcast bodies were soaked in a certain concentration of APS solution. The aim is to degrade the polymer; thereby, reticular macromolecular polymer chains (large molecules) are reduced to linear polymer chains (small molecules) 26,27 . Drying time versus linear shrinkage rate with different methods is shown in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…The aim is to degrade the polymer; thereby, reticular macromolecular polymer chains (large molecules) are reduced to linear polymer chains (small molecules). 26,27 Drying time versus linear shrinkage rate with different methods is shown in Fig. 7.…”

Section: ) Drying Of Gelcasting Partsmentioning

confidence: 99%

“…To inhibit the propagation of flaws, drying of parts by heating needs to be handled slowly and carefully at room temperature and under an appropriate humidity condition. 24,25 A novel predrying method, i.e., dipping pretreatment was introduced in the BNBT6 gelcasting process, which has been used in other gelcast ceramics parts, 26,27 thereby reducing a time-consuming and tedious drying step as well as removing the defects due to release of residual stress. Before drying green gelcast bodies, the dipping pretreatment was applied, in which green gelcast bodies were soaked in a certain concentration of APS solution.…”

Section: ) Drying Of Gelcasting Partsmentioning

confidence: 99%

See 1 more Smart Citation

Sodium Bismuth Titanate‐Based Lead‐Free Piezoceramics Prepared by Aqueous Gelcasting

Zhou

Gong

et al. 2008

Journal of the American Ceramic Society

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Aqueous gelcasting for 0.94Bi0.5Na0.5TiO3–0.06BaTiO3 (BNBT6) lead‐free piezoceramics was investigated in this paper. A stable BNBT6 suspension with 50 vol% of solid loading and <1Pa·s of viscosity was successfully prepared when 0.5 wt% of PMAA‐NH4 was added with the pH value controlled in the range 8–10. Dehydration and desiccation of the gelled parts could be controlled easily through dipping pretreatment with a 5 wt% ammonium persulfate solution for 24 h or with a 10 wt% ammonium persulfate solution for 12 h. Scanning electron microscopy micrographs show that the BNBT6 ceramic prepared by the gelcasting route exhibits a homogeneous microstructure and a high density. Optimal piezoelectric and dielectric properties were obtained: d33=132pC/N, , tg δ=0.019, and kp=0.25.

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“…The forming ability is only limited by the complex degree of the mold cavity rather than mold material, many kinds of materials such as wax, plastics, resin, metal, etc. can be used (Dhara et al , 2002; Yang et al , 2005). Compared with injection molding, gelcasting green bodies have advantages of higher strength, better uniformity, lower organic content, easiness of degreasing and no defects such as warpage, cracking, etc.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of integral ceramic mold for investment casting of hollow turbine blade based on stereolithography

Guo

2009

Rapid Prototyping Journal

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PurposeThe purpose of this paper is to develop a novel process of integral ceramic molds for investment casting of hollow turbine blades.Design/methodology/approachAt first, a resin pattern of a hollow turbine blade prototype is fabricated by stereolithography (SL). And then aqueous gelcasting process is utilized to fill the resin pattern with ceramic slurry of low viscosity and low shrinkage, through in situ polymerization of the slurry a ceramic mold is formed. At last, the ceramic mold for investment casting of hollow turbine blade is obtained by vacuum drying, pyrolyzing and sintering.FindingsAn integral ceramic mold is successfully fabricated by combining SL and gelcasting process, cores and shell are connected with each other and thus high relative position accuracy is guaranteed. Properties of integral ceramic mold at room temperature and high temperature satisfy the requirements of directional casting for complex‐shaped thin‐walled blades.Research limitations/implicationsBecause the integral ceramic mold is a close body, it is very difficult to directly measure its inner dimensions and the relative position accuracy of cores and shell, and the further research is needed.Originality/valueThis method enhanced the versatility of using SL prototype in the fabrication of integral ceramic mold for investment castings. Although this paper took a hollow turbine blade as an example, this method is also capable of fabricating integral ceramic molds for other complex investment castings.

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Controllable Forming Technology in Gelcasting

Cited by 6 publications

References 2 publications

Effect of sintering aids on microstructure and properties of textured SiC ceramics prepared in 6 T

Effect of sintering aids on microstructure and properties of textured SiC ceramics prepared in 6 T

Sodium Bismuth Titanate‐Based Lead‐Free Piezoceramics Prepared by Aqueous Gelcasting

Fabrication of integral ceramic mold for investment casting of hollow turbine blade based on stereolithography

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