New Low-Toxic PEG(200)DMA/AM Gel System for 3YSZ Gel-Casting

2014 ◽  
Vol 602-603 ◽  
pp. 159-163
Author(s):  
Hai Yan Wu ◽  
Heng Lu ◽  
Zhi Jie Liao ◽  
Feng Xia ◽  
Jian Zhong Xiao
Keyword(s):  
Flexural Strength ◽  
Ceramic Body ◽  
Monomer Concentration ◽  
Solid Loading ◽  
Green Body ◽  
Gel Casting ◽  
Body Strength ◽  
Low Toxic ◽  
Poly Ethylene ◽  
Gel System

Gel-casting is promising in fabricating uniform and complex-shaped ceramic body, but it is confined in industrial application for the neurotoxic acrylamid (AM) gel system. Ether-contained oligomer poly(ethylene glycol)(200) dimethacrylate (PEG(200)DMA) with methacrylate end-group on either side of the long chain can act as cross-linking agent in free radical polymerization to form branchy gel network structure, which improves the green body strength. In this study, low-toxic PEG(200)DMA was chosen as the main binder and crosslinker and small dosage AM was applied to adjust the viscosity of the ceramic slurry to gel-cast 3YSZ (PEG(200)DMA: AM = 4:1, mass ratio). Influence of monomer concentration, dispersant concentration and solid loading on the rheological behavior of the slurry and the flexural strength of the green body were investigated using aqueous PEG(200)DMA/AM gel system to gel-cast 3YSZ. The results show that the flexural strength of green bodies notably increases with the increasing of monomer concentration and reaches high up to 14.4 MPa when gel-cast 3YSZ ceramics using PEG(200)DMA/AM gel system with appropriate amount of PAA-NH4, monomer and solid loading. This gel system obviously reduces the toxicity of the conventional AM system and, at the same time, ensures high flexural strength of green bodies.

Preparation of RBSC Green Bodies by Gel-Casting

2008 ◽  
Vol 368-372 ◽  
pp. 834-836
Author(s):  
Hai Lin Liu ◽  
Yu Feng Chen ◽  
Hua Wang ◽  
Jie Tang
Keyword(s):  
Silicon Carbide ◽  
Flexural Strength ◽  
Monomer Concentration ◽  
Casting Process ◽  
Green Body ◽  
Carbon Particles ◽  
Gel Casting ◽  
Monomer Content ◽  
Silicon Carbide Particles ◽  
Carbide Particles

In this paper, green bodies of RBSC were prepared through the gel-casting process. The effects of monomer concentration and ratio of MBAM to AM on the strength and microstructure of the green bodies were studied. When the monomer content increased from 10wt% to 20wt %( relative to water in the slurry), the flexural strength increases efficiency. However, the flexural strength decreases when the monomer content was above 20wt%. Similarly, when the ratio of MBAM to AM increased from 1/19 to 1/9, it had the same effects on the flexural strength of green bodies. It was found that silicon carbide particles were packaged by the carbon particles with gel. When the monomer content was 20wt% and the ratio of MBAM to AM was 1/9, the green body showed the best homogeneous microstructures and its flexural strength achieved 8MPa.

Effect of Various Dispersants on the Gel-Casting of Silicon Nitride

2007 ◽  
Vol 336-338 ◽  
pp. 991-993 ◽  
Author(s):  
Li Peng Qian ◽  
Feng Hou ◽  
Ting Xian Xu
Keyword(s):  
Silicon Nitride ◽  
Gum Arabic ◽  
Solid Content ◽  
Solid Loading ◽  
Green Body ◽  
Nitride Powder ◽  
High Solid Loading ◽  
Gel Casting ◽  
Silicon Nitride Powder ◽  
Aqueous Silicon

A high solid loading of dispersed silicon nitride slurry was prepared with various dispersants, which allowed a stable silicon nitride suspension with sintering additives (cordierite) in alkaline regions to a solid content of 45 vol%. Gum arabic, PMAA-NH4, TMAH, PAA-NH4 and their composites were selected as dispersants. The results suggested that the composite dispersant which was obtained using PAA-NH4 and TMAH with the ratio in 4:1 was more effective in aqueous silicon nitride powder suspensions system than simplex dispersant. The green bodies derived exhibited a mechanical strength as high as 8.7MPa and SEM photos revealed that the green body also had a high homogeneity.

The Effects of Different Slurry on the Joining Characteristics of SiC Green Body

2012 ◽  
Vol 512-515 ◽  
pp. 411-414
Author(s):  
Yan Li Huo ◽  
Hai Lin Liu ◽  
Chun Peng Wang ◽  
Jie Tang ◽  
Yu Feng Chen ◽  
...  
Keyword(s):  
Grain Size ◽  
Binding Sites ◽  
Bending Strength ◽  
Solid Loading ◽  
Green Body ◽  
Gel Casting ◽  
Sic Ceramic ◽  
Welding Interface ◽  
Different Grain Size ◽  
Test Result

Experiments were carried out to join reaction-bonded silicon carbide (RBSC) ceramic in green body. SiC green bodies were fabricated by gel-casting method. The slurries for joint were prepared by different grain size of SiC. The results indicate the solid loading and the grain size of SiC influence the strength of welding. There is no clear welding interface between the two substrates in an appropriate solid volume loading and grain size. The average bending strength of welding after sintering can reach 300MPa. SEM was used to observe the cross-section morphology and microstructure of binding sites. The test result shows that its microstructure is similar to the RB-SiC ceramic. The mechanical properties of binding sites were tested. The result shows a desirable mechanical property.

Gel Casting of Large-Sized, Complex-Shaped RBSC Component

2012 ◽  
Vol 512-515 ◽  
pp. 395-398 ◽  
Author(s):  
Hai Lin Liu ◽  
Yan Li Huo ◽  
Chun Peng Wang ◽  
Jie Tang ◽  
Yu Feng Chen
Keyword(s):  
Rheological Property ◽  
Process Parameters ◽  
Casting Process ◽  
Sintered Body ◽  
Solid Loading ◽  
Green Body ◽  
High Solid ◽  
High Solid Loading ◽  
Low Viscosity ◽  
Gel Casting

In this paper, gel casting process of RBSC was deeply studied. The rheological property of C/SiC slurry was analyzed, high solid loading (67%) slurry with low viscosity was produced. Also the properties of green body and sintered body were studied. Finally, through optimizations of process parameters, a large-sized (650mm), complex-shaped (with thin ribs about 2.5mm) was fabricated through gel casting process with no cracks and deformation. It was showed that gel casting process is suitable for producing large-sized, complex-shaped RBSC components.

Research on Polymerization of PMN-PZT Piezoelectric Ceramic by Gelcasting Using NMAM System

2013 ◽  
Vol 652-654 ◽  
pp. 312-315
Author(s):  
Ping Zhou ◽  
Jing Hong Du
Keyword(s):  
Piezoelectric Ceramic ◽  
Bending Strength ◽  
Ph Value ◽  
Monomer Concentration ◽  
Piezoelectric Ceramics ◽  
Green Body ◽  
Low Toxicity ◽  
Gel System

The industrialization of gelcasting technique has been prevented because acryamide is a neurotoxin monomer. In this paper, a low-toxicity gel system based on the polymerization of low-toxicity N-hydroxymothl acrylamide was used for the gelcasting PMN-PZT piezoelectric ceramic. The effects of monomer concentration, the dosage of initiator and catalyst, pH value on polymerization were studied. The results showed that the condition suitable for gelcasting PMN-PZT piezoelectric ceramics could be obtained while monomer concentration was 10wt%～15wt%, the dosages of initiator and catalyst were respectively 0.4 vol%～0.5vol% and 0.4vol%, pH value of slurry was about 10. The highest bending strength of PMN-PZT green body prepared at the aboved conditions can reach 19.5Mpa

Gel-casting of Fine Zirconia Using DMAA Gel System

2011 ◽  
Vol 26 (10) ◽  
pp. 1105-1110 ◽  
Author(s):  
Hai-Xian XU ◽  
Tai QIU ◽  
Jian YANG ◽  
Jian GUO
Keyword(s):  
Gel Casting ◽  
Gel System

scholarly journals Synthesis of Network Polymers by Means of Addition Reactions of Multifunctional-Amine and Poly(ethylene glycol) Diglycidyl Ether or Diacrylate Compounds

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2047
Author(s):  
Naofumi Naga ◽  
Mitsusuke Sato ◽  
Kensuke Mori ◽  
Hassan Nageh ◽  
Tamaki Nakano
Keyword(s):  
Ethylene Glycol ◽  
Room Temperature ◽  
Addition Reaction ◽  
Monomer Concentration ◽  
Diglycidyl Ether ◽  
Porous Polymers ◽  
Addition Reactions ◽  
Poly Ethylene Glycol ◽  
Network Polymers ◽  
Poly Ethylene

Addition reactions of multi-functional amine, polyethylene imine (PEI) or diethylenetriamine (DETA), and poly(ethylene glycol) diglycidyl ether (PEGDE) or poly(ethylene glycol) diacrylate (PEGDA), have been investigated to obtain network polymers in H2O, dimethyl sulfoxide (DMSO), and ethanol (EtOH). Ring opening addition reaction of the multi-functional amine and PEGDE in H2O at room temperature or in DMSO at 90 °C using triphenylphosphine as a catalyst yielded gels. Aza-Michael addition reaction of the multi-functional amine and PEGDA in DMSO or EtOH at room temperature also yielded corresponding gels. Compression test of the gels obtained with PEI showed higher Young’s modulus than those with DETA. The reactions of the multi-functional amine and low molecular weight PEGDA in EtOH under the specific conditions yielded porous polymers induced by phase separation during the network formation. The morphology of the porous polymers could be controlled by the reaction conditions, especially monomer concentration and feed ratio of the multi-functional amine to PEGDA of the reaction system. The porous structure was formed by connected spheres or a co-continuous monolithic structure. The porous polymers were unbreakable by compression, and their Young’s modulus increased with the increase in the monomer concentration of the reaction systems. The porous polymers absorbed various solvents derived from high affinity between the polyethylene glycol units in the network structure and the solvents.

Preparation of Bimodal Porous Apatite Ceramics through Slip Casting Using Fine Hydroxyapatite Powders

2006 ◽  
Vol 317-318 ◽  
pp. 723-728 ◽  
Author(s):  
Yin Zhang ◽  
Yoshiyuki Yokogawa ◽  
Tetsuya Kameyama
Keyword(s):  
Flexural Strength ◽  
Size Range ◽  
Slip Casting ◽  
Fine Powder ◽  
Total Porosity ◽  
Solid Loading ◽  
Wet Milling ◽  
Hydrogen Phosphate ◽  
Optimum Amount ◽  
Porous Hydroxyapatite

A bimodal porous hydroxyapatite (HAp) body with high flexural strength was prepared through slip casting. HAp fine powder used in this study was synthesized by wet milling, drying and heating of a mixture of calcium hydrogen phosphate di-hydrate and calcium carbonate. The synthesized HAp powder was 0.320.05 μm in size and 38.10.8m2/g in specific surface area. The slip was prepared by adding deflocculant and foaming reagent. The optimum value for the minimum viscosity in the present HAp slip with respect to its solid loading and the optimum amount of the deflocculant were studied. The total porosity of the specimens obtained from a slip of 48 wt% HAp solid loading is in the range of 49 – 61vol %, and the resultant porous HAp sintered body had large spherical pores of 300 -m with interconnecting rectangular voids. Many small pores in the size range of 2-3 -m or below were observed in the specimen obtained by heating at 1100, and 1200 . The flexural strength of the bimodal porous HAp ceramics sintered at 1200 C showed a large value of 17.6 MPa, with a porosity of 60.5vol.

scholarly journals Rapid Fabrication of High-Performance CaO-Based Integral Ceramic Mould by Stereolithography and Non-Aqueous Gelcasting

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 934 ◽  
Author(s):  
Qiang Yang ◽  
Weijun Zhu ◽  
Zhongliang Lu ◽  
Dichen Li ◽  
Zhongrui Wang ◽  
...  
Keyword(s):  
High Performance ◽  
Bending Strength ◽  
Gelation Time ◽  
Butyl Alcohol ◽  
Solid Loading ◽  
Green Body ◽  
Excellent Thermal Stability ◽  
Tert Butyl Alcohol ◽  
Rapid Fabrication ◽  
Monomer Content

A high-performance CaO-based integral ceramic mould was fabricated for investment casting by stereolithography (SLA) and non-aqueous gelcasting. The rheology of tert-butyl alcohol (TBA)-based CaO slurries and the effect of gelation parameters on the gelation time and strength of the green body were investigated to obtain a high-quality green body of the CaO-based integral ceramic mould. Then the pre-sintering and sintering processes were optimized to avoid cracks, reduce the sintering shrinkage, and improve the strength of CaO-based ceramic mould. The results showed that the CaO-based slurry with 56 vol % solid loading and 3 wt % dispersant content exhibited high stability and good flowability. The optimized gelation parameters were determined to be a monomer content of 20 wt %, a ratio of crosslinker to monomer of 0.06, an initiator content of 1 wt % and a gelation temperature of 40 °C. A reasonable sintering regime was identified to avoid cracks and guarantee a low shrinkage of 0.6%, a room temperature bending strength of 14.12 MPa and a high temperature (1200 °C) strength of 8.22 MPa. The CaO-based integral ceramic mould fabricated in this study has many advantages including excellent thermal stability, reaction-resistance to molten active alloys, ease of dissolution, and enhanced efficiency and economy in comparison to SiO2 or Al2O3 ceramic moulds.

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