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.

Co-Deposition of Binary Particles during Slip Casting Process

2011 ◽  
Vol 189-193 ◽  
pp. 2917-2920
Author(s):  
Yuan Li ◽  
Yue Qiu
Keyword(s):  
Silicon Carbide ◽  
Mechanical Performance ◽  
Carbon Sources ◽  
Slip Casting ◽  
Casting Process ◽  
Carbon Particles ◽  
Mould Wall ◽  
Sharp Edges ◽  
Silicon Carbide Particles ◽  
Carbide Particles

Co-deposition of silicon carbide particles and carbon (or carbon sources) particles is essential for preparation of reaction bonded silicon carbide (RBSC) products by slip casting. The way of co-depositing of silicon carbide particles and carbon particles during slip casting process, and the influence of composition of raw particles on particle co-depositing in green bodies were studied. The experiment results show: 1.Co-deposition of binary particles is greatly affected by particle size distribution, and large proportion of rigid SiC particles increases the difficulty in demoulding procedure because of small shrinkage; 2. Dispersants in deposited cake trend to enrich at the surface in contact with mould wall, while this enrichment of dispersant has little effect on mechanical performance of RBSC products; 3. Sharp edges on surface of raw particles could result to friction among particles, which afford strength to green bodies but prevent particles packing more closely.

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.

scholarly journals A Finite Element Analysis for Improvement of Shaping Process of Complex-Shaped Large-Size Silicon Carbide Mirrors

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4136
Author(s):  
Ling Qiao ◽  
Jingchuan Zhu ◽  
Yingnan Wan ◽  
Congcong Cui ◽  
Ge Zhang
Keyword(s):  
Silicon Carbide ◽  
Finite Element ◽  
Structural Integrity ◽  
Casting Process ◽  
Green Body ◽  
Technological Parameters ◽  
Element Analysis ◽  
Gel Casting ◽  
Generation Mechanisms

In the gel-casting process, the proper selection of technological parameters is crucial for the final quality of a green body. In this work, the finite element method is used to investigate the mold characteristics in the gel-casting process, and the typical flow behaviors under different conditions are presented. Based on the distribution characteristics of temperature, pressure and flow field of gel polymer, the simulated results provide some possible reasons for the generation mechanisms of defects. Then, a series of simulations were performed to investigate the effect of process parameters on the molding quality of green gel-cast bodies. The results show that the decreasing loading speed can effectively reduce the number of defects and improve the molding quality. In addition, this paper presents a new technique by applying the exhaust hole to decrease the number of defects and, hence, improve structural integrity. The influence of the loading speed on the mold characteristics is well understood for the gating system with an exhaust hole, which suggests to us appropriate parameters for optimizing the molding design. This work provides a theoretical basis to explicate the generating mechanism of defects involved in the gel-casting process and acquires an optimized technique to produce a silicon carbide green body.

Effects of Mechanical Alloying on the Mechanical and Tribological Properties of Al-Cu-Mg Matrix Composites Reinforced by Sub-Micron Silicon Carbide Particles

2010 ◽  
Vol 123-125 ◽  
pp. 51-54
Author(s):  
Xiao Yan Deng ◽  
Jin Cheng Xu ◽  
Wei Hua ◽  
Liang Liang Tian ◽  
Li Jun Ai ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Mechanical Alloying ◽  
Tribological Properties ◽  
Matrix Alloy ◽  
Matrix Composites ◽  
Mechanical And Tribological Properties ◽  
Carbon Particles ◽  
The Matrix ◽  
Silicon Carbide Particles ◽  
Carbide Particles

Al-Cu-Mg alloy and its matrix composites reinforced with different volume fractions of sub-micron silicon carbide particles have been produced in powder metallurgy route. The effects of silicon carbon particles and mechanical alloying (MA) technology on the mechanical and tribological properties were investigated. The results show that the composites have better mechanical and tribological properties than the matrix alloy, and the 9vol%SiCp/Al-Cu-Mg composite has the best performances. Mechanical alloying (MA) technology further improves the hardness and tensile strength, hardly influences the wear rate of the 9vol%SiCp/Al-Cu-Mg composite but somewhat affects its friction coefficient.

Machining Behavior of Green RBSC Body Prepared by Gel-Casting

2010 ◽  
Vol 434-435 ◽  
pp. 853-855
Author(s):  
Hai Lin Liu ◽  
Yan Li Huo ◽  
Chun Peng Wang ◽  
Jie Tang ◽  
Hua Wang ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Casting Process ◽  
Gel Casting ◽  
Green Component ◽  
Rapid Fabrication ◽  
Cnc Grinding ◽  
Monomer Content ◽  
Potential Alternative ◽  
Grinding Machine ◽  
Micro Structures

In this paper, the green RBSC was prepared by gel casting process. The influences of the monomer content (MBAM and AM) and monomer ratio (MBAM to AM) on the flexural strength were investigated. The results indicated the flexural strength of green body was up to 8MPa and the micro- structures were homogeneous. The green RBSC bodies were machined by CNC grinding machine with diamond-coated grinding tools. Machining tests showed the green component could be machined without appended defects. It was found that green machining as a ‘top-down’ approach was a potential alternative for the rapid fabrication of complex-shaped ceramics, especially for some one-of-a-kind products.

The Effect of SiC Surface Treatment on the Interface Bonding Behavior of SiC/Cu Composite Particles

2012 ◽  
Vol 512-515 ◽  
pp. 951-954
Author(s):  
Bing Bing Fan ◽  
Huan Huan Guo ◽  
Jian Li ◽  
Hai Long Wang ◽  
Ke Bao ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Surface Treatment ◽  
Practical Importance ◽  
Functional Materials ◽  
Decomposition Reaction ◽  
Reduction Reaction ◽  
Temperature Oxidation ◽  
Reaction Method ◽  
Silicon Carbide Particles ◽  
Carbide Particles

The SiC/Cu composite is one of the "structural-functional" materials. It shows good mechanical properties and very high thermal, high electrical conductivity etc. But the co-dispersion, wetting and bonding between SiC and Cu interface are of practical importance in the preparation of SiC/Cu composites. In this work, surface treatment techniques such as high-temperature oxidation, acid dipping and alkaline wash were adopted separately on silicon carbide particles, in order to improve the wettability and physical and chemical compatibility between silicon carbide and copper, then we used the replacement reaction method and decomposition-reduction reaction method to generate Cu coating on the surface of silicon carbide. The results shown that, the surface of silicon carbide particle which treated by alkaline wash was cleaner and more rough than that only treated by high-temperture oxidation, moreover, the specific surface of the particle was increased, which resulted in a compact layer of Cu coating. for the same silicon carbide particles, the effect of the Cu coating prepared by decomposition reaction method was better than that by reduction reaction method.

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