Influence of the Binder Amount on the Properties of the Non-Sintering Ti(C,N)-Si3N4-SiC Composite Refractories

2013 ◽  
Vol 833 ◽  
pp. 221-224 ◽  
Author(s):  
Bo Tan ◽  
Kai Chen ◽  
Zhao Hui Huang ◽  
Ming Hao Fang ◽  
Yan Gai Liu ◽  
...  
Keyword(s):  
Flexural Strength ◽  
Phenolic Resin ◽  
Raw Materials ◽  
Silicon Powder ◽  
Volume Shrinkage ◽  
Natural Quartz ◽  
Complex Binder ◽  
Degradation Of Properties ◽  
Silicon Carbide Particles ◽  
Carbide Particles

The non-sintering Ti (C,N)-Si3N4-SiC composite refractories were prepared using natural quartz, rutile and silicon carbide particles/powders as the raw materials, phenolic resin and urotropin as a complex binder and silicon powder as the additive. The influence of the binder amount on the density, flexural strength, volume shrinkage and the microstructure of the non-sintering Ti (C,N)-Si3N4-SiC composite refractories was studied in detail. The results showed that the amount of binder has significant effects on the properties of the non-sintering Ti (C,N)-Si3N4-SiC composite refractories. The bulk density decreased and the apparent porosity increased as the amount of binder increased, and the flexural strength increased and then decreased as the amount of binder increased, and the volume shrinkage increased with the increase of the amount of binder. The binder is propitious to the properties of the non-sintering Ti (C,N)-Si3N4-SiC composite refractories, but excessive binder will result in the degradation of properties of the as-fabricated composite refractories, the optimum amount of complex adhesive is 15%.

Effect of Silicon Particle Size on Synthesis and Crystallinity of β-Silicon Carbide Particles

2014 ◽  
Vol 353 ◽  
pp. 239-243
Author(s):  
Woo Teck Kwon ◽  
Soo Ryong Kim ◽  
Young Hee Kim ◽  
Yoon Joo Lee ◽  
J.Y. Won ◽  
...  
Keyword(s):  
Silicon Oxide ◽  
Raw Materials ◽  
Silicon Powder ◽  
Raw Material ◽  
Sic Particles ◽  
Transmission Electron ◽  
Higher Temperature ◽  
Silicon Carbide Particles ◽  
Carbide Particles ◽  
Silicon Particles

β-SiC particles were synthesized using silicon powder and carbon black at 1300°C. The effect of grinding the silicon powder raw material into smaller particles on the synthesis and crystallinity of the SiC particles was investigated. The size of the silicon particles decreased and the surface of the silicon particles increasingly oxidized into silicon oxide with increasing grinding time, thus decreasing the yield of SiC because of the higher SiO2 content in the ground silicon powder, since SiO2 transforms into SiC at a higher temperature than does silicon. Although the sizes of the silicon particles in the raw materials were different, all the synthesized SiC crystallites showed similar size. Transmission electron microscopy-energy dispersive X-ray spectroscopy analysis showed that although most of the synthesized SiC particles were smaller than 100 nm, the primary SiC particles had aggregated, and some unreacted silicon was observed inside the large aggregated SiC particles.

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.

Effects of the Mould Pressure and Mould Pressing Time on the Properties of Graphite/Phenolic Resin Composites

2013 ◽  
Vol 706-708 ◽  
pp. 95-98
Author(s):  
Mi Dan Li ◽  
Dong Mei Liu ◽  
Lu Lu Feng ◽  
Huan Niu ◽  
Yao Lu
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
Flexural Strength ◽  
Polymer Matrix ◽  
Phenolic Resin ◽  
Polymer Matrix Composites ◽  
Resin Composites ◽  
Matrix Composites ◽  
Natural Graphite ◽  
Pressing Time

Polymer matrix composites made from phenolic resin are filled with natural graphite powders. They are fabricated by compression molding technique. The density, electrical conductivity and flexural strength of composite are analyzed to determine the influences of mould pressure and mould pressing time on the physical, electrical and mechanical properties of composite. It is found that the density, electrical conductivity and flexural strength of composites increased with increasing mould pressure. Under pressure of 40 MPa for 60 min, the density, electrical conductivity and flexural strength of composites were 1.85 g/cm3, 4.35  103 S/cm and 70 MPa, respectively. The decreased gaps could be the main reason for the increasing of density, electrical conductivity and flexural strength as mould pressure increases. The results also show that the density of composites increased with increasing mould pressing time.

scholarly journals Fabrication of (SiC-AlN)/ZrB2 Composite with Nano-Micron Hybrid Microstructure via PCS-Derived Ceramics Route

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 334
Author(s):  
Aidong Xia ◽  
Jie Yin ◽  
Xiao Chen ◽  
Zhengren Huang ◽  
Xuejian Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Flexural Strength ◽  
Hot Pressing ◽  
Raw Materials ◽  
Secondary Phase ◽  
Pressing Temperature ◽  
Xrd Pattern ◽  
Mean Grain Size ◽  
The Mean

In this work, a (SiC-AlN)/ZrB2 composite with outstanding mechanical properties was prepared by using polymer-derived ceramics (PDCs) and hot-pressing technique. Flexural strength reached up to 460 ± 41 MPa, while AlN and ZrB2 contents were 10 wt%, and 15 wt%, respectively, under a hot-pressing temperature of 2000 °C. XRD pattern-evidenced SiC generated by pyrolysis of polycarbosilane (PCS) was mainly composed by 2H-SiC and 4H-SiC, both belonging to α-SiC. Micron-level ZrB2 secondary phase was observed inside the (SiC-AlN)/ZrB2 composite, while the mean grain size (MGS) of SiC-AlN matrix was approximately 97 nm. This unique nano-micron hybrid microstructure enhanced the mechanical properties. The present investigation provided a feasible tactic for strengthening ceramics from PDCs raw materials.

STUDY OF EXTERNAL MASS TRANSFER DURING DRYING OF BERRY RAW MATERIALS TAKING INTO THE SHRINKAGE PHENOMENON

2019 ◽  
Author(s):  
А.В. АКУЛИЧ ◽  
Л.А. ГОСТИНЩИКОВА
Keyword(s):  
Mass Transfer ◽  
Energy Supply ◽  
Raw Materials ◽  
Mass Transfer Rate ◽  
Experimental Studies ◽  
Volume Shrinkage ◽  
External Mass Transfer ◽  
Transfer Coefficients ◽  
Ir Radiation ◽  
Criterial Equations

Исследованы закономерности внешнего массообмена при сушке ягодного сырья для различных способов энергоподвода. Установлено, что ягоды при сушке подвержены значительной объемной (72–81%) и линейной (35–43%) усадке, которую необходимо учитывать при расчете коэффициентов массоотдачи. Объекты исследования – ягоды черники, красной и черной смородины. Проведены экспериментальные исследования по сушке ягодного сырья при конвективном и конвективном с ИК-излучением способах энергоподвода. Исследования проведены при скорости сушильного агента хса1,2 м/с и температуре tса 70°С. Получены критериальные уравнения внешнего массоообмена при сушке ягод для периода постоянной скорости, учитывающие объемную усадку. Определено, что при сушке с конвективным энергоподводом объемная усадка при одном и том же значении критерия Рейнольдса оказывает на 12–20% большее влияние на интенсивность массоообмена для красной смородины по сравнению с черникой и черной смородиной. При сушке с конвективным энергоподводом, ИК-излучением и предварительным прокалыванием объемная усадка наиболее существенно влияет на массообмен для черной смородины, протекающий в 1,5–1,8 раза интенсивнее по сравнению с черникой и красной смородиной. Полученные критериальные уравнения могут быть использованы при расчете и проектировании установок для сушки ягодного сырья. The laws of external mass transfer during drying of berry raw materials for various methods of energy supply are investigated. It is established that the berries during drying are subject to significant volumetric (72–81%) and surface (35–43%) shrinkage, which must be taken into account when calculating the mass transfer coefficients. The objects of the study were various berries: blueberries, red and black currants. Experimental studies have been carried out on the drying of selected berries both in the case of convective and convective methods with IR radiation. Investigations were carried out at a drying agent velocity хса1,2 m/s and its temperature tca70°С. The criterion equations of external mass transfer during drying of berries for a period of constant speed, taking into account the volume shrinkage, are obtained. It was determined that during drying with convective energy supply, volume shrinkage with the same value of the Reynolds criterion on 12–20% has a greater effect on the mass transfer rate for red currants. When drying with convective energy supply, IR radiation and preliminary piercing, the volume shrinkage most significantly affects the mass transfer for black currants, which is 1,5–1,8 times more intense than blueberries and red currants. The obtained criterial equations can be used in the calculation and design of berries dryers.

Characterization of Ceramic Tiles Added with EAF Slag Waste

2014 ◽  
Vol 1024 ◽  
pp. 211-214 ◽  
Author(s):  
Pao Ter Teo ◽  
Abu Seman Anasyida ◽  
Mohd Sharif Nurulakmal
Keyword(s):  
Flexural Strength ◽  
Raw Materials ◽  
Solid Wastes ◽  
Arc Furnace ◽  
Ceramic Tiles ◽  
Total Percentage ◽  
Eaf Slag ◽  
Ball Clay ◽  
Slag Waste

The increasing production of steel leads to an increment of solid wastes generated especially Electric Arc Furnace (EAF) slag. This becomes a serious concern as the slag has to be disposed in a proper manner in order to avoid dumping in landfills which will eventually occupy available land and may cause permanent damage to the flora and fauna. In this project, an attempt was made to utilize the EAF slag as one of the raw materials in ceramic tiles. Results obtained showed that as percentage of EAF slag added was increased up to 60%, percentage of apparent porosity and water absorption were found to increase, accompanied by reduction in flexural strength due to more severe porosity was observed in the tiles. On the other hand, reducing the percentage of EAF slag up to 40% while increasing percentage of ball clay added led to formation of higher total percentage of anortite and wollastonite minerals. This would contribute to higher flexural strength of tiles. In addition, by adding silica and feldspar, the flexural strength of tile produced was further improved due to optimization of densification process. Highest flexural strength of EAF slag based tiles was attained at composition of 40% EAF slag 30% ball clay 10% feldspar 20% silica. It was observed that properties of ceramic tiles added with EAF slag, especially flexural strength are comparable with commercial ceramic tiles. Therefore, the EAF slag ceramic tiles have great potential to be made into high flexural strength or wear resistant floor tiles.

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