scholarly journals Preparation of lightweight corundum-mullite thermal insulation materials by microwave sintering

2021 ◽  
Vol 15 (2) ◽  
pp. 170-178
Author(s):  
Yaochen Si ◽  
Shuheng Fan ◽  
Hailong Wang ◽  
Miao Xia ◽  
Lingfeng Li ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Bending Strength ◽  
Hot Spot ◽  
Microwave Sintering ◽  
High Porosity ◽  
Insulation Materials ◽  
Burn Out ◽  
Lightweight Corundum ◽  
Shock Resistance ◽  
Mullite Whiskers

Lightweight corundum-mullite thermal insulation materials were successfully prepared by microwave sintering at low temperature. The effects of sintering temperatures, PMMA microspheres and SiC particles on structure and properties of as-prepared corundum-mullite materials were investigated. The SiC became a hot spot under the action of microwave field, and these local high temperature areas promoted the formation and growth of mullite whiskers. The PMMA microspheres were burn out, leaving pores which could provide space for the growth of mullite whiskers. It was found that the optimal sintering temperature was 1400?C and corresponding porosity, density and bending strength of the samples were 71.2%, 0.99 g/cm3 and 3.85MPa, respectively. The thermal conductivity was from 0.201 to 0.313W/(m?K) between 30?C and 950?C. This work demonstrated that lightweight corundum-mullite materials with low density, high porosity, good thermal shock resistance and excellent thermal insulation properties could be successfully prepared by microwave sintering.

scholarly journals Characterization of Thermal Bio-Insulation Materials Based on Oil Palm Wood: The Effect of Hybridization and Particle Size

Polymers ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 3287
Author(s):  
Indra Mawardi ◽  
Sri Aprilia ◽  
Muhammad Faisal ◽  
Samsul Rizal
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Particle Size ◽  
Water Absorption ◽  
Thermal Insulation ◽  
Oil Palm ◽  
Bending Strength ◽  
Fine Particles ◽  
Biomass Waste ◽  
Insulation Materials

Oil palm wood is the primary biomass waste produced from plantations, comprising up to 70% of the volume of trunks. It has been used in non-structural materials, such as plywood, lumber, and particleboard. However, one aspect has not been disclosed, namely, its use in thermal insulation materials. In this study, we investigated the thermal conductivity and the mechanical and physical properties of bio-insulation materials based on oil palm wood. The effects of hybridization and particle size on the properties of the panels were also evaluated. Oil palm wood and ramie were applied as reinforcements, and tapioca starch was applied as a bio-binder. Panels were prepared using a hot press at a temperature of 150 °C and constant pressure of 9.8 MPa. Thermal conductivity, bending strength, water absorption, dimensional stability, and thermogravimetric tests were performed to evaluate the properties of the panels. The results show that hybridization and particle size significantly affected the properties of the panels. The density and thermal conductivity of the panels were in the ranges of 0.66–0.79 g/cm3 and 0.067–0.154 W/mK, respectively. The least thermal conductivity, i.e., 0.067 W/mK, was obtained for the hybrid panels with coarse particles at density 0.66 g/cm3. The lowest water absorption (54.75%) and thickness swelling (18.18%) were found in the hybrid panels with fine particles. The observed mechanical properties were a bending strength of 11.49–18.15 MPa and a modulus of elasticity of 1864–3093 MPa. Thermogravimetric analysis showed that hybrid panels had better thermal stability than pure panels. Overall, the hybrid panels manufactured with a coarse particle size exhibited better thermal resistance and mechanical properties than did other panels. Our results show that oil palm wood wastes are a promising candidate for thermal insulation materials.

scholarly journals Crucial effect of SiC particles on in situ synthesized mullite whisker reinforced Al2O3-SiC composite during microwave sintering

2017 ◽  
Vol 11 (2) ◽  
pp. 106-112 ◽  
Author(s):  
Xudan Dang ◽  
Meng Wei ◽  
Rui Zhang ◽  
Keke Guan ◽  
Bingbing Fan ◽  
...  
Keyword(s):  
Particle Size ◽  
Flexural Strength ◽  
Thermal Shock ◽  
Thermal Shock Resistance ◽  
Hot Spot ◽  
Microwave Sintering ◽  
Sic Particles ◽  
Shock Resistance ◽  
Sic Particle

Mullite whisker reinforced Al2O3-SiC composites were in situ synthesized by microwave sintering at 1500?C for 30min. The influence of SiC particle size on heating process and properties of Al2O3-SiC composite were investigated. The XRD and SEM techniques were carried out to characterize the samples. The thermal shock resistance and flexural strength of the samples were examined through water quenching and three-point bending methods, respectively. It was found that the bridging of mullite whisker appeared between Al2O3 and SiC particles which enhanced the thermal shock resistance. A so-called local hot spot effect was proposed dependent on the coupling of SiC particles with microwave, which was the unique feature of microwave sintering. The maximal thermal shock resistance and flexural strength were obtained for the samples with SiC particle size of ~5?m.

scholarly journals ТЕПЛОИЗОЛЯЦИОННЫЙ МАТЕРИАЛ НА ОСНОВЕ ОСТАТКОВ ПИРОЛИЗА УГЛЯ И ОТХОДОВ СТЕКЛА

2021 ◽  
pp. 18-27
Author(s):  
M.V. Abrahamyan ◽  
B.V. Movsisyan ◽  
R.A. Avetyan ◽  
G.H. Torosyan
Keyword(s):  
Thermal Insulation ◽  
Foam Glass ◽  
Glass Production ◽  
Mineral Wool ◽  
Raw Material ◽  
Surface Finishing ◽  
High Porosity ◽  
Coal Pyrolysis ◽  
Gas Generator ◽  
Insulation Materials

In recent decades, materials with high thermal resistance, refractory, non-toxic, with high mechanical characteristics, durable, affordable easy-to-install thermal insulation materials are of great interest. Durability of available thermal insulating materials, for example cotton insulators is from 10 to 20 years, foam is from 7 to 10 years. During burning process of foam plastics, high-toxic material called phosgene is released. At the same time, fungus forms during the process, and it has adhesion incompatibility with cement. Mineral wool decomposes over time, turning into powder, and the installation of external thermal insulation materials in buildings requires surface finishing to protect it from direct weathering, which incurs additional costs. Recently, composite glasses, glass-crystalline materials synthesized from slag-ash wastes of rocks are in great demand. The goal of this research is to study coal and solid waste of coal pyrolysis as a raw material for the foam glass production. In this work, the chemical, phase and mineralogical composition of coal from the Magavuz deposit in the Republic of Artsakh and solid residues of its catalytic pyrolysis have been studied by the modern methods of analysis. Based on the results, a heat-insulating material has been developed, in which pyrolysis waste also plays the role of a gas generator. The selected heat treatment mode ensures the production of heat-insulating foam with high porosity, uniformly distributed in the volume, with sufficient mechanical properties.

Preparation and Characterization of Porous Alumina Insulation Materials by Gel-Foaming

2011 ◽  
Vol 412 ◽  
pp. 207-210
Author(s):  
Lin Zhang ◽  
Jing Hong Du ◽  
Guo You Gan ◽  
Ji Kang Yan ◽  
Jian Hong Yi
Keyword(s):  
Bending Strength ◽  
Sintering Temperature ◽  
Porous Alumina ◽  
Combination Method ◽  
Oxide Ceramic ◽  
High Porosity ◽  
Insulation Materials ◽  
Blowing Agent ◽  
Small Pore ◽  
Aluminum Oxide Ceramic

Porous alumina insulation materials were prepared by the combination method of gelcasting and foaming. The effects of the amount of blowing agent, the solid volume, and the sintering temperature on porosity of aluminum oxide ceramic were studied. The result showed that, when the amount of blowing agent is 1wt %, the solid volume is 45vol % and the sintering temperature is 1500°C, the porous alumina ceramics with high porosity, small pore diameters, evenly distributed, high bending strength and low heat conductance can prepared.

Cordierite thermal insulation materials reinforced by aluminosilicate fiber/mullite whiskers hierarchical structure

2018 ◽  
Vol 15 (4) ◽  
pp. 1047-1053 ◽  
Author(s):  
Meng Li Qin ◽  
Xi Tang Wang ◽  
Zhou Fu Wang ◽  
Yan Ma ◽  
Hao Liu
Keyword(s):  
Thermal Insulation ◽  
Hierarchical Structure ◽  
Insulation Materials ◽  
Mullite Whiskers

Preparation of Al 2 O 3 ‐mullite thermal insulation materials with AlF 3 and SiC as aids by microwave sintering

2020 ◽  
Vol 17 (5) ◽  
pp. 2250-2258
Author(s):  
Shuheng Fan ◽  
Han Zheng ◽  
Qiancheng Gao ◽  
Yang Li ◽  
Yongqiang Chen ◽  
...  
Keyword(s):  
Thermal Insulation ◽  
Microwave Sintering ◽  
Insulation Materials

scholarly journals Preparation of mullite whiskers reinforced SiC/Al2O3 composites by microwave sintering

2016 ◽  
Vol 10 (4) ◽  
pp. 243-248 ◽  
Author(s):  
Bingbing Fan ◽  
Wei Li ◽  
Binzhou Dai ◽  
Keke Guan ◽  
Rui Zhang ◽  
...  
Keyword(s):  
Hot Spot ◽  
Microwave Sintering ◽  
Sol Gel ◽  
Electro Magnetic Field ◽  
Sic Particles ◽  
Mullite Whiskers ◽  
Electro Magnetic ◽  
Reflected Power ◽  
Physical And Chemical ◽  
Gel Processing

Mullite whiskers reinforced SiC/Al2O3 composites were prepared by microwave sintering in a microwave chamber with TE666 resonantmode. Original SiC particles were coated with SiO2 using sol-gel processing and mixed with Al2O3 particles. Mullite was formed in the reaction between SiO2 and Al2O3. The isostatically pressed cylindrical pellets were sintered from 1350?C to 1600?C for 30min. Physical and chemical responses were investigated by detecting changes in reflected power during the microwave sintering process. XRD was carried out to characterize the samples and showed that mullite could be formed at 1200 ?C. Bridging of mullite whiskers between Al2O3 and SiC particles was observed by SEM and is due to a so-called local hot spot effect, which was the unique feature for microwave sintering. The optimized microwave sintering temperature was 1500?C corresponding to the maximum amount of mullite whiskers within SiC/Al2O3 composites. The high electro-magnetic field enhanced the decomposition of mullite at higher temperatures above 1550?C. The mechanical properties of mullite whiskers reinforced SiC/Al2O3 composites are much better than the SiC/Al2O3 composites without mullite whiskers.

Fire Safety Assessment of Exterior Thermal Insulation Materials using a Cone Calorimeter

2012 ◽  
Vol 22 (1) ◽  
pp. 131-141
Author(s):  
Qi Yanjun ◽  
Wang Xuegui ◽  
Cui Yu ◽  
Zhang Heping
Keyword(s):  
Thermal Insulation ◽  
Fire Safety ◽  
Cone Calorimeter ◽  
Safety Assessment ◽  
Insulation Materials
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