scholarly journals Fabrication and properties of Si2N2O ceramics for microwave sintering furnace

2020 ◽  
Vol 14 (1) ◽  
pp. 32-39
Author(s):  
Bingbing Fan ◽  
Wei Li ◽  
Fan Zhang ◽  
Hongxia Li ◽  
Rui Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Microwave Sintering ◽  
Xrd Analysis ◽  
Raw Material ◽  
Vacuum Sintering ◽  
Low Dielectric ◽  
Sintering Additive ◽  
Insufficient Amount ◽  
Shock Resistance ◽  
High Thermal Shock Resistance

The Si2N2O ceramics with low dielectric constant, low thermal diffusivity and high thermal shock resistance were successfully prepared by vacuum sintering. The amorphous Si3N4 was used as raw material with Li2CO3 as sintering additive. The phase, microstructure, oxidized resistance, mechanical and dielectric properties of the Si2N2O ceramics were investigated. XRD analysis showed that the suitable content of Li2CO3 could promote the generation of Si2N2O ceramics. However, the excess or insufficient amount of Li2CO3 additive would cause decomposition of Si2N2O phase. The Li2O volatilized at high temperature leaving highly pure (99.63%) porous Si2N2O ceramics. The flexural strength of the porous Si2N2O ceramics (with ?49.19%of open porosity) was about 30MPa, the residual strength ratio was more than 70% after 1300?C quenching in air. The SiO2 layer formed by oxidization could prevent Si2N2O ceramics from further oxidizing. Therefore, these Si2N2O ceramics will be excellent thermal insulation and wave-transparent materials for high temperature microwave sintering furnace.

scholarly journals Characterization of Li2O-Al2O3-SiO2 glass-ceramics produced from a Brazilian spodumene concentrate

Cerâmica ◽  
2019 ◽  
Vol 65 (375) ◽  
pp. 366-377 ◽  
Author(s):  
L. B. Rebouças ◽  
M. T. Souza ◽  
F. Raupp-Pereira ◽  
A. P. Novaes de Oliveira
Keyword(s):  
Structural Changes ◽  
Glass Ceramics ◽  
Nucleating Agent ◽  
Raw Material ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Heating Microscopy ◽  
Shock Resistance ◽  
High Thermal Shock Resistance

Abstract Glass-ceramics in the LAS (Li2O-Al2O3-SiO2) system with high thermal shock resistance were successfully obtained using Brazilian spodumene concentrate as the main raw material (80-70 wt%). Two compositions (Li2O.Al2O3.nSiO2) were produced with n= 2 and 4, near to the stoichiometric compositions of β-eucryptite and β-spodumene. The characteristic temperatures of parent glasses were determined by contact dilatometry, differential scanning calorimetry and heating microscopy. The crystallization mechanism and the effect of the nucleating agent (TiO2.2ZrO2) required to promote volume crystallization in the parent glasses were investigated. Microstructural and structural changes with temperature were also evaluated by optical microscopy and X-ray diffraction. The obtained glass-ceramics presented coefficients of thermal expansion between -0.370x10-6 and 4.501x10-6 °C-1 in the 22 to 700 °C range.

Properties of Silicon Nitride Using Cordierite as Sintering Additives

2007 ◽  
Vol 336-338 ◽  
pp. 313-315
Author(s):  
Miao Jiang ◽  
Feng Hou ◽  
Ting Xian Xu
Keyword(s):  
Silicon Nitride ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Porous Structures ◽  
Reaction Method ◽  
Low Dielectric ◽  
Sintering Additive ◽  
Low Sintering Temperature

Silicon nitride materials with low dielectric properties were prepared using nano and micron silicon nitride powders as raw materials and the green bodies were sintered with cordierite as sintering additive in flowing nitrogen. The additives of cordierite powders prepared by sol-gel method and solidstate reaction method could greatly decrease the sintering temperature. The dielectric constant of materials decreased as sintering temperature fell, whereas the strength showed relatively low as the low sintering temperature. XRD analysis showed the main phase of material was Si2N2O, which indicated that the Si3N4 could be integrated with SiO2. Porous structures were observed by SEM, showing compact sintering cannot be achieved at these temperatures, explaining the low strength.

scholarly journals Microwave Sintering of Titanium

2010 ◽  
Vol 436 ◽  
pp. 141-147 ◽  
Author(s):  
Shu Dong Luo ◽  
Colleen J. Bettles ◽  
Ming Yan ◽  
Graham B. Schaffer ◽  
Ma Qian
Keyword(s):  
Heating Rate ◽  
Microwave Sintering ◽  
High Vacuum ◽  
Vacuum Fluctuations ◽  
Vacuum Sintering ◽  
Cross Sectional ◽  
Heating And Cooling ◽  
Tube Furnaces ◽  
Titanium Powders ◽  
Shock Resistance

Effective sintering of titanium requires the use of a high sintering temperature (≥1200 °C), preferably in high vacuum (< 10-2 Pa). This confines the heating and cooling rates to ~ 4 °C/min because of the limited thermal shock resistance of ceramic tube furnaces. Consequently, it leads to lengthy sintering cycles (10-12 hr). This work presents an assessment of microwave (MW) sintering of titanium. Titanium powders in the size ranges of <20 µm, 45-63 µm, and 100-150 µm were used to make green samples with compaction pressures ranging from 200-800 MPa. Sintering was carried out at 1200 °C for 2 hr in a 3 kW MW furnace with a 2.45 GHz multimode cavity under a vacuum of 2-6×10-3 Pa. The characteristics of MW heating of green titanium samples in vacuum are described in terms of the heating rate, vacuum fluctuations, and sparking discharge. The actual MW heating rate achieved from 350 °C to 1200 °C was 34 °C/min. The attendant densities are comparable to those attained by conventional vacuum sintering. Cross-sectional examinations revealed a fairly uniform pore distribution in MW-sintered samples made from either the coarse or fine titanium powder.

Characterization of Furnace Sintered Mullite and Oxide Ceramic Matrix Composites (O-CMC) by Using Glass Solders

2014 ◽  
Vol 88 ◽  
pp. 162-171 ◽  
Author(s):  
Christian Gadelmeier ◽  
Jens Schmidt ◽  
M. Göthe ◽  
Dorde Jovanovic
Keyword(s):  
High Temperature ◽  
Ceramic Matrix Composites ◽  
Ceramic Matrix ◽  
Oxide Ceramic ◽  
Matrix Composites ◽  
High Temperature Processes ◽  
Novel Material ◽  
Shock Resistance ◽  
High Thermal Shock Resistance

Energy efficiency is becoming more and more important in high temperature processes or for high temperature applications. In order to achieve thermally efficient processes, heat accumulators and heat exchangers are increasingly being used to store or to recover the process heat [1]. Currently used commercial heat exchanger systems are based on stacked plates or tubes. Primarily they are produced from metals which have a high thermal conductivity and show gas-tightness. Ceramics or ceramic matrix composites (CMC) are novel material candidates due to their higher resistance in severe environments, their ability to withstand extremely high operating temperatures and especially, their high thermal shock resistance. In order to fabricate HX with ceramic designs, joining is the key technology to perform complex shaped components [2].

MANAURITE 900X

Alloy Digest ◽  
2019 ◽  
Vol 68 (4) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Thermal Shock ◽  
Creep Strength ◽  
Thermal Shock Resistance ◽  
Casting Alloy ◽  
Temperature Performance ◽  
Shock Resistance ◽  
High Thermal Shock Resistance

Abstract MANAURITE 900X is a casting alloy with good creep strength and high thermal shock resistance. This alloy is evolution from Manaurite 900 (Alloy Digest SS-1304, March 2019). This datasheet provides information on composition and physical properties as well as creep. It also includes information on high temperature performance as well as joining. Filing Code: SS-1305. Producer or source: Manoir Industries, Manoir Pîtres.

JESSOP G.39

Alloy Digest ◽  
1957 ◽  
Vol 6 (6) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Thermal Shock Resistance ◽  
Base Alloy ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
Temperature Performance ◽  
Shock Resistance ◽  
Nickel Base

Abstract JESSOP G.39 is an austenitic nickel-base alloy having low coefficient of expansion and good thermal shock resistance. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as heat treating and machining. Filing Code: Ni-35. Producer or source: Wm. Jessop & Sons Ltd.

Characterization and A Preliminary Study of TiO2 Synthesis from Lampung Iron Sand

2020 ◽  
Vol 849 ◽  
pp. 113-118
Author(s):  
Yayat Iman Supriyatna ◽  
Slamet Sumardi ◽  
Widi Astuti ◽  
Athessia N. Nainggolan ◽  
Ajeng W. Ismail ◽  
...  
Keyword(s):  
Food Packaging ◽  
Xrd Analysis ◽  
Major Elements ◽  
Raw Material ◽  
Solid Residue ◽  
X Ray Diffraction ◽  
X Ray ◽  
Leaching Solution ◽  
Ti Content

The purpose of this study is to characterize Lampung iron sand and to conduct preliminary experiments on the TiO2 synthesis which can be used for the manufacturing of functional food packaging. The iron sand from South Lampung Regency, Lampung Province that will be utilized as raw material. The experiment was initiated by sieving the iron sand on 80, 100, 150, 200 and 325 mesh sieves. Analysis using X-Ray Fluorescence (XRF) to determine the element content and X-Ray Diffraction (XRD) to observe the mineralization of the iron sand was conducted. The experiment was carried out through the stages of leaching, precipitation, and calcination. Roasting was applied firstly by putting the iron sand into the muffle furnace for 5 hours at a temperature of 700°C. Followed by leaching using HCl for 48 hours and heated at 105°C with a stirring speed of 300 rpm. The leaching solution was filtered with filtrate and solid residue as products. The solid residue was then leached using 10% H2O2 solution. The leached filtrate was heated at 105°C for 40 minutes resulting TiO2 precipitates (powder). Further, the powder was calcined and characterized. Characterization of raw material using XRF shows the major elements of Fe, Ti, Mg, Si, Al and Ca. The highest Ti content is found in mesh 200 with 9.6%, while iron content is about 80.7%. While from the XRD analysis, it shows five mineral types namely magnetite (Fe3O4), Rhodonite (Mn, Fe, Mg, Ca) SiO3, Quart (SiO2), Ilmenite (FeOTiO2) and Rutile (TiO2). The preliminary experiment showed that the Ti content in the synthesized TiO2 powder is 21.2%. The purity of TiO2 is low due to the presence of Fe metal which is dissolved during leaching, so that prior to precipitation purification is needed to remove impurities such as iron and other metals.

Fundamental Characterisation of Dredged Marine Sediments from Kuala Perlis Jetty by XRF, XRD and FTIR

2012 ◽  
Vol 620 ◽  
pp. 469-473 ◽  
Author(s):  
Norhashimah Ramli ◽  
Mohammad Hafizuddin Haji Jumali ◽  
Wan Safizah Wan Salim
Keyword(s):  
Heavy Metals ◽  
Marine Sediments ◽  
Xrd Analysis ◽  
Raw Material ◽  
Ftir Analysis ◽  
Huge Amount ◽  
The Us ◽  
Dredged Marine Sediment ◽  
Primary Mineral ◽  
Us Epa

Dredging along Kuala Perlis Jetty results in huge amount of marine sediments which has thrown considerable challenge for disposal. This research was conducted to characterize dredged marine sediment which was collected at Kuala Perlis Jetty as potential raw material for brick production. Three different characterizations were performed namely XRF, XRD and FTIR. XRF analysis showed the presence of SiO2 and Al2O3 as major quantities. Low concentration of heavy metals namely As, Cr, Cu, Pb, Ni and Zn presence in the sediment comply the US EPA guideline for brick production. XRD analysis indicated the presence of quartz as primary mineral while kaolinite and illite also present as secondary and ternary phases. FTIR analysis identified various form of minerals presence in the samples which strongly supported XRD results.

Experimental Study on Carbonization of Low-Rank Pulverized Coal with High Temperature Heat Pipe

2014 ◽  
Vol 953-954 ◽  
pp. 1035-1039
Author(s):  
Li Qun Wang ◽  
Zhong Bo Yi ◽  
Zhong Xiang Wei
Keyword(s):  
High Temperature ◽  
Heat Pipe ◽  
Pulverized Coal ◽  
Holding Time ◽  
Raw Material ◽  
Low Rank ◽  
Experimental Result ◽  
Operating Characteristics ◽  
Temperature Heat ◽  
High Temperature Heat Pipe

Aimed at improving the utilization of pulverized coal, high-temperature heat pipe technology was introduced into lignite carbonization.Under the design of power of 10kw semi-industrial pulverized coal carbonization test equipment, Fugu lignite coal as raw material to investigate the operating characteristics of the device and carbonization characteristics. Experimental result shows that the high temperature heat pipes heat steadily and meet the temperature requirement of low-temperature carbonization. With the extension of the holding time, the semi-coke fixed carbon content increasing, but volatile matter vice versa, however, holding time above 60 minutes, the effect of carbonization is not obvious, and the best carbonization time is 30 ~ 60 minutes. The length of the holding time has little effect on gas composition, the content of H2 and CH4 are relatively higher than the rest gas, (H2 + CH4) gas accounted for 70% of the total, the heating value remains at 18.76 ~ 19.22MJ/m3, belongs to medium-high value gas, could provide for industrial and civilian use.

Preparation of Iron Carbide from High Phosphorus Oolitic Hematite

2014 ◽  
Vol 881-883 ◽  
pp. 98-101
Author(s):  
Guang Qiang Li ◽  
Heng Hui Wang ◽  
Jian Yang ◽  
Jiang Hua Ma
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Iron Carbide ◽  
Xrd Analysis ◽  
Raw Material ◽  
Zonal Distribution ◽  
High Phosphorus ◽  
Hematite Ore ◽  
Oolitic Hematite Ore ◽  
Scanning Electron

In order to find a new way to utilize the high phosphorus oolitic hematite ore as raw material for steelmaking, the reduction and carburization of high phosphorus oolitic hematite by the gas of CH4-H2were studied. High phosphorus oolitic hematite, reduction and carburization products were investigated by the means of XRD and scanning electron microscope. The SEM-EDS and XRD analysis show that the main compositions of this ore are hematite and quartz, main microstructure is oolitic cluster with the zonal distribution of hematite and apatite, and iron carbide can be prepared from high phosphorus oolitic hematite.

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