Microwave Sintering of Large Products

1996 ◽  
Vol 430 ◽  
Author(s):  
Tasaburo Saji
Keyword(s):  
Dielectric Loss ◽  
Wave Energy ◽  
Microwave Sintering ◽  
Processing System ◽  
Uniform Electric Field ◽  
Sintering Process ◽  
Gyrotron Oscillator ◽  
Microwave Ceramic ◽  
Fine Crystalline Structure ◽  
Ceramic Sintering

AbstractA practical microwave ceramic sintering technology has been developed. To achieve the highest merit from microwave sintering, susceptors were not used. In this paper, the ceramic sintering process using the 28GHz mm-wave energy generated by a Gyrotron oscillator is described. Large sized (Φ 200 × 200 ) and complex shaped material of Si3N4, A12O3, and ZrO2 were successfully and reproducibly sintered. The sintered bodies exhibited high density and fine crystalline structure. The processed materials were found to have exceptional strength and toughness.The critical processing technology developed dealt with the means by which uniform and defect free sintered bodies are obtained. The processing stressed the importance of achieving a uniform electric field within the applicator and to decrease the sintering dependence on the materials’ temperature based dielectric loss properties. With the use of innovative support and thermal insulation structures, the processing system allowed for very precise temperature controls.

scholarly journals Microwave Sintering and Microwave Dielectric Properties of (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 Ceramics

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 438
Author(s):  
Shuwei Yang ◽  
Bingliang Liang ◽  
Changhong Liu ◽  
Jin Liu ◽  
Caisheng Fang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Mobile Communications ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Microwave Dielectric Properties ◽  
Conventional Heating ◽  
Sintering Process ◽  
Microwave Dielectric ◽  
Sintering Time ◽  
Frequency Temperature

The (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 [(1–x)CLT-xNMT, x = 0.35~0.60] ceramics were prepared via microwave sintering. The effects of sintering temperature and composition on the phase formation, microstructure, and microwave dielectric properties were investigated. The results show that the microwave sintering process requires a lower sintering temperature and shorter sintering time of (1–x)CLT-xNMT ceramics than conventional heating methods. All of the (1–x)CLT-xNMT ceramics possess a single perovskite structure. With the increase of x, the dielectric constant (ε) shows a downward trend; the quality factor (Qf) drops first and then rises significantly; the resonance frequency temperature coefficient (τf) keeps decreasing. With excellent microwave dielectric properties (ε = 51.3, Qf = 13,852 GHz, τf = −1.9 × 10−6/°C), the 0.65CLT-0.35NMT ceramic can be applied to the field of mobile communications.

Microstructure and Microwave Dielectric Properties of BaTi4O9 Ceramics Derived from a Sol-Gel Precursor

2011 ◽  
Vol 326 ◽  
pp. 127-130
Author(s):  
Xian Li Huang ◽  
Fu Ping Wang ◽  
Ying Song
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Dielectric Loss ◽  
Sol Gel ◽  
Microwave Dielectric Properties ◽  
Sintering Process ◽  
Temperature Coefficients ◽  
Microwave Dielectric ◽  
Ceramic Samples ◽  
Quality Factor Q

In the present work, the microstructure and microwave dielectric properties of BaTi4O9 ceramics derived from a sol-gel precursor were presented. Density measuring results demonstrated that the largest densities of ceramic sample about 96.7% could be reached by virtue of a cool iso-static press and a sintering process at at 1300 °C for 6 hours. The dielectric constant (εr), quality factor (Q×f) and the temperature coefficients (τf) of the BaTi4O9 ceramic samples were 36.65, 28000 GHz, +20.2 ppm/°C, respectively. XRD, SEM and XPS were used to characterize the microstructure of the ceramics samples. Substantial Ti3+ was proposed to be the cause of dielectric loss.

Correction to Hydrothermal-Assisted Cold Sintering Process: A New Guidance for Low Temperature Ceramic Sintering

2016 ◽  
Vol 8 (49) ◽  
pp. 34170-34170 ◽  
Author(s):  
Hanzheng Guo ◽  
Jing Guo ◽  
Amanda Baker ◽  
Clive A. Randall
Keyword(s):  
Low Temperature ◽  
Sintering Process ◽  
Ceramic Sintering

scholarly journals The viability of microwave sintering process to produce a ceramic tool insert

2016 ◽  
Vol 13 (2) ◽  
pp. 3462-3475
Author(s):  
S.H. Thauri ◽  
◽  
B.T.H.T Baharudin ◽  
Z. Leman ◽  
S.M Tahir ◽  
...  
Keyword(s):  
Microwave Sintering ◽  
Sintering Process ◽  
Ceramic Tool ◽  
Tool Insert

Structural and dielectric properties of (1-x)MgTiO3-xBa5Nb4O15 composites by microwave sintering process

2017 ◽  
Vol 519 (1) ◽  
pp. 145-151 ◽  
Author(s):  
Susmita Rabha ◽  
Anil Kumar Chikkala ◽  
Pamu Dobbidi
Keyword(s):  
Dielectric Properties ◽  
Microwave Sintering ◽  
Sintering Process

Surface Dissolution of Hydroxyapatite Prepared by Microwave Sintering

2007 ◽  
Vol 330-332 ◽  
pp. 227-230
Author(s):  
Dong Seok Seo ◽  
Hwan Kim ◽  
Kyu Hong Hwang ◽  
Jong Kook Lee
Keyword(s):  
Grain Size ◽  
Grain Boundary ◽  
Heating Rate ◽  
Microwave Sintering ◽  
Starting Material ◽  
Dissolution Behavior ◽  
Distilled Water ◽  
Sintering Process ◽  
Conventional Sintering ◽  
Boundary Dissolution

The aim of this study was to prepare dense hydroxyapatite (HA) by microwave sintering and to evaluate the dissolution behavior in distilled water. Commercially-obtained HA powders having Ca/P ratio of 1.67 were used as a starting material. The as-received powder of granular type consists of nano-sized particles. Microwave sintering was operated at 1200°C for 5 min with a heating rate of 50°C/min. Microwave sintering process reduced grain size of HA, compared with the case of conventional sintering. During the immersion in distilled water for 3-14 days, grain boundary dissolution occurred and the dissolution extended into the bulk following this path. As a result, particles were separated from the structure leaving micron-scale defects.

scholarly journals Discussion on the Local Magnetic Force between Reversely Magnetized Micro Metal Particles in the Microwave Sintering Process

Metals ◽  
2017 ◽  
Vol 7 (2) ◽  
pp. 47 ◽  
Author(s):  
Yu Xiao ◽  
Feng Xu ◽  
Bo Dong ◽  
Wenchao Liu ◽  
Xiaofang Hu
Keyword(s):  
Magnetic Force ◽  
Microwave Sintering ◽  
Metal Particles ◽  
Sintering Process
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