scholarly journals Microwave Sintering of Continuous Zirconia Ceramic Fibers

1994 ◽  
Vol 347 ◽  
Author(s):  
Gerald. J. Vogt ◽  
Wesley. P. Unruh ◽  
Ross. H. Plovnick
Keyword(s):  
Microwave Sintering ◽  
Single Mode ◽  
Ambient Air ◽  
Tensile Tests ◽  
Grain Structure ◽  
Microwave Cavity ◽  
Zirconia Ceramic ◽  
Ceramic Fibers ◽  
Single Filament ◽  
Tetragonal Crystal

ABSTRACTContinuous yttria-stabilized zirconia ceramic fibers approximately 10–15 μm in diameter have been rapidly sintered by pulling them through a tuned, 2.45 GHz single-mode TE103 microwave cavity in ambient air. The resulting fibers were analyzed by X-ray diffraction, scanning electron microscopy, and single-filament tensile tests. They were found to be unsplit, to have a submicron grain structure and a tetragonal crystal structure, and to exhibit considerable strength and flexibility.

Mathematical Model of Thermal Spikes in Microwave Heating of Oxide Ceramic Fibers

1994 ◽  
Vol 347 ◽  
Author(s):  
J. R. Thomas ◽  
Wesley P. Unruh ◽  
Gerald J. Vogt
Keyword(s):  
Mathematical Model ◽  
Hot Spots ◽  
Elevated Temperatures ◽  
Solid Phase ◽  
Microwave Sintering ◽  
Single Mode ◽  
Heat Transfer Process ◽  
Oxide Ceramic ◽  
Ceramic Fibers ◽  
Radiation Losses

ABSTRACTExperiments on microwave sintering of ceramic fibers in a single-mode cavity have revealed the presence of thermal spikes and “hot spots” which sometimes travel along the fiber and eventually disappear. They are triggered by relatively small increases in microwave power, and thus have obvious implications for the development of practical microwave-based fiber processing systems. These hot spots are conjectured to originate at slight irregularities in the tow morphology, and propagate as the result of solid phase transitions which take place at elevated temperatures and reduce the dielectric loss coefficient є”.An elementary mathematical model of the heat transfer process was developed which reproduces the essential features of the observed phenomena, thus lending support to our conjecture. This model is based on the assumption of one-dimensional heat conduction along the axis of the fiber tow, and radiation losses at the surface.

Cavity Effects and Hot Spot Formulation Inmicrowave Heated Ceramic Fibers

1996 ◽  
Vol 430 ◽  
Author(s):  
G. A. Kriegsmann
Keyword(s):  
Electric Field ◽  
Hot Spots ◽  
Hot Spot ◽  
Single Mode ◽  
Uniform Electric Field ◽  
Ceramic Fibers ◽  
Entire Sample ◽  
Mathematical Equations ◽  
Cavity Effects ◽  
Ceramic Cylinder

AbstractRecently the heating of a thin ceramic cylinder in a single mode applicator was modeled and analyzed assuming a small Biot number and a known uniform electric field through out the sample. The resulting simplified mathematical equations explained the mechanism for the generation and growth of localized regions of high temperature. The results predicted that a hot-spot, once formed, will grow until it consumes the entire sample. Most experimental observations show that the hot-spot stabilizes and moves no further.A new model is proposed which incorporates the effect of the cavity and the nlonuiniform character of the electric field along the axis of the sample. The resulting simplified mathematical equations indicate that these effects stabilize the growth of hot-spots.

scholarly journals Tuning, Impedance Matching, and Temperature Regulation during High-Temperature Microwave Sintering of Ceramics

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Sylvain Marinel ◽  
Nicolas Renaut ◽  
Etienne Savary ◽  
Rodolphe Macaigne ◽  
Guillaume Riquet ◽  
...  
Keyword(s):  
Material Processing ◽  
High Temperature ◽  
Microwave Sintering ◽  
Impedance Matching ◽  
Single Mode ◽  
Electrical Circuit ◽  
Ease Of Use ◽  
Heating Process ◽  
Process Technology ◽  
Volumetric Heating

Over the years, microwave radiation has emerged as an efficient source of energy for material processing. This technology provides a rapid and a volumetric heating of material. However, the main issues that prevent microwave technology from being widespread in material processing are temperature control regulation and heating distribution within the sample. Most of the experimental works are usually manually monitored, and their reproducibility is rarely evaluated and discussed. In this work, an originally designed 915 MHz microwave single-mode applicator for high-temperature processing is presented. The overall microwave system is described in terms of an equivalent electrical circuit. This circuit has allowed to point out the different parameters which need to be adjusted to get a fully controlled heating process. The basic principle of regulation is then depicted in terms of a block function diagram. From it, the process has been developed and tested to sinter zirconia- and spinel-based ceramics. It is clearly shown that the process can be successfully used to program multistep temperature cycles up to ∼1550°C, improving significantly the reproducibility and the ease of use of this emerging high-temperature process technology.

scholarly journals Heisenberg-limited single-mode quantum metrology in a superconducting circuit

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
W. Wang ◽  
Y. Wu ◽  
Y. Ma ◽  
W. Cai ◽  
L. Hu ◽  
...  
Keyword(s):  
Single Mode ◽  
Coherence Time ◽  
Microwave Cavity ◽  
Phase Estimation ◽  
Quantum Metrology ◽  
Practical Applications ◽  
Infinite Dimensional ◽  
Noise Limit ◽  
Quantum Error ◽  
Shot Noise Limit

Abstract Two-mode interferometers lay the foundations for quantum metrology. Instead of exploring quantum entanglement in the two-mode interferometers, a single bosonic mode also promises a measurement precision beyond the shot-noise limit (SNL) by taking advantage of the infinite-dimensional Hilbert space of Fock states. Here, we demonstrate a single-mode phase estimation that approaches the Heisenberg limit (HL) unconditionally. Due to the strong dispersive nonlinearity and long coherence time of a microwave cavity, quantum states of the form $$\left( {\left| 0 \right\rangle + \left| N \right\rangle } \right)/\sqrt 2$$ 0 + N ∕ 2 can be generated, manipulated and detected with high fidelities, leading to an experimental phase estimation precision scaling as ∼N−0.94. A 9.1 dB enhancement of the precision over the SNL at N = 12 is achieved, which is only 1.7 dB away from the HL. Our experimental architecture is hardware efficient and can be combined with quantum error correction techniques to fight against decoherence, and thus promises quantum-enhanced sensing in practical applications.

Susceptor-assisted fast microwave sintering of TiN reinforced SiAlON composites in a single mode cavity

2021 ◽  
Vol 47 (1) ◽  
pp. 828-835
Author(s):  
Özgür Sevgi Canarslan ◽  
Levent Koroglu ◽  
Erhan Ayas ◽  
Necip Suat Canarslan ◽  
Alpagut Kara ◽  
...  
Keyword(s):  
Microwave Sintering ◽  
Single Mode ◽  
Single Mode Cavity

Effect of Carbon Nanofiber on Thermal and Tensile Properties of Polypropylene

2006 ◽  
Author(s):  
Yuanxin Zhou ◽  
Mohammad Monirul Hasan ◽  
Shaik Jeelani
Keyword(s):  
Thermal Properties ◽  
Yield Strength ◽  
Strain Rate ◽  
Carbon Nanofiber ◽  
Tensile Modulus ◽  
Tensile Tests ◽  
Strain Rate Range ◽  
Mechanical And Thermal Properties ◽  
Single Filament ◽  
Polypropylene Powder

In the present study, effect of vapor grown carbon nanofiber on the mechanical and thermal properties of polypropylene was investigated. Firstly, nanofibers were dry-mixed with polypropylene powder and extruded into filaments by using a single screw extruder. Then the tensile tests were performed on the single filament at the strain rate range from 0.02/min to 2/min. Experiments results show that both neat and nano-phased polypropylene were strain rate strengthening material. The tensile modulus and yield strength both increased with increasing strain rate. Experimental results also show that infusing nanofiber into polypropylene can increase tensile modulus and yield strength, but decrease the failure strain. At the same time, thermal properties of neat and nano-phased polypropylene were characterized by TGA. TGA results have showed that the nanophased system is more thermally stable. At last, a nonlinear constitutive equation has been developed to describe strain rate sensitive behavior of neat and nano-phased polypropylene.

Preparation of mesoporous zirconia ceramic fibers modified by dual surfactants and their phosphate adsorption characteristics

2020 ◽  
Vol 46 (9) ◽  
pp. 14019-14029 ◽  
Author(s):  
Qing Dong ◽  
Shuying Shi ◽  
Yongshuai Xie ◽  
Yuping Wang ◽  
Xiaoqian Zhang ◽  
...  
Keyword(s):  
Zirconia Ceramic ◽  
Phosphate Adsorption ◽  
Ceramic Fibers ◽  
Adsorption Characteristics ◽  
Mesoporous Zirconia

Microwave Sintering of Nanocrystalline TiO2

1990 ◽  
Vol 189 ◽  
Author(s):  
J. A. Eastman ◽  
K. E. Sickafus ◽  
J. D. Katz ◽  
S. G. Boeke ◽  
R. D. Blake ◽  
...  
Keyword(s):  
Microwave Sintering ◽  
Phase Changes ◽  
Microwave Cavity ◽  
Oxygen Stoichiometry ◽  
X Ray Diffraction ◽  
Nanocrystalline Tio2 ◽  
Transmission Electron ◽  
Before And After ◽  
Maximum Temperatures ◽  
Short Time

ABSTRACTNanocrystalline TiO2 compacts having initial approximate mean grain sizes of 14 nm and approximate green densities of 70% of theoretical were sintered by short-time exposure in a 2.45 GHz microwave cavity to maximum temperatures of 800, 1000 or 1200 ºC. Sample densities were measured before and after exposure to microwaves using Archimede's method. Transmission electron microscopy and x-ray diffraction were utilized to monitor grain growth and phase changes. Rutherford backscattering was used to monitor any changes in oxygen stoichiometry. The results of this study indicate that enhanced densification behavior is obtained for microwavesintered samples relative to samples sintered using conventional pressureless-sintering techniques.

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