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.

Inorganic-organic Hybrid Materials (ORMOCERs) for Multilayer Technology – Passivation and Dielectric Behavior

2001 ◽  
Vol 665 ◽  
Author(s):  
R. Houbertz ◽  
L. Fröhlich ◽  
J. Schulz ◽  
M. Popall
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
Dielectric Behavior ◽  
Good Resolution ◽  
Physical And Chemical Properties ◽  
Coating Technology ◽  
Organic Hybrid ◽  
Physical And Chemical ◽  
Gel Processing ◽  
And Chemical Properties

ABSTRACTInorganic-organic hybrid polymers (ORMOCER®s) have been synthesized by sol-gel processing. The materials can be functionalized such that their physical and chemical properties can be reproducibly tailored towards the desired application, i.e., electronics, optics (passives/actives) or passivation technology. Besides, the materials which show negative resist behavior, can be patterned by UV exposure with good resolution. The materials are well-suited for thin and thick film technology using conventional coating technology, applied in multi-layer technology. We here particularly focus on materials for passivation against environmental influences, which additionally exhibit very good dielectric properties.

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 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.

Abstract #272: Management of Diabetic Peripheral Neuropathy (DPN) Using Low Frequency Pulsed Electro Magnetic Field (LF - PEMF)

2017 ◽  
Vol 23 ◽  
pp. 69
Author(s):  
Satish Wasoori ◽  
Deepak Pande ◽  
Chetan Bhardwaj ◽  
Manoj Naik
Keyword(s):  
Magnetic Field ◽  
Peripheral Neuropathy ◽  
Diabetic Peripheral Neuropathy ◽  
Low Frequency ◽  
Electro Magnetic Field ◽  
Electro Magnetic

Management of diabetic peripheral neuropathy (DPN) using low frequency pulsed electro magnetic field (LF-PEMF)

2017 ◽  
Author(s):  
Satish Chander Wasoori ◽  
Deepak G. Pande ◽  
Chetan Bhardwaj ◽  
Manoj Naik
Keyword(s):  
Magnetic Field ◽  
Peripheral Neuropathy ◽  
Diabetic Peripheral Neuropathy ◽  
Low Frequency ◽  
Electro Magnetic Field ◽  
Electro Magnetic

MAGNETIC FIELD IMPACT UPON TRIBOTECHNICAL CHARACTERISTICS OF PERMANENT CONNECTIONS IN RELATION TO FRICTION SHOCK ABSORBERS

2020 ◽  
Vol 2020 (10) ◽  
pp. 4-11
Author(s):  
Victor Tikhomirov ◽  
Aleksandr Gorlenko ◽  
Stanislav Volohov ◽  
Mikhail Izmerov
Keyword(s):  
Magnetic Field ◽  
Friction Factor ◽  
Physical Contact ◽  
Active Centers ◽  
Press Fit ◽  
Electro Magnetic Field ◽  
Investigation Methods ◽  
Electro Magnetic ◽  
The Impact ◽  
The Magnetic Field

The work purpose is the investigation of magnetic field impact upon properties of friction steel surfaces at fit stripping with tightness through manifested effects and their wear visually observed. On the spots of a real contact the magnetic field increases active centers, their amount and saturation with the time of dislocation outlet, and has an influence upon tribo-mating. The external electro-magnetic field promotes the increase of the number of active centers at the expense of dislocations outlet on the contact surface, and the increase of a physical contact area results in friction tie strengthening and growth of a friction factor. By the example of friction pairs of a spentonly unit in the suspension of coach cars there is given a substantiation of actuality and possibility for the creation of technical devices with the controlled factor of friction and the stability of effects achieved is also confirmed experimentally. Investigation methods: the fulfillment of laboratory physical experiments on the laboratory plant developed and patented on bush-rod samples inserted with the fit and tightness. The results of investigations and novelty: the impact of the magnetic field upon the value of a stripping force of a press fit with the guaranteed tightness is defined. Conclusion: there is a possibility to control a friction factor through the magnetic field impact upon a friction contact.

scholarly journals The internal conversion of gamma-rays.—Part II

1928 ◽  
Vol 121 (787) ◽  
pp. 447-456
Keyword(s):  
Magnetic Field ◽  
Quantum Mechanics ◽  
Wave Equation ◽  
Gamma Rays ◽  
Internal Conversion ◽  
Scalar Potential ◽  
X Ray ◽  
Electro Magnetic Field ◽  
Γ Rays ◽  
Electro Magnetic

In a previous paper the absorption of γ-rays in the K-X-ray levels of the atom in which they are emitted was calculated according to the Quantum Mechanics, supposing the γ-rays to be emitted from a doublet of moment f ( t ) at the centre of the atom. The non-relativity wave equation derived from the relativity wave equation for an electron of charge — ε moving in an electro-magnetic field of vector potential K and scalar potential V is h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV + ih ε/μ c (K. grad)) ϕ = 0. (1) Suppose, however, that K involves the space co-ordinates. Then, (K. grad) ϕ ≠ (grad . K) ϕ , and the expression (K . grad) ϕ is not Hermitic. Equation (1) cannot therefore be the correct non-relativity wave equation for a single electron in an electron agnetic field, and we must substitute h 2 ∇ 2 ϕ + 2μ ( ih ∂/∂ t + εV) ϕ + ih ε/ c ((K. grad) ϕ + (grad. K) ϕ ) = 0. (2)

Preparation of Pb(Zr,Ti)O3 thin films by sol gel processing: Electrical, optical, and electro‐optic properties

1988 ◽  
Vol 64 (5) ◽  
pp. 2717-2724 ◽  
Author(s):  
Guanghua Yi ◽  
Zheng Wu ◽  
Michael Sayer
Keyword(s):  
Thin Films ◽  
Sol Gel ◽  
Electro Optic ◽  
Gel Processing

scholarly journals The Influence Of NO/O2 On The NOx Storage Properties Over A Pt-Ba-Ce/γ-Al2O3 Catalyst

2019 ◽  
Vol 17 (1) ◽  
pp. 1459-1465
Author(s):  
Xuedong Feng ◽  
Jing Yi ◽  
Peng Luo
Keyword(s):  
Sol Gel ◽  
Chemical Properties ◽  
No Oxidation ◽  
Test Results ◽  
X Ray Diffraction ◽  
Storage Performance ◽  
Transmission Electron ◽  
Temperature Programmed ◽  
Physical And Chemical ◽  
Al2o3 Catalyst

AbstractWith the purpose of studying the influence of NO/O2 on the NOx storage activity, a Pt-Ba-Ce/γ-Al2O3 catalyst was synthesized by an acid-aided sol-gel method. The physical and chemical properties of the catalyst were characterized by X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) methods. The results showed that the composition of the catalyst was well-crystallized and the crystalline size of CeO2 (111) was about 5.7 nm. The mechanism of NO and NO2 storage and NOx temperature programmed desorption (NO-TPD) experiments were investigated to evaluate the NOx storage capacity of the catalyst. Pt-Ba-Ce/γ-Al2O3 catalyst presented the supreme NOx storage performance at 350℃, and the maximum value reached to 668.8 μmol / gcat. Compared with O2-free condition, NO oxidation to NO2 by O2 had a beneficial effect on the storage performance of NOx. NO-TPD test results showed that the NOx species stored on the catalyst surface still kept relatively stable even below 350℃.

Sign in / Sign up

Export Citation Format

Share Document