Microwave Sintering of Zirconia Toughened Mullite (ZTM)

1994 ◽  
Vol 347 ◽  
Author(s):  
J. Cai ◽  
C. Y. Song ◽  
B. S. Li ◽  
X. X. Huang ◽  
J. K. Guo ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Microwave Sintering ◽  
Single Mode ◽  
Microwave Processing ◽  
Toughening Mechanism ◽  
Conventional Sintering

ABSTRACTMicrowave sintering of zirconia toughened mullite (ZTM) has been performed in a single mode applicator. In comparison with conventional sintering, microwave processing of ZTM leads to a higher density and finer grain size. Microstructure of microwave sintered ZTM was characterized by TEM and HRTEM techniques. The pinning of intergranular ZrO2 dispersoids retarded the grain growth of mullite matrix. The observation of a considerable number of trans-granular microcracks indicates that microcracking toughening is the main toughening mechanism for ZTM.

Nanostructure Evolution of ZnO in Ultra-fast Microwave Sintering

2011 ◽  
Vol 691 ◽  
pp. 65-71 ◽  
Author(s):  
Rodolfo F. K. Gunnewiek ◽  
Ruth Herta Goldsmith Aliaga Kiminami
Keyword(s):  
Grain Size ◽  
Zinc Oxide ◽  
Grain Growth ◽  
Microwave Sintering ◽  
High Heating Rate ◽  
Heating Rates ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Conventional Sintering ◽  
Holding Temperature

Grain growth is inevitable in the sintering of pure nanopowder zinc oxide. Sintering depend on diffusion kinetics, thus this growth could be controlled by ultra-fast sintering techniques, as microwave sintering. The purpose of this work was to investigate the nanostructural evolution of zinc oxide nanopowder compacts (average grain size of 80 nm) subjected to ultra-rapid microwave sintering at a constant holding temperature of 900°C, applying different heating rates and temperature holding times. Fine dense microstructures were obtained, with controlled grain growth (grain size from 200 to 450nm at high heating rate) when compared to those obtained by conventional sintering (grain size around 1.13µm), which leads to excessively large average final grain sizes.

Microwave Processing of Silicon Nitride

1990 ◽  
Vol 189 ◽  
Author(s):  
T. N. Tiegs ◽  
J. O. Kiggans ◽  
H. D. Kimrey
Keyword(s):  
Silicon Nitride ◽  
Grain Boundary ◽  
Microwave Heating ◽  
Grain Growth ◽  
Microwave Power ◽  
Microwave Sintering ◽  
Microwave Processing ◽  
Microwave Furnace

ABSTRACTMicrowave sintering of Si3N4—based materials showed improved densification as compared to samples heated conventionally under similar conditions. Accelerated nitridation of Si in the microwave furnace to produce Si3N4 was also observed. Dense Si3N4, annealed by microwave heating, exhibited enhanced grain growth; however preferential coupling of the microwave power to the grain—boundary phases in the present experiments resulted in their degradation.

ELECTRICAL CONDUCTION IN SUBSTITUTED Li-FERRITES PREPARED BY MICROWAVE PROCESSING

2005 ◽  
Vol 19 (21) ◽  
pp. 1051-1055 ◽  
Author(s):  
MAMATA MAISNAM ◽  
SUMITRA PHANJOUBAM ◽  
H. N. K. SARMA ◽  
CHANDRA PRAKASH ◽  
L. RADHAPIYARI DEVI ◽  
...  
Keyword(s):  
Activation Energy ◽  
Lattice Constant ◽  
Electrical Conduction ◽  
Spinel Structure ◽  
Single Phase ◽  
Microwave Sintering ◽  
Microwave Processing ◽  
Conventional Sintering

Samples with representative formula Li 0.45 Ni 0.1 Mn 0.1 Fe 2.35 O 4 have been sintered by conventional sintering technique and microwave sintering technique. Both the samples showed single-phase with spinel structure. The lattice constant for the microwave sintered (MS) sample showed a lower value than the conventionally sintered (CS) sample. The density of the MS sample has been found to be higher than the CS sample. And MS sample showed a higher value of resistivity and activation energy compared to the CS sample. The possible mechanisms are discussed.

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.

Microwave Processing and Sintering of PZT and PLZT Ceramics

1988 ◽  
Vol 124 ◽  
Author(s):  
W. B. Harrison ◽  
M. R. B. Hanson ◽  
B. G. Koepke
Keyword(s):  
Lead Titanate ◽  
Microwave Sintering ◽  
Ferroelectric Properties ◽  
Lead Zirconate ◽  
Microwave Processing ◽  
High Density ◽  
Pzt Ceramics ◽  
Conventional Sintering ◽  
Processing Techniques ◽  
Fast Firing

ABSTRACTMicrowave processing techniques were established for all of the thermal treatment steps necessary to prepare high density PZT and PLZT. The microstructure and ferroelectric properties of the microwave processed materials were compared to conventionally sintered and fast fired PZT. Unique high density, small grain size, PZT and PLZT were obtained by microwave sintering either conventionally or fully microwave processed powders. It was estimated that microwave sintering would use only five percent of the energy used by conventional sintering.The suitability of microwave processing for the production of two modifications (Sr and La) of lead zirconate - lead titanate (PZT) ceramics was investigated in this program. A commercial microwave oven was used to evaluate drying, calcining, binder burnoff, and sintering. These materials were then compared to those produced by fast-firing and conventional sintering methods.

Densification kinetics of Alumina During Microwave Sintering

1992 ◽  
Vol 269 ◽  
Author(s):  
Jiping Cheng ◽  
Jinyu Qiu ◽  
Jian Zhou ◽  
Neng Ye
Keyword(s):  
High Temperature ◽  
Grain Growth ◽  
Microwave Field ◽  
Microwave Sintering ◽  
Alumina Ceramics ◽  
Kinetics Parameters ◽  
Fine Grained ◽  
Prolonged Time ◽  
Conventional Sintering ◽  
Kinetics Of

ABSTRACTSome kinetics parameters of alumina during microwave sintering were studied and compared with that during conventional sintering. The results demonstrated that the sintering rates for microwave processing were much greater than that for conventional processing, and the grain growth of alumina was rapid with prolonged time at high temperature in a microwave field. It was indicated that the microwave sintering at higher temperatures for a shorter time was favorable for preparing high density and fine-grained alumina ceramics.

Direct microwave sintering of pure alumina in a single mode cavity: Grain size and phase transformation effects

2016 ◽  
Vol 116 ◽  
pp. 53-62 ◽  
Author(s):  
Jeremy Croquesel ◽  
Didier Bouvard ◽  
Jean-Marc Chaix ◽  
Claude P. Carry ◽  
Sébastien Saunier ◽  
...  
Keyword(s):  
Grain Size ◽  
Phase Transformation ◽  
Microwave Sintering ◽  
Single Mode ◽  
Pure Alumina ◽  
Single Mode Cavity

Solid Solution Additives and the Sintering of Ceramics

1991 ◽  
Vol 249 ◽  
Author(s):  
Mohamed N. Rahaman ◽  
Ching-Li Hu
Keyword(s):  
Solid Solution ◽  
Grain Size ◽  
Grain Growth ◽  
Cerium Oxide ◽  
Systematic Study ◽  
Kinetic Data ◽  
Ceramic Materials ◽  
Initial Part ◽  
Conventional Sintering

ABSTRACTThe use of solid solution additives has been shown to be very effective for the formation, by conventional sintering, of ceramic materials with high density and with controlled grain size. However, the number of systems for which such additives have been successfully found remains quite small, and the role of the additives is fairly well understood in only two or three of these. This paper describes the initial part of a systematic study into the effects of solid solution additives on the sintering of ceramics. Cerium oxide was chosen as a model host powder for this work because it has appreciable solubility for many additives. A combination of kinetic data and microstructural observations indicate that the sintering and grain growth are influenced significantly by the additive size but less significantly by the additive charge. The density versus grain size relationship is almost independent of the additive below relative densities of = 0.90 but depends strongly on the additive above this density. The data are interpreted in terms of the effect of the additives on the densification to coarsening ratio.

Unconventional Methods of Sintering Inconel 718 MIM Samples

2016 ◽  
Vol 716 ◽  
pp. 830-839
Author(s):  
Olivier Dugauguez ◽  
Jose Manuel Torralba ◽  
Thierry Barrière ◽  
Jean Claude Gelin
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Heating Rate ◽  
Inconel 718 ◽  
Fine Particle ◽  
Alloy Powder ◽  
Microwave Sintering ◽  
Conventional Sintering ◽  
Unconventional Methods ◽  
Super Alloy

In this investigation, three different ways of sintering Inconel 718 MIM samples are compared. The conventional way of sintering in a furnace will be compared to FAHP and microwave sintering. The difficulty of these two methods is to be able to control the shrinkage of the sample and so its shape. These methods have yet not been investigated with a super alloy powder and so, the effects of a high sintering rate on a MIM sample. By accelerating the sintering kinetics, the thermal behavior may be modified. Hence, the behavior of the Inconel 718 sintered by field assisted and microwave sintering has been investigated. The sintered samples were all injected from a feedstock composed of a fine particle Inconel powder and a binder principally composed of CAB and PEG. They were debinded into water for 24h and put in a furnace at 500°C during 2 hours. The heating rate of the furnace was set to 5°C/min until 1290°C during 2 hours. The heating rate of the FAHP was set to 50°C/min until 1250°C during 15 minutes. The microwave samples were sintered around 1300°C during 1 hour, the temperature was increased progressively by steps of 100°C. The effects of the different process on the microstructure and the mechanical properties are then compared. There was no difference in distribution of pores between the conventional sintering and the FAHP sintering but a finer grain size showed better hardness. The microwave sintering of a MIM sample is more complex and the best properties were not obtained.

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