Microwave Nitrudation of Silicon Compacts Utilizing a Temperature Gradient

1992 ◽  
Vol 287 ◽  
Author(s):  
Jeffrey J. Thomas ◽  
Hamlin M. Jennings ◽  
D. Lynn Johnson
Keyword(s):  
Silicon Nitride ◽  
Temperature Gradient ◽  
Microwave Heating ◽  
Reaction Rate ◽  
Nitrogen Depletion

ABSTRACTSilicon compacts nitrided utilizing the temperature gradient inherent to microwave heating were more fully converted to silicon nitride than was possible with similar compacts nitrided isothermally. Although nitrogen depletion prevented the reaction rate in the center from exceeding that at the surface, the temperature gradient partially counteracted the effect of nitrogen depletion. Thus the microwave-heated specimens could be nitrided fully before the reduction in porosity that accompanies the reaction eliminated the diffusion of nitrogen into the compact.

Nitridation of Non-Isothermal Silicon Compacts

1992 ◽  
Vol 269 ◽  
Author(s):  
Jeffrey J. Thomas ◽  
Renee R. Jesse ◽  
D. Lynn Johnson ◽  
Hamlin M. Jennings
Keyword(s):  
Silicon Nitride ◽  
Temperature Gradient ◽  
Microwave Heating ◽  
Reaction Rate ◽  
Conventional Heating

ABSTRACTThe use of microwave heating for the processing of reaction-bonded silicon nitride offers at least two advantages over conventional heating methods. First, the reaction can be made to proceed preferentially in the interior of the reacting compact by maximizing the temperature gradient resulting from microwave heating. This helps maintain the flow of nitrogen into the compact during the later stages of the reaction, when the overall porosity is reduced. Second, the reaction rate can be controlled by changing the power, which gives better control over the processing than can be obtained using conventional heating.

Synthesis of Oximes in the Microwave Oven

1992 ◽  
Vol 57 (11) ◽  
pp. 2407-2412 ◽  
Author(s):  
Monika Puciová ◽  
Štefan Toma
Keyword(s):  
Microwave Heating ◽  
Reaction Rate ◽  
Microwave Oven ◽  
Effect Of Solvents

The synthesis of a broad range of oximes has been studied. It was found that the application of microwave heating enhanced dramatically the reaction rate, and practically quantitative yields of oximes were isolated after less than 1-min heating in the most cases. The effect of solvents on the course of the reaction was also studied.

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.

EFFECT OF TEMPERATURE GRADIENT ON MOISTURE MIGRATION DURING MICROWAVE HEATING

1994 ◽  
Vol 12 (4) ◽  
pp. 777-798 ◽  
Author(s):  
Liuming Zhou ◽  
Virendra M. Puri ◽  
Ramaswamy C. Anantheswaran
Keyword(s):  
Temperature Gradient ◽  
Microwave Heating ◽  
Effect Of Temperature ◽  
Moisture Migration

scholarly journals Studies on the Scale-Up of the Microwave-Assisted Nitridation and Sintering of Reaction-Bonded Silicon Nitride

1994 ◽  
Vol 347 ◽  
Author(s):  
J. O. Kiggans ◽  
T. N. Tiegs ◽  
H. D. Kimrey ◽  
Jon-Paul Maria
Keyword(s):  
Silicon Nitride ◽  
Boron Nitride ◽  
Microwave Heating ◽  
Scale Up ◽  
Batch Size ◽  
Temperature Uniformity ◽  
Control Groups ◽  
Microwave Assisted ◽  
Nitride Sample ◽  
Powder Compacts

AbstractStudies using laboratory test samples have shown that microwave heating produces sintered reaction-bonded silicon nitride materials with improved properties [1,2]. The final challenge for processing this material by microwave heating is the development of a technology for processing larger batch-size quantities of these materials. Initial microwave scale-up experiments were performed using powder compacts of a bucket tappet geometry. In experiments using microwave-transparent boron nitride sample crucibles, temperature gradients within some crucibles led to larger variations in the sample densities than were obtained with the conventionally processed samples. The use of a microwave-suscepter type crucible made of silicon carbide and boron nitride resulted in an improved temperature uniformity and in density variations comparable to those obtained for the control groups.

Characterization of Sintered Reaction-Bonded Silicon Nitride Processed by Microwave Heating

1992 ◽  
Vol 269 ◽  
Author(s):  
J. O. Kiggans ◽  
T. N. Tiegs
Keyword(s):  
Silicon Nitride ◽  
Microwave Heating ◽  
Microwave Processing ◽  
Conventional Heating ◽  
Processed Material

ABSTRACTSintered reaction-bonded silicon nitride (SRBSN) tiles were fabricated using microwave and conventional heating. Materials from both processes were analyzed at various stages in their fabrication. Microwave processing resulted in a SRBSN material of higher density and strength than the conventionally processed material.

Microwave heated reaction-bonded silicon nitride using an inverse temperature gradient

2003 ◽  
Vol 9 (2) ◽  
pp. 187-191 ◽  
Author(s):  
J. G. Fisher ◽  
K. Bai ◽  
S. K. Woo ◽  
I. S. Han ◽  
K. S. Lee ◽  
...  
Keyword(s):  
Silicon Nitride ◽  
Temperature Gradient ◽  
Inverse Temperature

Microwave Heating Assisted Biorefinery of Biomass

2015 ◽  
pp. 131-166 ◽  
Author(s):  
Sherif Farag ◽  
Jamal Chaouki
Keyword(s):  
Temperature Gradient ◽  
Electromagnetic Radiation ◽  
Microwave Heating ◽  
Chemical Reactions ◽  
Electromagnetic Waves ◽  
Thermochemical Treatment ◽  
Scaling Up ◽  
Conventional Heating ◽  
Essential Information ◽  
Pros And Cons

This chapter debates the potential of the biorefinery of biomass using microwave heating. First, the essential information regarding electromagnetic radiation is explained and the pros and cons of microwave heating versus conventional heating, especially in the thermochemical treatment of biomass, are discussed. Different methodologies for predicting and measuring the temperature gradient within a material subjected to electromagnetic waves are demonstrated. The chapter summarizes the key conclusions of various investigations regarding the effects of microwave heating on chemical reactions and presents how electromagnetic radiation can assist the biorefinery of biomass. Finally, the issues and limitations regarding scaling-up microwave heating are elucidated, along with possible solutions to these problems.

Sinthesys of Mullite Using Microwave Furnace from Kaolin and Alumina Residue

2014 ◽  
Vol 798-799 ◽  
pp. 63-68
Author(s):  
Michelle Félix da Silva ◽  
Valmir José da Silva ◽  
Romualdo Rodrigues Menezes ◽  
Lisiane Navarro de Lima Santana ◽  
Gelmires Araújo Neves ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Microwave Heating ◽  
Conventional Method ◽  
Microwave Power ◽  
Electromagnetic Energy ◽  
The Other ◽  
Heat Flows ◽  
Other Hand ◽  
Microwave Furnace

Heating with microwave power is a process in which the materials take up electromagnetic energy volumetrically and turn it into heat inside a piece. This is the great difference from the conventional method, where the heat flows between objects by means of conduction, radiation and convection, in which the surface of the materials is heated first, and then the heat is transferred to the interior of the piece, thus forming a temperature gradient. On the other hand, microwave heating generates heat first inside the piece, heating the whole volume later. [1]

Sign in / Sign up

Export Citation Format

Share Document