Simultaneous combustion synthesis and densification of refractory materials
When the temperature of a self-propagating combustion reaction is below the melting temperature of the product, which is usually the case, the product is a powder or has a highly porous structure. Contributing to the large volume of porosity is the difference of molar volume of the products and reactants, porosity in the reactant compact prior to combustion, and the evolution of impurity gases during combustion. Since there is no data on the effect of volatile gases on the amount of porosity and the morphology of the pores in combustion products we will present the preliminary results of our research on the influence of different outgassing temperatures on the structure of 0.5 TiB - 0.5 tiB/sub 2/, a product of the reaction Ti + 1.5 B. By combining the synthesis process with high pressure techniques, it is possible to densify the refractory products in one simple operation. Our experiments using a gas gun to apply large pressure waves immediately after combustion will be described for different chemical reactions. Both single phase (TiC) and composite materials (0.5 TiB - 0.5 TiB/sub 2/, TiB/sub 2/ - Fe and TiC - 2 Al/sub 2/O/sub 3/) have been simultaneously synthesized and densified to over 95% of theoretical density. 7 refs., 8 figs., 2 tabs.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6146787
- Report Number(s):
- UCRL-93467; CONF-8510280-1; ON: DE86006528
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360201 -- Ceramics
Cermets
& Refractories-- Preparation & Fabrication
360202 -- Ceramics
Cermets
& Refractories-- Structure & Phase Studies
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
BORIDES
BORON COMPOUNDS
CHEMICAL REACTIONS
COLD PRESSING
COMBUSTION
CRYSTAL STRUCTURE
DEGASSING
DENSITY
FABRICATION
MATERIALS WORKING
MICROSTRUCTURE
OXIDATION
PHYSICAL PROPERTIES
POROSITY
PRESSING
REFRACTORIES
SINTERING
THERMOCHEMICAL PROCESSES
TITANIUM BORIDES
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS