Control of Titanium Diboride SHS Reactions by Inert Dilutions and Mechanical Constraint.
ARMY BALLISTIC RESEARCH LAB ABERDEEN PROVING GROUND MD
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Self-Propagating High-Temperature Synthesis SHS is a relatively new process used to produce high technology ceramic materials. This method involves solid combustion reactions of elemental powders and is characterized by synthesis propagation velocities on the order of a centimeter per second and reaction temperatures well in excess of 2000 C. One advantage of the SHS process is that essentially all the heat energy required for the synthesis of the ceramic material is supplied by the exothermic solid combustion reaction. Reaction propagation velocities, material loss and post-reaction temperature have been controlled in titanium diboride samples by inert diluent addition and mechanical constraint of the reacting samples. An order-of-magnitude variation in propagation velocities has been observed. The temperatures and amounts of lost material vary inversely with the diluent concentrations and degree of constraint. The consequences of this ability to control the reaction to ceramics processing by SHS are discussed. aw
- Ceramics, Refractories and Glass