Self-Propagating reactions for Synthesis of High Temperature Materials
Abstract
This effort was undertaken to investigate the basic aspects of the condensed phase titanium-boron reaction leading to the formation of high density and quality TiB2 under self-propagating conditions. Candidate factors for controlling microstructure were addressed and were utilized as variables in series of runs which produced TiB2. The heat of formation of TiB2 was measured directly from the reacting elements in a modified bomb calorimeter; a change in entropy at 298F = 71.81 + or - 1.9 was determined which is sufficient to produce liquid TiB2 under adiabatic conditions. High density titanium diboride was prepared from elemental powders of titanium and boron through the self- propagation reaction process. By applying external pressure during the reaction period the product (TiB2) has been densified to 95-97% theoretical density. The microstructure and properties such as density, grain size, hardness, strength, toughness by indentation and modulus by elastic and sonic methods, are discussed as a function of variables such as starting stoichiometry, powder-particle size, mixing techniques and nucleation additives such as TiB2 powder. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1985
- Accession Number
- ADA159869
Entities
People
- Joseph F. D'andrea
- Peter D. Zavitsanos
Organizations
- General Electric