Combustion Synthesis of CoCr, NiTi Intermetallic and Calcium Phosphate Ceramic Biomaterials

Combustion synthesis offers the unique potential to synthesize dense or porous ceramic and intermetallic biomaterials. The authors utilize combustion synthesis to create CoCr and NiTi intermetallics as well as multiphasic calcium phosphate. Because the chemical reaction of Co+Cr, Ni+Ti and Ca+P are exothermic in nature, the heat released during their reactions can be used to generate a self-sustaining system by which materials are synthesized with small energy inputs. Product formation is then a function of its Gibbs Free Energy. However, product physico-chemical properties can be controlled by reactant stoichiometry, including alloying additions; green density; particle size of the reactant mix; use or presence of a gasifying agent; heating rate of the reactants and gravity. Each of these can be adjusted to affect the thermochemistry of reaction. By balancing these parameters, the heat of reaction is controlled to create the desired product stoichiometry, porosity and mechanical properties. Combustion synthesis provides a means to rapidly manufacture materials, saving time and production costs as well as enabling the synthesis of net shape devices through the use of individual molds. Mold materials can range from graphite to paper or paper machete.