Combustion Synthesis of Titanium Diboride and Zirconia Composite Powders. Part I

A new method of synthesizing titanium diboride-zirconium oxide composite powders under the combustion mode was investigated. In situ stabilization of formed or added unstabilized zirconia by magnesia and/or yttria, control of TiB2 particle size, as well as the formation of TiB2-ZrO2 composites in a wide range of concentrations was investigated. Two different synthesis routes were explored, namely: i) from elemental titanium and, boron powders with addition of zirconia or ii) from zirconium, boron, and titania with or without addition of zirconia. Yttrium oxide and/or magnesium present in boron reactant powder were used for zirconia product stabilization. The effect of initial mixture composition, dilution with stabilized or unstabilized zirconia, and other operating conditions, such as inert gas pressure during the combustion and initial mixture density on combustion front propagation velocity and maximum combustion temperature as well as product microstructure and its phase composition was investigated. Products morphology and compositions were examined using XRD, EDX, and SEM analyses.