The reactivity of a zirconium-silicon melt with boron carbide at ultrahigh temperatures
Surfaces with exceptional properties are needed for next generation materials. Hypersonic re-entry space vehicles or turbines are subjected to both oxidizing and neutral environments and nose-caps or wings on such vehicles could easily reach operating temperatures of over 2000°C. Ultrahigh temperature ceramics like ZrB2 and HfB2 have melting temperatures of 3245°C and 3380°C respectively. However, these materials need to be protected from oxidation, usually with an oxide layer. Zirconium is more affordable and will be used to study its reaction with B4C and ZrSi2 . Experimentation was conducted by melting Zr slugs into a B4C and ZrSi2 packed bed at 1860°C for 60 minutes, 120 minutes, 180 minutes, and 240 minutes. Two different compositions were studied. Melting was performed in an induction furnace using deoxidized helium and purified with titanium sponge heated to 850°C and 702°C in two furnaces. Samples were characterized using a scanning electron microscope, optical microscope, and X-ray diffractometer. Microstructures of 60 minute samples showed both non-reacted and partially reacted areas. Samples held at 1860°C for longer times began to demonstrate multiple regions and finally a more homogeneous structure throughout the sample.
Sandate, Alvaro V, "The reactivity of a zirconium-silicon melt with boron carbide at ultrahigh temperatures" (2010). ETD Collection for University of Texas, El Paso. AAI1477828.