Emission Spectroscopy Measurements of Boron Volatiles for Ultra-High Temperature Ceramic Material Boundary Layer in Air Plasma

This work investigates the plasma-material interactions of ZrB2-SiC (SiC: 30% by volume) ultra-high temperature ceramic samples in air plasma. Tests were carried out in the 30 kW UVM Inductively-Coupled Plasma Torch Facility. Application of near-surface emission spectroscopy, laser-induced fluorescence, and surface temperature measurements produced a comprehensive set of data on material response to air-plasma exposure. Specific attention was given to documenting the spatial extent of boron volatiles. Results showed a difference of approximately 3 mm between the location of peak boron and peak boron oxide emission. Similar measurements of BO2 spatial extent exhibited weak signal, but appeared to show significant BO2 presence only near the sample surface.