Effects of boronization on reversed field pinch plasmas

First successful gaseous boronization during a series of pulsed discharges is reported. Sublimation of o-carborane $(C_{2}B_{10}H_{12})$ combined with pulsed discharge plasmas with a repetition rate of 1 Hz produces a hard boron-containing coating for reversed field pinch (RFP) plasmas in MST. X-ray photoelectron spectroscopy with Ar ion beam etching for aluminum and silicon coupons installed at the plasma boundary shows about 60\% boron concentration in the deposited layer. Both profilometer and scanning electron microscope (SEM) analysis of the silicon coupons imply that the thickness of the B/C coating is about 80 nm. Ellipsometry calibrated with the SEM results yields a refractive index of 2.6 for the film. This high refractive index implies that the coating is hard and has a well-ordered morphology. A reduction in wall recycling has consistently been observed after all boronization sessions. Comparison of the x-ray spectra in standard RFP plasmas before and after boronization indicates a slight decrease in the effective ionic charge. A similar comparison will also be presented for improved confinement RFP plasmas.