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Surface pretreatments based on dilute hexafluorozirconic acid (FZ) solution were evaluated as replacements for the phosphating process before paint application. The behavior of a FZ coating was compared to those of a modified FZ (MFZ) coating and phosphating treatments. Results of electrochemical tests on painted cold rolled steel (CRS) samples with different conversion coatings show that the MFZ surface treatment in combination with various paints provides corrosion protection performance comparable to phosphate conversion coatings. AFM studies of MFZ coatings on CRS reveal that the coating surface exhibits small features tens of nm in size and clusters of these features that are on the scale of microns. Clusters have lower surface potentials (higher activity). Z-contrast TEM images of MFZ coatings show that the coating is about 20 nm thick, continuous and adherent to the substrate. Major components are Zr, Fe and O; the Fe amount decreases toward the coating surface.

The goal of this project is to develop and test in space a solid-state microdosimeter to directly assess astronaut risk to an unknown mixed radiation field. The instrument is rugged, has low power (< 1.25W), has low mass, and utilizes low voltages (± 5V). A microdosimeter can determine in real time dose equivalent in sieverts which is the regulatory quantity used to evaluate risk and limits of radiation exposure. The lineal energy spectrum that it measures can be multiplied by lineal-energy-dependent regulatory quality factors to determine dose equivalent. An early version of the instrument (MIDN on MidSTAR-I) has been designed and built for inclusion in the MidSTAR-1 USNA student built satellite to be launched in late fall 2006. The instrument is now undergoing test and minor modifications.