David E. Turcotte

Integration of Nanofluids into Commercial Antifreeze Concentrates with ASTM D15 Corrosion Testing

Abstract : Originally five candidates of nano material were chosen for making stable nano dispersions. Nano graphite particles remain a practical choice for nanofluids thermal application after taking divergent performance attributes into full account: significant thermal conductivity increases, minimal viscosity increase, low density for better dispersion stability, and relatively low cost, among others. Three different types of commercial antifreeze coolants were chosen for the integration with graphite nano fluids. Without corrosion inhibitors our nano coolants typically fail both ASTM D15 engine coolant corrosion tests: D1384 and D4340. Yet, heating up and adding in electrolytes are two common ways to destroy a nano particle dispersion. After making adjustments in particle loading, choosing an effective dispersant, and establishing proper dispersant levels, two nano graphite coolants made from two different nano sources passed both engine coolant corrosion tests plus the CID AA-52624A compatibility and storage stability tests. Compared with the base fluid, the nano graphite coolants thermal conductivity has more than a 25% increase at 2 volume percent particle loading, which is a significant enhancement.

USE OF ELECTROCHEMICAL NOISE IN THE STUDY OF INHIBITOR SYSTEMS FOR ALUMINUM

ABSTRACT Electrochemical noise appearing in corrosion potential (E corr )–time plots and electrochemical impedance (EI) spectra were used to study the synergism between nitrate and silicate in the inhibition of aluminum. Individually, nitrate and silicate did not protect aluminum; however, by combining them, the protection was greatly enhanced as deduced by the reduction of noise and the elevation of both E corr and polarization resistance (R p ). Unstable protective films are probably the cause of electrochemical noise. Then it follows that the elimination or reduction of noise would indicate improvement in the protectiveness of a film. Thus, noise reduction in E corr –time plots and EI spectra complements E corr and R p in the study of inhibitor interaction with metal surfaces.