Physical Sciences and Mathematics Commons^™

Crevice Corrosion Behavior Of Ni-Cr-Mo-W Alloys In Aggressive Environment, Ajit K. Mishra

Electronic Thesis and Dissertation Repository

Ni-Cr-Mo (W) alloys, having an optimum concentration of Cr. Mo and W, are highly corrosion resistant alloys which do not fail by uniform corrosion in aggressive environments. However, when creviced at high applied potential and high temperatures, these materials can be susceptible to crevice corrosion. This study focuses on a family of seven commercial Ni-Cr-Mo (W) alloys containing various amounts of Cr, Mo and W.

Different electrochemical techniques were used to determine the characteristic potentials and temperature which indicate susceptibility to crevice corrosion, and to investigate the individual and synergistic roles of major and minor alloying elements. The corroded alloys …

Study On The Surface Chemistry Behavior Of Pyrochlore During Froth Flotation, Saeed Chehreh Chelgani

Electronic Thesis and Dissertation Repository

Separation of pyrochlore from its associated minerals is typically accomplished by froth flotation. The surface chemistry of pyrochlore is similar to many of its associated non-value minerals. Therefore, understanding the surface chemical properties of the pyrochlore for selective pyrochlore flotation will potentially aid in the design of flotation strategies for optimized recovery. In this study, pyrochlore samples were collected from various points in the flotation scheme at the Niobec plant, Quebec, Canada. The SEM-EDX analysis revealed that pyrochlore from the Niobec deposit occurs as high and low iron varieties, and that recovery favours varieties with a lower Fe content. To …