CORROSION STUDY OF TUNGSTEN-COPPER ALLOYS by Guo Dawei Thesis Supervisor: Prof. Kwok Chi Tat M. Sc. in Electromechanical engineering Tungsten-Copper (W-Cu) alloy, a pseudo alloy, has already been widely used in aerospace, electronics and military area owing to its excellent performance in thermal and electrical conductivities. Thus the corrosion performance of W-Cu alloy is a valuable research topic. In this study, a commercially pure Cu (cp Cu), a commercially pure W (cp W), and two types of W-Cu alloys were characterized by potentiodynamic polarization in solutions at different pH without and with 0.6 mol/L chloride. The polarization behavior and the preference of attacked phase of W-Cu alloys would alter with pH value, where the micro-galvanic effect between W phase and Cu binder played a significant role. It was also proved that the existence of aggressive chloride anion would greatly affect the corrosion behavior of the W-Cu alloys in different solutions. Moreover, open-circuit potential (OCP) measurement would act as a pre-corrosion process, which obstructs the accuracy of subsequent polarization test. In order to investigate the corrosion behavior of W-Cu alloys close to the real conditions, immersion test was carried out in the solutions with various pH without and with chloride ion. Analyses were based on the Scanning Electron Microscope (SEM), Energy Dispersive Spectroscopy (EDS), X-ray Diffraction (XRD) and Atomic Absorption Spectroscopy (AAS) results, which give the information of corroded surface morphology, reaction products and also the content of the elements in the solutions for studying the corrosion mechanism. Mean depth of penetration vs time curves described the overall behavior of the W-Cu alloys. Preferential phase attack and corrosion rate would be affected by galvanic effect, pH value, existence of Cl- , W phase and Cu binder morphology