RESUMEN
A two-step aging treatment (50 L P, a peak aging following 50 â pre-precipitation) has been investigated for the in-situ TiB2/7050Al composite. The 50 L P composite has the comparable mechanical properties to the composite at peak-aged (T6) state, and even better stress corrosion cracking resistance over the composite with the retrogression and re-aging (RRA) treatment. In detail, the different aging conditions lead to different precipitate morphologies and grain boundary microchemistries. According to the microstructure characteristics in the Al matrix, the 50 L P composite has considerably increased grain boundary precipitate interspace in comparison with the T6 composite, since the lower aging temperature should result in the reduced grain boundary precipitate number. Furthermore, the 50 L P composite has more Cu content in the grain boundary precipitate and reduced precipitate free zone width over the RRA composite, indicating the improved stress corrosion cracking resistance. For the reinforcement, the TiB2 particles should slightly aggravate the stress corrosion cracking susceptibility, since the grain boundary precipitates are still the preferential corrosion sites due to their lower corrosion potentials.
RESUMEN
To reveal the effect of alloy element on the morphology of in situ TiB2 particles, a series of TiB2 particles with various morphology were obtained via controlling synthesis process. Si and Cu can affect the morphology transformation of TiB2 particles significantly. Si preferentially adsorbed on (101¯1), (112¯0) and (12¯13¯) planes resulting in the polyhedron morphology of TiB2. Cu adsorbed on (101¯0) preferentially leading to the minimum aspect (the ratio of the diameter and thickness).
RESUMEN
A novel structure TiO2/Ti film was prepared on a titanium matrix using anodic oxidation technique and applied to degrade Reactive Brilliant Red (RBR) dye in simulative textile effluents. The film was characterized by Field-Emission Scanning Electron Microscope (FE-SEM), Laser Micro-Raman Spectrometer (LMRS), UV-vis spectrophotometer (UVS) and Photoelectrocatalytic (PEC) experiment. The results show that the surface morphology of the film is coral structure, and the crystal structure of the film is anatase. The absorbency of the coral structure TiO2/Ti film is 87-93% in the UV light region, and 77-87% in the visible light region. PEC experiment indicates that the photocurrent density of the coral structure TiO2/Ti film electrode achieves 160 microA/cm(2). The color and Chemical Oxygen Demand (COD) removal efficiencies of RBR achieve 73% and 60% in 1h, respectively. These are 16% and 58% higher than those of nanotube TiO2/Ti film electrode. These were attributed to that these electrodes with different surface morphologies exhibit distinct surface areas and light absorption rate.