Improving the high temperature oxidation resistance of Ti-β21S by mechanical surface treatment

The improvement of the high temperature oxidation resistance of titanium alloys is currently a technological challenge. Mechanical surface treatments as shot-peening (SP) have shown their ability to improve the behaviour of pure zirconium and titanium. However, shot-peening treatments can induce a significant surface contamination. Laser shock peening (LSP) appears as a good alternative. Here, we have investigated the effect of SP and LSP treatments on the HT oxidation behavior of Ti-β21S. Samples treated by these methods have been compared to untreated ones for long exposures (3000 h) at 700 °C in dry air. The samples placed in a furnace at 700 °C were periodically extracted to be weighed. The results have been compared to that of pure commercial titanium (Ti-α) samples studied in the same conditions. The higher performances of the Ti-β21S alloy, and the beneficial effect of the SP treatment, and even more of the LSP one, on the HT oxidation resistance of Ti-β21S have been clearly shown. The effect of the mechanical treatments on the microstructure of the Ti-β21S samples and the changes induced by the long duration exposure at high temperature have been mainly studied by scanning electron microscopy combined with energy and wavelength dispersive spectrometry

Improving the high temperature oxidation resistance of Ti-β21S by mechanical surface treatment

The improvement of the high temperature oxidation resistance of titanium alloys is currently a technological challenge. Mechanical surface treatments as shot-peening (SP) have shown their ability to improve the behaviour of pure zirconium and titanium. However, shot-peening treatments can induce a significant surface contamination. Laser shock peening (LSP) appears as a good alternative. Here, we have investigated the effect of SP and LSP treatments on the HT oxidation behavior of Ti-β21S. Samples treated by these methods have been compared to untreated ones for long exposures (3000 h) at 700 °C in dry air. The samples placed in a furnace at 700 °C were periodically extracted to be weighed. The results have been compared to that of pure commercial titanium (Ti-α) samples studied in the same conditions. The higher performances of the Ti-β21S alloy, and the beneficial effect of the SP treatment, and even more of the LSP one, on the HT oxidation resistance of Ti-β21S have been clearly shown. The effect of the mechanical treatments on the microstructure of the Ti-β21S samples and the changes induced by the long duration exposure at high temperature have been mainly studied by scanning electron microscopy combined with energy and wavelength dispersive spectrometry

Removal of VOCs from Air Stream by Complexes of CNTs and Photocatalysis

奈米材料具有粒徑小、比表面積大的特徵，造就了與塊材截然不同的機械性質、電導性質、熱傳性質及化學活性等。其中又以奈米碳管最為眾所矚目的焦點，其應用於環境領域中無論為去除水中或是空氣中之污染物質已有相當之研究成果。而光觸媒之應用已被證實為環境污染物去除之有效技術，若將兩者奈米材料之優勢結合，勢必能夠提升單一奈米材料應用於環境污染物去除之效能。本研究之研究期程為二年。第一年度將以溶膠-凝膠法製備奈米吸附材(單、多壁奈米碳管)與奈米光觸媒之複合材料，借重奈米碳管之高且快速之吸附能力將空氣中的揮發性有機污染物質進行吸附後，再由光觸媒進行光催化反應去除之，吸附機制與光催化反應同時作用，以解決目前大部分單一吸附程序上需脫附再生的問題。第二年度將第一年度完成之奈米碳管-光觸媒複合材料固定於適合之支撐材上，並進行吸附/光催化效能之評估，進一步實現技術應用的可行性