Interfacial reactions between aluminium and polycrystalline cermet TiC_(0.6) were investigated using x-ray photoelectron spectroscopy,Auger electron spectroscopy and x-ray diffraction.It was found that titanium exists...Interfacial reactions between aluminium and polycrystalline cermet TiC_(0.6) were investigated using x-ray photoelectron spectroscopy,Auger electron spectroscopy and x-ray diffraction.It was found that titanium exists in two chemical states.The carbide and oxide of titanium can be detected simultaneously,and the atomic ratio of Ti:C:O is 5:3:2.This suggests that TiC^(0.6) is a Ti-oxycarbide or oxygenated TiC composite:Ti_(5)C_(3)O_(2)(TiO_(2)+4TiC_(0.75)).When Al is deposited in vacuum on the Ti-oxycarbide surface,the active Al atoms react chemically only with TiO_(2) at room temperature,but not with Tico.75 in Ti-oxycarbide.The reaction products are Al2O3 and theintermetallic compound Als Ti.Annealing the Al/TiC_(0.6) interface at 750℃,Al reacts also with TiC_(0.75) to form a brittle Al_(4)C_(3) phase.展开更多
The double peak structure of O_(18) in photoemission spectra of Bi-Sr-Ca-Cu-O superconductor is studied by XPS,and compared with that of SrCO_(3).The result indicates that the double peak structure of O_(18) spectra i...The double peak structure of O_(18) in photoemission spectra of Bi-Sr-Ca-Cu-O superconductor is studied by XPS,and compared with that of SrCO_(3).The result indicates that the double peak structure of O_(18) spectra is closely related with the Sr_(3d) and C_(1s) spectra,and arises primarily from the SrCO_(3)-like complex caused by the contamination of CO_(2) in air.展开更多
Discovery of the superconductivity in Ba-Y-Cu-O system above liquid nitrogen transition temperature has stimulated the extensive studies. The properties of superconducting material depend on the temperature and atmosp...Discovery of the superconductivity in Ba-Y-Cu-O system above liquid nitrogen transition temperature has stimulated the extensive studies. The properties of superconducting material depend on the temperature and atmosphere during its sinter. In fact, the oxygen content in sample can be affected seriously by sintering and annealing procedure. The results of X-ray and neutron diffraction analysis indicate that the oxygen vacancy plays an important role in superconductor Ba-Y-Cu-O展开更多
Ⅰ. INTRODUCTIONSince the discovery of oxide superconductor YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> with transition temperature above liquid nitrogen one year ago, a tremendou...Ⅰ. INTRODUCTIONSince the discovery of oxide superconductor YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> with transition temperature above liquid nitrogen one year ago, a tremendous amount of work has been done on oxide superconductors in thousands of laboratories in the world. It has already been shown that yttrium could be replaced by other rare-earth elements展开更多
基金Supported by the China and Israel joint-program,the Ministry of Science and Technology of China(ZYJ01-01).
文摘Interfacial reactions between aluminium and polycrystalline cermet TiC_(0.6) were investigated using x-ray photoelectron spectroscopy,Auger electron spectroscopy and x-ray diffraction.It was found that titanium exists in two chemical states.The carbide and oxide of titanium can be detected simultaneously,and the atomic ratio of Ti:C:O is 5:3:2.This suggests that TiC^(0.6) is a Ti-oxycarbide or oxygenated TiC composite:Ti_(5)C_(3)O_(2)(TiO_(2)+4TiC_(0.75)).When Al is deposited in vacuum on the Ti-oxycarbide surface,the active Al atoms react chemically only with TiO_(2) at room temperature,but not with Tico.75 in Ti-oxycarbide.The reaction products are Al2O3 and theintermetallic compound Als Ti.Annealing the Al/TiC_(0.6) interface at 750℃,Al reacts also with TiC_(0.75) to form a brittle Al_(4)C_(3) phase.
基金supported by The National Center for Research and Development on Superconductivity.
文摘The double peak structure of O_(18) in photoemission spectra of Bi-Sr-Ca-Cu-O superconductor is studied by XPS,and compared with that of SrCO_(3).The result indicates that the double peak structure of O_(18) spectra is closely related with the Sr_(3d) and C_(1s) spectra,and arises primarily from the SrCO_(3)-like complex caused by the contamination of CO_(2) in air.
基金Project supported by the National Natural Science Foundation of China & Academia Sinics.
文摘Discovery of the superconductivity in Ba-Y-Cu-O system above liquid nitrogen transition temperature has stimulated the extensive studies. The properties of superconducting material depend on the temperature and atmosphere during its sinter. In fact, the oxygen content in sample can be affected seriously by sintering and annealing procedure. The results of X-ray and neutron diffraction analysis indicate that the oxygen vacancy plays an important role in superconductor Ba-Y-Cu-O
文摘Ⅰ. INTRODUCTIONSince the discovery of oxide superconductor YBa<sub>2</sub>Cu<sub>3</sub>O<sub>7-δ</sub> with transition temperature above liquid nitrogen one year ago, a tremendous amount of work has been done on oxide superconductors in thousands of laboratories in the world. It has already been shown that yttrium could be replaced by other rare-earth elements
