Effects of rare earth element La on the microstructure of Cu matrix diamond tools were researched under the conditions of various materials componentsand the process parameters in order to improve materials properties...Effects of rare earth element La on the microstructure of Cu matrix diamond tools were researched under the conditions of various materials componentsand the process parameters in order to improve materials properties. SEM, XPS and X-ray were used to investigate the fracture section, microstructure and the element valence in materials. The results shown that the combination of rare earth element La and transition element Ti is advantageous to the bonding state between diamond particles and matrix, so it can improve the materials properties. Suitable sintering temperature is 790℃.展开更多
Ten tungstovanadogermanic complexes K 13 H 2[Ln(GeW 10 VO 39 ) 2]· n H 2O (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Yb) were synthesized for the first time. Their structures were characterized by IR, UV, ESR, XPS, ...Ten tungstovanadogermanic complexes K 13 H 2[Ln(GeW 10 VO 39 ) 2]· n H 2O (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Yb) were synthesized for the first time. Their structures were characterized by IR, UV, ESR, XPS, XRD and magnetic susceptibility. Their redox properties were studied by means of cyclic voctammetry and polargraphy. The results show that the complexes undergo three step reduction, the first step is the double electronic reversible, while the second and the third steps are irreversible. Their thermal stability studied by TG DTA, IR and XRD at various temperature shows that the range of pyrolysis temperature is 450～500 ℃. The complex stability in solution investigated by the acid alkali titration indicates that the range of pH in which the heteropoly anions can exist stably is pH=3 3～7 6 at room temperature.展开更多
文摘Effects of rare earth element La on the microstructure of Cu matrix diamond tools were researched under the conditions of various materials componentsand the process parameters in order to improve materials properties. SEM, XPS and X-ray were used to investigate the fracture section, microstructure and the element valence in materials. The results shown that the combination of rare earth element La and transition element Ti is advantageous to the bonding state between diamond particles and matrix, so it can improve the materials properties. Suitable sintering temperature is 790℃.
文摘Ten tungstovanadogermanic complexes K 13 H 2[Ln(GeW 10 VO 39 ) 2]· n H 2O (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Yb) were synthesized for the first time. Their structures were characterized by IR, UV, ESR, XPS, XRD and magnetic susceptibility. Their redox properties were studied by means of cyclic voctammetry and polargraphy. The results show that the complexes undergo three step reduction, the first step is the double electronic reversible, while the second and the third steps are irreversible. Their thermal stability studied by TG DTA, IR and XRD at various temperature shows that the range of pyrolysis temperature is 450～500 ℃. The complex stability in solution investigated by the acid alkali titration indicates that the range of pH in which the heteropoly anions can exist stably is pH=3 3～7 6 at room temperature.
