A series of zinc borotellurite glass co-doped with lanthanum and silver oxide with the chemical formula of [{[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}0.96(La2O3)0.04]1-x(Ag2O)x where the molar frac-tion of silver oxide, x = 0....A series of zinc borotellurite glass co-doped with lanthanum and silver oxide with the chemical formula of [{[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}0.96(La2O3)0.04]1-x(Ag2O)x where the molar frac-tion of silver oxide, x = 0.02, 0.04, 0.06, 0.08 and 0.10 had been successfully prepared via the conventional melt-quenching technique. The structural properties of the glasses were unveiled through X-ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) spectroscopy while optical properties of the glasses were investigated with Ultra Violet Visible (UV-Vis) spectropho-toscopy. The short range periodic atomic arrangement in the glass matrix that implies the amorphous nature of the glass was confirmed with the presence of a broad hump in the XRD pattern. On the other hand, the three absorption bands observable in the FTIR spectra had proven the existence of BO4, BO3 as well as TeO4 units in the glass network. The absorbance values retrieved from UV-Vis spectroscopy were utilized to calculate the indirect energy band gap and Urbach energy values of the fabricated glass. By employing the equations proposed by Mott and Davis, the obtained indirect energy band gap have val-ues ranging from 2.16 to 4.16 eV.The decreasing trend in indirect energy band gap and increasing Urbach energy values were related to the increasing num-ber of nonbridging oxygen (NBO) in the glass that is created from the breaking of Te-O-Te or B-O-B bonds after lanthanum as well as silver oxide are incor-porated into the zinc borotellurite glass network.展开更多
Quaternary glasses were successfully fabricated using melt quenching technique based on the chemical compound composition(x)Bi_(2)O_(3)–(0:5-x)ZnO-(0.2)B_(2)O_(3)–(0.3)SiO_(2),where(x=0.1,0.2,0.3,0.4,0.45)mole.The s...Quaternary glasses were successfully fabricated using melt quenching technique based on the chemical compound composition(x)Bi_(2)O_(3)–(0:5-x)ZnO-(0.2)B_(2)O_(3)–(0.3)SiO_(2),where(x=0.1,0.2,0.3,0.4,0.45)mole.The sources of SiO_(2)was produced from rice husk ash(RHA)at 99.36%of SiO_(2).The Urbach energy was increased from 0.16 eV to the 0.29 eV as the mole of Bi_(2)O_(3)increased in the glass structure.The indirect energy band gap is indicated in decrement pattern with 3.15 eV towards 2.51 eV.The results of Urbach energy and band gap energy that were obtained are due to the increment of Bi^(3+)ion in the glass network.The refractive indexes for the prepared glasses were evaluated at 2.36 to 2.54 based on the Lorentz–Lorentz formulation which correlated to the energy band gap.The calculated of molar polarizability,electronic polarizability and optical basicity exemplify fine complement to the Bi_(2)O_(3)addition in the glass network.The glass sample was indicated in amorphous state.展开更多
ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion tem...ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion temperature as well as the formation route for synthesizing ZrC powder particles were studied. The samples were characterized by XRD, SEM, TEM, and DTA. The XRD results revealed that, after 18 h of mechanical activation, ZrO2/ZC/Mg/Fe reacted with the self-propagating combustion(SHS) mode at 870 °C producing the ZrC–Fe nanocomposite. It was also found that both mechanical activation and Fe content played key roles in the ZrC synthesis temperature. With a Fe content of(5–40) wt%, the SHS reaction proceeded favorably and both the ZrC formation temperature and the adiabatic temperature(Tad) decreased. The Mg O content was removed from the final products using a leaching test process by dissolving in hydrochloric and acetic acids.展开更多
文摘A series of zinc borotellurite glass co-doped with lanthanum and silver oxide with the chemical formula of [{[(TeO2)0.7(B2O3)0.3]0.7(ZnO)0.3}0.96(La2O3)0.04]1-x(Ag2O)x where the molar frac-tion of silver oxide, x = 0.02, 0.04, 0.06, 0.08 and 0.10 had been successfully prepared via the conventional melt-quenching technique. The structural properties of the glasses were unveiled through X-ray Diffraction (XRD) and Fourier Transform Infra-Red (FTIR) spectroscopy while optical properties of the glasses were investigated with Ultra Violet Visible (UV-Vis) spectropho-toscopy. The short range periodic atomic arrangement in the glass matrix that implies the amorphous nature of the glass was confirmed with the presence of a broad hump in the XRD pattern. On the other hand, the three absorption bands observable in the FTIR spectra had proven the existence of BO4, BO3 as well as TeO4 units in the glass network. The absorbance values retrieved from UV-Vis spectroscopy were utilized to calculate the indirect energy band gap and Urbach energy values of the fabricated glass. By employing the equations proposed by Mott and Davis, the obtained indirect energy band gap have val-ues ranging from 2.16 to 4.16 eV.The decreasing trend in indirect energy band gap and increasing Urbach energy values were related to the increasing num-ber of nonbridging oxygen (NBO) in the glass that is created from the breaking of Te-O-Te or B-O-B bonds after lanthanum as well as silver oxide are incor-porated into the zinc borotellurite glass network.
基金the University Science Malaysia for the financial support for this research under two USM(Short Term Grant)which are 304/PFIZIK/6313152 and 304/PFIZIK/6313249.
文摘Quaternary glasses were successfully fabricated using melt quenching technique based on the chemical compound composition(x)Bi_(2)O_(3)–(0:5-x)ZnO-(0.2)B_(2)O_(3)–(0.3)SiO_(2),where(x=0.1,0.2,0.3,0.4,0.45)mole.The sources of SiO_(2)was produced from rice husk ash(RHA)at 99.36%of SiO_(2).The Urbach energy was increased from 0.16 eV to the 0.29 eV as the mole of Bi_(2)O_(3)increased in the glass structure.The indirect energy band gap is indicated in decrement pattern with 3.15 eV towards 2.51 eV.The results of Urbach energy and band gap energy that were obtained are due to the increment of Bi^(3+)ion in the glass network.The refractive indexes for the prepared glasses were evaluated at 2.36 to 2.54 based on the Lorentz–Lorentz formulation which correlated to the energy band gap.The calculated of molar polarizability,electronic polarizability and optical basicity exemplify fine complement to the Bi_(2)O_(3)addition in the glass network.The glass sample was indicated in amorphous state.
文摘ZrC nanoparticles in the matrix of Fe were produced by the mechanically activated self-propagating hightemperature method using ZrO2/C/Mg/Fe powder mixtures. The effects of milling time, Fe content, and combustion temperature as well as the formation route for synthesizing ZrC powder particles were studied. The samples were characterized by XRD, SEM, TEM, and DTA. The XRD results revealed that, after 18 h of mechanical activation, ZrO2/ZC/Mg/Fe reacted with the self-propagating combustion(SHS) mode at 870 °C producing the ZrC–Fe nanocomposite. It was also found that both mechanical activation and Fe content played key roles in the ZrC synthesis temperature. With a Fe content of(5–40) wt%, the SHS reaction proceeded favorably and both the ZrC formation temperature and the adiabatic temperature(Tad) decreased. The Mg O content was removed from the final products using a leaching test process by dissolving in hydrochloric and acetic acids.