The thermal conductivity of the mould fluxes containing transition metal oxides was measured by hotline method at different temperatures. The relationship between the thermal conductivity of mold fluxes and the conten...The thermal conductivity of the mould fluxes containing transition metal oxides was measured by hotline method at different temperatures. The relationship between the thermal conductivity of mold fluxes and the contents of transition metal oxides was discussed. The synthetic slags were composed of 30.0% - 35.4%CaO, 34.7% - 38.6% SiO2, 6% Al2O3, 9% Na2O, 14.4% CaF2, 0-4% Cr2O3 and 0-8% MnO in mass percent. The results indicated that Cr2O3 and MnO had a negative effect on thermal conductivity of mold fluxes. The thermal conductivity of mold fluxes was about 0.25-0.55 W/（m · K） when the temperature reached 1 300 ℃, and it increased sharply to about 1.32-1.99 W/（m · K） when the temperature reduced from 1300 to 1000 ℃. The thermal conductivity of mold fluxes containing Cr2 O3 and MnO was 10 %- 25% lower than those of original fluxes. The decrease in thermal conductivity was attributed to the change of molecular structure of mold fluxes. In addition, the poor integrity and regulation of polycrystal structure, complexity of crystal structure, and effects of impurities in the boundary and lat- tice distortion leaded to the reduction in the thermal conductivity. Na2 CrO4, Mn2 SiO4 and other minor phases were also found in the samples containing Cr2O3 and MnO, respectively.展开更多
基金Sponsored by Doctor Programs Foundation of Education Ministry of China(200806110006)
文摘The thermal conductivity of the mould fluxes containing transition metal oxides was measured by hotline method at different temperatures. The relationship between the thermal conductivity of mold fluxes and the contents of transition metal oxides was discussed. The synthetic slags were composed of 30.0% - 35.4%CaO, 34.7% - 38.6% SiO2, 6% Al2O3, 9% Na2O, 14.4% CaF2, 0-4% Cr2O3 and 0-8% MnO in mass percent. The results indicated that Cr2O3 and MnO had a negative effect on thermal conductivity of mold fluxes. The thermal conductivity of mold fluxes was about 0.25-0.55 W/（m · K） when the temperature reached 1 300 ℃, and it increased sharply to about 1.32-1.99 W/（m · K） when the temperature reduced from 1300 to 1000 ℃. The thermal conductivity of mold fluxes containing Cr2 O3 and MnO was 10 %- 25% lower than those of original fluxes. The decrease in thermal conductivity was attributed to the change of molecular structure of mold fluxes. In addition, the poor integrity and regulation of polycrystal structure, complexity of crystal structure, and effects of impurities in the boundary and lat- tice distortion leaded to the reduction in the thermal conductivity. Na2 CrO4, Mn2 SiO4 and other minor phases were also found in the samples containing Cr2O3 and MnO, respectively.
