Kesterite Cu2ZnSn(S,Se)4(CZTSSe)is one of the most promising next-generation thin-film photovoltaic materials due to its environmental friendliness and earthabundant constitutions,excellent optoelectronic propertie...Kesterite Cu2ZnSn(S,Se)4(CZTSSe)is one of the most promising next-generation thin-film photovoltaic materials due to its environmental friendliness and earthabundant constitutions,excellent optoelectronic properties(high absorption coefficient>104/cm and tunable band gap 1.0–1.5 eV)and high theoretical efficiency(32%).1,2 In 2014,12.6%3 efficiency was achieved by the IBM group using the hydrazine method.Based on the sputtering process,12.62%4 efficiency for CZTSSe and 12.5%5 efficiency for CZTSe have been achieved in recent years.However,the highest efficiency has stuck around 12.6%for several years.Lately,a breakthrough with certified 13%power conversion efficiency(PCE)has been demonstrated for CZTSSe thin-film solar cells,surpassing the dust-covered efficiency record since 2014.3,6 Along with the efficiency advancement of kesterite solar cells,a cost-effective fabrication process with low carbon footprint plays an increasingly important role considering the near-future industrialisation of this kind of solar cell with low energy payback time.展开更多
2 wt% Ca was added to molten brass containing 3.2 wt% Pb. The composition and grain size of the formed Ca-Pb compound were examined in detail using SEM-EDS and XRD. This revealed that the composition of the Ca-Pb comp...2 wt% Ca was added to molten brass containing 3.2 wt% Pb. The composition and grain size of the formed Ca-Pb compound were examined in detail using SEM-EDS and XRD. This revealed that the composition of the Ca-Pb compound depends on the grain size of the liquid phase Pb and the diffusion phenomenon of the Ca in the Ca-Pb compound formed on the surface of the Pb. When the Pb has a fine grain, a compound composed only of Ca-Pb compounds is formed. When the grain size of the Pb is several μm, Ca-Pb compounds containing unreacted Pb in the center are formed. These compounds aggregate into a larger compound grain. From the evaluation of the floating force (the resultant force of the weight and buoyancy of the Ca-Pb compounds formed) and the rising terminal velocity of the Ca-Pb compound within the molten brass, it was found that the floating force and rising terminal velocity depend on the composition and grain size of the Ca-Pb compound. It was found that since Ca-Pb compounds with a floating force greater than 10-6 g ·cm/s2 have a very large rising terminal velocity, they reach the surface of the molten brass in a short time after compound formation and then continue to float on the surface of the molten brass. Thus they can be removed by skimming. The effects of the grain size of the Ca-Pb compound on the floating force and the rising terminal velocity were greater than those of the composition of the Ca-Pb compound.展开更多
The Mechanism of Pb removal from brass scrap by compound separation using Ca and NaF addition was investigated. Because large Ca-Pb compound particles formed by Ca addition rise to the surface of the molten brass, the...The Mechanism of Pb removal from brass scrap by compound separation using Ca and NaF addition was investigated. Because large Ca-Pb compound particles formed by Ca addition rise to the surface of the molten brass, they can be skimmed off from the molten brass. However, fine Ca-Pb compound particles remain in the molten brass because of low buoyancy. By subsequent NaF addition, the reaction between Ca-Pb compound and NaF takes place at their contact regions, resulting in the formation of solid CaF2, liquid Pb and Na gas. Pb is mainly present at the Ca-Pb compound-CaF2 interface. CaF2 acts as a binder for aggregation of fine Ca-Pb compound particles, resulting in the formation of light and large composite compounds, which rise to the surface of the molten brass. A high Pb removal rate is achieved by skimming off.展开更多
The possibility of substituting 72.5Cu-22.7Zn-3.4Al brass for phosphorus bronze in some case that is now extensively used for elastic component,and purifying the scrap copper for recycling metal was investigated. By a...The possibility of substituting 72.5Cu-22.7Zn-3.4Al brass for phosphorus bronze in some case that is now extensively used for elastic component,and purifying the scrap copper for recycling metal was investigated. By adding a little amount of rare earth Y into scrap copper and 72.5Cu-22.7Zn-3.4Al brass to research their structure and characteristics,especially the electric conductivity for scrap copper and HV for the brass were researched. The results show that the tensile strength,elongation and electric conductivity(IACS) of 0.38 mm strip of scrap copper with 0.04% Y,are 213.8 MPa,23% and 98.5% that suit for the elastic components. The tensile strength,elongation and HV of 0.25mm strip of the brass with 0.03% Y are 665.1MPa,2.86% and 226 that satisfy the usage requirement for the elastic components. Meanwhile,the cost is cheaper than phosphorous bronze because of implying 22.7% zinc in the brass,which has the actual application value.展开更多
文摘Kesterite Cu2ZnSn(S,Se)4(CZTSSe)is one of the most promising next-generation thin-film photovoltaic materials due to its environmental friendliness and earthabundant constitutions,excellent optoelectronic properties(high absorption coefficient>104/cm and tunable band gap 1.0–1.5 eV)and high theoretical efficiency(32%).1,2 In 2014,12.6%3 efficiency was achieved by the IBM group using the hydrazine method.Based on the sputtering process,12.62%4 efficiency for CZTSSe and 12.5%5 efficiency for CZTSe have been achieved in recent years.However,the highest efficiency has stuck around 12.6%for several years.Lately,a breakthrough with certified 13%power conversion efficiency(PCE)has been demonstrated for CZTSSe thin-film solar cells,surpassing the dust-covered efficiency record since 2014.3,6 Along with the efficiency advancement of kesterite solar cells,a cost-effective fabrication process with low carbon footprint plays an increasingly important role considering the near-future industrialisation of this kind of solar cell with low energy payback time.
文摘2 wt% Ca was added to molten brass containing 3.2 wt% Pb. The composition and grain size of the formed Ca-Pb compound were examined in detail using SEM-EDS and XRD. This revealed that the composition of the Ca-Pb compound depends on the grain size of the liquid phase Pb and the diffusion phenomenon of the Ca in the Ca-Pb compound formed on the surface of the Pb. When the Pb has a fine grain, a compound composed only of Ca-Pb compounds is formed. When the grain size of the Pb is several μm, Ca-Pb compounds containing unreacted Pb in the center are formed. These compounds aggregate into a larger compound grain. From the evaluation of the floating force (the resultant force of the weight and buoyancy of the Ca-Pb compounds formed) and the rising terminal velocity of the Ca-Pb compound within the molten brass, it was found that the floating force and rising terminal velocity depend on the composition and grain size of the Ca-Pb compound. It was found that since Ca-Pb compounds with a floating force greater than 10-6 g ·cm/s2 have a very large rising terminal velocity, they reach the surface of the molten brass in a short time after compound formation and then continue to float on the surface of the molten brass. Thus they can be removed by skimming. The effects of the grain size of the Ca-Pb compound on the floating force and the rising terminal velocity were greater than those of the composition of the Ca-Pb compound.
文摘The Mechanism of Pb removal from brass scrap by compound separation using Ca and NaF addition was investigated. Because large Ca-Pb compound particles formed by Ca addition rise to the surface of the molten brass, they can be skimmed off from the molten brass. However, fine Ca-Pb compound particles remain in the molten brass because of low buoyancy. By subsequent NaF addition, the reaction between Ca-Pb compound and NaF takes place at their contact regions, resulting in the formation of solid CaF2, liquid Pb and Na gas. Pb is mainly present at the Ca-Pb compound-CaF2 interface. CaF2 acts as a binder for aggregation of fine Ca-Pb compound particles, resulting in the formation of light and large composite compounds, which rise to the surface of the molten brass. A high Pb removal rate is achieved by skimming off.
基金Project (2006AA03Z522) supported by the Hi-tech Research and Development Program of ChinaProject (50704006) supported by the National Natural Science Foundation of ChinaProject (550033) supported by the Natural Science Foundation of Jiangxi Province, China
文摘The possibility of substituting 72.5Cu-22.7Zn-3.4Al brass for phosphorus bronze in some case that is now extensively used for elastic component,and purifying the scrap copper for recycling metal was investigated. By adding a little amount of rare earth Y into scrap copper and 72.5Cu-22.7Zn-3.4Al brass to research their structure and characteristics,especially the electric conductivity for scrap copper and HV for the brass were researched. The results show that the tensile strength,elongation and electric conductivity(IACS) of 0.38 mm strip of scrap copper with 0.04% Y,are 213.8 MPa,23% and 98.5% that suit for the elastic components. The tensile strength,elongation and HV of 0.25mm strip of the brass with 0.03% Y are 665.1MPa,2.86% and 226 that satisfy the usage requirement for the elastic components. Meanwhile,the cost is cheaper than phosphorous bronze because of implying 22.7% zinc in the brass,which has the actual application value.
