The phase transformation of chalcopyrite and the effect of its phase status on bacterial leaching were studied. Under the protection of high-purity argon, different temperatures(203, 382 and 552℃) were applied to nat...The phase transformation of chalcopyrite and the effect of its phase status on bacterial leaching were studied. Under the protection of high-purity argon, different temperatures(203, 382 and 552℃) were applied to natural chalcopyrite to complete the phase change. In addition, the chalcopyrite was bioleached before and after the phase change. The results show that the chalcopyrite heated at 203 and 382℃ remained in the α phase, whereas the chalcopyrite changed from α to β phase at 552℃. The leaching rates of chalcopyrite after the phase transitions at 203, 382 and 552℃ were 32.9%, 40.5% and 60.95%, respectively. Further, the crystal lattice parameters of chalcopyrite increased and lattice energy decreased, which were the fundamental reasons for the significant increase in leaching rate. Electrochemical experiments demonstrated that with increasing annealing temperature, the polarization resistance decreased and corrosion current density increased. The higher the oxidation rate was, the higher the leaching rate was.展开更多
Fe_(y)Te_(1-x)Se_(x),an archetypical iron-based high-temperature superconductor with a simple structure but rich physical properties,has attracted lots of attention because the two end compositions,Se content x=0 and ...Fe_(y)Te_(1-x)Se_(x),an archetypical iron-based high-temperature superconductor with a simple structure but rich physical properties,has attracted lots of attention because the two end compositions,Se content x=0 and 1,exhibit antiferromagnetism and nematicity,respectively,making it an ideal candidate for studying their interactions with superconductivity.However,what is clearly lacking to date is a complete phase diagram of Fe_(y)Te_(1-x)Se_(x)as functions of its chemical compositions since phase separation usually occurs from x~0.6 to 0.9 in bulk crystals.Moreover,fine control of its composition is experimentally challenging because both Te and Se are volatile elements.Here we establish a complete phase diagram of Fe_(y)Te_(1-x)Se_(x),achieved by high-throughput film synthesis and characterization techniques.An advanced combinatorial synthesis process enables us to fabricate an epitaxial composition-spread Fe_(y)Te_(1-x)Se_(x)film encompassing the entire Se content x from 0 to 1 on a single piece of CaFsubstrate.The micro-region composition analysis and X-ray diffraction show a successful continuous tuning of chemical compositions and lattice parameters,respectively.The micro-scale pattern technique allows the mapping of electrical transport properties as a function of relative Se content with an unprecedented resolution of0.0074.Combining with the spin patterns in literature,we build a detailed phase diagram that can unify the electronic and magnetic properties of Fe_(y)Te_(1-x)Se_(x).Our composition-spread Fe_(y)Te_(1-x)Se_(x) films,overcoming the challenges of phase separation and precise control of chemical compositions,provide an ideal platform for studying the relationship between superconductivity and magnetism.展开更多
基金Project(2018zzts768) supported by the Fundamental Research Funds for the Central South University,ChinaProject(51204207) supported by the National Natural Science Foundation of China
文摘The phase transformation of chalcopyrite and the effect of its phase status on bacterial leaching were studied. Under the protection of high-purity argon, different temperatures(203, 382 and 552℃) were applied to natural chalcopyrite to complete the phase change. In addition, the chalcopyrite was bioleached before and after the phase change. The results show that the chalcopyrite heated at 203 and 382℃ remained in the α phase, whereas the chalcopyrite changed from α to β phase at 552℃. The leaching rates of chalcopyrite after the phase transitions at 203, 382 and 552℃ were 32.9%, 40.5% and 60.95%, respectively. Further, the crystal lattice parameters of chalcopyrite increased and lattice energy decreased, which were the fundamental reasons for the significant increase in leaching rate. Electrochemical experiments demonstrated that with increasing annealing temperature, the polarization resistance decreased and corrosion current density increased. The higher the oxidation rate was, the higher the leaching rate was.
基金supported by the National Key R&D Program of China(2021YFA0718700,2017YFA0302902,2017YFA0303003,and 2018YFB0704102)the National Natural Science Foundation of China(11834016,11961141008,11927808,and 12174428)+3 种基金the Strategic Priority Research Program(B)of Chinese Academy of Sciences(XDB25000000 and XDB33000000)the Beijing Natural Science Foundation(Z190008)CAS Interdisciplinary Innovation Team,Key-Area Research and Development Program of Guangdong Province(2020B0101340002)the Center for Materials Genome。
文摘Fe_(y)Te_(1-x)Se_(x),an archetypical iron-based high-temperature superconductor with a simple structure but rich physical properties,has attracted lots of attention because the two end compositions,Se content x=0 and 1,exhibit antiferromagnetism and nematicity,respectively,making it an ideal candidate for studying their interactions with superconductivity.However,what is clearly lacking to date is a complete phase diagram of Fe_(y)Te_(1-x)Se_(x)as functions of its chemical compositions since phase separation usually occurs from x~0.6 to 0.9 in bulk crystals.Moreover,fine control of its composition is experimentally challenging because both Te and Se are volatile elements.Here we establish a complete phase diagram of Fe_(y)Te_(1-x)Se_(x),achieved by high-throughput film synthesis and characterization techniques.An advanced combinatorial synthesis process enables us to fabricate an epitaxial composition-spread Fe_(y)Te_(1-x)Se_(x)film encompassing the entire Se content x from 0 to 1 on a single piece of CaFsubstrate.The micro-region composition analysis and X-ray diffraction show a successful continuous tuning of chemical compositions and lattice parameters,respectively.The micro-scale pattern technique allows the mapping of electrical transport properties as a function of relative Se content with an unprecedented resolution of0.0074.Combining with the spin patterns in literature,we build a detailed phase diagram that can unify the electronic and magnetic properties of Fe_(y)Te_(1-x)Se_(x).Our composition-spread Fe_(y)Te_(1-x)Se_(x) films,overcoming the challenges of phase separation and precise control of chemical compositions,provide an ideal platform for studying the relationship between superconductivity and magnetism.
