Thermochromic materials based on solid-state oxides exhibit many potential photo-thermal regulation applications.Herein,we report a new thermochromic pure-phase CaCrO_(4) pigment with merits of high chromatic aberrati...Thermochromic materials based on solid-state oxides exhibit many potential photo-thermal regulation applications.Herein,we report a new thermochromic pure-phase CaCrO_(4) pigment with merits of high chromatic aberration,fully reversible thermochromism,and high stability.CaCrO_(4) crystalized into a tetragonal zircon-type structure,which showed a successively reversible color change from greenish yellow to reddish orange with the highest chromatic aberration (ΔE^(*)_(CIE)) of 59.60.In situ variable temperature X-ray diffraction analysis results revealed that the expansion of the lattice was uniaxial along the c-axis with a dilation rate of 2.06×10^(−5),while that along the a-axis remained nearly unchanged in the temperature range of 25–575℃.In situ variable temperature UV–vis absorption spectra of CaCrO_(4) revealed a successive bandgap reduction with an average temperature dependency rate(dE_(g)/dT)_(aver age) of 0.27 meV K^(−1).Continuous color change or bandgap reduction originated from the successive elongation of Cr–O bonds in the CrO_(4) tetrahedral chromophore in the lattice.The most sensitive temperature range was between 175℃ and 400℃,which rendered a naked-eye-detection accuracy rate of over 85%for a standard temperature deviation(ΔT)of 25℃,demonstrating the potential of the pigment as a pan-bottom temperature indicator for healthy cooking.展开更多
One of characteristics of Cr2O3-containing refractory is excellent corrosion resistance. However, there is a problem of hexavalent chromium, which is noxious to the human body, and easily formed by the reactions among...One of characteristics of Cr2O3-containing refractory is excellent corrosion resistance. However, there is a problem of hexavalent chromium, which is noxious to the human body, and easily formed by the reactions among the refractory and CaO, Na2O and/or K2O in slag. In this article, the reason why the Cr2O3-containing refractory has excellent corrosion resistance, the forming conditions of hexavalent compounds, and the methods for suppressing generation of the compound, are described as a base of further development of excellent refractories.展开更多
基金funded by the National Key Research and Development Program of China(No.2022YFB3603802)the Key Research and Development Program of Jilin Scientific and Technological Development Program(No.20220201068GX)+1 种基金the National Natural Science Foundation of China(Nos.51902127,62374073)Changbai Mountain Industrial Project R&D Leading Team,Jilin Provincial Department of Science and Technology,China.
文摘Thermochromic materials based on solid-state oxides exhibit many potential photo-thermal regulation applications.Herein,we report a new thermochromic pure-phase CaCrO_(4) pigment with merits of high chromatic aberration,fully reversible thermochromism,and high stability.CaCrO_(4) crystalized into a tetragonal zircon-type structure,which showed a successively reversible color change from greenish yellow to reddish orange with the highest chromatic aberration (ΔE^(*)_(CIE)) of 59.60.In situ variable temperature X-ray diffraction analysis results revealed that the expansion of the lattice was uniaxial along the c-axis with a dilation rate of 2.06×10^(−5),while that along the a-axis remained nearly unchanged in the temperature range of 25–575℃.In situ variable temperature UV–vis absorption spectra of CaCrO_(4) revealed a successive bandgap reduction with an average temperature dependency rate(dE_(g)/dT)_(aver age) of 0.27 meV K^(−1).Continuous color change or bandgap reduction originated from the successive elongation of Cr–O bonds in the CrO_(4) tetrahedral chromophore in the lattice.The most sensitive temperature range was between 175℃ and 400℃,which rendered a naked-eye-detection accuracy rate of over 85%for a standard temperature deviation(ΔT)of 25℃,demonstrating the potential of the pigment as a pan-bottom temperature indicator for healthy cooking.
文摘One of characteristics of Cr2O3-containing refractory is excellent corrosion resistance. However, there is a problem of hexavalent chromium, which is noxious to the human body, and easily formed by the reactions among the refractory and CaO, Na2O and/or K2O in slag. In this article, the reason why the Cr2O3-containing refractory has excellent corrosion resistance, the forming conditions of hexavalent compounds, and the methods for suppressing generation of the compound, are described as a base of further development of excellent refractories.
