The corrosion of refractory crucibles by a highly cor- rosive steel （18CrNiMo7-6） with a high aluminum con- tent and casting temperature of 1 580℃ was investiga- ted. The tested refractories were alumina, muUite an...The corrosion of refractory crucibles by a highly cor- rosive steel （18CrNiMo7-6） with a high aluminum con- tent and casting temperature of 1 580℃ was investiga- ted. The tested refractories were alumina, muUite and alumina doped with zirconia and titania （ AZT）. The samples were decreasingly attacked in the sequence AZT, alumina and mullite with corrosion layers of about 14, 6 and 1 mm, respectively. In the alumina and AZT, compositions corresponding to manganese aluminates and subsequently manganese aluminosilicates formed with manganese and silicon from the steel. In the mullite cru- cible, compositions corresponding to manganese aluminosilicates formed directly with manganese from the steel giving a highly viscous interfacial melt which retarded the further corrosion.展开更多
Composites containing biological materials with nanostructured architecture have become of great interest in modem materials science, yielding both interesting chemical properties and inspiration for biomimetic resear...Composites containing biological materials with nanostructured architecture have become of great interest in modem materials science, yielding both interesting chemical properties and inspiration for biomimetic research. Herein, we describe the preparation of a novel three-dimensional （3D） nanostructured MnO2-based com- posite developed using a carbonized proteinaceous spongin template by an extreme biomimetics approach. The thermal stability of the spongin-based scaffold fadlitated the formation of both carbonized material （at 650 ℃ with exclusion of oxygen） and manganese oxide with a defined nanoscale structure under 150 ℃. Remarkably, the unique network of spongin fibers was maintained after pyrolysis and hydro^ermal processing, yielding a novel porous support. The MnO2-spongin composite shows a bimodal pore distribution, with macropores originating from the spongin network and mesopores from the nanostructured oxidic coating. Interestingl3~ the composites also showed improved electrochemical properties compared to those of Mno2. Voltammetry cycling demonstrated the good stability of the material over more than 3,000 charging/discharging cydes. Additionally, electrochemical impedance spectroscopy revealed lower charge transfer resistance in the prepared materials. We demonstrate the potential of extreme biomimetics for developing a new generation of nanostructred materials with 3D centimeter-scale architecture for the storage and conversion of energy generated from renewable natural sources.展开更多
基金The German Research Foundation(DFG)(Grant No.AN 322/27-1,AN 322/19-1,and AN 322/17-2)
文摘The corrosion of refractory crucibles by a highly cor- rosive steel （18CrNiMo7-6） with a high aluminum con- tent and casting temperature of 1 580℃ was investiga- ted. The tested refractories were alumina, muUite and alumina doped with zirconia and titania （ AZT）. The samples were decreasingly attacked in the sequence AZT, alumina and mullite with corrosion layers of about 14, 6 and 1 mm, respectively. In the alumina and AZT, compositions corresponding to manganese aluminates and subsequently manganese aluminosilicates formed with manganese and silicon from the steel. In the mullite cru- cible, compositions corresponding to manganese aluminosilicates formed directly with manganese from the steel giving a highly viscous interfacial melt which retarded the further corrosion.
文摘Composites containing biological materials with nanostructured architecture have become of great interest in modem materials science, yielding both interesting chemical properties and inspiration for biomimetic research. Herein, we describe the preparation of a novel three-dimensional （3D） nanostructured MnO2-based com- posite developed using a carbonized proteinaceous spongin template by an extreme biomimetics approach. The thermal stability of the spongin-based scaffold fadlitated the formation of both carbonized material （at 650 ℃ with exclusion of oxygen） and manganese oxide with a defined nanoscale structure under 150 ℃. Remarkably, the unique network of spongin fibers was maintained after pyrolysis and hydro^ermal processing, yielding a novel porous support. The MnO2-spongin composite shows a bimodal pore distribution, with macropores originating from the spongin network and mesopores from the nanostructured oxidic coating. Interestingl3~ the composites also showed improved electrochemical properties compared to those of Mno2. Voltammetry cycling demonstrated the good stability of the material over more than 3,000 charging/discharging cydes. Additionally, electrochemical impedance spectroscopy revealed lower charge transfer resistance in the prepared materials. We demonstrate the potential of extreme biomimetics for developing a new generation of nanostructred materials with 3D centimeter-scale architecture for the storage and conversion of energy generated from renewable natural sources.
