A new compound Sr6Sn2Nb8O30 was found in the ternary system of SrO-SnO2-Nb2O5. The transparent colorless crystal with needle-like shape can be grown by flux method. The crystal structure of new compound was determined...A new compound Sr6Sn2Nb8O30 was found in the ternary system of SrO-SnO2-Nb2O5. The transparent colorless crystal with needle-like shape can be grown by flux method. The crystal structure of new compound was determined by X-ray diffraction, and its belongs to tungsten bronze structure. Sr6Sn2Nb8O30 crystallizes in orthorhombic system with unit cell parameters a= 17. 579 (DA,6= 17. 509(DA,c=7. 7880(5)A,Z = 4 and space group Cmm2.展开更多
The optimal composition of a CaO-SiO_(2)-Al_(2)O_(3)-MgO slag in the ladle furnace refining process was investigated to precisely control the contents of[0]and[Si]and improve the cleanliness of 30Cr2Ni4MoV steel.The i...The optimal composition of a CaO-SiO_(2)-Al_(2)O_(3)-MgO slag in the ladle furnace refining process was investigated to precisely control the contents of[0]and[Si]and improve the cleanliness of 30Cr2Ni4MoV steel.The iso-[O]lines and iso-[Si] lines of the equilibrium between the CaO-SiO_(2)-Al_(2)O_(3)-MgO refining slag and 30Cr2Ni4MoV steel at 1873 K were calculated by the thermodynamic software FactSage 7.3,and the activities of SiO_(2),Al_(2)O_(3)and CaO in the refining slag were discussed to achieve the optimal composition range of the refining slag.Finally,combined with high-temperature"slag-steel"equilibrium experiments,the effects of different refining slags on the oxygen contents,chemical composi-tions,quantities and sizes of inclusions in steels were studied,and then the thermody namic formation mechanism of MgAl_(2)O_(4) inclusions in 30Cr2Ni4MoV steel was discussed.The results showed that the contents of dissolved[O]nd[Si]in steel can be controlled below 10 × 10^(-6)and 0.05%.respectively;when the slag basicity is above 7.the CaO/Al_(2)O_(3)ratio is above I.and the mass fraction of SiO_(2)in the slag docs not cxcced 7%.The chemical composition of the slag has a great influence on the removal and composition of inclusions.The assessed stability phase diagrams of MgO.Al_(2)O_(3)and MgOAl_(2)O_(3) inclusion formation in the Fe-Al-Mg-O system calculated by FactSage 7.3 show good agreement with the experimental results.展开更多
基金Funded by International Centre for Diffraction Data(ICDD).
文摘A new compound Sr6Sn2Nb8O30 was found in the ternary system of SrO-SnO2-Nb2O5. The transparent colorless crystal with needle-like shape can be grown by flux method. The crystal structure of new compound was determined by X-ray diffraction, and its belongs to tungsten bronze structure. Sr6Sn2Nb8O30 crystallizes in orthorhombic system with unit cell parameters a= 17. 579 (DA,6= 17. 509(DA,c=7. 7880(5)A,Z = 4 and space group Cmm2.
基金supported by the National Natural ScienceFoundation of China(Grant Nos.51774217,52074198 and51604201).
文摘The optimal composition of a CaO-SiO_(2)-Al_(2)O_(3)-MgO slag in the ladle furnace refining process was investigated to precisely control the contents of[0]and[Si]and improve the cleanliness of 30Cr2Ni4MoV steel.The iso-[O]lines and iso-[Si] lines of the equilibrium between the CaO-SiO_(2)-Al_(2)O_(3)-MgO refining slag and 30Cr2Ni4MoV steel at 1873 K were calculated by the thermodynamic software FactSage 7.3,and the activities of SiO_(2),Al_(2)O_(3)and CaO in the refining slag were discussed to achieve the optimal composition range of the refining slag.Finally,combined with high-temperature"slag-steel"equilibrium experiments,the effects of different refining slags on the oxygen contents,chemical composi-tions,quantities and sizes of inclusions in steels were studied,and then the thermody namic formation mechanism of MgAl_(2)O_(4) inclusions in 30Cr2Ni4MoV steel was discussed.The results showed that the contents of dissolved[O]nd[Si]in steel can be controlled below 10 × 10^(-6)and 0.05%.respectively;when the slag basicity is above 7.the CaO/Al_(2)O_(3)ratio is above I.and the mass fraction of SiO_(2)in the slag docs not cxcced 7%.The chemical composition of the slag has a great influence on the removal and composition of inclusions.The assessed stability phase diagrams of MgO.Al_(2)O_(3)and MgOAl_(2)O_(3) inclusion formation in the Fe-Al-Mg-O system calculated by FactSage 7.3 show good agreement with the experimental results.
