The ferrites of PC30 （Mn-Zn ferrites） were prepared by using a dry processing route. The effect of Mn-Zn ferrites doped with H3BO3 was investigated on the basis of microstructure analysis. The results of the samples...The ferrites of PC30 （Mn-Zn ferrites） were prepared by using a dry processing route. The effect of Mn-Zn ferrites doped with H3BO3 was investigated on the basis of microstructure analysis. The results of the samples doped with H3BO3 less than 5 × 10^-5 showed that the doping had no significant effect on power loss, initial permeability, fine grain microstructure, and density of Mn-Zn ferrites. With the further increase in H3BO3 doping （up to 1 × 10 ^-4 ）, the microstructure of Mn-Zn ferrites is in the critical state between fine grain and ＂sandwich＂, and the initial permeability and density of Mn-Zn ferrites begin falling quickly; the increased H3BO3 doping also results in deteriorated power loss properties. Thus, the control of the boron content in iron oxide is of utmost importance for the quality of Mn-Zn ferrites in producing process.展开更多
The boron adsorption kinetic experiment in soil by means of a flow displacement technique showed that the kinetic data could be described with some mathematic equations. The average values of the correlation coefficie...The boron adsorption kinetic experiment in soil by means of a flow displacement technique showed that the kinetic data could be described with some mathematic equations. The average values of the correlation coefficient for zero-order, first-order, parabolic diffusion, Elovich, power function and exponential equations were 0.957, 0.982, 0.981, 0.984, 0.981 and 0.902, respectively. The correlation between adsorbed boron or its other expression form and time were the highest for first-order, parabolic diffusion, Elovich, and power function equations, the second for the zeroorder equation, and the lowest for the exponential equation. The parabolic diffusion equation fitted well the experimental results, with the least standard error among the six kinetic equations, showing that the movement of boron from soil solution to soil colloid surface may be controlled by boron diffusion speed. The boron content of rape seedling obtained from soil cultivation was correlated with the rate constants of the kinetic equations. The constants of first-order, parabolic diffusion,and exponential equations were significantly correlated with the boron content of the crop of NPK treatment at a 95% probability level, with correlation coefficients being 0.686, 0.691 and 0.641, respectively. In the case of zero-order equation, it was significant at 99% probability level (r =0.736). These results showed that the absorption kinetic constants of soil boron were closely related with the rape plant response to boron.展开更多
The current research focused on adjusting the low hydration activity of the metallurgical slag by phase reconstruction technique. Boron oxide was used as a phase regulator to improve the amorphous phase composition of...The current research focused on adjusting the low hydration activity of the metallurgical slag by phase reconstruction technique. Boron oxide was used as a phase regulator to improve the amorphous phase composition of the manganese slag, consequently enhancing its hydraulic activity. The effects of boron oxide dosage and calcination temperature on the manganese slag amorphous phase content were investigated. XRD and DTG were performed to analyze the hydration mechanism of the manganese slag powder and cement. Results show that, when boron oxide dosage is 15%, calcination temperature is 1 300℃, and holding time for 1 hour, the amorphous content of the modified manganese slag reaches 95% and its 28-day activity index reaches 8 1.7%. The manganese slag powder can then be used as cement or concrete admixtures for the building materials industry.展开更多
Boron and carbon contents are the main factors influencing the properties of high-boron steel.In this study,experimental samples with different boron-to-carbon ratios(%B/%C)were prepared.The microstructures of the dif...Boron and carbon contents are the main factors influencing the properties of high-boron steel.In this study,experimental samples with different boron-to-carbon ratios(%B/%C)were prepared.The microstructures of the different samples were observed,and their hardness,bending strength,and impact toughness were investigated.Results show that the main microstructures in the investigated high-boron steel samples are the eutectic Fe_(2)B structure with a fishbone shape and the ternary peritectic Fe_(3)(C,B)structure with a chrysanthemum shape.When the boron content is 2.5wt.%and the carbon content is 0.43wt.%(i.e.,%B/%C=5.82),the overall mechanical properties of the alloy are the best.The alloy's hardness,bending strength and impact toughness reach their maximums,which are 67.3 HRC,1,267.36 MPa and 6.19 J·cm^(-2),respectively.The optimized alloy is compared with conventional materials exhibiting excellent wear resistance(namely,high-manganese steel and high-chromium cast iron)through two-body and three-body abrasion tests.The wear resistance of this high-boron steelinvestigated in this work is found to be superior to those of the more common materials.展开更多
文摘The ferrites of PC30 （Mn-Zn ferrites） were prepared by using a dry processing route. The effect of Mn-Zn ferrites doped with H3BO3 was investigated on the basis of microstructure analysis. The results of the samples doped with H3BO3 less than 5 × 10^-5 showed that the doping had no significant effect on power loss, initial permeability, fine grain microstructure, and density of Mn-Zn ferrites. With the further increase in H3BO3 doping （up to 1 × 10 ^-4 ）, the microstructure of Mn-Zn ferrites is in the critical state between fine grain and ＂sandwich＂, and the initial permeability and density of Mn-Zn ferrites begin falling quickly; the increased H3BO3 doping also results in deteriorated power loss properties. Thus, the control of the boron content in iron oxide is of utmost importance for the quality of Mn-Zn ferrites in producing process.
文摘The boron adsorption kinetic experiment in soil by means of a flow displacement technique showed that the kinetic data could be described with some mathematic equations. The average values of the correlation coefficient for zero-order, first-order, parabolic diffusion, Elovich, power function and exponential equations were 0.957, 0.982, 0.981, 0.984, 0.981 and 0.902, respectively. The correlation between adsorbed boron or its other expression form and time were the highest for first-order, parabolic diffusion, Elovich, and power function equations, the second for the zeroorder equation, and the lowest for the exponential equation. The parabolic diffusion equation fitted well the experimental results, with the least standard error among the six kinetic equations, showing that the movement of boron from soil solution to soil colloid surface may be controlled by boron diffusion speed. The boron content of rape seedling obtained from soil cultivation was correlated with the rate constants of the kinetic equations. The constants of first-order, parabolic diffusion,and exponential equations were significantly correlated with the boron content of the crop of NPK treatment at a 95% probability level, with correlation coefficients being 0.686, 0.691 and 0.641, respectively. In the case of zero-order equation, it was significant at 99% probability level (r =0.736). These results showed that the absorption kinetic constants of soil boron were closely related with the rape plant response to boron.
基金Funded by the National High-tech Research and Development Prograrn of China(863 Program)(No.2012AA06A112)the National Natural Science Foundation of China(No.51162004)the Guangxi Science and Technology Development Plan(Nos.12118014-3D,12118019-2-15,1348011-2)
文摘The current research focused on adjusting the low hydration activity of the metallurgical slag by phase reconstruction technique. Boron oxide was used as a phase regulator to improve the amorphous phase composition of the manganese slag, consequently enhancing its hydraulic activity. The effects of boron oxide dosage and calcination temperature on the manganese slag amorphous phase content were investigated. XRD and DTG were performed to analyze the hydration mechanism of the manganese slag powder and cement. Results show that, when boron oxide dosage is 15%, calcination temperature is 1 300℃, and holding time for 1 hour, the amorphous content of the modified manganese slag reaches 95% and its 28-day activity index reaches 8 1.7%. The manganese slag powder can then be used as cement or concrete admixtures for the building materials industry.
基金supported by the National Natural Science Foundation of China(Grant No.51965005)the Natural Science Foundation of Guangxi(Grant No.2018GXNSFAA281258)+1 种基金the Guangxi Science and Technology Major Project(Grant Nos.AA17204036-1,AA17202008-1,AA17202001)the open foundation of Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials,Guangxi University(Grant No.2020GXYSOF12).
文摘Boron and carbon contents are the main factors influencing the properties of high-boron steel.In this study,experimental samples with different boron-to-carbon ratios(%B/%C)were prepared.The microstructures of the different samples were observed,and their hardness,bending strength,and impact toughness were investigated.Results show that the main microstructures in the investigated high-boron steel samples are the eutectic Fe_(2)B structure with a fishbone shape and the ternary peritectic Fe_(3)(C,B)structure with a chrysanthemum shape.When the boron content is 2.5wt.%and the carbon content is 0.43wt.%(i.e.,%B/%C=5.82),the overall mechanical properties of the alloy are the best.The alloy's hardness,bending strength and impact toughness reach their maximums,which are 67.3 HRC,1,267.36 MPa and 6.19 J·cm^(-2),respectively.The optimized alloy is compared with conventional materials exhibiting excellent wear resistance(namely,high-manganese steel and high-chromium cast iron)through two-body and three-body abrasion tests.The wear resistance of this high-boron steelinvestigated in this work is found to be superior to those of the more common materials.
