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Hydrogen storage thermodynamic and kinetic characteristics of PrMg12-type alloys synthesized by mechanical milling

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Journal of Iron and Steel Research International 2017年第2期24卷 198-205页

作者： Jin-liang Gao Yan Qi Ya-qin Li Hong-wei Shang Dong-liang Zhao Yang-huan Zhang Weishan Cisri-Eare Earth Materials Co. Ltd. Jining 277600 Shandong China Department of Functional Material Research Central Iron and Steel Research Institute Beijing 100081 China

To improve the hydrogen storage performance of PrMg12-type alloys, Ni was adopted to replace partially Mg in the alloys. The PrMgllNi＋x wt.% Ni （x=100, 200） alloys were prepared via mechanical milling. The phase structures and morphology of the experimental alloys were in vestigated by X-ray diffraction and transmission electron microscopy. The results show that increasing milling time and Ni content accelerate the formation of nanocrystalline and amorphous structure. The gaseous hydrogen storage properties of the experimental alloys were determined by differential scanning calorimetry （DSC） and Sievert apparatus. In addition, increasing milling time makes the hydrogenation rates of the alloys augment firstly and decline subsequently and the dehydrogenation rate always increases. The maximum capacity is 5. 572 wt. % for the x = 100 alloy and 5. 829 wt. % for the x = 200 alloy, respectively. The enthalpy change （ △H ）, entropy change （△S） and the dehydrogenation activation energy （Exde） markedly lower with increasing the milling time and the Ni content due to the generation of nanocrystalline and amorphous structure.

关键词： PrMg12 alloy Mechanical milling Activation energy Hydrogen storage dynamics Thermodynamics

An Innovative Approach to Separate Iron Oxide Concentrate from High-sulfur and Low-grade Pyrite Cinders

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Journal of Iron and Steel Research International 2016年第8期23卷 756-764页

作者： Yong LI Fu-chun ZHOU Zhao-xin ZHOU Zhi-han TIAN Chao YANG Xi-ke TIAN Faculty of Materials science and Chemistry China University of Geosciences

High-sulfur and low-grade pyrite cinders are the waste products of sulfuric acid manufacturing *** valuable components,such as iron oxide,are contained in pyrite cinders and difficult to be separated and purified just via the high temperature roasting *** this,an innovative method including water-washing,aqua regia leaching,hydrothermal alkali activation and acid-washing was *** the effects of different parameters on recovery efficiency of iron oxide were systematically *** optimum parameters were proposed as follows：water rinse-leaching at room temperature for 5-20 min,and melting at 160 ℃ for 2.0h with NaOH（concentration of 30mass%）,followed by leaching with aqua regia solution（3.0vol.%）for *** the treatment,the content of iron oxides increased from 54.3to 96.0mass% with the recovery rate exceeding 85%.Meanwhile,calcium sulphate was recovered as the high value-added products by alkali extraction ***,the phase transformation and microstructure of the samples in the process were studied by physicochemical methods to reveal the separation mechanisms of different components in the pyrite cinders.

关键词： sulfur leaching contained alkali regia pyrite recovered hydrothermal systematically leached

Oxidation Behavior of Fe-based Amorphous Ribbons

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Journal of Iron and Steel Research International 2016年第11期23卷 1219-1225页

作者： Shu-lan ZHANG He-ping LIU Xiao-tong FU Central Iron and Steel Research Institute Beijing 100081China

The oxidation behavior of Fe-based amorphous ribbons was tested by annealing at 380℃ in air for different time with heat treatment furnace and analyzed by X-ray photoelectron spectroscopy （XPS） and scanning electron micros- copy （SEM）. The mechanism of oxides formation of the amorphous ribbons was discussed in detail. The results showed that the oxides were mostly B2O3 , SiO2 and Fe2O3 or FeO. With the increase of annealing time and holding temperature, the fraction of the oxides on the ribbon surface increased and the size of the oxides became larger due to the generation of new oxides and the coalescence of small oxides. The oxides have different shapes, such as round, rod and needle-shaped. Experimental results also showed that the oxides nucleated at fish scale, air pocket and impu-rities in priority, and the growth of the oxides was controlled by the diffusion of atoms. With the increase of the distance to the ribbon surface, the oxygen concentration decreased dramatically. Due to the low binding energy of B2O3 and the large diffusion coefficient of B atom, the B elemaent was oxidized firstly compared with other elements. More- over, the oxidation deoths of the B2O3 and SiO2 were larger than that of Fe2O3.

关键词： oxidation amorphous ribbon nucleation~ oxide growth

Effect of Nitrogen Content on Primary Recrystallization Behavior and Magnetic Property of Hi-B Steel

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Journal of Iron and Steel Research International 2016年第10期23卷 1080-1085页

作者： Hai-jun WANG Bing FU Li XIANG Zhe RONG Sheng-tao QIU national Engineering Research Center of Continuous Casting Technology Central Iron and Steel Research Institute School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The effect of nitrogen content on primary recrystallization microstructure,texture and magnetic property of Hi-B steel was studied by means of optical microscopy（OM）,scanning electron microscopy（SEM）,and electron backscatter diffraction（EBSD）.When nitrogen content increased gradually from 0.005 5% to 0.031 0%,the primary grain size and variation coefficient of nitrided sheet reduced from 26.85μm,0.590 to 18.87μm,0.525-0.565,***,the primary recrystallization texture style of nitrided sheet was nearly identical to the texture style of decarburized sheet before nitriding treatment,but exhibiting a certain change on texture *** variation of average magnetic induction value（B8）and core loss value（P17/50）were manifested to be Mshaped and W-shaped curves,*** nitrogen content reached 0.016 0%,the best value of the average magnetic property of the final product was obtained as follows：the B8 and P17/50 were 1.921 Tand 0.968W/kg,***,the best performance,B8 and P17/50,of single sheet was 1.964 Tand 0.854 W/kg.

关键词： nitriding decarburization primary recrystallization magnelic property texture Hi-B steel

Effect of Sodium Sulfate on Direct Reduction of Beach Titanomagnetite for Separation of Iron and Titanium

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Journal of Iron and Steel Research International 2016年第5期23卷 428-433页

作者： En-xia GAO Ti-chang SUN Zhi-guo LIU Chao GENG Cheng-yan XU School of Civil and Environmental Engineering University of Science and Technology Beijing

The effect of sodium sulfate on direct reduction of beach titanomagnetite,followed by magnetic separation,to separate iron and titanium was investigated. Direct reduced iron（ DRI） with a high Fe content,low TiO_2 content and low iron recovery was obtained after adding sodium sulfate. When the sodium sulfate dosage was increased from 0 to 10 mass%,the Fe content of the DRI increased from 90. 00 mass% to 93. 55 mass% and the TiO_2 content decreased from 1. 27 mass% to 0. 70 mass%. The reduction mechanism of sodium sulfate was investigated by X-ray diffraction（ XRD） and scanning electron microscopy（ SEM） with energy dispersive spectrometer（ EDS）. Results revealed that the metallic iron grains in the reduced ore with sodium sulfate were larger than those in the ore without sodium sulfate. Sodium sulfate promoted the migration of iron as well as the accumulation and growth of metallic iron grains by low-melting-point carnegieite and troilite formed in the redox system. Low-melting-point carnegieite decreased the melting point of the system and then promoted liquefaction. Troilite could decrease the surface tension and melting point of metallic iron grains.

关键词： beach titanomagnetite sodium sulfate direct reduction separation iron titanium

Recognition of Blast Furnace Gas Flow Center Distribution Based on Infrared Image Processing

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Journal of Iron and Steel Research International 2016年第3期23卷 203-209页

作者： Lin SHI You-bin WEN Guang-sheng ZHAO Tao YU School of Mathematics and Physics and Biological Engineering University of Science and Technology of Inner Mongolia School of Materials and Metallurgy University of Science and Technology of Inner Mongolia

To address the problems about the difficulty in accurate recognition of distribution features of gas flow center at blast furnace throat and determine the relationship between gas flow center distribution and gas utilization rate,a method for recognizing distribution features of blast furnace gas flow center was proposed based on infrared image processing,and distribution features of blast furnace gas flow center and corresponding gas utilization rates were categorized by using fuzzy C-means clustering and statistical methods.A concept of gas flow center offset was *** results showed that,when the percentage of gas flow center without offset exceeded 85%,the average blast furnace gas utilization rate was as high as 41%;when the percentage of gas flow center without offset exceeded50%,the gas utilization rate was primarily the center gas utilization rate,and exhibited a positive correlation with no center offset degree;when the percentage of gas flow center without offset was below 50% but the sum of the percentage of gas flow center without offset and that of gas flow center with small offset exceeded 86%,the gas utilization rate depended on both the center and the edges,and was primarily the edge gas utilization *** method proposed was able to accurately and effectively recognize gas flow center distribution state and the relationship between it and gas utilization rate,providing evidence in favor of on-line blast furnace control.

关键词： infrared image processing gas flow center recognition gas utilization rate fuzzy C-means clustering

Constitutive Modeling for Thixoforming of 9Cr18 Semi-solid Alloy and 3D Forecast Mapping

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Journal of Iron and Steel Research International 2016年第12期23卷 1309-1315页

作者： Ya-ping LI Ren-bo SONG Yong-jin WANG School of Materials science and Engineering University of Science and Technology Beijing

Thixotropic Compression tests were carried out on 9Cr18 semi-solid alloy through Gleeble-1500 thermal simulation machine. According to the experiment analysis, macro separation occurred during thixoforming. The liquid film was extruded outside to the surface and solidified to form eutectic structure. The solid particles were connected with each other and underwent plastic deformation. According to the comparison between Zhou-Guan model and modified Zhou-Guan model, it could be observed that the adding of thixotropic factor played an important role in the regression and the latter one was more credible. The modified Zhou-Guan model could well describe the thixoforming behavior. 3D forecast mapping was built for 9Cr18 semi solid alloy in thixoforming temperature range. It would provide valuable information for selecting process parameters during thixoforming in the manufacture process.

关键词： thixoforming constitutive model liquid fraction thixotropic factor 3D forecast

Thiolated arsenicals in arsenic metabolism: Occurrence,formation, and biological implications

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Journal of Environmental sciences 2016年第11期28卷 59-73页

作者： Yuzhen Sun Guangliang Liu Yong Cai Institute of Environment and Health Jianghan University Department of Chemistry and Biochemistry&Southeast Environmental Research Center Florida International University

Arsenic（As） is a notoriously toxic pollutant of health concern worldwide with potential risk of cancer induction, but meanwhile it is used as medicines for the treatment of different conditions including hematological cancers. Arsenic can undergo extensive metabolism in biological systems, and both toxicological and therapeutic effects of arsenic compounds are closely related to their metabolism. Recent studies have identified methylated thioarsenicals as a new class of arsenic metabolites in biological systems after exposure of inorganic and organic arsenicals, including arsenite, dimethylarsinic acid（DMAV）, dimethylarsinous glutathione（DMAIIIGS）, and arsenosugars. The increasing detection of thiolated arsenicals,including monomethylmonothioarsonic acid（MMMTAV）, dimethylmonothioarsinic acid（DMMTAV） and its glutathione conjugate（DMMTAVGS）, and dimethyldithioarsinic acid（DMDTAV） suggests that thioarsenicals may be important metabolites and play important roles in arsenic toxicity and therapeutic effects. Here we summarized the reported occurrence of thioarsenicals in biological systems, the possible formation pathways of thioarsenicals, and their toxicity, and discussed the biological implications of thioarsenicals on arsenic metabolism, toxicity, and therapeutic effects.

关键词： Arsenic Thioarsenicals Occurrence Formation pathways Toxicity

Microstructures and high-temperature self-lubricating wearresistance mechanisms of graphene-modified WC–12Co coatings

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Friction 2021年第2期9卷 315-331页

作者： Haoliang TIAN Changliang WANG Mengqiu GUO Yongjing CUI Junguo GAO Zhihui TANG Aviation Key Laboratory of science and Technology on Advanced Corrosion and Protection for Aviation Material Beijing Aero Engine Corporation of China Beijing Institute of Aeronautical MaterialsBeijing 100095China

To reduce the friction coefficient of cobalt-cemented tungsten carbide(WC–12Co)wear-resistant coatings,graphene was compounded into WC–12Co powder via wet ball milling and spray *** and wear-resistant graphene coatings were prepared via detonation gun *** presence,morphologies,and phase compositions of graphene in the powders and coatings that are obtained through different powder preparation processes were *** analysis was performed using the following technologies:energy-dispersive X-ray-spectroscopy(EDXS),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and Raman *** mechanical properties of the coatings were studied using a microhardness tester and a universal drawing *** friction and wear properties of the coatings were studied using an SRV-4 friction and wear *** results showed that the graphene content in the WC–12Co coating modified with graphene was higher than that without modification;graphene was embedded in the structure in a transparent and thin-layer *** adhesive strength of this coating at approximately 25°C was approximately 60.33 MPa,and the hardness was approximately 984 *** high-temperature treatment,the adhesive strength and hardness of the graphene oxide(GO)/WC–12Co coating decreased slightly(the lowest adhesive strength of 53.16 MPa was observed after treatment at 400°C,and the lowest hardness of approximately 837 HV0.3 was observed after treatment at 300°C).Compared to the friction coefficient(0.6)of the WC–12Co coating obtained at room temperature,the friction coefficient of the GO/WC–12Co coating was decreased by approximately 50%of that *** graphene-modified coating was continuously exposed to the wear tracks on the surface of the contacting materials during friction,and a lubricating film was formed in the microareas in which the wear tracks were *** coating exhibited improved self-lubricating and wear-resistant effects

关键词： graphene wear-resistant coating detonation gun spraying self-lubricating wear-resistance mechanism high-temperature friction