添加剂对NiFe2O4尖晶石性能的影响

研究了3种添加剂对NiFe2O4尖晶石性能和微观结构的影响.对试样的体积密度、三点抗弯强度、抗热震性、导电率进行了测试,并结合SEM和EDX进行了微观结构分析.结果表明,添加剂M使试样的体积密度变化最快,含有3%M试样的抗弯强度较纯尖晶石提高了25MPa,添加T的试样热震性最好,添加剂M和T均能提高试样的导电能力.     

锰酸锂表面掺杂TiO2的工艺及性能测试

尖晶石锰酸锂电池容量衰减是限制其大规模应用的瓶颈问题,抑制锰溶解是减少其容量衰减的重要措施之一.本文以MnCO_3和Li_2CO_3为原料,采用球磨结合高温固化的方法制备了尖晶石LiMn_2O_4原材料,采用溶胶-凝胶法实现对尖晶石锰酸锂进行表面包覆二氧化钛.将包覆后材料经过高温长时间煅烧,使得金属钛离子能扩散到锰酸锂颗粒材料表层中,形成LiTi_xMn_(2-x)O_4尖晶石结构薄层.通过对锰酸锂在高温电解液中的溶解对比性试验,给出掺杂薄层作用的直接证据,并对全电池高温环境下电化学循环性能进行了对比测试.结果表明,锰酸锂颗粒表面涂覆TiO_2后,经过750℃煅烧6 h,实现了在尖晶石LiMn_2O_4表面形成了LiMn_(2-x)Ti_xO_4掺杂薄层,其形态、结构均与LiMn_2O_4类似.表面掺杂TiO_2工艺能够显著抑制LiMn_2O_4高温环境下的锰离子溶解,提高锰酸锂电池的使用寿命和高温性能.     

Mastering Surface Reconstruction of Metastable Spinel Oxides for Better Water Oxidation

Developing highly active electrocatalysts for oxygen evolution reaction (OER) is critical for the effectiveness of water splitting. Low‐cost spinel oxides have attracted increasing interest as alternatives to noble metal–based OER catalysts. A rational design of spinel catalysts can be guided by studying the structural/elemental properties that determine the reaction mechanism and activity. Here, using density functional theory (DFT) calculations, it is found that the relative position of O p‐band and M_Oh (Co and Ni in octahedron) d‐band center in ZnCo_2?xNi_xO₄ (x = 0–2) correlates with its stability as well as the possibility for lattice oxygen to participate in OER. Therefore, it is testified by synthesizing ZnCo_2?xNi_xO₄ spinel oxides, investigating their OER performance and surface evolution. Stable ZnCo_2?xNi_xO₄ (x = 0–0.4) follows adsorbate evolving mechanism under OER conditions. Lattice oxygen participates in the OER of metastable ZnCo_2?xNi_xO₄ (x = 0.6, 0.8) which gives rise to continuously formed oxyhydroxide as surface‐active species and consequently enhances activity. ZnCo_1.2Ni_0.8O₄ exhibits performance superior to the benchmarked IrO₂. This work illuminates the design of highly active metastable spinel electrocatalysts through the prediction of the reaction mechanism and OER activity by determining the relative positions of the O p‐band and the M_Oh d‐band center.     

Effect of additive V2O5 on sintering mechanism and properties of inert anodes of NiFe2O4 spinel

In order to improve the properties of inert anode of NiFe2O4 spinel, some additive V2O5 was added to raw materials-powders of NiO and Fe2O3. The powders of NiO, Fe2O3 were mixed with slight amount of V2O5, then they are moulded and sintered at 1200℃ for 6h. The sintering mechanism of powders of NiO and Fe2O3 with some additive V2 O5 was researched. The effect of V2O5 on density, electrical conductivity and corrosion resistance of inert anode of NiFe2O4 spinel was studied at the same time. The results show that the sintering mechanism for powders of NiO and Fe2O3 with some additive V2O5 is liquid-phase sintering. Additive V2O5 can increase the density of the samples, especially it improves the corrosion resistance of the samples remarkably. When the amount of V2 O5 is 1.5 ,, the sample''s corrosion rate is 1/80 of that of sample without V2 O5. But the electrical conductivity of the samples with V2O5 is lower than that of the sample without V2O5.     

国内外油井管钢中非金属夹杂物的对比分析

 为了提高国内油井管钢质量,采用扫描电镜对比了日本和国内油井管钢中夹杂物成分和形貌,统计了夹杂物尺寸分布、夹杂物间距和夹杂物分布等参数,基于FactSage热力学软件平衡凝固模型分析了冷却过程中夹杂物的演变过程,基于夹杂物碰撞数量平衡模型,讨论了油井管钢中夹杂物碰撞率。结果表明,日本油井管钢中夹杂物主要为CaS包裹的镁铝尖晶石,国内油井管钢中夹杂物主要为钙铝酸盐包裹的镁铝尖晶石夹杂物和纯镁铝尖晶石夹杂物。日本油井管钢夹杂物比国内油井管钢夹杂物数量少、尺寸小、分布更均匀。日本油井管钢中夹杂物数量密度达到7.5个/mm2,国内油井管钢中夹杂物数量密度达到28.3个/mm2。日本油井管钢中夹杂物最大尺寸不超过5 μm,国内油井管钢中夹杂物最大尺寸达到20 μm。FactSage计算冷却过程中夹杂物演变结果与试验结果吻合。国内油井管钢中夹杂物碰撞率比日本油井管钢中夹杂物的碰撞率高2个数量级。     

提高中碳锰铁精炼电炉炉龄的实践

通过对精炼电炉炉体改造和出铁口材质、砖型的更新，解决了在中碳锰铁生产过程中炉眼易损问题，提高了炉龄，降低了生产成本。     

NiFe2O4/Ag复合材料的制备及其耐蚀和导电性能

以Fe2O3、NiO和Ag2O为主要原料,采用固相烧结工艺制备了NiFe2O4/Ag复合材料,用X射线衍射和扫描电子显微镜对材料的组成和微观结构进行了研究,并测量了样品在冰晶石熔盐中的静态热腐蚀速率及其高温电导率.结果表明,复合材料由NiO、NiFe2O4尖晶石和Ag三相组成.随着Ag2O含量的增多,复合材料的致密化程度先增加而后降低,当Ag2O含量为6%时,试样的致密化程度最高.Ag2O的加入在不提高试样在冰晶石熔盐中的静态热腐蚀速率的前提下,提高了试样的高温电导率.     

MnO2/NiCo2O4复合材料的控制合成及其电化学性能研究

采用两步合成法制备了MnO_2/NiCo_2O_4核壳结构纳米棒,使用场发射扫描电子显微镜、X射线衍射和电化学工作站研究了其形貌特征和电化学性能。研究结果表明,在α-MnO_2纳米棒上生长了均匀的NiCo_2O_4纳米片,这种核壳结构纳米棒所制备的电极在充放电电流密度为0.5A/g时比电容达到了434F/g,明显比纯α-MnO_2的比电容(256F/g)高,循环测试2 000次后,比电容保留量为91.8%,表现出了优秀的电化学性能,具有广阔的应用前景。     

取向硅钢高温退火时内氧化层与MgO反应过程研究

对取向硅钢高温退火工艺进行实验室模拟,采用聚焦离子束显微镜（FIB）观察了氧化层中二氧化硅和氧化镁反应的微观形貌演变过程,采用能谱仪（EDS）分析了试样截面近表层Mg、Al、Si等元素的分布规律,最后采用透射电镜（TEM）分析了对成品试样硅酸镁底层的结构特征。结果表明：（1）Mg离子的扩散速度是影响硅酸镁底层反应的主要因素;（2）Mg离子最初沿着二氧化硅颗粒与铁基体之间的界面扩散,逐渐将二氧化硅颗粒包覆;随着温度的进一步升高,Mg离子开始向二氧化硅颗粒内部扩散,并与之反应;（3）随着温度的升高,特别是在AlN分解后,钢基中的Al会逐渐将钉扎部位的硅酸镁（Mg2SiO4）完全转化成为镁铝尖晶石（MgO·Al2O3）。     

自蔓燃法合成MgO-MgO·Al_2O_3材料的显微结构

自变燃法（简称SHS：Self-propagatingHightemperatureSgnthesis）合成MgO－MgO·Al2O3耐火材料是一种新的工艺方法。岩相分析证明：该方法合成的材料具有大颗粒方镁石＋中颗粒方镁石＋铬和尖晶石交织气孔构造。反应合成的尖晶石将方镁石包裹起来,使材料具有更好的使用性能。