淬火对含ZrC的20Mn2钢的组织及力学性能的影响

研究了淬火冷却对含0.2%(体积分数)ZrC颗粒(粒径0.2～1.2μm)的20Mn2钢在大形变量轧制后的组织与力学性能的影响.结果表明,ZrC粒子作为大形变量热轧变形中的奥氏体形变核心及再结晶核心,对奥氏体晶粒的超细化有显著的作用,而显著细化的晶粒提高了完全获得马氏体组织的临界冷却速度,使水冷淬火态马氏体的数量、长度和宽度减小,使油淬态珠光体的数量减少、渗碳体片变短、变薄.在冷却过程中,细小的奥氏体晶粒转变为更细小(1～2μm)的铁素体晶粒,保留了热轧变形时的形变位错组织,使水淬态20Mn2钢的延伸率不下降的同时强度成倍提高,油淬态20Mn2钢在强度大幅度提高的同时延伸率成倍提高.     

Influence of filament thickness, thermal process and magnetic field on misalignment angles in multifilament Bi2212 tapes

Misalignment angles in multifilament Bi2212 tapes have been studied by transport current density (J_c) measurements. Transversal misalignment angles depend on the filaments thickness due to the crystal growth along the Bi2212/silver interface. Therefore, the thinner the filaments, the higher the J_c.A dynamic thermal treatment improves grain alignment inside the tapes due to preferential crystal growth along the thermal gradient direction. Furthermore, melting in high magnetic field reduces the misalignment angle due to magnetic anisotropy effects. Therefore, good transport J_c performances can be expected for thicker multifilament Bi2212 tapes prepared using a combination of the dynamic process and melting in a high magnetic field.     

锌锰异常共沉积的理论分析

从合金电沉积电极和溶液界面各因素的变化对合金电沉积的影响出发,在考虑一般电极过程动力学的基础上,进一步考虑到电极表面、溶液双电层OHP面上状态的变化及放电离子和非放电离子在OHP面上的相互影响,提出了电极溶液界面层作用模型,以期揭示锌锰异常共沉积发生的原因。     

Effects of Dopants on Properties of PZN-PSN-PMN-PZT Ceramics

In order to obtain high Qm ceramics,different additives including MnO2,Fe2O3 and K2CO3 were added into the base PZT composition of xPb（Zn0.2Sn0.3Mn0.5）1/3 Nb2/3 O3-（1-x）Pb（Zr0.3Ti0.5）O3.The mechanical quality factor Qm increased while the piezoelectric constant decreased to some degree as MnO2 was added alone,Although apparent decreasing was observed in piezoelectric constanl d33 after MnO2 and Fe2O3 were added simultaneously,the mechanical quality factor Qm was kept at the same level as before,The values of d33 and Qm decreased dramatically as K2CO3 was added in combination with MnO2 and Fe2O3.The structure of grain boundary was damaged and more defects were generated by low valence K adding in this multi-impurified PZT solid.Mn doped sample presented a wide range of sintering temperatare,The properties parameters of Mn doped PZT are listed as follows;piezoelectric constant d33-256pC/N,mechanical quality factor Qm=2079,coupling coefficient Kp=0.53,Coercive field Ec=22.5kV/cm,Cure Temperature Tc=286℃.These parameters shonc that Mn-doped PZT ceramics are suitable for application in high Qm and transmitting materials.     

65Mn盘条拉拔过程中的断裂分析

对首钢65Mn弹簧盘条在拉拔过程中的断裂问题进行了探讨，通过观察分析不同形态的断口发现．杯锥状断裂、齐平状断裂和表面横裂是盘条在拉拔过程巾断裂的主要形式，盘条中的中心残余缩孔、大型夹杂及表面缺陷等是导致65Mn弹簧盘条断裂的主要因素。     

臭氧预氧化与混凝联用工艺处理低温微污染水的试验研究

目的研究臭氧投加量、接触氧化时间等因素对臭氧预氧化与混凝联用工艺处理低温微污染水的影响,以及臭氧预氧化在常规水处理工艺基础上的净水效果.方法采用静态试验,改变臭氧投加量,接触氧化时间等参数,分别对比了高锰酸盐指数、浊度和色度的去除效果.结果臭氧投加量0.5(mg.L-1)时,沉淀出水各项指标就具有明显的去除效果.在投加量为3(mg.L-1)接触氧化时间为15 min时,沉淀后出水的高锰酸盐指数、浊度、色度分别降低了18.4%、95.9%和81.9%.比直接采用聚合氯化铝混凝的去除率分别提高了5.8%、23.6%和22.4%.结论对于低温微污染水源水,臭氧预氧化与混凝联用工艺能有效地去除有机物、浊度、色度,使处理后水质达到标准.     

Nd2AlFe12Mn4化合物的本征磁致伸缩

通过X射线衍射及磁测量手段研究了Nd2AlFe12Mn4化合物的热膨胀性质及本征磁致伸缩性质.研究结果表明Nd2AlFe12Mn4化合物在103～654K的温度范围内具有菱方相的Th2Zn17型结构.在183～244K的温度范围内具有负热膨胀性质,其平均热膨胀系数α=-9.01×10-5/K.对本征磁致伸缩的研究结果表明Nd2AlFe12Mn4化合物中存在着较强的各向异性的本征磁致伸缩,103K时其本征体磁致伸缩约为9.3×10-3.磁测量研究结果表明Nd2AlFe12Mn4化合物的居里温度约为210K,比其母合金Nd2AlFe16低约260K,分析认为这是3d次晶格中Mn磁矩与Fe磁矩反铁磁耦合的结果.     

从人造金刚石触媒酸洗废液中回收镍、钴和锰

探讨了用纯碱-氨水混合液从人造金刚石催化剂酸洗废液中分离回收镍、钴和锰。在热力学分析的基础上，对纯碱、氨水浓度以及pH值与溶液中金属离子浓度之间的关系进行了试验研究，确定了沉淀分离锰及回收钴的最佳条件。也进行了台架试验，确定了生产条件。该方法反应速度快，金属综合回收率高。     

On Restricting Aspects in the Production of Nonmagnetic Cr‐Mn‐N‐alloyed Steels

Cr‐Mn steel grades with high nitrogen contents are becoming increasingly important in the field of austenitic stainless steels. Industrial production facilities allow to use two different strategies to reach a high nitrogen content. The first involves taking advantage of the pressurised‐electroslag remelting process, which is operated at elevated nitrogen partial pressure; the second consists of adding elements which increase the nitrogen solubility of the melt so that high nitrogen contents can be achieved at atmospheric pressure. This paper focuses on nitrogen solubility and austenite stability. These have been observed as important and in some cases restricting for the successful implementation and production of high alloyed Cr‐Mn austenitic steels. The precondition for a stable austenitic microstructure can be predicted with the help of equations using chromium and nickel equivalents. Different formulae were tested and their results compared to the microstructure of the alloys. The nitrogen solubility in the melt is particularly important for the steel grades cast under atmospheric conditions. It has been found feasible to produce steel grades up to 0.9 mass percent nitrogen at atmospheric pressure on an industrial scale. Several theoretical approaches for calculating the nitrogen solubility in the melt were tested for atmospheric conditions and compared to the chemical analyses of conventionally cast Cr‐Mn steel grades.     

锌锰异常共沉积的研究

研究发现锌锰合金电沉积时，在一定条件下也存在异常共沉积现象。首次采用分电流法，在阴极电流密度超过一定值之后锌的分电流随阴极电流密度的增大而下降，同时锰的分电流却在增加，当锰的分电流与锌的分电流之比超过一定值时就出现了异常共沉积。同时还研究了溶液中锌、锰离子的浓度比对锌锰合金电沉积由正常到异常的转变规律。