钼粉中N元素控制要素分析

论述了钼粉工业生产中N元素的存在机理,根据生产中遇到的N元素含量高低不稳定的情况,通过一系列的实验和检测找到钼粉中N含量的变化规律。通过对Mo_2N的生成温度条件的确定,采取控制温度方法,从而达到钼粉中的N元素降低并稳定下来,彻底解决N含量偏高的问题。     

Preparation and Properties of Rare Earths with 6-Methyl-2- Picolinic Acid N Oxide and 2,2′-Bipyridine N,N′-Dioxide

2,2′ｂｉｐｙｒｉｄｉｎｅＮ,Ｎ′ｄｉｏｘｉｄｅ(ｂｉｐｙＯ2)(ｂｉｐｙＯ2=ＮＯＮＯ)ｗａｓｋｎｏｗｎｔｏｆｏｒｍｃｏｏｒｄｉｎａｔｉｏｎｃｏｍｐｏｕｎｄｓｗｉｔｈｍａｎｙｍｅｔａｌｉｏｎｓ,ｉｎｃｌｕｄｉｎｇｒａｒｅｅａｒｔｈｉｏｎｓ[1,2].ＯｗｉｎｇｔｏｔｈｅｐｒｅｓｅｎｃｅｏｆｔｗｏｄｏｎｏｒｏｘｙｇｅｎａｔｏｍｓｉｎｂｉｐｙＯ2,ｉｔｗｏｕｌｄｆｏｒｍａｓｅｖｅｎｍｅｍｂｅｒｅｄｒｉｎｇ,ｗｈｉｃｈｉｓａｆｉｎｅｆｌｕｏｒｅｓｃｅｎｃｅｃｈｒｏｍｏｐｈｏｒｅ,ｗｈｉｌｅｃｈｅｌａｔｉｎｇｗｉｔｈｔｈ…     

变压吸附制氮设备的控制运行与分析

以PN—5000型变压吸附制氮设备为例，叙述了8台碳分子筛塔的运行和切换，分析了压力、流量与纯度之间的关系，碳分子筛的性能，变负荷运行，提出了几点建议。     

反硝化过程中温室气体N2O产生和积累的影响因素

污水反硝化处理过程中不但会产生最终产物氮气,而且会产生中间产物N2O气体.氧化亚氮(N2O)是一种强力的温室气体,深入了解N2O产生机制及影响因素,有着重要的理论及实际意义.笔者对C/N比、溶解氧、pH、温度、NO2-N等影响N2O积累的因素进行了总结分析,并对氧化亚氮还原酶Nos的活性与N2O积累的关系进行了探讨.     

钼及其化合物的最新用途

给出了钼及其化合物的4种新用途。钼的同位素99Mo及其衰变后的"孪生"元素99mTc在癌症的诊断等医疗诊断流程中显示出极其重要的作用。Mo S2作为新一代半导体材料使半导体芯片厚度降低2/3,储用功率可降低10万倍,极大地促进集成电路的微型化和异型化。Mo2C和Mo2N作为催化物的基底材料,可有效提高催化物的比表面积,Mo2C和Mo2N基催化剂在制氢和制烃的反应中具有强烈的催化作用。Mo-Mo2C等离子喷涂技术在活塞环表面形成具有一定韧性的致密涂层,远优于钼金属火焰喷涂效果,涂层使用寿命可达到150 000 km。     

微波消解--AAS法联合测定Mg质耐材中MgO CaO Al2O3的试验研究

通过微波消解条件的选择、共存成分的干扰与消除、测定波长的选择、基体干扰的讨论、准确度以及精密度试验等一系列试验研究,提出了以H3PO4作为溶样酸,应用微波消解技术,在密闭容器中高温高压消解试样,用AAS法(N20-C2H2火焰)直接进行联合测定Mg质耐材中MgO,CaO,Al2O3的试验方法.该方法测定结果令人满意,是一条准确、快速分析测定Mg质耐材中MgO,CaO,Al2O3的新途径.     

CO2分压对油管钢CO2/H2S腐蚀的影响

采用高温高压釜、失重法和扫描电镜，对不同CO2分压(310．2642、930．7926、1551．3210、2171．8494kPa)条件下油管钢N80和P110的CO2／H2S腐蚀进行了研究。结果表明，随着CO2分压的升高，两种钢的CO2／H2S腐蚀速率均单调增加；除了CO2分压极低的情况以外，P110钢的腐蚀速率总是大于N80钢。     

武钢50吨复吹转炉底吹N2—Ar切换工艺的研究与应用

一、前言以改善LD法冶金动力学条件为目的而出现的转炉复吹法,历经十余年的不断开发和提高,目前在国外已渐趋成熟和完善。其技术核心内容之一,就是选择合适的底吹气源。二炼钢厂的三座50吨转炉自1984年7月全部实现复吹化后,取得了明显的冶金效果和经济效益。根据当时的气源条件、冶炼钢种等特点和底部供气系统装备条件,采用的底吹气体为Ar气。Ar气可以保证良好的搅     

复合陶瓷刀具材料的现状与发展

介绍了一些复合陶瓷刀具材料的性能和应用。     

武钢复吹转炉底吹N2—Ar切换时机研究

本文论述了底吹 N_2过程中熔池[N]含量的变化规律,确定了武钢二炼钢厂在目前操作条件下底吹供气强度0.02Nm~3/m.t 和0.03Nm~3/m.t 的 N_2—A_r 切换最佳时机,指出了影响底吹 N_2—A_r 切换终点[N]含量的主要因素。应用底吹 N_2—A_r 切换工艺,节 A_r0.46Nm~3/t 钢,年经济效益为171.96万元。     

使用抗氧化剂提高氮化铁磁性液体的抗氧化稳定性

介绍了用添加抗氧化剂来提高氮化铁磁性液体的抗氧化方法。抗氧化剂石油磺酸盐A在氮化铁磁性颗粒和表面活性剂层上吸附 ,可有效提高氮化铁磁性液体的抗氧化稳定性。     

Salt Bath Nitriding of Fe<Subscript>3</Subscript>Al Based Intermetallic Compound

Iron aluminide Fe₃Al was produced in a vacuum arc melting furnace. The alloy was heat treated by salt bath nitriding at 580 °C for durations of 3, 6, and 9 h. The nitride layers formed on the surface were characterized with light optical microscopy (LOM), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDXS), X-ray diffraction (XRD), and micro hardness measurements. The results showed that the nitride layer thickness increased with an increase in nitriding duration, while the layer hardness did not vary. The nitride layers were composed chiefly of iron nitride and aluminum nitride phases. The dry sliding friction and wear behaviors of nitrided iron aluminides were determined. The results revealed that the wear resistance decreased with increase in the length of nitriding.     

高频燃烧红外吸收法测定氮化硅铁中碳

称取0.2g样品,置于预先盛有(0.300±0.005)g锡粒的坩埚内,覆盖(0.400±0.005)g纯铁和(2.000±0.005)g钨粒进行分析,建立了高频燃烧红外吸收法测定氮化硅铁中碳含量的分析方法。实验中,考虑到氮化硅铁标准样品较少,故选择由0.04g氮化硅标准样品JCRM R008和0.16g纯铁标准样品GBW 01148a混合配制的氮化硅铁合成校准试样(w(C)=0.025 7%)与氮化硅铁标准样品GSB 03-2469-2008(w(C)=0.35%)来绘制校准曲线。方法中碳的线性范围为0.025%~0.35%,检出限为0.000 45%。由0.10g氮化硅标准样品JCRM R008和0.10g纯铁标准样品GBW 01148a混合配制氮化硅铁合成样品1,以及由0.08g氮化硅铁标准样品GSB 03-2469-2008和0.12g氮化硅标准样品JCRM R006混合配制氮化硅铁合成样品2,采用实验方法对其中碳进行测定,测定值与认定值基本一致。采用实验方法对氮化硅铁实际样品中的碳进行测定,所得结果的相对标准偏差(RSD,n=6)为1.2%~1.7%。     

Dissolution of boron nitride in liquid iron

The rate of dissolution of boron nitride in liquid iron and Fe-B alloys has been measured using a volumetric technique. The solution process was found to be diffusion controlled and directly related to the concentration of boron in the liquid metal. Diffusion control was substantiated further by experiments utilizing boron nitride rods which were rotated in liquid iron. Formerly Research Associate, Department of Chemical and Metallurgical Engineering, The University of Michigan, Ann Arbor, Mich.     

Aluminium nitride probes for application in iron melts

Review on high-temperature properties of aluminium nitride AIN. Investigations on aluminium nitride as a possible solid electrolyte at temperatures around 1600°C. Presentation of available data on the electrical conductivity, the thermal conductivity and the thermal expansion coefficient of AIN at elevated temperatures. Experimental study on the oxidation behaviour of AIN in oxidizing gases and oxygen-containing iron melts. EMF measurements on electrochemical cells of the type iron melt ‖ AIN (Al₂O₃) solid electrolyte ‖ reference representing oxygen and aluminium probes in iron melts under long-term conditions.     

Formation of TiN/TiC-Fe composites from ilmenite (FeTiO3) concentrate

The production of a ceramic hard material-metal composite directly from a mineral concentrate has great potential application. An homogenizing pretreatment of a mixture of ilmenite (FeTiO₃) and graphite, followed by annealing under an argon ambient, showed the formation of titanium carbide and elemental iron. Annealing of the same powder in nitrogen resulted in the formation of a composite of elemental iron and titanium nitride. The nitride was formed at a lower temperature than the carbide with almost complete conversion after 1 hour at 1000 °C. The rate of carbide formation was controlled by carbon diffusion, whereas the nitridation reaction was controlled by either oxygen or nitrogen diffusion. The TiC was found to form via TiC_0.5, which slowly increased its carbon content until near stoichiometric TiC was formed; stoichiometric TiN formed directly with no intermediate phases. Titanium carbide showed the presence of a second phase with a slightly smaller unit cell size; this was due to interdiffusion between the iron and TiC. The titanium carbide composite was found to be composed of 3 to 4 μm anhedral iron grains dispersed in the titanium-rich matrix. There was no segregation in the iron/titanium nitride composite with apparently submicron distribution.     

Fabrication of Porous Iron with Directional Pores through Thermal Decomposition of Chromium Nitride

Lotus-type porous iron with long directional pores was fabricated by a continuous zone melting technique through thermal decomposition of chromium nitride Cr_1.18N. Nitrogen decomposed from the nitride powders dissolves in the molten iron. Insoluble nitrogen evolves the directional gas pores when the melt is solidified in a direction. The porosity increases with increasing transference velocity, while the pore diameter is almost constant. The porosity change with the transference velocity is attributed to the difference in decomposition rate of chromium nitride. The compound Cr_1.18N is composed of CrN and Cr₂N, the latter of which is considered to evolve the pores because of the coincidence of heating rate of the continuous zone melting with that for the decomposition of Cr₂N.     

Formation of nitride phases in the nitriding of porous iron

Conclusions When sintered iron with a certain porosity (14–20%) is saturated with nitrogen, the amount of absorbed N₂ and the depth of the nitride layer increase jumpwise. If we regard the porous material as a biphase mixture (of pores and iron particles), such a phenomenon can be associated with the jumpwise increase of the effective diffusion coefficient at a certain quantitative ratio of the phases (the so-called percolation effect of diffusion). When porous iron is nitrided, a peculiar morphological form of the nitride phases forms in the diffusion layer; this, in distinction to the acicular nitrides, which are typical of the nitriding of compact iron, has a comparatively equiaxial shape and sinuous phase boundaries.Translated from Poroshkovaya Metallurgiya, No. 4(340), pp. 24–28, April, 1991.     

利用氮化铬铁合金生产高氮无镍奥氏体不锈钢的研究

为在常压下能够生产出高氮无镍奥氏体不锈钢,选用了氮化铬铁合金作氮源,通过破碎、熔化微碳纯铁、加入锰合金及氮化铬铁合金颗粒,控制浇注时间和温度,以保证钢中有足够高的氮含量,测试结果表明,熔炼钢经固溶处理,可获得稳定的高氮无镍奥氏体不锈钢。     

氮化铁磁流体专用表面活性剂研究

对合成氮化铁磁流体专用表面活性剂进行了探索性研究，以四乙烯五胺和油酸为原料，采用溶剂法合成了酰胺系列的多条件表面活性剂。将其应用于等离子体法制备氮化铁磁流体的工艺中，部分获得了磁饱和强度较高、化学稳定性较好的氮化铁磁流体，从而确定出较佳的表面活性剂的合成工艺参数。以四乙烯五胺和油酸为原料制备酰胺表面活性剂时，原料的配比和反应的温度对该类表面活性剂性能影响较大。