奥氏体耐热钢21-4N碳化物析出行为研究

通过对奥氏体耐热钢21-4N碳化物析出行为的研究,探讨了对性能的影响,提出了改善其综合性能的措施和方法.     

我国硬质合金工业发展现状与资源保护

分析了我国硬质合金工业的发展现状,论述了战略资源保护的重要性,提出了增强我国硬质合金企业核心竞争力的方法及途径。     

大型预焙铝电解槽使用碳化硅砖与普通碳砖复合块的探讨

碳化硅砖和碳化硅砖与普通碳砖复合侧块，在上世纪末期我国铝电解槽上开始推广应用。使用后各厂家普遍发现碳化硅砖及碳化硅砖与普通碳块复合侧块均出现不同程度的断裂、上抬和脱落现象，该文对断裂、上抬和脱落原因进行了分析，并提出了改进措施。     

Kinetic study of the deep hydrodesulfurization of dibenzothiophene over molybdenum carbide supported on a carbon black composite: Existence of two types of active sites

Hydrodesulfurization (HDS) is part of the hydrotreating process, which is an ensemble of several reactions (HDN, HDO, HDS, etc.) taking place simultaneously at the industrial scale. Only sulfur is currently submitted to drastic Europeans specifications and conventional commercial catalysts cannot reach the specifications at low cost. This paper presents the behavior of a potential substitute catalyst tested for the deep HDS of a model molecule such as the dibenzothiophene (DBT). The substitute is molybdenum carbide supported on a mesoporous carbon black composite of surface area 240 m² g⁻¹. A global kinetic study of the deep HDS of DBT (300 ppm S) was performed at 623 K and 5.0 MPa and a global kinetic model was proposed as well as global rate constants were calculated to obtain theoretical plots of concentration versus contact time to compare with the experimental data. The kinetic model and global kinetic orders were confirmed as an acceptable correlation was found between calculated and experimental data. Furthermore, the determination of the global kinetic orders indicated that two types of active sites must be present on the surface in order to explain the observed results.     

Synthesis and characterisation of a submicrometre silicon carbide powder

A beta-silicon carbide powder with a surface area of 30m²g^?l and a mean particle size of < 1μm was produced from the thermal conversion of silicon resin in an atmosphere of hydrogen. The amount of product increased with increasing iron content (0–2.1 wt%) and firing temperature (1200–1500°C). Chemical analysis, X-ray diffraction and i.r. absorption spectrometry were used to follow the conversion reaction.     

Oxidation behavior of silicide coating on Ti3SiC2-based ceramic

A silicide coating was prepared on Ti₃SiC₂-based ceramic by pack cementation to improve the oxidation resistance of Ti₃SiC₂, which is a technologically important material for high temperature applications. The microstructure, phase composition and oxidation resistance of the coated sample were investigated. The results demonstrated that the silicide coating was mainly composed of TiSi₂ and SiC. A single layer of a mixture of SiO₂ and TiO₂ was formed on the surface of the coated sample during isothermal oxidation at 1100 °C and 1200 °C for 20h. Compared to Ti₃SiC₂, the parabolic rate constant of silicide coated Ti₃SiC₂ decreased by 2~3 orders of magnitude. Furthermore, the coated sample showed much better cyclic oxidation resistance than Ti₃SiC₂ during the cyclic oxidation at 1100 °C for 400 times. However, during the preparation of the coating, a number of fine cracks formed in the outer layer of the coating. When these cracks penetrated the whole coating during the cyclic oxidation, the oxidation rate was accelerated, which degraded the oxidation resistance. Electronic Publication     

攀钢转炉炼钢用碳化硅提温的试验研究

低品位碳化硅是转炉炼钢的有效提高温剂。工业性试验结果表明，碳化硅加入８．０ｋｇ／ｔ钢水提温４０．３－７０．３℃（平均４８．４℃）；渣中ＴＦｅ降低１．３％；加提温剂有利于转炉内造渣脱硫和碱少炉渣对耐火砖的侵蚀。文中还给出了攀钢转炉半钢冶炼铸用钢不水时加与不加碳化硅的ｔλ，［Ｃ］λ区域。     

树脂热解炭制备碳化硅晶须

用自制的配合醛树脂热解和炭源，用ＳＩＯ２超细汾作原，根据碳热还原原理，利用常规加热和微波加热两种方式，分别制备了直径在纳米级的ＳｉＣ晶须，Ｘ射线衍射、透射电检测结果表明：制备工艺和条件对ＳｉＣ晶须的性质有较大的影响。     

碳热还原法制备氮化硅粉体的反应过程分析

对以碳热还原法制备氮化硅粉体的ＳｉＯ２－Ｃ－Ｎ２系统进行化学反应热力学和动力学的分析，从而发现在氮气氛不足的条件下，这一系统的反应产物将由氮化硅变为碳化硅；在氮气充足的情况下，随着温度的升高，生成物中碳化硅的量也会逐步增加，这一分析结果通过实验得到了验证。     

压力对Fe－29wt％Ni合金超细微粒特性的影响

利用蒸发冷凝法，制备了不同平均粒径的Ｆｅ－２９ｗｔ％Ｎｉ合金超细微粒。在不同压强下，将超细微粒压制成片。随压强增大，马氏体体积分数和比饱和磁化强度σｓ明显增大，而矫顽力Ｈｃ呈线性下降。压力效应与平均粒径ｄ大小密切相关