Self-Propagating High-Temperature Synthesis of Silicon Carbide Nanofibers

Russian Journal of Non-Ferrous Metals - The results of investigations into the organization of the synthesis of silicon carbide fibers in the gas phase using silicon powder, an energy additive of...     

Secondary Silicon Carbide Formed in the Interaction of Nanosized Silicon Carbide with Iron Oxide

The characteristics of superfine powder composites formed in the interaction of nanosized silicon carbide with iron oxide in vacuum and argon at 1200 and 1400°C, respectively, are analyzed. Silicon carbide (β-SiC), iron silicide and carbide, silicon oxide, and silicon oxynitride are main components of the powder composites. The lattice parameter of SiC in the powder composites synthesized in the SiC–Fe2O3 system is determined. In the interaction in the SiC–Fe2O3 powder mixture in vacuum, secondary SiC is synthesized with a lattice parameter that corresponds to the standard parameter for cubic β-SiC. The interaction in an argon atmosphere is accompanied by the synthesis of secondary SiC with a decreased lattice parameter. The minimum lattice parameter (0.4336 nm) is 0.6% smaller than the standard parameter for cubic β-SiC. The morphology of the powder composite synthesized in the SiC–Fe2O3 system is studied. The average particle size of the powder composite decreases with increasing weight content of secondary SiC.     

Structurization of Reaction-Sintered Silicon Carbide Modified by Chromium Carbide

Powder Metallurgy and Metal Ceramics - The structurization and phase composition of reaction-sintered silicon carbide (RSSC) modified by chromium carbide are examined. When hexagonal silicon...     

Silicon Carbide Formed in Mixtures of Silicon with Carbon in Various Structural Modifications Under Shock Compression

Powder Metallurgy and Metal Ceramics - The interaction of silicon with carbon in various structural modifications under shock compression in cylindrical recovery fixtures was studied. X-ray...     

不同含量复式碳化物对细晶硬质合金性能的影响

选取含TiC和TaC的复式碳化物,采用真空烧结,分别制备含复式碳化物0、4%、8%、12%的细晶WC-8Co硬质合金。研究不同含量的复式碳化物对细晶硬质合金横向断裂强度、硬度、相对密度的影响。实验结果表明,复式碳化物的添加能够提高硬质合金的硬度,但同时降低了合金的横向断裂强度和相对密度。当添加复式碳化物12%时,合金的横向断裂强度为1 480 MPa,硬度为93.6 HRA,相对密度为99.2%。     

碳化硅制品生产工艺技术改造

针对碳化硅制品生产过程中存在的制约因素,客观分析经济性、实用性,保障生产、节能降耗等各方面的情况,通过创新型的技术改造,碳化硅制品各项经济技术指标显著提高,取得了比较好的经济效益和社会效益。     

Structural Changes during Milling of Silicon Carbide

The kinetics of milling and structural changes during milling of commercial silicon carbide powder in a ball mill lined with hard alloy are studied. Data are provided for the specific surface, x-ray patterns, and infrared spectra. It is shown that milling kinetics are described best of all by an exponential relationship and that milling of silicon carbide powder is accompanied by changes in polytype composition. The x-ray patterns and infrared spectra obtained make it possible to assume that during milling the 15R polytype content in the powder composition decreases while the content of structures with less layering (the 4H polytype and -SiC) increases; in this case the number of absorption bands in the infrared spectra decreases.     

SiC复相陶瓷的强化增韧趋势

SiC陶瓷因其具有优良的性能而广泛应用于军事和民用领域.但陶瓷固有的脆性严重影响了其作为结构材料的应用潜力,因此sic陶瓷的强化增韧成为了近年来研究的热点.综述了siC基复相陶瓷的几种主要强化增韧方式,讨论了其强化增韧机制.采用纳米颗粒、晶须协同强化增韧和特殊技术制备纳米复相陶瓷将是提高SiC基陶瓷性能的有效途径.     

Formation of Silicon Carbide from Rice Hulls

Abstract

SiC whiskers and particles have been produced from rice hulls. The process involves three major steps: coking in free air, reaction at high temperature in a reducing atmosphere of hydrogen gas, and separation of formed SiC from excess carbon by wet methods. The processing steps are reviewed and the chemistry of the process is discussed. The produced SiC was added to a molten Zn–5%Al alloy to check its potency as a reinforcing material. © 1998 Published on behalf of Canadian Institute of Mining and Metallurgy by Elsevier Science Ltd. All rights reserved.

Resume

Des barbes et des particules de SiC ont été produites à partir d'enveloppes de riz. Le processus implique trois é tapes majeures: cokefaction a l'air libre, réaction à haute température dans une atmosph è re reductrice de gaz hydrogene et separation du SiC forme de l'exces de carbone par des methodès humldes. On revoie les etapes de traitement et on discute de la chimie du processus. On a ajoute le SiC ainsi produit à un alliage fondu de Zn–5%Al afin de verifier son potentiel comme matériau de reforcement. © 1998 Published on behalf of Canadian Institute of Mining and Metallurgy by Elsevier ScienceLtd. All nghts reserved.     

碳化硅及其在工业炉行业的应用

本文着重介绍了碳化硅制品的基本技术特性及其在工业炉行业的应用     

Use of Silicon Carbide Materials in Reduction Smelting of Metallic Silicon and Siliceous Ferroalloys

Metallurgist - Industrial implementation of the method of smelting industrial silicon with some fraction of the reducing agent replaced with silicon carbide is exemplified. The prospects for using...     

碳化硅冶炼炉透气炉底的设计

本文通过对碳化硅生成反应的分析,结合碳化硅的实际生产情况,得出了既便于碳化硅生产中机械化作业,又提高热利用率的碳化硅冶炼炉炉底设计方式。     

Wettability of Silicon Carbide by CaO-SiO2 Slags

The wettability of silicon carbide by liquid CaO-SiO₂ slags that contain 47 to 60 wt pct SiO₂ was studied using the sessile drop wettability technique. The experiments were carried out in Ar and CO atmospheres. A small piece of slag was melted on SiC substrates under different heating regimes up to 1600 °C. It was found that the wetting is not significantly dependent on the temperature and the heating rate. However, the wettability is relatively high, and the wetting is higher for slags that contain lower SiO₂ concentrations. Moreover, the wettability between the slags and SiC is dependent on the gas phase composition, and it is higher in Ar than that in CO. When the SiO₂ concentration changes from 47 pct wt to 60 pct wt, the wetting angle changes from 20 deg to 73 deg in Ar and from 58 deg to 87 deg in a CO atmosphere. The formation and bursting of gas bubbles also was observed after some contact time, which indicates that the wetting system is a reactive type. However, microscopic studies indicated that no metal phase exists at the slag/silicon–carbide interface. Therefore, it was concluded that chemical reactions between the slag and SiC take place and that SiO₂ is slowly reduced to form CO and SiO gases. Based on the experimental data, the dependence of the Girifalco–Good coefficient on the slag composition and the relationship between the interfacial tension of CaO-SiO₂ slags and SiC also were estimated.     

Electric Explosion Comminution of Silicon Carbide in an Elastic Shell

Comminution of silicon carbide powder in an elastic shell by electric explosion is less efficient than powder comminution in an elastic shell by mechanical impact because of its greater energy consumption. The level of silicon carbide powder comminution is the same by both methods and it is 40 m with an original size of _300+160 m. Comparative analysis showed that for more efficient powder comminution in elastic shells by pulsed methods it is desirable to match the duration of applied loads with frequency characteristics of the shell.     

含碳化硅的耐火材料制品中SiC含量的测定

介绍了含碳化硅的耐火材料制品中ＳｉＣ含量的测定方法,即采用氢氟酸挥散除去ＳｉＯ２,以混合溶剂在１０５０℃的高温炉中熔融分解试样,以盐酸溶液浸取,用硅钼蓝光度法测定溶液中硅含量,再换算为ＳｉＣ含量。该方法操作简单,分析结果稳定、可靠。     

硬质合金成形铣刀切削性能的试验研究

以硬质合金成形铣刀与高速钢成形铣刀为研究对象,在试验的基础上,从切削力的大小、耐磨性的好坏、切削速度的高低以及工件表面粗糙度的改善四个方面对其切削性能做了分析比较,结果证明,硬质合金成形铣刀的切削性能比高速钢成形铣刀的切削性能有很大提高。     

Production Technology Features for Aluminum Matrix Alloys with a Silicon Carbide Framework

Metallurgist - Currently, good mechanical properties and a high level of thermal stability of aluminum alloy components with a composite matrix attract considerable interest for use in aerospace...     

用X光射线衍射法定量分析碳化硅砖的矿物组成

X光射线衍射法是定性定量分析、检测耐火材料矿物组成中同质异象、多晶转变等准确简便的方法,而且它可以完成光学显微镜和图像分析仪等因晶粒太小或在灰度上难以区别等不能定量工作的一些问题.在这种情况下,用X光射线衍射法既不损坏物质原有的矿物结构,又能快速分析其同质异象矿物的含量.