含碳耐火材料的自修复功能

自修复功能可以在含碳耐火材料,如MgO-C、Al2O3-C等中观察到。非氧化物,如纯金属、合金、碳化物和氮化物有意地加入到耐火材料中可带来这种功能。作为自修复耐火材料发展的基础,文中叙述了含碳耐火材料的自修复机理。     

A Versatile Carbon-Containing Refractory Material with a Ceramic Bond

A technology for fabrication of corundum-based carbon-containing refractories with a ceramic bond has been developed and put in service under industrial conditions at the Kombinat Magnezit JSC. The microstructure, preparation technique, and mechanisms of wear are considered. The physical, ceramic, and thermal properties of the newly developed material are discussed and compared to those of conventional refractory materials. The unique and advantageous properties of this material are emphasized.     

Investigation of Refractory Black Carbon-Containing Particle Morphologies Using the Single-Particle Soot Photometer (SP2)

An important source of uncertainty in radiative forcing by absorbing aerosol particles is the uncertainty in their morphologies (i.e., the location of the absorbing substance on/in the particles). To examine the effects of particle morphology on the response of an individual black carbon-containing particle in a Single-Particle Soot Photometer (SP2), a series of experiments was conducted to investigate black carbon-containing particles of known morphology using Regal black (RB), a proxy for collapsed soot, as the light-absorbing substance. Particles were formed by coagulation of RB with either a solid substance (sodium chloride or ammonium sulfate) or a liquid substance (dioctyl sebacate), and by condensation with dioctyl sebacate, the latter experiment forming particles in a core-shell configuration. Each particle type experienced fragmentation (observed as negative lagtimes), and each yielded similar lagtime responses in some instances, confounding attempts to differentiate particle morphology using current SP2 lagtime analysis. SP2 operating conditions, specifically laser power and sample flow rate, which in turn affect the particle heating and dissipation rates, play an important role in the behavior of particles in the SP2, including probability of fragmentation. This behavior also depended on the morphology of the particles and on the thermochemical properties of the non-RB substance. Although these influences cannot currently be unambiguously separated, the SP2 analysis may still provide useful information on particle mixing states and black carbon particle sources.

Copyright 2015 American Association for Aerosol Research     

Optical Properties of Carbon-Containing film Composites

It was found that the structure of FC carbon filler significantly affects transmission and reflection of IR radiation. The penetrating power of FC is higher the more ordered the structure of the filler. The lowest transmission of IR radiation is observed in FC with a filler characterized by a macropore structure; microporosity has almost no effect on the penetrating power of FC. The carbon filler significantly affects the reflectivity of FC in the IR region: the intensity of reflection of carbon-containing film materials is one order of magnitude less than for films with no filler. The reflectivity of FC is higher the more perfect the structure of the carbon-containing filler is.     

含碳耐火材料的抗热震性

由于抗热震性评估的综合过程所涉及的费用和时间，通常选用有良好导热性的含碳耐火材料。文中探讨了USIMINAS为确定浇注钢包用含碳耐火材料抗热震性所用的方法。所采用的检测方法涉及到根据裂纹开口位移和热震参数(R″″和Rst)测定断裂功。现已证实这种方法对选择和研究合适的显微结构借以延长耐火材料内衬寿命是有用的。     

The Heat Conductivity of Carbon-Containing Refractories

Results of an experimental study of the heat conductivity of carbon-containing refractories, commercially available from the Magnezit Kombinat JSC, a leading manufacturer in the field in Russia, are presented. Heat conductivity anisotropy has been revealed in most materials studied. The heat conductivity in the pressing force direction is shown to be smaller than in the perpendicular direction. For comparison, data on analogous carbon-free refractories are considered.     

Physicomechanical Properties of Carbon-Containing Film Composite Materials

Addition of 5 to 20% carbon filler to film composite material (FCM) decreases its strength and mechanical modulus of elasticity. Addition of porous carbon fillers (Aktilen fibre, industrial carbon, activated carbon) decreases the physicomechanical properties of FCM even at a low content, under 5%. FCM made from a liquid composition and containing carbon fibres exhibit anisotropy of the mechanical properties due to orientation of the filler; the strength and modulus of elasticity are higher in the longitudinal than in the transverse direction. A hypothesis is advanced concerning the presence of defective regions on the polymer—filler interface and stress concentration on the ends of the fibres, which probably also causes the decrease in the mechanical properties of the FCM. Acoustic studies suggested the existence of contacts between the carbon fibres at a content in FCM of 10% and higher. __________ Translated from Khimicheskie Volokna, No. 4, pp. 52–55, July–August, 2005.     

Towards Increasing Endurance of Carbon-Containing Refractories for Converter Steel-Making Technology

The many-years cooperation of the Magnitogorskii Metal-and-Steel Works Joint-Stock Co. and the Kombinat Magnezit Joint-Stock Co. has resulted in the development of advanced periclase-carbon refractories for converter linings with an endurance of 2536 heats (maximum 3388 heats), and for steel-teeming ladle linings — more than 60 heats. The refractory consumption rate is decreased by a factor of 3.7, with a corresponding decrease in the consumption of refractory per ton of steel.     

Young's Modulus of Various Refractory Materials as a Function of Temperature

Young's modulus as a function of temperature was determined by a dynamic method for single-crystal sapphire and ruby and for polycrystalline aluminum oxide, magnesium oxide, thorium oxide, mullite, spinel, stabilized zirconium oxide, silicon carbide, and nickel-bonded titanium carbide. For the single crystals, Young's modulus was found to decrease linearly with increasing temperature from 100°C. to the highest temperature of measurement. For all the polycrystalline materials, except silicon carbide, stabilized zirconium oxide, and spinel, Young's modulus was found to decrease approximately linearly with increasing temperature until some temperature range characteristic of the material was reached in which Young's modulus decreased very rapidly and in a nonlinear manner with increasing temperature. This rapid decrease at high temperature is attributed to grain-boundary slip. Stabilized zirconium oxide and spinel were found to have the same rapid decrease in Young's modulus at high temperature, but they also had a decidedly nonlinear temperature dependence at low temperature.     

Natural Graphites Used as Additions and Their Effect on the Performance of Carbon-Containing Refractories

Natural graphites as additions to periclase-carbon refractory materials are considered. The effect of ash components and natural graphites with different specific surface on the oxidizability, mechanical strength, and slag resistance of the refractory material are studied. Low-ash natural graphites with low specific surface are recommended for production of periclase-carbon refractories.     

基于六官能度异氰酸酯用于自修复防腐涂料的微胶囊的制备与表征

微胶囊自修复技术是将自修复微胶囊埋植于基体,在破坏后实现自我修复。IPDI作为低官能度异氰酸酯在湿气中固化修复能力有限,本文设计基于六官能度异氰酸酯DiPE-IPDI/DiPE-TDI合成用于自修复防腐涂料的新型微胶囊,着重对六官能度异氰酸酯DiPE-IPDI合成过程中溶剂、温度进行反应条件优化,通过傅里叶红外光谱、核磁等对产物结构进行表征。同时对微胶囊制备过程中粒径结构进行可控组装, 通过TGA/DSC表征该自修复微胶囊热力学性能。制备负载微胶囊的自修复环氧树脂基防腐涂料,盐雾试验结果显示其具有优异的自修复性能。     

炼钢工业用耐火材料的磨蚀

论述了耐火材料磨蚀的几个主要机理,即腐蚀和氧化、热机械磨蚀和剥落、磨蚀和侵蚀。找出磨蚀原因,并有效加以控制,以延长耐火材料使用寿命。     

渗透结晶型自修复剂及油井水泥浆体性能试验

通过对混凝土渗透结晶防水材料的研究,发现活性组分苹果酸(CA),并对CA改性合成了适用于油井水泥的水泥基微裂缝自修复剂CT.将CT直接添加到水泥浆中,通过与其他外加剂调配,能够满足油田固井水泥浆基本性能要求.抗压强度恢复率达92.8%,渗透率修复率达94.0%.SEM显示CT能在裂缝处生成枝蔓结晶,有效修复裂缝.最后通过XRD、孔结构分析了自修复剂CT的渗透结晶修复机理.     

球形/球柱形微胶囊自修复水泥基复合材料修复效率数值模拟

水泥基复合材料因其固有的脆性和较低的抗拉强度,在工程结构中不可避免会发生开裂。胶囊法自修复系统为水泥基材料基体开裂的修复和延缓潜在危害提供了一种可行的方法。借助扩展有限元方法,模拟了微胶囊自修复水泥基模型材料内微裂缝的产生、扩展、断裂过程及胶囊破裂行为,验证了裂缝迫使胶囊发生破裂的概率;应用复合材料理论,计算出了不同掺量下球形/球柱形微胶囊修复前后水泥基复合材料的有效弹性模量,表征了该复合材料的修复效率。     

New Carbon-Containing Refractories for the Lining of Steel-Teeming Ladles from the Kombinat Magnezit Joint-Stock Co.

Test results for new carbon-containing refractories for the lining of steel-teeming ladles — PUSK, PShUK, PShUP, PUPK, and ShPUP-grade, available from the Kombinat Magnezit JSC, are presented. The properties of refractory components (including heat resistance) in the as-received and subjected to coking condition are reported. The enhanced resistance of the new materials to thermal spalling under varying temperature conditions is noted. Results of the tests (carried out at the Magnitigorsk Iron-and-Steel Works and Oskol'skii Electrical ISW) provide the basis for an analysis of the economic feasibility of large-scale production of these materials.