球置形成机理的热力学和动力学分析

在对现有的球墨形成长大观点即石墨球化的各种学说进行分析的基础上,从热力学因素－石墨与铁液间的界面能,与动力学因素－石默默周围铁液中球化元素、杂质元素（S,P等）和C、Si等元素的分布及C、Fe元素牟扩散速度等两大方面讨论分析了球墨形成机理各种学说。     

石墨表面镀铜对石墨—铜复合材料强度影响的研究

石墨与铜的界面结合及石墨在基体中的分布方式是影响石墨－铜基复合材料抗弯强度的重要因素。本文用镀铜石墨粉制备石墨－铜复合材料,并测定了材料的抗弯强度,对断口进行扫描分析。结果表明,石墨经镀铜处理后,使得石墨－铜复合材料抗弯曲强度显著提高。     

Al-Ti-C系中TiC形成的热力学与动力学研究

研究了在用熔体反应法制备Ａｌ－Ｔｉ－Ｃ中间合金过程中ＴｉＣ形成的热力学与动力学,实验结果表明：在８５０℃的Ａｌ熔体中,石墨颗粒周围的Ｋ２ＴｉＦ６与Ａｌ发生剧烈的化学反应放出大量的热,在熔体中形成大量的局部高温微区。在这些高温微区内,熔体中的Ｔｉ或ＴｉＡｌ３达到了与Ｃ形成ＴｉＣ的热力学条件,从而在石墨颗粒周围生成大量ＴｉＣ粒子,根据熔体化学反应的热力学条件,提出了８５０℃下在Ａｌ－Ｔｉ－Ｃ中间合金中     

铸铁件电弧冷焊熔合区白口组织的控制

进行了冷焊条件下控制铸铁件焊补区白口组织的试验．结果表明，采用Ｓｉ－Ｃａ－Ａｌ－Ｂｉ系合金粉层对焊补熔合区进行集中强石墨化孕育处理及焊前在缺陷表面形成Ｎｉ基合金粉末喷涂层，均可消除熔合区白口     

孕育处理对大断面球铁件力学性能和石墨形态的影响

基于金相组织、力学性能、拉伸断口特征、石墨结晶核心及变异石墨形态分析,研究了孕育处理对大断面QT600－3球铁件力学性能和石墨形态的影响。结果表明,电炉熔炼工艺生产大断面球铁件时,采用随流瞬时孕育,孕育衰退作用减慢,抗拉强度和伸长率提高;YFY－1A作瞬时孕育剂,石墨形态良好,石墨球大小稳定;SPI作瞬时孕育剂,导致石墨形态发生变异。     

铝—石墨最佳复合工艺参数的正交试验研究

本文采用正交试验法研究了用半固态搅拌法制造铝－石墨复合材料的工艺参数，分析讨论了几种工艺参数对石墨复合效果及基体组织的影响。     

金刚石—金属化合键合的微观判据

本文给出用非真空低温沉积法实现金刚石－金属直接形成碳化物的微观判据。选区电子衍射和Ｘ－ｒａｙ衍射结果表明，形成金属碳化物的碳源是由金刚石的碳直接与金属化合，并非经历由金刚石转变成石墨再行化合。     

镀铜石墨粉含量对铜-镀铜石墨复合材料组织与性能的影响

比较了用粉末冶金法制备的铜－镀铜石墨复合材料的显微组织与部分性能。结果表明，随镀铜石墨含量的增加，铜－镀铜石墨复合材料的密度和导性降低，但其组织中石墨分布更均匀，并且铜有利于构成三维网状，使该复合材料具有更好的导电性。     

锰铸铁的结晶过程与组织特点

研究了锰量在小于2．5％范围内变化时，灰铸铁的结晶特性与组织变化。试验表明：锰显著增大铸铁共晶过冷度，细化共晶团，促进D、E型石 墨的形成，有较强的白品倾向，可有效细化基体组织，促进硬化相网孔组织的形成。试验发现，反石墨化的正偏析元素可促进一种新型的“逆B型”石墨出现，其分布特征完全区别于现已命名的A型－F型石墨。     

含Pb、As、Sn D型石墨铸铁抗氧化性能的研究

利用含Pb、As、Sn地方生铁制取D型石墨铸铁并测定了这种铸铁的抗氧化性能。结果表明：这种含Pb、As、Sn D型石墨铸铁的抗氧化性能明显优于A型石墨铸铁。在600℃时，其抗氧化性能比A型石墨铸铁提高了56％－64％；在900℃时，其抗氧化性能也比A型石墨铸铁提高了约5％－27％。     

High Temperature Oxidation Behavior of Flake and Spheroidal Graphite Cast Irons

Flake and spheroidal graphite cast irons with similar composition were subjected to high temperature oxidation to investigate graphite morphology and distribution effects on the oxidation behavior. High temperature oxidation tests were conducted between 400 and 750 °C in air. For comparison low carbon steel was also tested.Graphite morphology obviously affected high-temperature oxidation resistance. The flake graphite cast iron exhibited the worst high-temperature oxidation resistance compared with spheroidal graphite cast iron. Since graphite flakes provide suitable sites for the iron oxide growth and are almost interconnected, the iron oxide grows faster and penetrates along the graphite flakes boundaries resulting in the subsurface oxidation. Due to the severe subsurface oxidation flake graphite cast iron parabolic rate constants are five times higher than that of the spheroidal graphite cast iron. However, spheroidal graphite cast iron parabolic rate constants and oxide layer thickness are similar to those of the low carbon steel. Therefore, graphite flakes have negative effect on the cast iron high temperature oxidation resistance.     

石墨—铝基复合材料的制备及耐磨性能

用复合铸造及压铸法制备了石墨颗粒铝基复合材料。研究了在制备过程中石墨的烧损率及石墨含量对复合材料磨损特性的影响。结果表明,石墨的烧损率在48%左右;石墨的加入可降低摩擦系数和磨损时的温升,且少量的石墨可以提高材料的耐磨性;石墨含量较高时,会破坏基体强度,导致剧烈的磨损率。     

轮胎模具电火花加工中石墨材料的应用研究

通过分析石墨电极材料的性能和特点,总结出石墨材料用于轮胎模具电火花加工的优势,并在实际电火花轮胎模具加工机上对多种牌号的石墨材料进行放电加工对比试验,得出采用不同石墨材料电极进行放电加工时的加工工艺结果.     

Synthesis and studies of properties of graphite oxide and thermally expanded graphite

Graphite oxide is synthesized using various reaction parameters. Stagewise evaluation of graphite oxidation dynamics in the course of synthesis is carried out using the method of sample collection and thermogravimetric analysis. Thermally expanded graphite with high texture characteristics was obtained from graphite oxide. Properties of graphite oxide and thermally expanded graphite were determined using scanning electron microscopy, X-ray diffraction, thermogravimetry, differential scanning calorimetry, energy dispersive spectroscopy, and low-temperature adsorption of nitrogen. The values of capacity of supercapacitors based on graphite oxide and expanded graphite are found.     

Effect of graphite size on the tribological behavior of Ti (C,N)-based cermets self-mated wear pairs

In the present work, graphite of different particle size ranging from 2 μm to 32 μm is added into the system to lubricate the Ti (C, N) cermets, but the addition amount is fixed at 1 wt%. The sliding wear tests were carried out using block-on-ring equipment. The distribution morphology of graphite, mechanical properties and wear behavior were studied in this paper. The results indicate that when the graphite is added into the cermet, graphite particles join together and are distributed to clusters of different size which are like bird nests. The range of the “bird-nest” clusters increase with the improvement of graphite size when the graphite particle size is smaller than 12 μm but decrease when larger than 12 μm. Furthermore when the graphite grain size increase to 32 μm, most of the particles exist in the cermets individually instead of distributing like bird nest The mechanical properties decrease with the improvement of graphite size, and when the particles size of graphite increase to 32 μm the mechanical properties get worse sharply. The wear mechanism of the cermets with graphite, adhesion and plastic deformation are dominated. The extruded graphite forms a tribofilm, and protects the surface from the hard abrasive particles ploughing. When the particles size of graphite added is 22 μm, cermets which have coarser graphite particles and more but moderate-in-size graphite clusters possess the best effect of lubrication     

Precipitation and evolution of nodular graphite during solidification process of ductile iron

The quantity and morphology of spheroidal graphite have an important effect on the properties of ductile iron,and the characteristics of spheroidal graphite are determined by the solidification process.The aim of this work is to explore the precipitation and evolution of graphite nodules in hypoeutectic,eutectic,and hypereutectic ductile irons by thermal analysis,liquid quenching and metallographic technique.Results show that hypoeutectic ductile iron has the longest solidification time and the lowest eutectic temperature;eutectic ductile iron has the shortest solidification time;hypereutectic ductile iron has the highest eutectic temperature.After solidification is completed,hypoeutectic ductile iron has the lowest nodule count,nodularity and graphite fraction;eutectic ductile iron has the highest nodule count,nodularity and the smallest nodule diameter;hypereutectic has the highest nodule diameter and graphite fraction.The nucleation and growth of graphite nodules in hypereutectic ductile iron starts before bulk eutectic crystallization stage,however,the precipitation and evolution of graphite nodules of hypoeutectic and eutectic ductile irons mainly occur in the eutectic crystallization stage.The graphite precipitated in eutectic crystallization of hypoeutectic,eutectic,and hypereutectic ductile irons,are 61%,68% and 43% of total graphite volume fraction,respectively.Simultaneously,there are plenty of austenite dendrites in hypoeutectic and hypereutectic ductile irons,which are prone to shrinkage defects.Therefore,the eutectic ductile iron has the smallest shrinkage tendency.     

天然石墨特征对合成金刚石性能影响的研究

金刚石合成工业中所用天然石墨应具有极低灰分,同时杂质的种类、含量及状态都是影响金刚石品质的重要因素。本文结合对天然石墨原矿、高纯石墨及由其合成的金刚石进行了光学显微镜、X射线粉末衍射(XRD)、碳硫分析仪、场发射环境扫描电子显微镜(FESEM)和电子能谱(EDX)等测试分析,研究了天然鳞片石墨作为合成金刚石碳源的特点,认为天然鳞片石墨纯度、粒度以及杂质硫元素等对合成金刚石特征和性能有重要影响。     

石墨表面金属化处理及检测

石墨是一种较为理想的锂离子电池负极材料,但由于其与溶剂的相容性差等缺点,降低了电池的容量和寿命,研究发现,通过对石墨材料进行修饰与改性可有效提高石墨电极性能.介绍了在石墨表面进行金属化处理的方法以及处理后对石墨电化学性能的影响,并概括介绍了所包覆金属的检测方法,结果表明,石墨表面包覆一层金属后,不仅电阻率大大降低,且改善了电极在充放电过程中石墨体积的变化,降低了电极膨胀,电极热稳定性和循环性均得到了提高.     

浅谈石墨电极在模具加工中的应用

介绍了石墨电极材料特性和加工特点,并以挂机面板注射模定模型芯石墨电极为例,详细阐述了普通石墨电极的加工方法和编程要点,通过采用石墨电极取代铜电极进行模具制造,从而大大缩短了模具的制造周期,提高了劳动生产效率,降低了模具的制造成本。