共查询到19条相似文献,搜索用时 109 毫秒
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石墨表面镀铜对石墨—铜复合材料强度影响的研究 总被引:8,自引:2,他引:6
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。 相似文献
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铸铁件电弧冷焊熔合区白口组织的控制 总被引:3,自引:0,他引:3
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 相似文献
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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。 相似文献
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孙毓超 《金刚石与磨料磨具工程》1999,(2):10-15
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。 相似文献
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锰铸铁的结晶过程与组织特点 总被引:3,自引:1,他引:2
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。 相似文献
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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. 相似文献
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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。 相似文献
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A. G. Bannov A. A. Timofeeva V. V. Shinkarev K. D. Dyukova A. V. Ukhina E. A. Maksimovskii S. I. Yusin 《Protection of Metals and Physical Chemistry of Surfaces》2014,50(2):183-190
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. 相似文献
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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 相似文献
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Liu Jin-hai Yan Jian-shuai Zhao Xue-bo Fu Bin-guo Xue Hai-tao Zhang Gui-xian Yang Peng-hui 《中国铸造》2020,17(4):260-271
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. 相似文献
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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。 相似文献
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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。 相似文献