高碳当量薄壁灰铸铁纺机铸件的孕育处理

采用Ba、Ca、Si、稀土、石墨、Al为主要成分的复合孕育剂对高碳当量(CE＝4.3%～4.4%)薄壁灰铸铁件进行孕育处理,研究了复合孕育处理对薄壁铸件的白口倾向、石墨形态及力学性能的影响.结果表明,与常用的FeSi75孕育剂相比,复合孕育剂对降低薄壁铸件的白口倾向、改善石墨形态及力学性能等方面均具有显著效果.当复合孕育剂的加入量w为0.35%时效果最佳,消除了薄壁灰铸件的白口现象,且薄壁和厚壁部分的A型石墨形态均匀、细小,抗拉强度提高近10%.     

浅谈石墨电极圆锥接头外螺纹大端中径及中径锥度检查验收的相关问题

由于石墨电极圆锥接头不具备检验基准面、石墨电极圆锥接头分体式螺纹工作环规在设计上有原理误差，对炭素行业使用此分体式螺纹工作环规检查验收时应注意的相关问题进行了讨论。     

Electrochemical insertion of lithium ions into disordered carbons derived from reduced graphite fluoride

Both covalent (obtained by direct fluorination at high temperature) and semi-ionic carbon fluorides (synthesized at room temperature) were reduced in order to obtain disordered carbons containing very small content of fluorine and different physical properties according to the reduction treatment (chemical, thermal or electrochemical). After a physical characterization (X-ray diffraction, electron spin resonance and FT-IR spectroscopies), the electrochemical behaviours of the pristine carbon fluorides and of the treated samples were investigated during the insertion of lithium using liquid carbonate-based electrolytes (LiClO₄-EC/PC, 50:50%, v/v). Both galvanostatic and voltammetric modes were performed and revealed that the voltage profiles and the capacities differed according to the starting material and the reduction treatment. Semi-ionic carbon fluoride treated in F₂ atmosphere for 2 h at 150 °C and then chemically reduced in KOH exhibits high reversible capacities (the reversible capacity is 530 mAh g⁻¹ in the second cycle); in this case, the voltage profiles show a large flat portion at potentials lower than 0.3 V which is attributed to the insertion/deinsertion of lithium ions between the small graphene sheets and/or the absorption of pseudo metallic lithium into the microporosity of the sample. Nevertheless, a part of the lithium ions are removed at potentials higher than 0.5 V versus Li⁺/Li limiting the useful capacity.     

浸渍增重率和反渗率研究

对浸溃过程中浸渍剂沥青的浸入率和反渗率进行了分析与探讨。提出了理想增重率、理论增重率与实际增重率的概念和计算方法。并比较了实际增重率与操作增重率的差别。同时分析了抽真空的绝对压力与施压的绝对压力对各项增重率和反渗率的影响。     

SiC/Si-MoSi2抗氧化涂层的制备及性能研究

为了提高石墨材料的抗氧化性,在石墨表面制备SiC/Si-MoSi2抗氧化涂层。首先以Si粉为原料,采用液硅渗透法制备SiC内层;然后以Mo粉和Si粉为原料,配制成m(Mo)∶m(Si)分别为1∶5、1.5∶5、2∶5和2.5∶5的料浆,采用料浆烧结法制备Si-MoSi2外层。利用SEM和EDS分析SiC/Si-MoSi2涂层于1400℃氧化前后的结构及组成。结果表明,料浆的Mo粉和Si粉配比对涂层的抗氧化性能有很大影响,当m(Mo)∶m(Si)=2∶5时,涂层具有最佳的抗氧化性能,且表现出长时间的抗氧化能力。     

Novel tin-graphite composites as negative electrodes of Li-ion batteries

For the purpose of obtaining an improved performance of the graphite negative electrode of Li-ion batteries, a novel graphite-tin composite has been synthesized by reduction of tin chloride (SnCl₂) with KC₈ in THF medium. This composite contains nano-sized tin particles dispersed on the graphite surface and free tin aggregates. Lithium electrochemical insertion occurs both in graphite and in tin. An experimental reversible specific charge of 489 mA h g⁻¹ is found stable upon cycling. Such a value is lower than the maximum theoretical one of 609 mA h g⁻¹ suggesting that only a part of tin is involved in the lithium insertion/extraction process. This part of active tin responsible for the stable capacity could be that bound to graphite. To the contrary, free tin aggregates could contribute to an extra capacity that decreases upon cycling in relation with the volume changes that occurs during alloying/dealloying.     

石墨粉镀银新工艺研究

研究了镀液中硝酸银浓度、石墨粉加入量和阴极电流密度等工艺条件对镀银石墨粉含银量和电镀效果的影响。用扫描电镜对镀银石墨粉的微观形貌和镀覆效果进行分析，通过X射线衍射仪对镀银石墨粉高温灼烧后的剩余物进行分析测试并计算镀银石墨粉的含银量。研究结果表明：采用惰性电极作为电镀阳极，在化学镀预处理过的石墨粉表面可成功镀覆一层银，其含银量达76%。     

附加载荷作用下螺栓法兰连接的强度和紧密性分析

运用三维有限元方法模拟了垫片的非线性特性,分析了附加载荷对螺栓法兰连接结构的强度和紧密性的影响,确定了连接系统的紧密性、附加载荷和垫片残余压紧应力三者之间的关系。分析结果表明,附加弯矩对螺栓法兰连接结构的紧密性有较大影响。     

两种不同石墨电极上溴离子电氧化的研究

通过测定溴离子在两种不同石墨电极上的循环伏安曲线及电流效率，探索了溴离子在石墨电极上氧化的电解条件，比较了两种石墨电极对溴离子电氧化的影响。研究发现，由于电极材料的不同和析氧反应的存在，两种电极材料对溴离子氧化的催化作用有一定差别。溴离子在石墨电极上氧化的电流效率一般在80％以上，最高可达88．5％。     

Study on the graphite nanosheets/resin shielding coatings

Shielding coatings based on graphite nanosheets were prepared by compounding method. The surface morphology of the graphite nanosheets and conductive coatings was examined by scanning electron microscopy. The surface resistivity of the coatings was greatly declined by incorporating the graphite nanosheets. The electromagnetic interference shielding effectiveness (SE) from 0.3 MHz to 1.5 GHz was also studied, and found that the SE of the coatings was consistent with its conductivity. The best sample was shown to exhibit up to 38 dB of SE at 1.5 GHz (with a thickness of 400 μm). The main shielding mechanism of the system was reflection and multiple reflections.