添加剂—磷酸及其盐类对柔性石墨材料的影响

采用添加剂[H_3PO_4、NH_4H_2PO_4、(NH_4)_2HPO_4]浸渍处理酸化石墨,然后将其烘干,高温膨胀,最后模压成柔性石墨试片(纸)。初步探讨了浸渍液浓度、浸渍时间对柔性石墨试片高温抗氧化能力的影响,同时考察了添加剂的加入对柔性石墨试片抗拉强度、回弹性的影响。实验结果表明,与未经添加剂浸渍处理的对比样相比,经添加剂浸渍处理可明显提高柔性石墨高温抗氧化能力,同时其抗拉强度,回弹性也均有所提高。所用添加剂溶液最佳浓度为0.5～1.0mol/1,最佳浸渍时间为2～8h。     

氧化剂对柔性石墨材料力学性能的影响研究

采用液相氧化法制备可膨胀石墨，在10MPa下压制柔性石墨试样并测定其抗拉强度和抗压强度，考察了氧化剂的氧化性和氧化程度对柔性石墨力学性能的影响，探讨了柔性石墨的微观结构和内部孔结构与其力学性能的关系。结果表明：柔性石墨材料的抗拉强度和抗压强度随氧化剂氧化性的提高而增大，氧化程度过高和过低都不利于获得高力学性能的柔性石墨材料。通过工艺优化可得到抗拉强度为4．02MPa、抗压强度为52．3MPa的高性能柔性石墨。膨胀石墨的微观结构和内部孔结构对柔性石墨的力学性能有较大的影响，膨胀率较高的膨胀石墨孔隙细长、孔径较大、开孔数量较多，在压制过程中孔隙内的气体容易排除，所得柔性石墨的气孔数目少，体积小，因而具有较高的力学性能。     

金属铝结合镁-尖晶石-碳滑板的研制

研究了不同添加物(电熔刚玉、镁铝尖晶石、碳化硅和阿隆)对镁碳材料物理性能和抗热震性的影响,炭素种类对镁碳材料物理性能和抗氧化性的影响以及抗氧化剂种类和加入方式对镁碳材料常温抗折强度和抗氧化性的影响,根据确定的最佳添加物研制连铸钢包用滑板材料。结果表明:加入镁铝尖晶石有利于提高材料的抗热震性;与炭黑相比,添加597微细石墨可显著提高材料的常温抗折强度、致密度以及抗氧化性;以碳化硼和硅粉作为复合添加剂,有利于提高材料中、高温处理后的常温抗折强度,同时也提高了材料的抗氧化性;研制的镁-尖晶石-碳滑板材料在实际使用中的抗拉毛性优于重烧铝锆碳滑板,达到了钢厂的使用要求。     

添加剂对尖晶石碳质材料性能的影响

为提高尖晶石碳质材料的抗热震性和抗冲刷性,以尖晶石、石墨和不同种类添加剂(铝-硅合金、硅粉、B4C、Si C)为原料,热塑性酚醛树脂为结合剂,在氮气保护下经950℃热处理后,制备了石墨含量为8%(w)的尖晶石碳质材料,探究了添加剂对尖晶石碳材料力学性能、抗热震性和抗氧化性的影响。结果表明:1)铝-硅合金或B4C能明显提高尖晶石碳材料的常温抗折强度,但会降低材料的抗热震性,B4C对材料的抗热震性最不利,硅粉和Si C对常温抗折强度影响不大,但能显著提高抗热震性;2)铝-硅合金或硅粉能显著提高材料的高温抗折强度,B4C或Si C对高温强度影响不大。3)经950℃热处理后,B4C对提高材料的抗氧化性作用不明显,单独加入硅粉、铝-硅合金和B4C复合添加均能提高抗氧化性能。     

膨胀石墨对镁碳耐火材料显微结构和性能的影响

以膨胀石墨为碳源,部分取代镁碳耐火材料(含5wt％的鳞片石墨)中的鳞片石墨,借助X射线衍射仪、场发射扫描电镜、能谱仪以及三点弯曲测试仪等研究了膨胀石墨的添加对热处理后镁碳材料的显微结构、力学性能、抗热震性和抗氧化性的影响.结果表明:镁碳材料中引入0.2wt％的膨胀石墨在高温下可促进材料基体内片状AlN相形成,进而使试样的抗折强度和弯曲模量达到最大,分别为12.35 MPa和2.82 GPa;但是过量的添加将对材料的致密度产生负面影响,从而降低了材料的抗折强度和弯曲模量;膨胀石墨的添加显著提高了镁碳材料的抗热震性但对材料的抗氧化性不利;当膨胀石墨的加入量为0.5wt％时,镁碳材料的综合性能最好,若想加大膨胀石墨的添加量,需对其抗氧化性进行改善.     

石墨化催化剂对石墨抗氧化性的影响

通过添加石墨化催化剂制备出高石墨化度材料,利用X射线衍射和拉曼光谱对材料结构变化进行分析;对石墨样品进行恒温氧化失重率测定,并采用扫描电子显微镜观察氧化前后材料的微观形貌。结果表明:Pr_6O_(11)添加剂可促进石墨氧化;H_3BO_3添加剂可抑制石墨氧化;Ni_2O_3添加量较少时可提高石墨抗氧化性,而当添加量较高时则促进石墨氧化。     

浸渍法提高石墨材料抗氧化性能的研究

用磷酸复合盐浸渍法对石墨材料进行浸渍,研究其抗氧化性.讨论了当浸渍剂中添加不同比例的硼酸盐、碳化硅、二氧化钛等成分后,对提高浸渍效果和增强抗氧化性的影响.结果显示,在磷酸和氢氧化铝的摩尔比为25:1,硼酸盐含量为4%,碳化硅(或二氧化钛)含量为2%的条件下,在石墨表面形成白色的偏铝酸盐硬壳具有良好的抗氧化作用.而不加入硼酸盐的浸渍剂,抗氧化效果明显降低.结果表明,石墨材料经过复合磷酸盐溶液的浸渍和热处理,可在表面形成抗氧化层,增强石墨材料的抗氧化性,延长使用寿命.     

4种炭素材料的抗氧化性能研究

在熔炼炉中对电极石墨、模压石墨、挤压石墨、等静压石墨4种炭素材料从室温逐渐加热至700℃,并在一定温度下保温1h,测其质量,绘制材料质量变化曲线图,以质量变化表征其抗氧化性的强弱.通过SEM、XRD等手段分析这几种炭素材料抗氧化性差异的本质原因.研究表明,这4种炭素材料的抗氧化性强弱顺序为等静压石墨、电极石墨、挤压石墨、模压石墨,影响石墨材料的抗氧化性能主要因素有石墨材料的石墨化程度、晶体结构缺陷、体积密度及杂质含量等.     

添加剂对炭材料浸渍金属性能的影响

在炭材料浸渍金属的过程中,添加剂的加入对产品性能有很大的影响。本文就几种添加剂加入炭原材料配方中分别浸渍巴氏合金、锑金属、铜合金、银金属进行一些研究,试验结果表明,在相同的浸渍条件下,加入适量添加剂能有效降低浸润角、改善浸渍效果,较大幅度提高碳石墨材料浸渍金属性能。实践证明,添加剂作为一种有效的材料加入到炭材料中,在浸渍金属系列产品方面有着很好的发展前景。     

石墨加入量对低碳镁碳砖性能的影响

通过检测含有2%～14%石墨镁碳砖1400℃的高温抗折强度、1500℃的热膨胀系数、1000℃×2 h煅烧后的抗氧化性,比较低碳镁碳砖与传统镁砖的性能差异,研究了石墨加入量对低碳镁碳砖性能的影响。结果表明:在有2%Al存在的情况下,低碳镁碳砖高温抗折强度与石墨加入量无关;石墨加入量为6%时,可保证低碳镁碳砖具有较优良的抗剥落性及抗氧化性。     

石墨碎在电极生产中的作用

通过石墨碎、大庆石油焦、锦州石油焦的对比试验，分析了石墨碎的性能，并通过生产试验，分析了石墨电极生产中NA石墨碎对生产及产品的影响。石墨碎具有真密度高、体积密度大，电阻率、CTE偏低，振实密度、颗粒强度大等优点。在石墨电极生产中加入一定的石墨碎可以提高产品的体积密度、强度，降低电阻率等。     

轧制工艺对柔性石墨力学性能的影响

研究了柔性石墨生产过程中初压力、轧制方向、轧制咬入角和轧制辊径等因素对其宏观力学性能的影响,结合对不同密度的柔性石墨取向度的分析,对柔性石墨的强度机制作了进一步的探讨。     

抗氧剂1010对3D打印用聚乳酸氧化降解性能的影响

为研究抗氧剂1010(KY1010)对3D打印用聚乳酸(PLA)氧化降解性能的影响,以PLA和KY1010为原料,通过挤出成型工艺制得3D打印用PLA丝材,并采用FDM工艺制备复合材料,研究KY1010添加量对PLA丝材拉伸性能、动态热机械性能、氧化诱导期以及复合材料力学性能的影响.结果表明,KY1010可有效改善PL...     

Effect of Treated Graphite on Properties of Al_2O_3-SiC-C Castables

Al2O3-SiC-C castables with 2% pitch or 2%,4% and 6% treated graphite,respectively,were prepared based on the basic formulation of traditional Al2O3-SiC-C castables. The flowability of castables,and bulk density,volume stability,strength,oxidation resistance and slag resistance of specimens fired at 110 ℃,1 100 ℃ and 1 500 ℃ respectively were comparatively studied. The results showed that:(1) With carbon source changing from pitch to treated graphite and the increase of treated graphite addition,water additi...     

石墨改性超高分子量聚乙烯的性能研究

采用物理共混改性的方法,制备了具有不同性能的超高分子量聚乙烯／石墨合金。研究了填料含量对合金性能的影响,DSC分析结果表明UHMWPE的热分解温度在455℃而熔点超过140℃,拉伸强度随石墨的添加明显下降,当石墨含量为5％时其拉伸强度下降到O．24MPa,冲击强度和摩擦磨损性能的测试结果表明,石墨填料的加入可以一定程度的改善合金材料的冲击性能和耐磨性能,石墨含量为1％时合金的摩擦系数由原来的0．14下降到0．12,而石墨较少时其冲击强度亦有所提高。     

Improved thermal shock stability and oxidation resistance of low-carbon MgO–C refractories with introduction of SiC whiskers

This research focuses on the utilization of SiC whiskers synthesized from rice husk powders in low-carbon magnesia–carbon (MgO–C) refractories, and attempts to reduce the flake graphite content in refractories by adding synthesized SiC whiskers. The effect of the addition amount of SiC whiskers on the microstructure, mechanical properties, thermal shock stability and oxidation resistance of MgO–C refractories with different graphite content was studied. The results indicated that the introduction of SiC whiskers facilitated the generation and growth of ceramic phases in MgO–C refractories. By adding 1 wt% SiC whiskers, the graphite content could be reasonably reduced (from 5 wt% to 4 wt%), and the strength, thermal shock stability and oxidation resistance of refractories were enhanced by the synergistic effect of the introduced SiC whiskers and the generated ceramic phases, the CMOR, CCS, residual CCS, and oxidation resistance were increased by 44, 6, 12 and 27% respectively.     

CONE法研究聚磷酸铵和硼酸对环氧树脂复合材料的阻燃作用

采用锥形量热法研究了聚磷酸铵(APP)、硼酸及由这两者组成的复配阻燃剂对环氧树脂(EP)复合材料燃烧性能的影响.结果表明:APP可使EP复合材料燃烧时的热释放量和烟释放量大大降低,到495s时累积热释放量为27.3MJ/m2,烟产生速率为2243m2/m2,与未阻燃EP复合材料相比分别下降了37%和49%,阻燃抑烟效果显著;硼酸推迟EP复合材料热解时间,延缓了烟尘和有毒气体的释放;APP与硼酸之间存在着协同阻燃作用,APP在燃烧前期催化EP成炭,硼酸降低燃烧后期的累积热释放量.     

Synergistic effects of carbon fillers on tensile and flexural properties in liquid‐crystal polymer based resins

One emerging market for thermally and electrically conductive resins is bipolar plates for use in fuel cells. Adding carbon fillers to thermoplastic resins increases the composite thermal and electrical conductivity. These fillers have an effect on the composite tensile and flexural properties, which are also important for bipolar plates. In this study, various amounts of three different types of carbon (carbon black, synthetic graphite particles, and carbon fibers) were added to Vectra A950RX liquid‐crystal polymer. In addition, composites containing combinations of fillers were also investigated via a factorial design. The tensile and flexural properties of the resulting composites were then measured. The objective of this study was to determine the effects and interactions of each filler with respect to the tensile and flexural properties. The addition of carbon black caused the tensile and flexural properties to decrease. Adding synthetic graphite particles caused the tensile and flexural modulus to increase. The addition of carbon fiber caused the tensile and flexural modulus and ultimate flexural strength to increase. In many cases, combining two different fillers caused a statistically significant effect on composite tensile and flexural properties at the 95% confidence level. For example, when 40 wt % synthetic graphite particles and 4 wt % carbon black were combined, the composite ultimate tensile and flexural strength increased more than what would be expected from the individual additive effect of each single filler. It is possible that linkages were formed between the carbon black and synthetic graphite particles that resulted in improved ultimate tensile and flexural strength. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Effect of 60Co gamma radiation on the mechanical properties of epoxy blends and epoxy-graphite fiber interface

The effect of ⁶⁰Co gamma radiation of up to 100 Mrads on an IM6-G graphite fiber-epoxy interface was studied using the single-fiber-composite (SFC) technique. Flexible epoxy blends were formulated using diglycidylether of bisphenol-A (DGEBA) based and polyglycol diepoxide epoxies which were cured with aliphatic and aromatic curing agents. Bulk epoxy specimens and graphite fibers were tension tested to obtain their tensile properties. The fragment length distribution from SFC tests, single fiber strength data, and a Monte Carlo simulation of Poisson/Weibull model for fiber strength and flaws were used to obtain the effective interfacial shear strength values. The results indicate that while graphite fiber strength is not affected by radiation, the tensile properties of the epoxies used are adversely affected by the radiation. The interfacial shear strength, however, increases significantly with the radiation dose. The study also supports the earlier results of many workers that the interfacial shear strength for flexible epoxies is much higher than the shear yield strength of the epoxies.