4种炭素材料的抗氧化性研究

采用SEM、Raman光谱和TG-Dsc等手段研究了纳米碳管、天然石墨、酚醛树脂热解炭、炭黑改性酚醛树脂热解炭的抗氧化性.研究表明,这4种炭素材料的抗氧化性由强到弱的顺序为天然石墨、纳米碳管、炭黑改性酚醛树脂热解炭、酚醛树脂热解炭.     

炭/石墨材料的成型工艺综述

由于炭/石墨材料在冶金、太阳能、核能、原子能、半导体、航空航天等领域的广泛应用,本文针对当前国内炭/石墨材料的成型方式,主要探讨挤压成型、模压成型和等静压成型,以及它们的技术特点.     

吉林市高科特种炭素材料有限责任公司

<正>吉林市高科特种炭素材料有限责任公司是国内一家综合性炭素制品生产企业,隶属于吉林炭素有限公司的直属全资子公司,是集研发、生产、经营、内外贸易于一体的高新技术企业。公司具有雄厚的科研技术实力和先进的生产技术装备,2006年通过GB/T19001/2000质量保证体系认证。目前主要生产特种石墨和普通异型石墨二大系列、十几个品种、几百个规格的炭素制品。主导产品有细结构等静压、模压、挤压石墨,石墨阳极、石墨流槽、坡板、发热体、石墨坩埚及各种模具等。十多项产品通过国家、部省级鉴定,填补多项国内空     

特种石墨的分类、市场和生产

特种石墨的涵盖范围很广，电炭制品行业、天然石墨制品行业和冶金用炭制品行业对此有不同的理解和分类方法，就冶金用炭制品行业的习惯分类解释，特种石墨主要指高强度、高密度、高纯度石墨制品（简称三高石墨）。三高石墨从材料组织结构上可以分为粗颗粒、细颗粒和特细颗粒结构三种；从成型方法上区分主要有模压、挤压和等静压成型特种石墨三类，此外，振动成型也可用于生产特种石墨。高品质的特种石墨——各向同性石墨是用等静压工艺生产的。按其主要用途分类有：电火花加工用特种石墨；制作铸造模具用特种石墨；钢铁或铜、铝连续铸造用特种石墨；直拉单晶硅炉用或冶炼贵金属、高纯材料使用的高纯石墨；合成人造金刚石用石墨；火箭、导弹技术用特种石墨。     

铝电解槽用无烟煤基石墨化阴极材料的初步研究

选取优质电煅无烟煤,分别配以一定比例的石油焦和沥青焦作为骨料,与煤沥青混合后按照模压成型、焙烧、高压浸渍、二次焙烧和石墨化等常规炭素制品生产工艺流程制备石墨化阴极材料试样。考察了无烟煤和3种少灰料以不同配比混合制成的试样在焙烧和石墨化过程中的尺寸变化及理化性能变化规律,并通过对4种以单一原料制备的试样的理化性能分析,探讨了原料种类对试样性能的影响。结果表明,以无烟煤为主要原料,配以一定比例的少灰料作为骨料,通过适当的炭素工艺制备的石墨化阴极材料试样,其常规理化性能可以满足大电流铝电解槽用阴极材料的要求。     

等静压石墨评论

等静压石墨是炭石墨材料家族中的新成员.其成型方法与传统的热挤压、冷模压、振动成型等不同,是采用等静压机(冷、温、热)压制成型.从而给制造细结构、大规格、各向同性炭石墨材料创造了条件.它广泛应用于半导体行业、光伏产业、电火花加工、金属连铸、光纤、模具制造以及宇航和核工业,是与当今高科技发展紧密相联的不可替代的新材料,其发展迅猛,方兴未艾.     

臭氧氧化法用于炭素材料表面改性的研究进展

炭纤维、炭黑、石墨等多种炭素材料在进行表面改性后能够提高品质,增强分散性.工业上炭素材料表面改性的传统方法多以强酸为氧化剂,易造成较为严重的环境污染.而臭氧氧化法因其氧化效率高、绿色环保、成本低等优点,可取代强酸氧化成为更为理想的炭素材料表面改性方法.本文介绍了臭氧氧化法及其在各种炭素材料表面改性中的应用及研究进展,并对其存在问题和研究前景进行了说明和展望.     

铝电解槽用石墨化阴极材料的研究

以4种国产焦炭、3种国产煤沥青为原材料，采用热模压成型、一次焙烧、高压浸渍、二次焙烧和石墨化等工艺开展了铝电解槽用石墨化阴极材料的研究。在对原材料结构和理化性能分析的基础上，考察了原材料种类和配比不同的15个试样在热处理过程中的收缩率和体积密度的变化，并对石墨化后的试样的各项理化性能与工业发达国家生产的石墨化阴极炭块的性能指标进行了对比分析。结果表明，以国产焦炭和煤沥青为原材料，经过适当的混配和热处理工艺得到的石墨化阴极材料试样，其综合性能指标已达到铝电解槽对高性能石墨化阴极材料的要求。     

核工程中的石墨和炭素材料(第六讲)

6　核石墨和炭素材料的发展特点、现状和趋势61　核石墨和炭素材料的发展特点由于核用石墨和炭素材料的工作环境在地球上前所未有,在其服役过程中炭素和石墨材料中发生的过程和问题也是闻所未闻。这些问题的解决需要物理、数学、化学,核科学与工程和材料科学与工程等学科的知识;大型现代研究装备,如电子显微镜、加速器、核反应堆、热室;不同科技领域的科学和工程技术人员的共同努力。因为所涉及的问题的特殊性和巨大的投资,国际上核石墨的研制大都是由国家主管部门组织核科学与工程、材料科学与工程的研究、设计和生产单位共同来完成的。核…     

文摘

高性能石墨材料注凝成型研究【刊,中】,黄翔,戴金辉。朱志斌．等,材料开发与应用,2013（1）：67—71传统方法制备高性能炭素和石墨材料是一个高能耗的漫长过程。本文首次对高性能石墨材料进行注凝成型工艺研究,讨论了分散剂含量、pH值、有机单体含量、石墨固相含量等对石墨料浆黏度的影响,并对注凝成型石墨素坯样品进行抗弯强度、显微形貌分析。结果表明,注凝成型石墨素坯样品在微观结构、力学性能等方面均远优于传统模压成型方法制备之石墨素坯样品。     

核石墨材料的性能、类型、制备及其在核反应堆中的应用

因为炭材料具有热膨胀系数低、抗热冲击性好、中子活化性能低等优异的性能,是核反应堆(特别是高温气冷堆)不可缺少的慢化、反射和结构材料.本文综合分析炭材料的核物化性能,重点剖析了核石墨的材料类型和制备方法.提出采用化学与物理并用的方法,去除炭石墨原料、大尺寸石墨块体的杂质,有可能使炭材料达到核石墨纯度要求;采用编织和化学沉积等复合材料技术制备炭/炭复合材料,制造核反应堆热结构件;采用热等静压工艺技术和振动成型制备各向同性石墨材料和核石墨块,并在2 800-3 000℃进行高温石墨化处理.采用先进的电子显微学、同步辐射等技术,研究核石墨的结构和性能,特别是其在中子辐射条件下的性能特征和行为特性,在此基础上,制定和建立科学合理的核石墨生产工艺流程、工艺技术条件.     

不同碳材料对铝碳浇注料性能的影响

含碳浇注料因碳材料的水润湿性差及高温氧化引起的材料性能差等问题一直备受关注。分别以热氧化石墨、ZrC包覆改性石墨和水热碳化生物质碳材料为碳源制备铝碳浇注料,研究不同碳材料对铝碳浇注料显气孔率、物理性能、物相组成,以及抗氧化性和抗渣侵蚀性能的影响。结果表明:引入热氧化石墨的浇注料具有最高的加水量,残留孔隙破坏了材料内部结构,浇注料机械性能较差;添加ZrC表面改性石墨可以降低浇注料的加水量,抗氧化性能较好,但对力学性能的提升无显著影响;以生物质碳材料为碳源可以显著提高浇注料的物理性能,相比于添加石墨的试样,生物质碳材料并未显著提升试样的抗渣侵蚀性能。     

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...     

The Effect of Graphite Particle Size on Properties of Low Carbon MgO-C Composite Materials

The effects of graphite granularity on the properties of low carbon MgO-C based materials have been investigated in the work. Large crystal fused magnesia, natural flake graphite with different particle sizes and anti-oxidant were adopted as raw material for preparation of specimens. However, the results show that the physical properties oxidation resistance and thermal shock resistance of low carbon MgO-C materials with content of 4.0 wt% graphite are improved obviously through the use of special and suitable size graphite. The excellent performance achieved was considered as a result of microstructure modification of MgO-C materials. Therefore, it is suggested that both fine and micro grade natural flake graphite used for production of low carbon MgO-C bricks.     

Large-scale fabrication of TiC@C powders and its effect on the properties of Al2O3-MgO-C castables

High performance carbon containing castables have always been pursued by researchers and steelmaking producers, unfortunately, poor water-wettability of graphite flakes was greatly limited their application in castables. To respond this, we proposed a large-scale and low-cost modified molten salt shielding synthesis technique for fabricating TiC coated graphite in air atmosphere using graphite flake and Ti powder as raw materials. Microstructure, wettability and oxidation resistance of TiC@C powders, and effect of TiC@C powders on the properties of Al₂O₃-MgO-C castables were investigated. The results demonstrate that TiC coated graphite was synthesized via modified molten salt shielding synthesis route in air atmosphere. A uniform and continuous TiC layer was formed on the surface of graphite, thereby significantly improving the water-wettability and oxidation resistance of graphite flakes. The castables with 5% TiC@C powders possessed lower apparent porosity, higher cold strength, good oxidation resistance, and slag resistance in comparison with the castables with graphite flakes, and slag resistance were also better than Al₂O₃-MgO castables. The as-fabricated TiC@C powders have good water-wettability and oxidation resistance, making them as a prime carbon source for producing carbon containing castables for steel ladle linings.     

Antioxidant Coating of SEN for Thin Slab Con-casting

The SEN for thin slab con-casting is easy to break and damage because of the oxidation during preheating and application. The enamel coating material is generally applied on the surface of SEN to avoid the oxidation. The coating material with born glass and silicon as main starting materials and silica sol as binder was studied. ZrO2 - C and Al2O3 - C materials containing 15% carbon were isostatic pressed, and heated at 600 ℃ , 900 ℃ , 1 200 ℃ , 1 500 ℃ for 2 h, respectively. The results show that the coating material with 70% of boron glass and 30% of silicon bonded by silica sol can form denser protection layer in the above mentioned materials at the range of 600 -1 500 ℃. The oxidation area ratio and weight loss ratio with the coating are much lower than those without the coating.     

浅谈炭石墨材料抗氧化性能的研究

采用改善炭石墨基体材料抗氧化性能和浸渍磷酸无机高分子复合盐的内外结合的方法，制备的石墨料具有较好的抗氧化性能，本文论述了其研制情况，列出了其静态性能和抗氧化试验测试结果。     

熔融渗硅对石墨氧化行为的影响

分别在500 ℃、700 ℃、900 ℃及1 100 ℃空气条件下,对石墨及渗硅石墨进行氧化实验,以分析熔融渗硅对等静压石墨氧化行为的影响。采用扫描电镜(SEM)分析了样品表面及内部形貌,通过压汞法表征了样品的孔隙结构,并对材料的力学性能进行了测试分析。结果表明:500 ℃条件下,石墨和渗硅石墨均未发生明显的氧化失重现象;温度为700 ℃时,石墨的氧化失重率随时间延长明显增加,而该温度下渗硅石墨的氧化失重率变化较小。而且,渗硅石墨在700 ℃时仍能保持较好的强度,而此温度下,石墨随氧化时间的延长,强度明显降低,甚至被氧化成粉末状。因此,熔融渗硅在提高材料抗氧化性能的同时能够显著提升材料的强度。     

氧化铝微粉加入量对低碳镁碳砖性能的影响

以电熔镁砂、石墨、金属Al和氧化铝微粉为主要原料,热塑性酚醛树脂为结合剂,制备了w(C)5%的低碳镁碳砖试样,研究了氧化铝微粉加入量(其质量分数分别为0、3%、5%、7%、9%)对低碳镁碳砖的常温物理性能、抗热震性和抗氧化性的影响。结果表明:(1)随着氧化铝微粉加入量的增加,低碳镁碳砖试样的体积密度、常温强度和高温强度均先升高后降低,显气孔率则先降低后升高;抗热震性和抗氧化性随微粉加入量的增加呈先改善后变差的趋势;其中,微粉加入量为5%的低碳镁碳试样综合性能最好。(2)低碳镁碳砖试样性能的改善主要是由于加入的氧化铝微粉和MgO在高温下原位反应生成连续分布的尖晶石,增强了基质的陶瓷结合;但氧化铝微粉加入量过大时,由于大量原位反应引起材料产生过大的体积膨胀,会导致基质结构疏松,从而恶化镁碳砖的性能。     

Molten salt synthesis of a SiC coating on graphite flakes for application in refractory castables

A silicon carbide coating was formed on the surface of graphite flakes by reaction of molten Si with carbon at 1100–1300 °C in a 95%KCl-5%NaF molten salt under Ar atmosphere. The effect of temperature and Si/graphite ratio in the initial mixture on the quality and the amount of SiC were investigated by XRD and SEM/EDS analyses. Also, the water wettability, oxidation resistance and zeta potential of un-coated and coated graphite were examined by TGA analysis and sedimentation test. The results show the amount of coating to increase in the coated flakes with increasing temperature and Si/graphite ratio. The SiC coating improves water wettability of graphite and acts as a protective layer to enhance oxidation resistance. The zeta potential of coated graphite was also increased which indicated a better dispersion in water based systems. These improvements in both the water dispersivity and oxidation resistance of SiC coated graphite would make it as promising candidate raw materials for application in C-containing refractory castables.