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研究了Al、Si和B4C几种抗氧化添加剂对低碳镁碳砖抗氧化性能的影响.利用热重法分析了加热过程中耐火材料试样的失重率;测定耐火材料的脱碳层厚度;探讨了抗氧化添加剂的作用机理;并明确了适合于低碳镁碳砖用抗氧化添加剂的种类.研究结果表明,与添加Al和Si相比,添加B4C能更好地提高低碳镁碳砖的抗氧化性能.通过在低碳镁碳砖中... 相似文献
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无锡县钢铁厂在1987年从意大利引进一台34t 高功率电炉,变压器功率20000KVA,并采用水冷炉壁,炉盖。在电炉渣线区我厂采用无锡县镁碳砖厂生产的树脂结合镁碳砖,炉坡和炉底采用沥青镁砂砖和沥青镁砂打结综合砌炉。自1987年8月投产以来,到1988年底共进行48个炉役,炼钢1600多炉,一次性炉龄最高为45炉。一年多来,通过不断改进制砖质量,并选用不同品种的镁碳砖砌炉试验,改进砌筑方法,在降低耐火材料成本、提高炉龄方面取得一定进展,使镁碳砖在高功率电炉生产中发挥了较好的作用。 相似文献
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以电熔刚玉、天然石墨以及利用碳热还原法合成的ZrO2-SiC复合粉体为原料制备了Al2O3-C质耐火材料,研究了ZrO2-SiC复合粉体加入量对Al2O3-C质耐火材料抗热震性能的影响.结果表明:添加质量分数为4%的ZrO2-SiC复合粉体试样的显气孔率最低为18.8%;添加6%ZrO2-SiC复合粉体的试样,在1 200 ℃的温度下热震次数达到10次后,其表面并未出现明显裂纹,且其残余耐压强度为16.71 MPa,耐压强度保持率为40.9%,具有良好的抗热震性能. 相似文献
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MnFe2O4粉体的燃烧合成 总被引:7,自引:0,他引:7
采用燃烧合成法制备了MnFe2O4铁氧体粉体。研究了铁氧体的转化率、燃烧波速率与放热反应控制系数、氧压力之间的相互关系。通过XRD和Mossbauer谱等手段对产物的物相组成和结构进行了分析。结果表明,以燃烧合成方法制备MnFe2O4粉体的转化率较低(35%~50%),产物存在较多的晶格缺陷,并且存在部分亚稳相,如FeMnO3。亚稳相的存在增加了粉体的烧结活性。氧压力和放热反应控制系数对MnFe2O4相的转化率影响较小。随氧压力的增加,转化率和燃烧波速率均有所增加,而且放热反应控制系数较小时,随氧压力增加的幅度更为明显。1200℃下在空气和水中对产物进行淬火,均可得到结构较完整的单相尖晶石型MnFe2O4,且阳离子趋向反型分布(反分布率α≈0.7)。 相似文献
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氮化硅铁是近年来高温材料领域的新型复相材料,主要由氮化硅和硅铁合金组成。自20世纪70年代以来,氮化硅铁作为高炉用炮泥材料取得了良好的使用效果,但其制备成本过高制约了进一步的发展。20世纪90年代,北京科技大学无机非金属结构材料研究室利用闪速燃烧合成技术实现了氮化硅铁高性价比的大规模产业化制备,大大推动了氮化硅铁材料的研究与应用,在铁钩浇注料等领域取得了良好的使用效果。本文介绍了氮化硅铁的制备、结构及性能,分析了闪速燃烧合成氮化硅铁的工艺原理,总结了氮化硅铁在不同应用环境下的使用性能,以及目前的应用状况,并展望了氮化硅铁材料的研究方向及其潜在的应用领域。 相似文献
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The oxidation-inhibiting action of B4C as an antioxidant is to be attributed to two possible mechanisms. The first describes the formation of reactive gases (Mg vapour and B2O2) that react with oxygen reducing its partial pressure in pores of the material. The second mechanism results in the formation of a borate layer which includes carbon between the oxide grains and thus protects it from further oxidation. The present study made an examination as to whether these mechanisms also play a part in the use of CaB6. The results confirm the pattern of chemical behaviour in MgO-C materials with boron-containing antioxidants recorded in previous tests. However, the temperature at which the protective effect begins lies in this case at about 200°C lower when compared to B4C. It is obviously due to the formation of a eutectic melt in system MgO-CaO-B2O3 at approx. 1080°C. 相似文献
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There are two main functions of ZrB2additionin carbon-containing materials . First one is that itcould i mprove the corrosion resistance and erosionresistance of materials ,for instance , Kaji[1]have de-veloped the ZrB2-C used for the slag line zone ofsubmerged nozzle ,of whichthe corrosion rateis on-ly half of that of ZrO2-C,and the thermal shock re-sistance is modified greatly as well . Second one isthat the oxidation resistance of the materials contai-ning ZrB2is much better owing to th… 相似文献
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In this work, a Mg-based composite material with in-situ formed LaH3, Mg2NiH4-LiBH4 + 20 wt% LaH3, was prepared by ball milling LiBH4 and hydrogenated LaMg2Ni and Mg2Ni powder mixture, followed by heat treatment at 573 K. The onset dehydrogenation temperature of the composite is reduced by 50 K compared with that of Mg2NiH4-LiBH4. The LaH3-doped composite shows faster kinetics, absorbing 1.43 wt% hydrogen within 100 s at 423 K, which is 6.5 times faster than Mg2NiH4-LiBH4. Moreover, the composite releases 1.24 wt% hydrogen within 500 s at 573 K, 0.69 wt% higher than Mg2NiH4-LiBH4. The activation energy of the composite is reduced by 8.2 and 80 kJ/mol compared with that of Mg2NiH4-LiBH4 and commercial MgH2, respectively. The improvement in hydrogen storage properties is attributed to the fact that LaH3 promotes the generation of nano-sized spongy Mg structure, which has good catalytic activity during the subsequent hydrogenation/dehydrogenation process. 相似文献
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采用高能球磨细化晶粒、原位反应合成及热压技术制备了致密的Al2 O3 p TiCp/Al复合材料 ,并用XRD、SEM、以及EDAX等手段分析了复合材料的相组成、显微组织。结果表明 :Al TiO2 C三元体系在热压反应烧结后 ,可制得致密度较高的Al2 O3p TiCp/Al原位复合材料 ,其显微组织中Al2 O3 和TiC颗粒尺寸为 1μm左右 ,分布均匀。高能球磨有利于增强颗粒细化及弥散分布和反应。 相似文献
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The so called Geographical Information System (GIS) is one of the basic tools for wide range of public health applications. We had developed a general purpose GIS and applied it to represent geographical distribution of patients of the bacterium E. coli O-157 which bursted out in Japan last early summer particularly at Sakai City in Osaka Prefecture. The patient record have been supplied from the Food Safety Office of the Ministry of Health and Welfare. These records were handled by EXCEL. The basic geographical data was constructed from the map data provided by Japan Geographical Survey Institute, and ArcView 2 was used as the map system. The maps were converted to Graphics Interchange Format (GIF) files and put on our Web server. 相似文献