共查询到20条相似文献,搜索用时 15 毫秒
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《粉末冶金学》2013,56(8):196-212
AbstractThe paper summarizes the known physical, mechanical, and chemical properties of silicon nitride. These are compared with the properties of several ceramics and other materials in common use, and it is shown how the combination of certain properties in silicon nitride make it an ideal material for six general types of application. For example, it is shown how the combination of thermal shock-resistance and electrical resistivity can be used to develop high-temperature electrical insulators. 相似文献
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《粉末冶金学》2013,56(8):152-163
AbstractThe paper describes experiments to establish the conditions under which α- and β-silicon nitride may be produced independently or in varying proportions. It also suggests a method for varying the properties of silicon nitride by incorporating a dispersion or continuous network of other elements and compounds. 相似文献
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《粉末冶金学》2013,56(8):145-151
AbstractA method is described for preparing silicon nitride bodies of almost theoretical density. Silicon nitride powder is hot pressed with a small proportion of catalyst, preferably magnesium oxide or nitride, at 1850°C. The bodies have very high flexural strength up to high temperatures, and preliminary measurements of creep rate and thermal shock-resistance indicate that dense silicon nitride should be a suitable material from which to make components required to operate under high stress at temperatures up to ~1200°C. 相似文献
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介绍了高硅(6.5%Si)电工钢的特性及生产方式,同时叙述了该牌号电工钢国内外的发展有应用情况。高硅电工钢的研制和开发具有重要的现实意义。 相似文献
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超细氮化硅粉的组成分析和评估 总被引:3,自引:1,他引:2
采用X荧光光谱、等离子发射光谱、原子吸收光度、气相色谱以及重量法、容量法等多种分析技术对超细氮化硅粉中硅、氮、氧、氯根、水分及金属杂质等组成进行了分析方法研究。确定了测值可信且再现性好的分析方法。通过程序升温、红外检测及微机解卷重叠峰形,探讨了氮化硅中不同状态的氧量,进而对主相量作出评估。国内用高频等离子法和激光诱导合成的氮化硅超细粉,主相量均达97%以上,其组成式接近为Si_(30)N_(10)O。 相似文献
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SHS法工艺参数对制备氮化硅粉体的影响 总被引:1,自引:0,他引:1
本文采用自蔓燃高温合成方法(Self-propagating High-temperature Synthesis)简称(SHS)合成氮化硅粉体,借助于XRD、SEM等检测方法,分析了自蔓燃高温合成氮化硅过程中氮气、温度、稀释剂与孔隙率等方面的影响。结果表明:只要最高燃烧温度不高于相应氮气压力下Si3N4的热分解温度,就可以用SHS方法合成Si3N4;氮气压力下硅粉的自蔓燃合成反应,必须要引入Si3N4稀释剂,来控制反应温度,以获得高α相含量的粉体。压坯气孔率控制在30%~70%,否则反应不能进行。研究发现SHS法可以制备纯度较高的氮化硅粉体。此法较传统方法合成的氮化硅设备简单,成本低廉,纯度高,填充性及烧结活性好。 相似文献
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《粉末冶金学》2013,56(21):73-82
AbstractThe flexural and tensile strengths and the fatigue limits of sintered iron materials have been measured as a function of porosity and pore size. The resulting experimental values were lower than the theoretical. This discrepancy is attributed to a pore-size effect, analogous to the results of earlier work in which the influence of pore size on elastic modulus was studied (G. Artusio, V. Gallina, G. Mannone, and E. Sgambetterra, Powder Met., 1966, 9, (17), 89). 相似文献
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炼焦煤中添加不同粒度、比例及成分的铁矿粉制备高反应性焦炭,测定焦炭的转鼓强度、等温与非等温气化反应参数,综合评定添加催化剂对高反应性焦炭机械强度和气化反应的影响。配入铁矿粉后焦炭的机械强度有不同程度的下降,当添加比例小于10%时,焦炭的机械强度变化幅度较小;大于10%时,焦炭的机械强度大幅度下降;添加铁矿粉的成分和粒度均对焦炭机械强度有较大影响。添加铁矿粉的比例处于容惰范围内时,增加添加铁矿粉的比例、添加高品位铁矿粉或适当地减小添加铁矿粉的粒度均有利于降低焦炭的起始反应温度、提高低温反应指数。 相似文献
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硅对GD钢下贝氏体组织形态及力学性能的影响 总被引:3,自引:0,他引:3
本文研究了不同硅含量的高强韧低合金冷模具钢(代号GD钢)经马氏体—下贝氏体复相处理后下贝氏体的组织形态、亚结构和数量,讨论了GD钢的成分、组织和性能之间的关系。结果表明,GD钢的硅含量对下贝氏体的相变过程和显微结构起决定性的作用。当GD钢的硅含量达到1.82%时,复相组织中下贝氏体呈准下贝氏体形态,且复相组织表现出最佳的强韧性配合。 相似文献
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对不同取样点焦炭的机械强度及筛分组成的探讨 总被引:1,自引:0,他引:1
刘建星 《金属材料与冶金工程》2005,33(6):17-19,23
对不同取样点焦炭机械强度及筛分组成检测结果进行了详细的的分析与研究,提出了在现有配煤炼焦工艺的基础上,通过对焦炭采取后处理等措施来提高焦炭质量,以满足湘钢高炉大型化的生产需要. 相似文献
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PRESSING AND SIZING FACTORS AFFECTING THE PRECISION AND MECHANICAL CHARACTERISTICS OF SINTERED PARTS
《粉末冶金学》2013,56(35):150-158
AbstractAll stresses, and particularly those due to friction, which occur during pressing and sizing operations have consequences on the dimensions, on internal stresses, and eventually on micro-cracks. This friction can have an influence on the variations of the density from one point to another but, when used in a proper way, it can help the movement of punches and increase homogeneity. Three different types of re-pressing are considered—drawing, sizing, and coining—and examples are given to show their influence on mechanical properties and especially on the fatigue limit. 相似文献
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对HQ80钢进行了930℃淬火及200~600℃回火处理,并对不同温度回火状态进行了力学性能测试和显微组织的电子显微镜分析。硬度(HB),屈服强度(σ0.2),抗拉强度(σb)及冲击功[Akv(-15℃)]随回火温度的变化可分为三个区间:①在200~400℃之间,HB,σb单调下降;σ0.2出现峰值,Akv(-15℃)呈现出低谷。②在450~600℃之间,各项性能变化很小。③620℃以上回火时,H 相似文献
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本文针对山西朔州典型黄土,利用素黄土与石灰粉煤灰、石灰水泥、水泥粉煤灰三种改良黄土,进行了击实特性、抗剪强度特性及崩解特性试验研究,提出了黄土改良的最佳方案,并采用该方案对山西某煤矿电梯井填方段进行了数值模拟分析,验证了石灰粉煤灰改良黄土工程应用的可行性.试验结果表明:粉煤灰与黄土形成致密的混合结构,石灰的掺入,激活了粉煤灰的活性,发生了一系列的水化反应,使改良黄土的强度大大提高,改良黄土在物理力学性质方面有明显改善. 相似文献