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A. N. Sementsov 《Powder Metallurgy and Metal Ceramics》1984,23(7):514-517
Conclusions At low temperatures water predominates in the compositions of desorbed gases. As the temperature is raised, CO2, CO, O2, CH4, and H2 begin to be liberated, their amount increasing with rising temperature, while the amount of H2O decreases. Prolonged (30-h) vacuum annealing at 523–573°K enables a specimen of the material to be almost completely degassed. A degassed specimen exhibits increased sorptive power, especially with respect to water.Translated from Poroshkovaya Metallurgiya, No. 7(259), pp. 25–29, July, 1984. 相似文献
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V. V. Nemoshkalenko N. A. Tomashevskii V. B. Chernogorenko L. Ya. Solomatina 《Powder Metallurgy and Metal Ceramics》1982,21(1):50-53
Conclusions The Mössbauer spectra of iron phosphides at 65°K were recorded for the first time. It was established that in the Fe3P, FeP, and FeP2 crystal structures, the crystallographically equivalent positions of iron are not equivalent with respect to the magnitude of effective magnetic field or of electric field gradient on the nucleus. Mössbauer spectra enable phase analysis to be carried out on iron phosphide powders.Translated from Poroshkovaya Metallurgiya, No. 1(229), pp. 57–61, January, 1982. 相似文献
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采用喷雾干燥-氢还原法制备超细/纳米晶W-10Cu(质量分数,%)复合粉末,并经过压制和烧结制备W-Cu复合材料,系统研究烧结温度和保温时间对该材料性能和组织的影响,以及在1 100~1 300℃温度范围内的烧结激活能。结果表明,W-10Cu还原粉末晶粒度仅为30~60 nm;在1 200℃烧结时开始发生明显的致密化行为;随烧结温度升高相对密度增大,当烧结温度升高到1 300℃时W-10Cu复合材料的相对密度为90%,但当温度达到1 460℃时有所降低。1 420℃保温90 min时材料相对密度高达99.1%,且此时晶粒度仅为1.8μm。W晶粒尺寸为30~60 nm的W-10Cu复合粉末在1 100~1 300℃烧结的平均激活能为129.14 kJ/mol。烧结温度为1 420℃时W-10Cu的电导率随保温时间延长先增大后减小,保温90 min时最大达到19 MS/m,超过国标有关规定。 相似文献
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Combustion of nitrate-citrate gel was employed to prepare REFeO3(RE=Y,La and Gd) nanocrystalline powders.The samples were characterized with X-ray diffraction(XRD) analysis,thermal analysis(TG/DTA) and transmission electron microscopy(TEM).LaFeO3 crystallites were directly obtained by the sol-gel combustion process,and orthorhombic YFeO3 and GdFeO3 were formed when annealed at 800 oC.The investigation of magnetic properties showed that YFeO3 and LaFeO3 exhibited ferromagnetic behavior,while GdFeO3 presented... 相似文献
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N. M. Khokhlacheva A. V. Lyushinskii V. N. Paderno T. G. Khokhlacheva M. P. Gryunval'd M. E. Bel'chikova 《Powder Metallurgy and Metal Ceramics》1992,31(7):555-558
Translated from Poroshkovaya Metallurgiya, No. 7(355), pp. 5–9, July, 1992. 相似文献
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K. A. Gogaev A. K. Radchenko T. K. Gogaeva 《Powder Metallurgy and Metal Ceramics》2005,44(11-12):517-522
The flowing capacity and relative poured density (RPD) of different fractions of original gas-sprayed high-speed steel powders and those treated in rolls as well as the strength of compacts prepared from them are studied. It is established that with this treatment powder particles are mainly broken down, and their flowability and RPD decrease. The ultimate RPD for treated powders with which quite strong compacts are obtained under normal cold pressing conditions is about 0.45.Compacts with satisfactory processing characteristics are obtained from powders with a RPD below 0.45. A relative poured density of 0.45 may serve as a production criterion of the suitability of powders that are difficult to deform for normal compaction. 相似文献
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AbstractThe addition of Cu3P for developing the high strength 465 maraging stainless steel from elemental powders was studied. The sintering parameters investigated were sintering temperature, sintering time and wt-%Cu3P. In vacuum sintering, effective sintering took place between 1300 and 1350°C. The maximum sintered density of 7·44 g cm?3 was achieved at 1350°C for 60 min with 4–6 wt-%Cu3P. More than 6 wt-%Cu3P content and temperature >1350°C caused slumping of the specimens. The sintered specimens were heat treated and a maximum ultimate tensile strength (UTS) of 767 MPa was achieved with 4 wt-%Cu3P content. The maximum hardness of 45·5 HRC was achieved in heat treated condition with 4 wt-%Cu3P content. Above 4 wt-%Cu3P content increase in density was observed whereas the response to heat treatment decreased. Fracture morphologies of the sintered specimens were also reported. A comparison of sintering behaviour and mechanical properties of elemental powders with prealloyed powders was also given in the present study. 相似文献
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V. G. Mel'nikov A. M. Kozlovskii E. A. Nogovitsin S. V. Zvonov 《Powder Metallurgy and Metal Ceramics》1979,18(2):73-75
Conclusions A study was made of the tinning of copper powders from solutions. Under optimum conditions (duration 10–15 min, temperature 40°C) the process enables a tinned copper powder to be obtained of any desired tin content.Translated from Poroshkovaya Metallurgiya, No. 2(194), pp. 1–3, February, 1979. 相似文献
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Translated from Poroshkovskaya Metallurgiya, No. 12 (360), pp. 70–72, December, 1992. 相似文献
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非均相沉淀-热还原法制备Fe/Si3N4颗粒复合粉末及常压烧结与热压。通过SEM、TEM、EDS、XRD等方法观察Fe/Si3N4复合粉末的结构形貌,常压烧结与热压后的微观组织。结果表明:复合粉末主要存在Fe相与Si3N4相,结构为纳米薄层Fe均匀包覆Si3N4颗粒;常压烧结与热压的样品微观组织有较大的不同:常压烧结样品存在的主要衍射峰为Fe/Si化合物、SiC和Si3N4,SEM图观察Fe/Si化合物晶粒粗大(2~3μm),分布在Si3N4(1μm左右)相之中;热压样品存在的主要衍射峰为Fe、Fe/Si化合物和Si3N4,SEM图观察Fe/Si化合物晶粒较细(1μm左右),镶嵌在类似玻璃态物质中。并通过热力学分析进行讨论与解释。 相似文献
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《粉末冶金学》2013,56(2):129-133
AbstractFine oxide reduced copper powders of about 10 μm mean grain size are irregular in particle shape and high in oxygen content, which poses a difficulty in achieving good properties from injection moulding. Injection moulding was possible when a multicomponent binder with a large fraction of the backbone polymer was used. Injection moulded parts could be sintered to a density of about 95% theoretical, if reduction of the residual oxides in the powder was effectively carried out prior to closure of pores during sintering. Under such a condition, the injection moulded parts could attain an electrical conductivity higher than 80% of pure copper. July 2004. 相似文献