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101.
巴利新(原苏联)是世界知名的粉末冶金学家。1938年他提出的压制方程ln p=—AV+B仍为美国1984年出版的《金属手册》第九版第七卷‘粉末冶金’所引用。早在70年代,巴利新就根据他提出的一系列新理论,提出一个新的压制或固结方程式组α=~2z,f=F(,α),p=pαf,但除原苏联外,该方程鲜为人知。鉴于此,本文作者对巴利新60年代以来发表的一系列关于粉末冶金理论的论著进行了整理,现扼要地予以阐述,这对我国粉末冶金理论的研究或许是有益的。 相似文献
102.
The effect of reducing the reactor air pressure on the morphology of spray dried magnesium sulphate powders is investigated, experimentally. A reactor, capable of drying and pyrolyzing solution sprays at low pressures, is designed and manufactured. A vibrating mesh nebulizer is employed to generate the spray. Four different pressures, starting from 60 Torr to the atmospheric pressure, and two different reactor air temperatures of 130°C and 420°C, are considered. In addition, two different concentrations of magnesium sulphate solutions are tested. The results are explained based on the effect of reactor air pressure on the droplet evaporation rate. 相似文献
103.
Dental amalgams are based on a broad spectrum of materials differing in their chemical composition, metallurgical treatment, and in the way the initial alloys powders are prepared. In addition to their chemical composition, amalgams based on various powders differ in both their microstructure and the amount of mercury needed for preparation. All these facts may affect electrochemical processes occurring during their interaction with oral fluids, and also mercury release. While verifying the effect of the technology used for the preparation of the high‐copper ternary alloy powder on the properties of resulting amalgams, this study aimed at the mechanism of their interaction with a model saliva solution as well as mercury release was included. Measurements were done in a model saliva solution using standard electrochemical methods and exposition measurements. The interaction of individual types of amalgams with artificial saliva did not reveal any significant differences. The free corrosion potential of all these amalgams in an aerated solution settled in the range of values in which tin oxidation, resulting in a layer of insoluble corrosion producsts, turned out to be the dominant anodic process. The rate of mercury release was the lowest for amalgams based on a gas‐atomized alloy. The highest rate of mercury release, and also its dependence on time, was exhibited by lathe‐cut powder based amalgam. In addition to different volume fraction of the Ag‐Hg phase and the level of its tin alloying, this different behaviour may be explained by differences in the rate at which a layer of tin corrosion products acting as a barrier to mercury release is formed. 相似文献
104.
105.
对迁安地区磁选精矿粉添加磷石粉和B2O3,生产二元碱率为2.0左右的高碱度烧结矿,在实验室和现场进行了试验。结果表明:加入少量磷灰石粉或硼即可完全抑制烧结矿冷却过程中的自然粉化现象;MgO含量对烧结矿质量影响明显;烧结矿的冶金性能良好。 相似文献
106.
以δ-FeOOH为前驱体,用氨水调节溶液的pH值,分别采用(1)90℃水浴加热动态转化、(2)沸腾回流动态转化,(3)90℃静态转化及(4)200℃水热法四种方法合成了锰锌铁氧体纳米粉体.采用X射线衍射仪(XRD),透射电子显微镜(TEM)、振动样品磁强计(VSM)和X射线荧光光谱仪(XRF)等方法对粉体进行了表征,对四种液相法制备的锰锌铁氧体纳米粉体的结构和性能等进行了对比和分析.结果表明,四种方法中沸腾回流相转化法得到的产物具有磁性能较好、形状较规则、粒径可控等优点. 相似文献
107.
108.
焦作市石灰岩储量极为丰富,要把资源优势转变为经济优势,就要搞好综合开发利用,生产出科技含量高,具有市场竞争能力的新产品。本文旨在探讨石灰岩资源综合利用的新途径,为焦作矿业经济可持续发展作出新贡献,并为焦作市矿产资源规划提供科学依据。 相似文献
109.
简要介绍了硅粉的理化性能,分析了WG硅微粉的形成过程,并进行了用于塑料制品的使用性能的试验研究,为硅粉用于塑料制品工艺提供了有利的借鉴。 相似文献
110.
Giovanni Maizza Salvatore Grasso Yoshio Sakka Tetsuji Noda Osamu Ohashi 《Science and Technology of Advanced Materials》2007,8(7-8):644
A combined experimental/numerical methodology is developed to fully consolidate pure ultrafine WC powder under a current-control mode. Three applied currents, 1900, 2100 and 2700 A, and a constant pressure of 20 MPa were employed as process conditions. The developed spark plasma sintering (SPS) finite-element model includes a moving-mesh technique to account for the contact resistance change due to sintering shrinkage and punch sliding. The effects of the heating rate on the microstructure and hardness were investigated in detail along the sample radius from both experimental and modeling points of view. The maximum hardness (2700 HV10) was achieved for a current of 1900 A at the core sample, while the maximum densification was achieved for 2100 and 2700 A. A direct relationship between the compact microstructure and both the sintering temperature and the heating rate was established. 相似文献