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The production of metal powders

In die production of metallic objects for technological applications, an important way to produce drese is via die compacting of metal powders. One [Pg.201]

The particle size distribution of ball-milled metals and minerals, and atomized metals, follows approximately the Gaussian or normal distribution, in most cases when the logarithn of die diameter is used rather dran the simple diameter. The normal Gaussian distribution equation is [Pg.202]

This mathematical form of the size distribution does not take account of the fact that die particle size does not stretch over die range from minus to plus infinity but has a limited range, and a modification such as the empirical Rosin-Rammler (1933) equation [Pg.202]

The cumulative function, F, for all of these distributions is dehned tlrrough the equation [Pg.203]


A. T2cM y,A.tomicyation The Production of Metal Powder, Metal Powder Industries Federation, Princeton, N.J., 1992. [Pg.193]

The recovery or removal of metals from solutions derived from the leaching of minerals is an important step in any hydrometallurgical process. Precipitation by reduction to the metallic state in electrochemical cells will be discussed in Section 63.3.5 this section will cover the use of chemical reagents to control the precipitation process. Therefore, although the production of metallic powders by the reduction of metal ions with hydrogen or less-noble metals (cementation) is electrochemical in nature, it will be discussed under this heading. [Pg.827]

Figure 3.5. Illustration of an atomizer for the production of metallic powders. The molten metal/alloy is sprayed into a cooling tower under the flow of an atomizing gas. The particulates are allowed to cool as they descend downward, and are collected in a hopper at the bottom of the tower. Reproduced with permission from Crucible Materials Corporation (http //www.cruciblecompaction.com/... Figure 3.5. Illustration of an atomizer for the production of metallic powders. The molten metal/alloy is sprayed into a cooling tower under the flow of an atomizing gas. The particulates are allowed to cool as they descend downward, and are collected in a hopper at the bottom of the tower. Reproduced with permission from Crucible Materials Corporation (http //www.cruciblecompaction.com/...
Reisse and co-workers [147-149] were the first to describe a novel device for the production of metal powders using pulsed sonoelectrochemical reduction. This device exposes only the flat circular area at the end of the sonic tip to the electrodeposition solution. The exposed area acts as both cathode and ultrasound emitter, named by Reisse et al. as sonoelectrode . A pulse of electric current produces a high density of fine metal nuclei. This is immediately followed by a burst of ultrasonic energy that removes the metal particles from the cathode, cleans the surface of the cathode, and replenishes the double layer with metal cations by stirring the solution. In [145], a list is given of chemically pure fine crystalline powders, mostly metals or metallic alloys, prepared by this method, with particle sizes varying between 10 and 1000 run depending on deposition conditions. [Pg.149]

A. Lawley Atomization, the Production of Metal Powder, MPIP, Princeton, New Jersey,... [Pg.847]

A. Lawley Atomization the Production of Metal Powders, MPIF, Princeton, 74 (1992). [Pg.848]

Different methods for the production of metal powders including mechanical commuting, chemical reaction, electrolysis, and liquid metal atomization are used in practice [1]. Powders of about 60 metals can successfully be produced by electrolysis. The majority of metallic powders are obtained by molten-salts electrolysis. However, due to technological advantages and various industrial applications most of the practically useful powders, e.g., copper, iron, and nickel, are produced from aqueous solutions [3]. [Pg.126]

The production of metallic powders without an external current source has many advantages compared to electrochemical (electrolytic) methods. Generally speaking, all the powders that can be produced electrolyticaUy from aqueous solutions can also be obtained using chemical methods, i.e. without an external current source. Classical examples of metallic powders produced from aqueous solutions by chemical methods on an industrial scale via the so-called hydrometallurgical processes include nickel and copper. [Pg.369]

Examples of the application of autoclave processes in the production of metal powders with hydrogen reduction at high temperature and pressure include nickel, cobalt, copper, noble metals, and less common metals [2]. [Pg.371]

The production of metallic powders through hydrometallurgical or electrodeposition routes has extensively been studied over the last century. The formation of metallic powders during electroless deposition of films of metals or alloys is observed when the so-called bath instability takes place [1, 16, 17]. As such, the electroless deposition was far less investigated than its electrolytic counterpart. The bath instability is usually seen in the experimental conditions at elevated temperatures or when the concentration of the reducing agent is too high. [Pg.374]

In this section, the production of metallic powders via galvanic displacement or cementation as well as via electroless deposition using different reducing agents is discussed. [Pg.374]

Electroless deposition can successfully be used for the production of metallic powders with various sizes and shapes. A traditional approach in the production of metallic powders from aqueous solutions without the application of an external current, e.g., Ni, Co etc., is based on the reduction of the respective metal ions with hydrogen at elevated temperatures and under pressure. These hydrometallurgical processes are well established in industry. [Pg.396]

The present volume of Modern Aspects of Electrochemistry brings readers the newest developments and achievements in the production of metallic powders by electrochemical and electroless methods from aqueous solutions. Although the deposition of metallic powders from aqueous solutions was intensively studied for years, the last summarized results (Calusam) on this topic were published in 1979. [Pg.408]

Two applications which might be expected to be dependent upon the factors affecting jet break-up are the production of metal powders and metallic ribbons. [Pg.266]

Numerous atomization techniques have evolved for the production of metal/alloy powders or as a step in spray forming processes. Atomization of melts may be achieved by a variety of means such as aerodynamic, hydrodynamic, mechanical, ultrasonic, electrostatic, electromagnetic, or pressure effect, or a combination of some of these effects. Some of the atomization techniques have been extensively developed and applied to commercial productions, including (a) two-fluid atomization using gas, water, or oil (i.e., gas atomization, water atomization, oil atomization), (b) vacuum atomization, and (c) rotating electrode atomization. Two-fluid atomization... [Pg.66]

Uses. Structural material in construction, automotive, and aircraft industries in the production of metal alloys in cookware, cans, food packaging, and dental materials pyro powders are used in fireworks and aluminum paint. [Pg.36]

In the occupational setting, exposure to cobalt alone occurs primarily in the production of cobalt powders. With other industrial exposures, such as hard metal exposure, additional... [Pg.180]

An unusual new synthesis method involves carrying out reactions in a molten salt medium, and has been used on an industrial scale for the production of metallic nitride, carbide or carbonitride powders.25 An illustration of this CEREX process is the preparation of oxygen-free titanium nitride in molten calcium chloride. The method involves the reaction between titanium tetrachloride and calcium nitride ... [Pg.144]

Schur D.V., Dubovoi A.G., Anikina N. S., Zaginaichenko S. Yu., Dobrovol skij V.D., Pishuk V.K., Tarasov B.P., Shul ga Yu.M., Meleshevich K.A., Pomytkin A.P., and Zolotarenko A.D. (2001) The production of ultrafine powders of fullerites by the salting out method, Proceedings of VII International Conference Hydrogen Material Science and Chemistry of Metal Hydrides , Alushta-Cremia-Ukraine, September lb-22, pp. 478-484. [Pg.53]

The preparation of TiC, VC, NbC, TaC, M02C, WC, and the chromium carbides are important technical processes for the production of carbide powders for hardmetals. Generally, the carbides are prepared by the reduction of oxides with carbon only M02C and WC are manufactured by reaction of the metal powders with graphite or carbon black. [Pg.589]

Atomization is particularly useful for the production of homogeneous powdered alloys, since the constituent metals are intimately mixed in the molten state. Further, this process is also useful to produce powders of difficult compositions. For instance. [Pg.95]

DFG MAK DFG TRK 0.5 mg/m calculated as cobalt in that portion of dust that can possibly be inhaled in the production of cobalt powder and catalysts hard metal (mngsten carbide) and magnet production (processing of powder, machine pressing, and mechanical processing of unsintered articles) other cobalt alloys and compounds 0.1 mg/m calculated as cobalt in that portion of dust that can possibly be... [Pg.377]


See other pages where The production of metal powders is mentioned: [Pg.201]    [Pg.201]    [Pg.91]    [Pg.527]    [Pg.773]    [Pg.1045]    [Pg.882]    [Pg.205]    [Pg.350]    [Pg.201]    [Pg.201]    [Pg.91]    [Pg.527]    [Pg.773]    [Pg.1045]    [Pg.882]    [Pg.205]    [Pg.350]    [Pg.28]    [Pg.288]    [Pg.202]    [Pg.214]    [Pg.309]    [Pg.336]    [Pg.202]    [Pg.214]    [Pg.220]    [Pg.395]    [Pg.404]    [Pg.581]    [Pg.196]    [Pg.1185]    [Pg.288]    [Pg.309]    [Pg.336]   


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