Hydrogen plasma-metal reaction

Two methods of producing nanostructured MgH were already briefly mentioned in Sect. 2.1.3.3 and 2.1.5. Shao et al. [44] used the hydrogen plasma-metal reaction to obtain ultrafine magnesium with an average size of about 300 nm. The activation of... 

H. Shao, Y. Wang, H. Xu, X. Li, Hydrogen storage properties of magnesium ultrafine particles prepared by hydrogen plasma-metal reaction, Mater Sci. Eng. B 110 (2004) 221-226. 

Shao et al. [25] prepared Mg Ni from magnesium and nickel nanoparticles produced by hydrogen plasma-metal reaction. Two preparation methods were developed to obtain the compound. One is heating the nanoparticles under 0.10 MPa argon pressure at 430°C and the other is under 3.00 MPa hydrogen pressure at 280°C. No hydrogen storage properties of this material were assessed. 

In addition, the hydrogen plasma-metal reaction (HPMR) method was applied to synthesize rare earth oxide nanoparticles [13], which has been used to prepare better metallic ultrafine particles industrially at low cost. Pure Sm and Nd oxide nanoparticles were prepared through the HPMR method followed by oxidation treatment. The first step is to fabricate hydride nanoparticles the second is to oxidize them at room or elevated temperatures. Cubic neodymium and samarium oxides were synthesized with their average sizes of 20 and 40 nm, respectively. 

In order to improve the kinetics of the Li-N-H system, Xie et al. [96] prepared Li2NH hollow nanospheres by plasma metal reaction based on the Kirkendall effect. The special nanostructure showed significantly improved hydrogen storage kinetics compared to that of the Li2NH micrometer particles. The absorption temperature decreased markedly, and the absorption rate was enhanced dramatically because... 

Hydrogen reduction of chlorides in thermal plasma can be apphed not only to produce powder of individual metals but also to produce different intermetalhc compounds. The composition of the generated crystals copies the composition of the chloride mixture in the gas phase. This effect permits the production of the intermetallic compounds with the required composition. Refractory intermetallic compounds based on niobium and vanadium were synthesized from their chlorides (conversion close to 100%) in a hydrogen plasma jet generated by RF-ICP discharge (Bashkirov Medvedev, 1968). The reaction products were crystallized on a substrate sustained at a temperature of about 1000°C. The plasma-metallurgical technology is proven to be effective in the synthesis of vanadium-Hsilicon... 

The reaction products formed in plasma metal etchers are a complex mixture of chlorinated and fluorinated compounds. The maintenance of metal etchers often involves short duration operations that generate strong odors. Hexachloroethane was found to be the major cause of odor in one type of aluminum etcher.h l In another, cyanogen chloride was the main problem exposure levels were 11 times the 0.3 ppm TLV .[20] In still other types of etchers, hydrogen chloride is associated with the odor (maximum exposure measured was 68 ppm odor threshold for HCl is less than 5 ppm). The paper by Mueller and Kunesh is a good source of additional information on the subject.I l... 

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