Hydrogen contamination

At many plants, fluxes are added to the metal to reduce hydrogen contamination, remove oxides, and eliminate undesirable trace elements. Solid fluxes such as hexachloroethane, aluminum chloride, and anhydrous magnesium chloride may be used, but it is more common to bubble gases such as chlorine, nitrogen, argon, helium, and mixtures of chlorine and inert gases through the molten metal. 

Several facts can give some suspicion for the origin of the hydrogen contamination in GaAs ... 

Asg ° by applying the valence bond concept (Fig. 9a). The bonding situation of the electron-deficient chains shown in Fig. 9b is not as trivial. In these cases, on one hand, multiple element-element bonding is discussed, and on the other hand, the possibility of partial protonation cannot be excluded completely, especially for compounds of the sometimes hydrogen-contaminated metal barium. 

HIDROXILAMINA (Spanish) (7803-49-8) A powerful reducing agent. Aqueous solution is a base. Contact with water or steam causes decomposition to ammonium hydroxide, nitrogen, and hydrogen. Contaminants and/or elevated temperatures above (reported at 158°F/70°C and 265°F/129°C) can cause explosive decomposition. Moisture in air or carbon dioxide may cause decomposition. Violent reaction with oxidizers, strong acids, copper(II) sulfate, chromium trioxide, potassium dichromate, phosphorus chlorides, metals calcium, sodium, zinc. Incompatible with carbonyls, pyridine. Forms heat-sensitive explosive mixtures with calcium, zinc powder, and possibly other finely divided metals. Aqueous solution incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, carbonyls, cellulose nitrate, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, glycols, isocyanates, ketones, nitrates, phenols, pyridine, vinyl acetate. Attacks aluminum, copper, tin, and zinc. 

In addition to this prepeak, a shoulder appears at smaller q values (fig. l.b)and transforms into a well-defined peak at 35 % Cu ( fig. l.c). We will see in the next section that this peak can be attributed to a small hydrogen contamination. 

The FCVA used by Xu et al. [48] was an elbow-shaped evacuated tube with electrodes at each end. The substrate was mounted near one end, and a carbon arc discharge was operated for short intervals at the other. Electric and magnetic fields steered the carbon ions around the bend, but particulate matter was trapped (filtered). Care was exercised to avoid hydrogen contamination. 

Face-Centered Cubic (fee) and Face-Centered Orthorhombic (fco) Martensites. Face-centered cubic martensite has been found during TEM studies in binary Ti-Cr, -Fe, -Mo, -Mn alloys, as weU as in other more complex systems. This martensite is not typical of the bulk material. It seems to be an artifact produced during thin-foil electropolishing as a result of hydrogen contamination, although this cause is not... 

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