Magnesium alloys techniques

Application of SPD techniques to metal hydrides is a new field of research. Skripnyuk and Rabin were the first to use ECAP to improve the hydrogen storage properties of Mg-based alloys [254, 255]. The first study on ECAP-processed magnesium alloy ZK90 showed an improvement in sorption kinetics without loss of hydrogen capacity or change in thermodynamic parameters [254]. figure 4.12 shows comparable results for the Mg-Ni eutectic alloy [255]. 

The methods involving Chrome Azurol S and surfactants were used for determining aluminium in water [27,89-93], steel [94,95], copper alloys [26], magnesium alloys [21], chromium alloys [96], and titanium [3]. Trace amounts of aluminium were determined in tap water by means of CAS and CP (pH 5.7 30% ethanol) using the flow-injection technique (FIA) [91]. 

Zirconium has been determined by the Alizarin S method in uranium alloys [45], titanium alloys [92], magnesium alloys [27], and rutile [3]. Determination of Zr by the differential technique has also been applied [44]. 

C. Chemical modification of the glued surfaces by the formation of passivating layers. The modification technique depends on the nature of the metal. The parts are most often subjected to acid pickling, e.g. aluminum alloys are anodized in sulfuric and chromic acids. It is preferable to anodize aluminum parts in sulfuric acid followed by treatment of the anodic film in a bichromate. There are several methods of pickling carbon and stainless steels, chemical oxidation of magnesium alloys as well as copper and titanium alloys before gluing [4]. 

Hot-chamber HPDC machines comprise a molten metal reservoir, the die, and a metaltransferring device, which automatically withdraws molten metal from the reservoir and forces it under pressure into the die. A steel piston and a cylinder system with a gooseneck is used to create the necessary pressure within the die. A gooseneck machine utilises a cast iron channel to transfer the molten metal from the reservoir to the die. Pressures can range from a few bar to over 350 bar. Hot-chamber techniques are mainly used for zinc alloys and magnesium alloys. 

Song G-L. (2008a), An electroless e-coating bath sealing technique for anodized and conversion coated magnesium alloys , MPL-641(GM confidential report). 

Kannan M B and Singh R (2010), A mechanistic study of in vitro degradation of magnesium alloy using electrochemical techniques , Journal of Biomedical Materials Research Part A, published online 14 Sep 2009 (http /www3.interscience, wiley.com). 93A, 3, 1050-1055. 

X Cao, M Jahazi, JP Immarigeon, W Wallace, A review of laser welding techniques for magnesium alloys. Journal of Materials Processing Technology, 2006, 171, 188-204. 

The combination of immersion, hydrogen collection and weight loss measurement is an easy corrosion evaluation method, particularly for magnesium alloys. The method, first established and used by Song et al. [5] to estimate and monitor the corrosion rate of magnesium in a NaCl solution, has been widely adopted as a common corrosion rate measurement technique for magnesium alloys in various aqueous solutions. The reliability of the method has been theoretically and experimentally demonstrated [24,25] and the details will not be repeated here. 

The nickel-magnesium-cerium technique involves the following vacuum procedure, which originates from Kraus and Paesold (25) the sample is introduced into the reaction furnace at 1200°C simultaneously with 1.5 to 2 g nickel, 0.03 g magnesium and sufficient nickel-cerium master alloy to give a concentration of 1 % cerium in the melt. The temperature is then raised to 1700°C. 

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