Pushing Magnesium to new heights. (Magnesium).The Magnesium Div.'s six presentations covered a wide range of topics including grain structure, molding methods, thermophysical properties and the development of new magnesium casting processes. A presentation by B. Davis, Queen's Univ., "Mold Coatings for Magnesium Permanent Mold Casting," (03-184) gave an overview of the problems of longevity for coatings used for permanent mold casting of magnesium, specifically studying the interaction between various coatings for aluminum permanent mold casting and molten magnesium. According to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. Davis, the properties necessary for a coating to be successful when used in magnesium permanent mold are a reasonably high insulation value, a sufficiently rough surface from which gas can escape and a low wear rate. While none of the tested coatings fulfilled all the requirements, Davis found that magnesium reacts with the moisture released by the sodium silicate sodium silicate, any one of several compounds containing sodium oxide, Na2O, and silica, Si2O, or a mixture of sodium silicates. Sodium orthosilicate is Na4SiO4 (or 2Na2O·SiO2); sodium binder and the silica and oxygen to produce magnesium oxide magnesium oxide: see magnesia. which reacts with the silica in the binder to form an interfacial layer of magnesium silicate silicate, chemical compound containing silicon, oxygen, and one or more metals, e.g., aluminum, barium, beryllium, calcium, iron, magnesium, manganese, potassium, sodium, or zirconium. Silicates may be considered chemically as salts of the various silicic acids. . In "Electrical Resistivity Electrical resistivity The electrical resistance offered by a homogeneous unit cube of material to the flow of a direct current of uniform density between opposite faces of the cube. and Thermal Conductivity of Magnesium Alloy AZ91E by Contactless Measurement Technique," (03-050) a presentation by S.I. Bakhtiyarov, S.G. Teodorescu and RA. Overfelt, Auburn Univ., a rotational inductive measurement technique was modified and used to determine the electrical resistivity of the AZ91E magnesium alloy over a range of temperatures (in both solid and liquid states). It was found that the temperature coefficient of the electrical resistivity for AZ91E alloy is smaller in the liquid state than that in the solid state. The technique used to measure the resistivity resistivity Electrical resistance of a conductor of unit cross-sectional area and unit length. The resistivity of a conductor depends on its composition and its temperature. also appeared to be applicable to all magnesium alloys over a wide range of temperatures. |
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