Preparation and characterization of high-purity vanadium by EBFZM

Bressers, J.; Creten, R.; Holsbeke, G. Van

doi:10.1016/0022-5088(75)90213-1

Cited by 31 publications

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“…Similar residual resistivity ratios have been obtained by electron-beam floating-zone melting of a double electrorefined vanadium starting material consolidated into rods by pressing under ultra-high vacuum (10-7 -10-8 Pa) conditions [16]. The residual resistivity results were obtained by suppressing the superconductivity with a magnetic field of varied strength, and extrapolating the measured values to zero field.…”

Section: The Purification Of Vanadiummentioning

confidence: 96%

The Purification of Base Transition Metals

Kékesi¹,

Isshiki²

2002

Purification Process and Characterization of Ultra High Purity Metals

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Possible methods of purification, outlined in Sect. 2.1, are applied in practice to purify the technically important 3d-type (first series) transition metals used in modern industry. This group includes the elements in the d-block of the fourth row of the periodic table, from titanium to zinc. Although zinc is not considered a transition metal by virtue of its chemical characteristics, it is also included in the discussion due to the similar practical significance and purification techniques. These metals are produced in large quantities at a commercial level of purity and are used as pure materials (Fe, Cu, Zn and Ti), or as components in various grades of alloys (V, Cr, Mn, Co, Ni and Zn).Having discussed the principles underlying the methods of metal purification in the previous chapters, the attention is now focused on:• the major industrial applications of high-purity grades • starting materials for purification • practically proven methods of separation • achieved levels of purity for each important transition metal, approaching the subject primarily from the angle of overall purification by chemical methods, supplemented by physical steps of specific effects.In general, similarities in the properties of the base metal and the impurities usually make the elimination of certain elements especially difficult. Therefore, a combination of different chemical and physical purification methods may have the desired effect of overall purification. It is especially difficult to remove impurities from the most reactive members in the first transition series, such as Ti, V and Cr. The attainable levels of global purity, indicated by the measured RRR values, are relatively low in these cases. The Purification of TitaniumThe application of ultra-high-purity titanium in VLSI chips requires virtually complete elimination of: (i) alkali metals, which migrate into the gate insulation film and cause deterioration of MOS interface characteristics; (ii) radioactive elements, which cause microprocessor operational errors by (Yparticle emission; and (iii) heavy metals, especially Fe, Cr and Ni, which impair interface junctions [1]. Titanium is also used as a minor addition to low-activation structural alloys, to improve the metallurgical properties. Y. Waseda et al. (eds.), Purification Process and Characterization of Ultra High Purity Metals

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