Wyniki 1-5 spośród 5 dla zapytania: authorDesc:"KUSIŃSKI J."

Korzystny wpływ powłok CaO w procesach wysokotemperaturowego utleniania stopów na bazie niklu lub kobaltu


  Oxidation of nickel and cobalt base alloys has been a subject of interest for many years [1÷4]. However, there is still uncertainty with regard to many aspects, not least the influence of reactive cations, such as Ca2+, Zr4+or Al3+, for instance. This is mainly due to the complexity of the metal/oxide reactivity regarding oxygen. Then introduction of reactive elements as a surface coating of the metal has the advantage to eliminate their effect in the alloy diffusion processes. In the present study, an investigation into the influence of calcium both on the transport properties of Ni1–xO and Co1–xO single crystals and on the thermodynamic and microchemistry properties of these oxides [5, 6] was carried out. The results allowed us to have a better insight into the understanding of the influence of CaO coatings on the oxidation of Ni and Co base alloys. MATERIALS AND METHODS Corrosion experiments Nickel was taken as reference metal for this study. The specimens were square coupons (1 cm2 by 0.1 cm thick), prepared from high purity (99.995%) nickel powder, sintered at 1100°C under an argon-(5%) hydrogen gas mixture. The coupons were first oxidized at 1165°C for 30 h. The oxide scale was removed from one main surface (1 cm2), which was then polished to a 1 m diamond finish. This surface was subsequently coated with a thin layer of CaO, by reactively sputtering CaO target in an ambient of 7 Pa argon, during one hour. Oxidation experiments were carried out in Setaram thermobalance between 800°C and 1200°C, in[...]

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