Investigation of the High Temperature Oxidation Behavior of $${\mathrm{MgF}}_2$$ MgF 2 in Air Atmosphere
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Investigation of the High Temperature Oxidation Behavior of MgF2 in Air Atmosphere Erfan Kadivar1 · Zahra Mozafari1 Received: 18 February 2020 / Revised: 24 July 2020 © Springer Science+Business Media, LLC, part of Springer Nature 2020
Abstract In the present study, we investigate the effect of annealing temperature, annealing time, particle size,and impurity concentration on the oxidation behavior of the MgF2 and MgF2-Cu alloy powder. MgF2 and MgF2-Cu alloy samples have been prepared by mechanical alloying process. The samples have been annealed at different temperatures and times. The oxidation treatment of MgF2 and MgF2-Cu cermets in the air oven at different annealing temperature and time have been studied using XRD, SEM, and EDS. Our experimental results indicate that the oxidation rate increases by decreasing the particle size and increasing the annealing time. The results illustrates that the participation of copper material accelerates the oxidation reaction of MgF2. Keywords MgF2 · MgF2-Cu cermet · Oxidation rate · Impurity concentration
Introduction Magnesium fluoride is the most widely used in the antireflective films [1–4], protective films [5–8], and metal ceramic material (cermet) [9–11] due to high optical transmittance, good insulation, and chemically stable material. Magnesium fluoride has low refractive index, wide band gap, wide transparent range up to mid-IR range (8 μ m), and high mechanical strength. The electronegativity of fluorine is larger than the electronegativity of oxygen. Therefore, the MgF2 compound is much more stable than MgO. Hence at normal temperature and pressure conditions, MgF2 compound cannot react with oxygen forming MgO molecule. However, at high temperature in the air atmosphere, MgF2 tends to react with oxygen and changes to MgO [12–14]. The oxidation behavior of molten magnesium and AZ91D magnesium alloy at 750 °C has been experimentally investigated by Liu et al. [15]. Their experimental results indicate that the oxidation rate of magnesium alloy is greater than that of molten magnesium. * Erfan Kadivar [email protected] 1
Department of Physics, Shiraz University of Technology, 71555‑313 Shiraz, Iran
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Oxidation of Metals
The magnesium fluoride has been also widely used as an interesting material in the development of metal ceramic material (cermet). The oxidation treatment of MgF2 in Ag − MgF2 cermet has been experimentally studied by Sun et al. [14]. Their experimental results show that MgO was formed on the sample surface of 30 wt% Ag − MgF2 cermet in a low vacuum (>100 Pa) at annealing temperature above 600 °C. Chen et al. have studied the reaction kinetics of MgF2 in the air oven at different annealing temperature [16]. The experimental results show that the MgO is formed on the surface of MgF2 at annealing temperature higher that 800 °C. The effect of annealing treatment on the optical and physical properties of TiO2 and MgF2 thin films has been experimentally investigated by Woo et al. [17]. Their experimental results in
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