Kinetics and Mechanism of Oxidation Induced Contraction of MgAl 2 O 4 Spinel Carbon Composites Reinforced by Al 4 C 3 in
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https: //doi. org/10.1007/s11595-020-2320-7
Kinetics and Mechanism of Oxidation Induced Contraction of MgAl2O4 Spinel Carbon Composites Reinforced by Al4C3 in situ Reaction YANG Mengyao1, XIAO Guoqing 1, YANG Ding'ao1,2,3, YUAN Shouqian1, ZHAO Jizeng2,3, ZHAO Wei2,3, GAO Song3
(1.College of Materials Science and Engineering, Xi’an University of Architecture and Technology, Xi’an 710055, China; 2.Beijing Lier High-Temperature Materials Co., Ltd., Beijing 102211, China; 3.Luoyang Lier Refractories Co., Ltd., Luoyang 471023, China)
Abstract: Kinetics and mechanism of oxidation induced contraction of MgAl 2O 4 spinel carbon composites reinforced by Al4C3 in situ reaction were researched in air using vertical high temperature thermal dilatometer from 25 ℃ to 1 400 ℃. It is shown that oxidation induced contraction of MgAl2O4 spinel carbon composites reinforced Al4C3 in situ reaction is the common logarithm of oxidation time t and the oxygen partial pressure P inside MgAl2O4 spinel carbon composites reinforced by Al4C3 in situ reaction in air at 1 400 ℃ is as follows: P=F(-2.75×10-4A+2.13×10-3) lnt. The nonsteady diffusion kinetic equation of O2 at 1 400 ℃ inside the composites is as follows: J=De lnt . Acceleration of the total diffusional flux of oxygen inside the composites at 1 400 ℃ is in inverse proportion to the oxidation time. The nonsteady state effective diffusion coefficient De of O2(g) inside the composites decreases in direct proportional to the increase of the amount of metallic aluminium. The method of preventing the oxidation induced contraction of MgAl2O4 spinel carbon composites reinforced by Al4C3 in situ reaction is to increase the amount of Al. The slag erosion index of MgO-Al2O3 spinel carbon composite reinforced by Al4C3 in situ reaction is 0.47 times that of MgO-CaO brick used in the lining above slag line area of a VOD stainless steel-making vessel. HMOR of MgO-Al2O3 spinel carbon composite reinforced by Al4C3 in situ reaction is 26.7 MPa, HMOR of the composite is 3.6 times the same as that of MgOCaO brick used in the lining above slag line area of a VOD vessel. Its service life is two times as many as that of MgO-CaO brick. Key words: kinetics;mechanism; oxidation;contraction; MgAl2O4 spinel; carbon; Al4C3 in situ reaction
1 Introduction With the development of steel making in recent year,the excellent thermal shock resistance and the corrosion resistance are required [1-3]. In the past 20 years, the materials combined with carbon which have excellent thermal shock resistance and corrosion resistance have rapidly grown up and occupied the important parts in the steel making process[4-6]. MgAl2O4 spinel carbon composites as one of carbon containing materials with excellent thermal shock resistance and corrosion resistance can be used to prolong the life-time of steel-making ladle and pretreatment vessel of molten © Wuhan University of Technology and Springer-Verlag GmbH Germany, Part of Springer Nature 2020 (Received: Sept. 12, 2019; Accepted: Nov. 27, 2019) YANG Mengyao(杨梦瑶): E-mail:
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