corrosion mechanism of spinel forming and
Reaction behavior of slag and spinel in steel ladle castables
The difference in corrosion behavior between alumina-spinel and alumina-magnesia castables in a steel slag was investigated with emphasis on the composition of spinel phase. The spinel primarily-added to the alumina-spinel castable had the 3.2 Mechanism of spinel formation in A-M casta- microstructure of alumina-spinel and alumina-magnesia ladle castables after a corrosion test using a rotary furnace. Tab. 1 gives the mass composition of these castables MA1 and MA2 use pre-reacted sintered spinel whilst castables M1 and M2 contain a sintered MgO which reacts with alumina to form in-situ spinel after firing.
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ew I INto CorrosIoN MeChaNIsMs of D r Castables
microstructure of alumina-spinel and alumina-magnesia ladle castables after a corrosion test using a rotary furnace. Tab. 1 gives the mass composition of these castables MA1 and MA2 use pre-reacted sintered spinel whilst castables M1 and M2 contain a sintered MgO which reacts with alumina to form in-situ spinel after firing. The difference in corrosion behavior between alumina-spinel and alumina-magnesia castables in a steel slag was investigated with emphasis on the composition of spinel phase. The spinel primarily-added to the alumina-spinel castable had the 3.2 Mechanism of spinel formation in A-M casta-
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Corrosion Mechanism of A Density-Reduced Steel Ladle
and corrosion mechanism of the lightened alumina spinel castable. 2. Materials and Methods Four di erent MagA aggregate fractions (0–1 mm 1–3 mm 3–5 mm 5–10 mm) were prepared by crushing and sieving a sintered clinker containing in each grain a micro-phase assemblage consisting of MA spinel CA2 and CA. They consisted of about 70 (spinel structure) that form on alloys have a tendency to incorporate radioactive cobalt circulating in the reactor coolant. To fully understand the corrosion mechanism and to evaluate the effectiveness of potential fixes it is of importance to determine the chemistry of spinel phase as a function of water conditions. In this work only
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Modelling of the oxide scale formation on Fe‐Cr steel
Jan 12 2011 · Previous studies showed that the oxidation of T91 (Fe‐9Cr martensitic steel) in liquid Pb‐Bi eutectic leads to the formation of a duplex oxide layer containing an inner Fe 2.3 Cr 0.7 O 4 spinel layer and an upper magnetite layer. The magnetite layer is easily removed by the Pb‐Bi flow when the oxygen concentration is low and the flow velocity is high. The mechanism of the spinel formation from MgO and A1203 has been an important research subject for several workers. Wagnerh1 first sug gested that such reaction occurs by interdiffusion of cations through the anion lattice of the product. Carter51 carried out inert marker experiments in a
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Corrosion of MgO-C with Magnesium Aluminate Spinel
Fundamental investigations of the corrosion mechanism of MgO-MgAl 2 O 4-C refractories for application in steel ladles are not available so far.For the properties of MgO-MgAl 2 O 4-C refractories the chemical composition of the spinel raw material is essential.Hence the aim of this paper is to describe the influence of two common coarse-grained spinel raw materials on the corrosion mechanism Whereas the in situ spinel (MgAl2O4) formation provides an enhanced corrosion and thermal-shock resistance to the castable the composition with pre-formed grains shows higher volumetric stability
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Corrosion of spinel clinker by CaO–Al2O3–SiO2 ladle slag
A two-fold mechanism has been proposed to explain the good anti-corrosion performance of MgO-Al 2 O 3 . First the MgAl 2 O 4 spinel that forms in this material following a reaction between MgO The difference in corrosion behavior between alumina-spinel and alumina-magnesia castables in a steel slag was investigated with emphasis on the composition of spinel phase. The spinel primarily-added to the alumina-spinel castable had the 3.2 Mechanism of spinel formation in A-M casta-
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CORROSION-INHIBITIVE EFFECTS OF SPINEL TYPE PIGMENTS
represented by the corrosion of steel plate in clean distilled water. The results given in Table 4 show clearly different efficiencies of the spinel pigments investigated. It is of course necessary to consider that these results inform only on the part of potential inhibition mechanism of anticorrosive spinel The spinel forming castable contains 5 dead burnt magnesia ≤90 µm thus leading to a theoretical spinel formation of 22 . In practical applications a combination of spinel formation with pre-reacted spinel is also widely used. The two remaining cast-ables belong to this group of products one with an ultra low cement bond (SP-SF) and
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The effective modification of spinel inclusions by Ca
The Mechanisms of Spinel Formation in Liquid Steel In previous research it has been proposed that spinels are formed from the interaction between low-oxygen steel and MgO-containing refractories 9–11arc-heat- ing on slags at a ladle furnace 12as well as from alloys containing Mg. Corrosion of MgAl 2 O 4 Spinel with Different Al 2 O 3 Contents in Iron-Containing FeO x in the slag was absorbed around the surface of spinel block to form the multiple solid J.P. Bennett A. Nakano A and J. Nakano J Gasification slag and the mechanisms by which phosphorous additions reduce slag wear and corrosion in high Cr2O3
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Metal Dusting Corrosion and Mechanics of Materials
Apr 21 2016 · The composition of the oxide scale is important in metal dusting corrosion. Cr 2 O 3 is a better phase than spinel to resist metal dusting since spinel can be reduced. If alloys can generate more Cr 2 O 3 and less spinel on the surface their abilities to resist metal dusting will increase. Therefore alloys with more Cr and less Fe content sition influence both SCC susceptibility and corrosion be-havior the mechanism of SCC is considered to be inevitably related to corrosion behavior. Some of the authors conducted microstructural analysis on crack tips of SCC in simulated PWR primary water.9) The crack tips were filled with chro-mium-rich spinel oxide. The morphology of the
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R ole of Oxygen in Spinel Formation from MgO and Al2O3
The mechanism of the spinel formation from MgO and A1203 has been an important research subject for several workers. Wagnerh1 first sug gested that such reaction occurs by interdiffusion of cations through the anion lattice of the product. Carter51 carried out inert marker experiments in a react with magnesia forming a spinel which decreases open porosity and slag infiltration. The amount grain size and chemistry of the added spinel impact the properties of spinel-containing MgO-C. Corrosion tests have been performed in a steel casting simulator at 1580 C using 18CrNiMo7-6 steel and Fe-rich slag as corrosion medium.
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BASIC MECHANISMS OF CORROSION AND CORROSION
BASIC MECHANISMS OF CORROSION AND CORROSION CONTROL FOR WATER AND WASTEWATER SYSTEMS Graham E.C. Bell Ph.D. P.E. • Dominated by Formation of Sulfuric Acid "Indirect" Impact of Regulations on Corrosion H 2 S crown 210 ppm pH 3 Corrosion InhibitorsPrinciples Mechanisms and Applications •the inhibitor leads a formation of a film by oxide protection of the base metal •the inhibitor reacts with a potential corrosive component present in aqueous media and the product is a complex. 4 14 15 1.2. Historic review
Get PriceImproved Corrosion Resistance of Alumina-Spinel Castable
Sep 09 2011 · spinel castables corrosion resistance Received 04.07.2011 Accepted 09.09.2011 spinel castables present relevant values of residual expansion after firing due to the cal-cium hexaluminate formation which may lead to cracks and reduce its service life. Moreover Braulio et al. 9 pointed out that cement-bonded alumina-spinel castables Experiments on the corrosion of alumina based refractory castables containing 1 2 5 and 10 mass- of cement and 10 mass- of spinel were conducted in an induction furnace at 1550 1650 and
Get Priceew I INto CorrosIoN MeChaNIsMs of D r Castables
microstructure of alumina-spinel and alumina-magnesia ladle castables after a corrosion test using a rotary furnace. Tab. 1 gives the mass composition of these castables MA1 and MA2 use pre-reacted sintered spinel whilst castables M1 and M2 contain a sintered MgO which reacts with alumina to form in-situ spinel after firing. Jul 18 2013 · The application of high alumina materials with additions of spinel and/or spinel forming magnesia as wear linings in steel ladles has increased in recent years. Corrosion of high alumina spinel castables by steel ladle slag The influences of mechanical properties and chemical composition on the wear mechanism are discussed. Although the
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Corrosion of MgO-C with Magnesium Aluminate Spinel
Fundamental investigations of the corrosion mechanism of MgO-MgAl 2 O 4-C refractories for application in steel ladles are not available so far.For the properties of MgO-MgAl 2 O 4-C refractories the chemical composition of the spinel raw material is essential.Hence the aim of this paper is to describe the influence of two common coarse-grained spinel raw materials on the corrosion mechanism represented by the corrosion of steel plate in clean distilled water. The results given in Table 4 show clearly different efficiencies of the spinel pigments investigated. It is of course necessary to consider that these results inform only on the part of potential inhibition mechanism of anticorrosive spinel
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Eight forms of corrosion
Eight Forms of Corrosion by Fontana Greene 1967 The idea of describing the various ways corrosion can damage metals by it appearance had be used by many before Fontana and Greene coauthored their famous book in 1967.McKay and Worthington were already discussing various forms of corrosion in their 1936 book on corrosion. following Alan Pollitt in his own book published thirteen The difference in corrosion behavior between alumina-spinel and alumina-magnesia castables in a steel slag was investigated with emphasis on the composition of spinel phase. The spinel primarily-added to the alumina-spinel castable had the 3.2 Mechanism of spinel formation in A-M casta-
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Corrosion of magnesium aluminate spinel-rich refractories
May 01 2015 · During corrosion test next to alumina also the spinel component is slightly corroded by slag. It is assumed that spinel primarily reacts with sulphur SiO2 and CaO from the slag forming compositions with low melting point which will get dissolved by the slag. This leads to regions in the slag in which Al Mg S Ca and O are enriched. Jul 18 2013 · The application of high alumina materials with additions of spinel and/or spinel forming magnesia as wear linings in steel ladles has increased in recent years. Corrosion of high alumina spinel castables by steel ladle slag The influences of mechanical properties and chemical composition on the wear mechanism are discussed. Although the
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In-Situ Synthesis and Formation Mechanism of Al2 3-Spinel
3-spinel(N) composite. The mechanism for formation of the spinel(N) can be described as follows in nitrogen atmosphere with low oxygen partial pressure magnesia is unstable and decomposes into Mg(g). Mg(g) diffuses and transfers along the pores or gaps in Al 2O 3-MgO composites and reacts with corundum or spinel forming gas aluminum at the (spinel structure) that form on alloys have a tendency to incorporate radioactive cobalt circulating in the reactor coolant. To fully understand the corrosion mechanism and to evaluate the effectiveness of potential fixes it is of importance to determine the chemistry of spinel phase as a function of water conditions. In this work only
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Ceramics Free Full-Text Corrosion Mechanism of A
Steel ladle linings with spinel-containing or spinel-forming high alumina refractories in the metal zone (wall and bottom) are the state-of-the-art 1 2 3 .While magnesia-carbon refractories potentially pollute steel with carbon the high purity and carbon-free alumina spinel refractories facilitate the production of ultra-low carbon steel.. Traditionally ladle castable developers try to react with magnesia forming a spinel which decreases open porosity and slag infiltration. The amount grain size and chemistry of the added spinel impact the properties of spinel-containing MgO-C. Corrosion tests have been performed in a steel casting simulator at 1580 C using 18CrNiMo7-6 steel and Fe-rich slag as corrosion medium.
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