Corrosion mechanisms of low porosity ZrO2 based materials during near net shape steel casting

Aneziris, C. G.; Pfaff, E.M.; Maier, Henning

doi:10.1016/s0955-2219(99)00149-1

Cited by 48 publications

(19 citation statements)

References 6 publications

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“…Reactions in the system CrÀAlÀO as shown by JACOB, [10] or ANE-ZIRIS, [11] could not be observed although Al 2 O 3 is an impurity in zirconia starting powder. As a result of chemical destabilization with low remaining magnesia amounts around chromium particles the monoclinic phase after sintering at 1400 8C is increased to nearly 66%.…”

Section: Resultsmentioning

confidence: 85%

Screening of the Interactions Between Mg‐PSZ and TRIP‐Steel and Its Alloys During Sintering

et al. 2010

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Metal-ceramic composite materials have been investigated for several years. The combination of a ductile metal with hard and brittle ceramic offers a range of high strength and wear resistant materials. [1][2][3] Metal matrix composites (MMC) are denoted by the ability of plastic deformation and high strain with reinforcements of ceramic particles. Ceramic matrix composites (CMC) with typical ceramic behavior are advantageous in terms of chemical stability, wear resistance, and hardness with elevated fracture toughness caused by metal phase.In recent times, a new type of steel has been developed: TRIP-steel (TRansformation Induced Plasticity). The key to excellent properties is a martensitic phase transformation from austenite to martensite on mechanical load. [4] This change is related with a considerable increase in toughness higher than in normal steels. As a secondary effect, an increase of strength can be observed. Metastable austenitic CrÀNiÀsteels offer tough and high-strength applications combined with economical advantages. [5] The ability of transformation is besides stress and temperature a function of the chemical composition. Austenite stabilizing elements and there factorized impact in comparison to nickel is summarized in formula (1). For sufficient TRIP-effect a calculated sum of 12-16 is necessary. Due to corrosive behavior additions of chromium are necessary in stainless steel. Ferrite phase is stabilized by chromium and other alloying elements as presented in formula (2). As a result a Cr-equivalent of 16-20 enables stainless steel with improved mechanical properties. The most critical alloying element with respect to economical reasons is nickel with up to 90% of costs in steel. Replacing nickel partially by manganese which is 30 orders of magnitude lower in costs offers the ability of cost reductions at similar mechanical properties. For this reason CrÀMnÀNiÀsteels are of interest for both metal and composite applications. [6] Ni À equivalent : %Ni þ 30%C þ 18%N þ 0:5%Mn þ 0:3%Co þ 0:2%Cu þ 0:2%Al(1) Cr À equivalent : %Cr þ %Mo þ 1:5%Si þ 0:5%W þ 0:9%Nb þ 4%Al þ 4%Ti þ 1:5%V(2) Zirconia (ZrO 2 ) ceramics have been used since decades in a wide range of applications due to their corrosive, chemical, and mechanical properties. ZrO 2 appears in three modifications: between melting and 2370 8C the cubic phase (c-ZrO 2 ) is stable. Further cooling leads to transformation into the tetragonal phase (t-ZrO 2 ) and below 1170 8C highly distorted monoclinic ZrO 2 (m-ZrO 2 ) is thermodynamically preferred. The t $ m transformation appears with a volume change of 3-5% which COMMUNICATION Ceramic-steel compound materials are used in a wide range of applications up to date. Major advantages are the mechanical properties due to the combination of brittle ceramic with tough steel. This study deals with effects of the sintering process on austenitic TRIP-steel/Mg-PSZ composite materials for mechanical load applications. Both, the FeÀCrÀNiÀsteel and partially stabilized zirconia offer their special mechanical b...

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Section: Resultsmentioning

confidence: 85%

Screening of the Interactions Between Mg‐PSZ and TRIP‐Steel and Its Alloys During Sintering

et al. 2010

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“…The phase transformation phenomenon in stabilized zirconia based ceramics has also been observed by several researchers and may be considered as the most important cause of ceramics corrosion in slag. [52][53][54] Therefore, one of the corrosion processes of zirconia membrane in this work can be described: the slag penetration into the zirconia membrane, the leaching of the MgO stabilizing agent from the cubic into the slag and transformation of exposed grains to monoclinic zirconia. Besides, the partial dissolved zirconia crystals can be observed at the interface between the zirconia membrane and the slag, and the corresponding grain shows an irregular shape with a serrated border, as shown typically in Fig.…”

Section: (17′)mentioning

confidence: 99%

Effect of Applied Voltage on Electroreduction with Controlled Oxygen Flow of Molten Slag Containing FeO at 1723 K

et al. 2015

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“…The cellular tissue will induce a phase transformation of zirconia from the fully stabilized cubic or the partially stabilized tetragonal phase with large size into the monoclinic phase with small size. The phase transformation phenomenon in stabilized zirconia-based ceramics has also been studied by several investigators and may be considered as the most important cause of ceramics corrosion in the molten slag [36][37][38].…”

Section: Microscopic Observationsmentioning

confidence: 99%

Effect of Basicity on Electroreduction with Controlled Oxygen Flow of Molten Slag Containing FeO

Gao

Duan

Yang

et al. 2015

J. Sustain. Metall.

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This paper reports on electroreduction with controlled oxygen flow (COF) for extraction of iron along with oxygen by-product from molten slags containing iron oxide at 1723 K. An electrolytic cell with COF was constructed by an iridium wire cathode and a porous platinum anode sintered on a one-end-closed magnesia-stabilized zirconia-based solid electrolyte tube. Effect of basicity of SiO 2 -CaO-Al 2 O 3 -MgO-FeO slag on electroreduction behavior of FeO was investigated by means of the linear sweep and the potentiostatic electrolysis. The possibility of the zirconia membrane as conductive noncorrosive anode material was also discussed. The results indicate that both cathode alloying and increasing slag basicity are helpful to the FeO electrolytic reduction in the molten slag. With the iridium wire as a cathode and an applied voltage at 2.5 V, higher slag basicity results in higher electrolysis rate and higher reduction ratio of the FeO; however, silicon is also precipitated during electrolysis. The applied voltage can cause the increased porosity in the zirconia membrane. The corrosion of the molten slag to the zirconia membrane during electrolysis is evidently aggravated when the slag basicity reaches 0.8. In order to minimize the corrosion of the molten slag to the zirconia membrane during electrolysis, the slag basicity of 0.6 is relatively advisable for extraction of iron under conditions of experimentation.

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Corrosion mechanisms of low porosity ZrO2 based materials during near net shape steel casting

Cited by 48 publications

References 6 publications

Screening of the Interactions Between Mg‐PSZ and TRIP‐Steel and Its Alloys During Sintering

Screening of the Interactions Between Mg‐PSZ and TRIP‐Steel and Its Alloys During Sintering

Effect of Applied Voltage on Electroreduction with Controlled Oxygen Flow of Molten Slag Containing FeO at 1723 K

Effect of Basicity on Electroreduction with Controlled Oxygen Flow of Molten Slag Containing FeO

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