Increasing Cr Content Research Articles

Evaluating of the Relationships between aAverage Particle Size and Microstructure-Mechanical Properties of Materials Produced in Different Compositions using Ultrasonic Method

Pulse-echo ultrasonic test, which is one of the non-destructive testing methods, was used to measure ultrasonic quantities such as longitudinal velocity (VL), shear velocity (VT) and attenuation coefficient (α) in FeCrMn composites. The corresponding elastic constants were determined depending on the longitudinal and transverse velocity. The aim was to reveal the correlation between the microstructural and mechanical properties of FeCrMn composites and ultrasonic quantities. The effect of adding Cr particles on VL and VT velocities is obviously attributed to the change in elastic and shear modulus of FeCrMn composites. It was found that both VL and VT velocities, Young’s modulus (E) and shear modulus (G), as well as hardness values, changed approximately linearly with increasing Cr content. In this study, samples with different volumetric compositions were produced using the powder metallurgy method. It has been revealed that both the applied method and the increase in the amount of Cr have a significant effect on the velocities of VL and VT. The increase in VL and VT is due to the increase of Cr particles, the homogeneous distribution of Cr, the formation of samples especially at a certain temperature, and the decrease of porosity. As a result of these, a decrease in attenuation values was observed depending on the mean grain size. Elastic constants were found to vary in the same way as ultrasonic velocities. By increasing the Cr content both the hardness values and the shear modulus were improved and a good correlation was observed with the grain size.

Influence of atomic substitution on the structural stability and half-metallicity of Fe2-xCrxCoSi (x = 0 to 1) alloys

Bulk Fe2-xCrxCoSi (x = 0, 0.25, 0.5, 0.75, and 1) Heusler alloys have been prepared by arc melting method. Alloys with 0.0 ≤ x ≤ 0.75 show a highly ordered phase pure XA structure. However, 17 % of an impurity (A15 phase) was detected in the alloy with x = 1. The saturation magnetization (Ms) and Curie temperature (TC) decreased linearly with an increase in Cr content for alloys with x ≤ 0.75. Ms measured at 5 K followed the Slater–Pauling rule for half-metals. Ab initio calculations with the GGA + U approach revealed that spin polarization (P) increased with an increase in Cr and eventually reached 100 % for the alloys with x = 0.5. Though Fe-Co disorder affects P, it is still high (>98 %) for alloys with x ≥ 0.5. Despite the smaller bandgap (0.61 eV) of Fe1.5Cr0.5CoSi than FeCrCoSi (0.91 eV), it has higher Ms, elevated TC, and 100 % P. These factors, coupled with the challenges associated with obtaining phase pure FeCrCoSi alloy, make Fe1.5Cr0.5CoSi a preferred candidate for spintronic device applications.

Exploring the kinetics and thermodynamics of TiFe0.8CrxMn0.2-x hydrogen storage alloys

The influence of Fe substitution by Cr and/or Mn on the hydrogenation properties of TiFe0.8CrxMn0.2-x hydrogen storage alloys was explored for several substitution amounts (x = 0, 0.05, 0.1, 0.15 and 0.2). The synthesized alloys consisted of a dominant TiFe (cubic, CsCl-type) and a secondary C14 Laves phase (hexagonal, MgZn2-type). The increase in Cr content, and consequently in C14 Laves phase fraction, improved the first hydrogenation kinetics and the hydrogen intake after activation (1.60–1.70 wt% H2 at 30 °C within 3 min), while substantially stabilizing the monohydride phase. The reaction enthalpy obtained from pressure-composition-temperature (PCT) curves hence increased along Cr substitution, ranging 24.35 ± 0.34 to 35.39 ± 1.00 kJmol-1 for the absorption, and 31.08 ± 1.39 to36.34 ± 1.99 kJmol−1for the desorption (absolute values). These experimental findings were in good agreement with density functional theory (DFT) predictions performed across the explored composition space. The estimated entropy values on the other hand remained nearly constant, fluctuating between 84.28 ± 4.76 and 102.64 ± 3.12 J mol−1 H2 K−1 for the absorption, and 100.46 ± 9.71 up to 105.45 ± 4.31 J mol−1 H2 K−1 for the desorption. Solid-gas reaction modeling showed that, under practical service conditions, the hydrogenation of activated alloys was interface-controlled followed by diffusion-controlled mechanisms as the reaction proceeded.

Thermodynamic Study on the Solubility of N in High Cr, Ni and Mo Content Fe-Cr-Ni-Mo-O Melts

The aim of the present study is to investigate the solubility of nitrogen in super or hyper duplex stainless steel, which is characterized by a very high Cr content, as well as the activity interaction parameters between N and other alloy elements. The chemical equilibrium method was employed in the present experiment. High Cr, Ni, and Mo content Fe−Cr−N−O and Fe−Cr−Ni−Mo−N−O melt are equilibrated at 1873 K under atmospheres of pure nitrogen and Ar/N2 gas mixture. The melts were placed in Al2O3 crucibles and coated with graphite crucibles. The experimental results showed that the solubility of N significantly increased with increasing Cr content, reaching over 1 wt pct at a Cr content of about 40 wt pct. In addition, the solubility of Cr increased slightly with a decrease in Ni content and an increase in Mo content. The activity interaction parameters were fitted using WIPF (Wagner’s Interaction Parameter Formalism), as shown as follows: eNCr=−0.07083, rNCr=+0.0005888, rNN=−0.00926, eNNi=+0.30885, rNNi=−0.03963, eNMo=−0.05882, rNMo=+0.00616; the comprehensive set of thermodynamic basic parameters obtained in this study can be effectively used to assess the N solubility in USSD with a Cr content exceeding 30 wt pct.

Corrosion Ferritic Stainless Steel in a Simulated Hydrothermal Liquefaction Bioconversion Aqueous Solution: Effect of Surface Cr Content

Abstract The objective of this study was to determine the effect of surface Cr content on the corrosion of ferritic stainless steels in hot pressurized alkaline water (310 °C at 10 MPa) simulating a hydrothermal liquefaction bioconversion medium. Two methods to increase the Cr surface content were investigated: (i) selecting commercial grades of ferritic stainless steel with an increasing Cr content and (ii) applying a Cr coating (chromizing) to a low-Cr (Type 409) ferritic stainless steel. The observed parabolic-like corrosion kinetics were analyzed and discussed in terms of the structure and composition of the double layered oxide films that formed. The (surface) Cr content is a critical factor affecting corrosion. Corrosion was reduced by 66% (after 20 days exposure) when increasing the Cr content from 9 wt.% (P91) to 21 wt.% (SS443) in the commercial grades of ferritic stainless steel. Moreover, corrosion was reduced by 84% (after 20 days exposure) by chromizing the surface of a low-Cr (Type 409) ferritic stainless steel. Improved corrosion protection was attributed to increased Cr incorporation into the inner (barrier) Fe(Fe1-nCrn)2O4 layer, with the formation of a Cr2O3 layer (resulting from chromizing) being most beneficial.

Atomistic insight into the interfacial reaction and evolution between FeCr alloys and supercritical CO2 with impurities

The supercritical CO2 cycle offers high thermal efficiency and flexibility, enhancing energy conversion efficiency and utilization. As the commercialization of supercritical CO2 cycles advances, the stability of the metal-CO2 interface is the key to ensure the safety of this power cycle. In this paper the interfacial reactions between FeCr alloys and CO2 with impurities were investigated using the oxidation thermodynamics and molecular dynamics. With the increase of Cr content in FeCr alloy, the adsorption stability of SO2 and CO2 molecules on the surface of FeCr alloy became stronger, in which CO2 molecules were adsorbed and decomposed in two ways. When the C-O bond was broken, the detached O atom was in a free state or reorganized into O2 molecule, while the CO molecule would be separated from the CO2 molecule. In the initial oxidation stage, adding appropriate amount of H2S in CO2 environment could reduce the diffusion of O atoms from the CO2 molecule to Fe20Cr alloy, and the stress in the oxide film would not increase. The early oxidation behavior of Fe20Cr alloy in CO2 with H2S impurity gas may prove to be an effective method for enhancing its oxidation resistance of Fe20Cr alloy.

Effect of liquid droplet impingement on electrochemical passivation behavior of 321 stainless steel in 0.5 wt% NaCl solution

Liquid droplet impingement (LDI) treatment changes the roughness and introduces residual compressive stress on 321 stainless steel (SS). Compared to untreated 321 SS, 1 h of LDI treatment with 100, 150 and 175 m/s gradually increases the pitting potential of 321 SS, while 1 h of LDI treatment with 200 m/s decreased the pitting potential of 321 SS. The passive films grown on the 321 SS after LDI treatment with 100, 150 and 175 m/s show a decreased receptor density, an increased Cr content and an increased thickness, whereas a dense passive film with good corrosion resistance cannot be formed on the 321 SS after LDI treatment with 200 m/s. The effect of the change in surface state due to LDI treatment on the electrochemical passivation behavior is explained in detail.

Phase, Microstructure and Corrosion Behaviour of Al0.3FeCoNiCrx High-Entropy Alloys via Cr Addition.

The microstructure evolution of Al0.3FeCoNiCrx (x = 0, 0.3, 0.5, 1, 1.5) high-entropy alloys (HEAs) were studied using X-Ray diffraction technique and scanning electron microscope equipped with energy dispersive spectrometer. The short-term and long-term corrosion behaviours of these alloys in 3.5 wt.% NaCl solution were studied by electrochemical impedance spectroscopy, potentiodynamic polarisation measurement, immersion test and corrosion morphology analysis. The results show that all the designed HEAs present single-phase FCC structure, and the increase in Cr content changes the microstructural morphology from cellular to a typical dendritic-interdendritic state. Without the influence of phase transformation, the corrosion resistance of Al0.3FeCoNiCrx HEAs gradually increases with the increase in Cr content. Our designed alloys exhibit excellent corrosion resistance compared to the existing HEAs in the AlFeCoNiCr composition system.

The electronic and magnetic properties of Cr-doped ZnO monolayer at higher percentage by first principles calculations

The crystal structure, structural stability, electronic band structures and magnetization of Cr-doped ZnO monolayer (ML) have been investigated by GGA+U method using first principles calculations in this work. The stability of these systems is confirmed by the negative formation energies at different Cr concentrations. The calculated band gaps with and without the Hubbard U correction aligned well with other computational results. With the increase of Cr concentration, the band gap of Cr-doped ZnO monolayer decreases for the spin-up configuration. However, in the spin-down configuration, the band gap increases first and then decreases and the maximum band gap is obtained at 22.22% Cr concentrations. At 33.33% Cr concentration, the ZnO ML exhibits metallic behavior. The density of states (DOS) analysis reveals an asymmetric nature, indicating ferromagnetism in Cr-doped ZnO MLs at various concentrations, with a magnetic moment per Cr atom of approximately 3.99 μB. The total magnetic moment rises with increasing Cr concentration. Charge density difference analysis shows increased magnetization with higher Cr concentration. At 22.22% Cr concentration, the ZnO ML exhibits ferromagnetism and semiconducting properties, suggesting significant potential for spintronic applications as a diluted magnetic semiconductor.

Effect of Cr on nano-indentation Young's modulus and hardness of the β-Ti phase in equilibrium with α2-Ti3Al and γ-TiAl phases in Ti-Al-Cr alloys

Young's modulus and hardness of the constituent phases of β-Ti (bcc or B2), in equilibrium with α2-Ti3Al (D019) and γ-TiAl (L10) phases in Ti-Al-Cr ternary alloys were quantitatively evaluated in terms of the chemical composition analysis and nano-indentation method, in order to identify the Cr concentration dependence on the mechanical properties of the β phase. An alloy with a nominal composition of Ti-43Al-3Cr (at.%) decomposes into the three phases of β, α2, and γ by equilibrium heat treatment at 1373 K, with chemical composition of Ti-37.2Al-5.2Cr, Ti-38.9Al-2.2Cr, and Ti-47.4Al-1.4Cr, respectively. The β phase shows a Young's modulus of 141 ± 5 GPa, smaller and less orientation dependent than the other two phases of α2 (174 ± 9 GPa) and γ phases (164 ± 15 GPa). In contrast, the β phase has a hardness of 5.9 ± 0.3 GPa, slightly softer than the α2 phase (6.4 ± 0.8 GPa) but much harder than the γ phase (3.7 ± 0.6 GPa). The alloys Ti-44Al-4Cr and Ti-45Al-6Cr consist of two phases of β and γ phases, and the chemical composition of the β phase in these two alloys is Ti-36.5 Al-8.5 Cr and Ti-36.3 Al-13.9 Cr, respectively, with nearly the same Al concentration. The Young's modulus and hardness of the β phase with the latter composition become 158 GPa and 6.7 GPa, respectively, with increasing Cr content. These results found that the effect of solid solution Cr on the Young's modulus for β phase is relatively weak, and that on the hardness is strong, in comparison with that for the other two phases.

Effect of Cr content on the high temperature oxidation behavior of FeCoNiMnCrx porous high-entropy alloys

FeCoNiMnCr porous high-entropy alloys were prepared using the activation reaction sintering method with Fe, Co, Ni, Mn, and Cr as raw materials. The oxidation behaviors of FeCoNiMnCrx porous high-entropy alloys with different Cr contents, such as pore structure, the surface oxide film phase composition, structure, and morphology, were characterized by X-ray diffraction (XRD), electron probe micro analysis (EPMA), energy dispersive X-ray spectroscopy (EDS), and pore tester after high-temperature oxidation at 800–1000 °C. The results indicate that the initial porous high-entropy alloy comprises a single FCC solid solution phase. With the increase in Cr content, the average pore diameter, average porosity, and air permeability of the porous high-entropy alloy also increase. The oxidation kinetics of the porous high-entropy alloy after exposure to temperatures between 800 °C and 1000 °C follows a single-stage parabolic evolution law. At the same oxidation temperature, With the increase of Cr content, the oxidation gains gradually increased, at the same Cr content at different temperatures, the antioxidant performance of 1000 °C was the weakest, followed by 800 °C, and 900 °C showed excellent antioxidant performance. The oxidation products are mainly Mn2O3, Mn3O4, (Mn, Cr)3O4, Cr2O3and Fe2O3.

ДОСЛІДЖЕННЯ АДСОРБЦІЇ CrО42- ТА Cr2О72- ПОЛІАНІЛІНОМ ІЗ ВОДНИХ РОЗЧИНІВ

The optical properties of aqueous solutions of chromate CrО42- and dichromate Cr2О72- ions were studied. Optical spectra were used to study the adsorption of chromate CrО42- and dichromate Cr2О72- ions by a sample of polyaniline (PAn) from aqueous solutions of different concentrations. It was established that the removal and adsorption of CrО42- and Cr2О72- by the PAn sample depends on the concentration of oxyanions in the initial solutions. Adsorption studies of PAn sample with respect to oxyanions CrО42- and Cr2О72- were carried out from solutions with concentrations of 50, 100, 150, 200 and 250 mg/L. Examination of the samples after the adsorption tests revealed that the polyaniline sample retains adsorbed chromium, apparently in the Cr(III) state. The analysis of SEM-images, EDX-spectra and maps of elements proves that the distribution of adsorbed chromium is practically uniform over the surface of the adsorbent, and the intensity of its signal on the elemental maps depends on the initial concentrations of solutions of oxyanions CrО42- and Cr2О72-. Examination of the PAn sample using SEM-EDX spectra before and after adsorption revealed that the morphologies of the samples differ. The analysis of the EDX spectra of the elemental composition of the samples after adsorption of CrО42- and Cr2О72- confirmed that they contain, in addition to the PAn elements, also chromium. The distribution of chemical elements in the samples after adsorption revealed that they are almost uniformly distributed surfaces, and the intensity of its signal on EDX spectra depends on the initial concentrations of oxyanion solutions CrО42- and Cr2О72-. The value of CrО42- adsorption by the PAn sample is almost twice as small as the value of Cr2О72- adsorption. By comparing the contents of atoms of elements, in particular sulfur (S) and oxygen (O), before and after adsorption, it was found that S is replaced by Cr, and the content of O slightly increases with an increase in the initial concentration of Cr(VI) in the solutions.

Evolution of interface voids and columnar grains of the FeCrAl/RAFMs HIP bonding joint

Hot Isostatic Pressing (HIP) diffusion bonding of FeCrAl and reduced-activation ferritic/martensitic steels (RAFMs) is a novel method for preparing the tritium permeation barrier (TPB) in nuclear fusion reactors. This study primarily investigates the formation mechanisms and evolution of interfacial voids and columnar grains under different bonding temperatures and post-welding heat treatment (PWHT) conditions. It is found that increasing bonding temperature facilitates element diffusion, leading to the closure of interfacial voids. Decarbonization of RAFMs and the increase in Cr content facilitates the formation of interfacial columnar grains, with C playing a crucial role in this process due to its lower diffusion activation energy than Cr. Although appropriate PWHT can reduce the size of interfacial columnar grains, it cannot entirely diminish them. The FeCrAl/IPFs joint effectively prevents the formation of brittle (Cr, C) compounds and interfacial AlN defects. After HIP (1050 °C) + PWHT (750 °C), the joint achieves high tensile strength and ductility both at room temperature and 300 °C. The enhancement in ductility is primarily attributed to the high Schmid factor of interfacial columnar grains, which facilitated the activation of the primary slip system under tensile load, resulting in a high elongation of joints.

Comparison of the corrosion behavior of four Fe-Cr-Ni austenitic alloys in supercritical water

The corrosion behavior of four Fe-Cr-Ni austenitic alloys were investigated after exposure to deaerated supercritical water (SCW) at 650°C. Results show that the corrosion resistance follows the trend:Fe-29Cr-61Ni > Fe-16Cr-75Ni > Fe-25Cr-20Ni > Fe-21Cr-31Ni. The increase in Cr and Ni contents promote a transition from low-protective multilayer oxide scales to protective Cr2O3 scales. After surface grinding, the weight gains of all specimens dropped by one order of magnitude. Surface grinding induces the formation of ultrafine grains and a high density of dislocations, which enhances the corrosion resistance among all studied austenitic alloys. However, the beneficial effects of grinding diminish with increased Cr and Ni contents due to the pre-existing portion of Cr2O3 scales. The lower critical Cr content required to form Cr2O3 scales in high Ni austenitic alloys is primarily attributed to their lower solubility of O and the slower diffusion rates of Ni, which inhibit corrosion behavior.

High-Temperature Oxidation of NbTi-Bearing Refractory Medium- and High-Entropy Alloys.

The oxidation of six NbTi-i refractory medium- and high-entropy alloys (NbTi + Ta, NbTi + CrTa, NbTi + AlTa, NbTi + AlMo, NbTi + AlMoTa and NbTi + AlCrMo) were investigated at 1000 °C for 20 h. According to our observation, increased Cr content promoted the formation of protective CrNbO4 and Cr2O3 oxides in NbTi + CrTa and NbTi + AlCrMo, enhancing oxidation resistance. The addition of Al resulted in the formation of AlTi-rich oxide in NbTi + AlTa. Ta addition resulted in the formation of complex oxides (MoTiTa8O25 and TiTaO4) and decreased oxidation resistance. Meanwhile, Mo's low oxygen solubility could be beneficial for oxidation resistance while protective Cr2O3/CrNbO4 layers were formed. In NbTi + Ta, NbTi + AlTa and NbTi + CrTa, a considerable quantity of Ti-rich oxide was observed at the interdendritic region. In NbTi + AlCrMo, the enrichment of Cr and Ti at the interdendritic region could fasten the rate of oxidation. Compared to the recent research, NbTi + AlCrMo alloy is a light-weight oxidation-resistant alloy (weight gain of 1.29 mg/cm2 at 1000 °C for 20 h and low density (7.2 g/cm3)).

Viscosity and structure correlation mechanism of Fe[sbnd]Cr[sbnd]C melt based on MD simulation

The viscosity of FeCCr melt affects the mass transfer behavior during steelmaking processes. Reasonable regulation of viscosity can improve production efficiency. There is a close relationship between melt viscosity and structure. Therefore, it is of great theoretical significance to analyze the correlation between viscosity and structure of chromium-containing iron melt for the optimization of the whole metallurgical process. This study experimentally investigated the viscosity of FeCCr melt and utilized molecular dynamics simulation to analyze the formation and growth behavior of atomic clusters, revealing the correlation mechanism between structure and viscosity. As the Cr content increased from 11 % to 13 %, the melt viscosity increased by 10.05 %. At a temperature range from 1773 K to 1473 K, the viscosity reached a maximum of 15.5 mPa·s, representing a 40.9 % increase. Simulation results indicated that CrC clusters within the melt act as intermediaries, connecting with CrFe and FeC clusters to form FeCrC clusters. The key influence of increased Cr content on viscosity lies in promoting the generation of FeCrC multicomponent clusters, while the key influence of temperature reduction lies in promoting cluster growth. With the increase in Cr content, the number of clusters at 1773 K increased from 154 to 175, and the average volume of clusters increased from 212 Å3 to 224 Å3. When the temperature decreased from 1773 K to 1473 K, the number of clusters increased by 51.2 %, and the average volume of clusters increased by 18.75 %. In comparison, the thermal state change had a greater impact on clusters, where temperature reduction led to rapid cluster growth, reduction of free volume within the melt, and ultimately resulted in increased viscosity due to the combined effects.

Adapting high-speed indentation mapping for investigating microstructure-property correlations in chromium carbide-nickel alloy coatings: Challenges and solutions

This study investigates the microstructural and mechanical characteristics of chromium carbide‑nickel rich alloy coatings produced through laser cladding, detonation spraying, and plasma spraying techniques. While all three processing techniques used the same feedstock powder, each method yields coatings with unique microstructures encompassing varying compositions and length scales. Employing Field Emission Scanning Electron Microscopy (FE-SEM) in combination with Energy Dispersive Spectroscopy (EDS) and nanoindentation mapping, local microstructure and mechanical properties were assessed at the micrometre length scale. Laser-clad coatings exhibit a typical metal matrix composite microstructure with high carbide content, distinct (MoNb)C2 phases, and Fe in the metallic matrix, while the thermal sprayed coatings showed carbides of varying sizes and metallic matrix with varying degrees of chromium dissolved in it. The instrumented indentation technique helped precisely record the microstructural features in all the coatings. Chromium carbide consistently emerges as the hardest phase across all coatings, with variations in metallic matrix hardness. Higher matrix hardness in thermal sprayed coatings correlates with increased Cr content, attributed to extended solid solubility of Cr and the presence of Mo and Nb. Energy dispersive spectroscopy and transmission electron microscopy provided clearer insight into the microstructure. This study highlights a direct one-to-one correlation between microstructure and mechanical properties mapped using instrumented indentation techniques in chromium carbide‑nickel rich coatings across different deposition methods.

Effect of Cr addition on the microstructure and mechanical properties of MoNbVTa0.5Crx refractory high-entropy alloys

To increase strength and decrease density of traditional refractory high-entropy alloys (RHEAs), the MoNbVTa0.5Crx RHEAs were synthesized by mechanical alloying (MA) and spark plasma sintering (SPS). The effect of Cr content on microstructure and mechanical properties of the MoNbVTa0.5Crx RHEAs was systematically studied. The results showed the addition of Cr could refine the microstructure, decrease density and increase strength of RHEAs. The microstructure of the sintered alloy was composed of BCC phase and a small amount of oxide phase (Ta2VO6), and Ta2OV6 (200) has a semi-coherent relationship with BCC phase (110), with a lattice mismatch degree of 7.34 %. The compressive yield strength of the MoNbVTa0.5Crx RHEAs initially increased and then decreased with increasing Cr content. The MoNbVTa0.5Cr0.75 RHEAs demonstrated the best mechanical properties, and the compressive yield strength and ultimate compressive strength at room temperature were 3180 MPa and 3596 MPa, respectively, which were far higher than traditional WNbMoTaV RHEAs. And the density of MoNbVTa0.5Cr0.75 RHEAs was 21 % lower than that of sintered WNbMoTaV RHEAs. The strengthening mechanism of sintered MoNbVTa0.5Crx RHEAs involved O/C atoms interstitial solid solution strengthening, grain boundary strengthening, and metal atoms solid solution strengthening, while the contribution of oxide precipitation strengthening was negligible.

Effect of Cr on high-temperature oxidation resistance of Cr–Si–Mn alloyed press-hardened steel during press hardening

It is of great interest to overcome the problem of high-temperature oxidation of press-hardened steels (PHS) in press hardening with a cost-effective Cr alloying strategy. Therefore, since Cr is one of the expensive metals, the effect of Cr (Cr ≤ 3 wt%) content on the oxidation resistance of Cr–Si–Mn alloyed steels was investigated. It was found that Cr–Si–Mn alloyed PHS with a Cr content of about 1.5 wt% or less cannot form a continuous Cr2O3 layer during press hardening. However, when the Cr content reaches around 2.5 wt%, the PHS shows excellent oxidation resistance due to the formation of continuous Cr2O3 and amorphous SiO2 layers, as well as an Mn-rich oxide layer. However, further addition of 0.5 wt% could not significantly improve the oxidation resistance of this PHS. Moreover, the increase in Cr content simultaneously enhances the positive role of Si and Mn in high-temperature oxidation resistance. This work provides new insights into the design of the next generation of PHSs with economical and superior performance.

The effect of chromium on the corrosive performance of novel high manganese steel frogs in a simulated industrial atmosphere

Abstract The corrosion behavior of three novel high manganese steel frogs with different Cr contents in a simulated industrial corrosive atmospheric environment is studied through the corrosion weight gain, x-ray diffraction (XRD), scanning electron microscopy (SEM), x-ray photoelectron spectroscopy (XPS), and electrochemical testing. The results indicate that the content of Cr in the steel affects the phase composition, density, and electrochemical stability of the rust layer. For instance, as the Cr content increases, the content of the amorphous phase in the rust layer continuously increases while that of γ-FeOOH decreases, leading to enhanced density and electrochemical stability of the rust layer. The study reveals that Cr exists in the rust layer in the form of Cr2O3 and Cr(OH)3, providing nucleation cores to nanoscale colloidal rust particles. Consequently, a higher Cr content leads to more nucleation cores, which improves the density of the rust layer and enhances the corrosion resistance of the novel high manganese steel frogs in industrial corrosive atmospheric environments.