Comparative Analysis Over Tribology Characterization of TiAlN and TiAlSiN PVD Coating On Plasma Nitride Alloy 20

The nickel-iron-chromium (alloy 20) is enriching by hybrid surface treatment through plasma nitride (PN) and physical vapor deposition (PVD) process. The plasma nitriding process takes 12 hours at 500°C. Potentiodynamic testing is used to characterize the corrosion performance of the treated material, followed by morphological analysis of the exposed surface; XRD, EDX, SEM, hardness, and tensile testing are used to investigate appropriate coating properties. Plasma nitride and hybrid PVD nickel-iron-chromium alloys exhibit perlite (γ + α ’) phases and martensite (γ + α) phases, respectively. The martensite microstructure ensures superior tensile strength and hardness. The pin-on-disc tribometer test proposes to analyze friction and hard-faced behavior in the dry sliding position. The inclusion of Si improves the adherent oxide film, resulting in a low wear rate in TiAlSiN alloy 20. Due to the presence of the passive film, TiAlSiN alloy 20 exposes the most passive region to attain better corrosion resistance.

Hardness and Microstructure Homogeneity of Pure Copper and Iron-Chromium Alloy Processed by Severe Plastic Deformation

Hardness and microstructure homogeneity of pure copper and iron-chromium alloy processed by severe plastic deformation (SPD) were investigated in grain refinement. Equal channel angular pressing (ECAP) is one of the well-known techniques of the SPD technique due to their up-scale ability and other methods. SPD was applied to pure copper and iron-chromium alloy at comparable temperatures up to four passes. The microstructure and microhardness were observed and measured in the transverse plane for each billet. The homogeneity observation was carried out from the sub-surface until in the middle of the billet. The result showed that the deformed structure appeared adequately after the first pass and had a higher hardness level. The first pass showed a higher inhomogeneity factor than the fourth pass due to the homogeneity microstructure. The hardness also showed homogeneous value along the transverse plane, and it was concluded that ECAP could achieve complete homogeneity in grain refinement

Determination of Zn, Fe, Cr and Cu in Marine Fish Commonly Consumed in Senegal

The content of four heavy metals (zinc, iron, chromium and copper) in muscles, liver and gonads has been studied for the five most consumed fish species (Cephalopholus taeniops, Scomber japonicus, Lagocephalus laevigatus, Pagellus bellottii and Pagrus caeruleostictus) in the Soumbedioune region. The samples were digested by acid digestion. The metal contents were quantified using a PF-11 type photometer. The results obtained show that metals such as zinc, iron and chromium are significantly higher (p <0.05) in the muscles of the four species than in the liver and gonads. However, the levels of heavy metals in the muscles, liver, and gonads of the five species are above the acceptable limit recommended by the FAO and WHO, with the exception of the copper levels in the gonads of the species Pagellus bellottii.

Microstructure and Strain Hardening Behaviour of Iron Chromium Alloy Subjected by Severe Plastic Deformation

Microstructure and strain hardening behaviour of iron-chromium alloy subjected to severe plastic deformation (SPD) have been investigated in grain refinement and deformation routes. Equal channel angular pressing (ECAP) was used in this SPD technique due to their un-change dimension billet. The purpose of this research is to investigate the structure and the strain hardening of iron chromium alloy subjected by ECAP process. The ECAP process was carried by routes A, Bc and C up to four passes at 423 K temperature. The strength of the material was measured by tensile testing with 3 mm gauge length, and the strain hardening behaviour was investigated based on the true stress-strain curve. The effect of the deformation route on microstructure and texture was observed by electron backscattered diffraction (EBSD) analysis at the normal, transverse and rolling direction. The result showed that route Bc showed the highest strength and ductility of the ECAP processed material compare to other routes due to their 90 degrees rotation of each ECAP passes number. The increased strength of materials was also associated with grain refinement and accumulation dislocation. It concluded that the ECAP process by route Bc could be used for further material treatment and application for industrial purposes.

Effect of Preliminary Deformation on Microstructure and Texture of Iron-Chromium Alloy Prepared by Severe Plastic Deformation

The effect of preliminary deformation on the microstructure and texture of iron-chromium alloy prepared by severe plastic deformation (SPD) has been investigated in grain refinement and inhomogeneity structure. Equal channel angular pressing (ECAP) is a well-known SPD process that uses a die channel with a sharp angle. The texture and misorientation map of ECAP processed material was observed electron backscattered diffraction (EBSD) analysis, providing information on structure evolution. The observation was done in the transverse plane from the middle to the sub-surface. The data logger also records the pressure of the ECAP process. The result showed that the sub-surface has a more deformed structure than the middle due to the die channel's sharp angle and shear direction. The texture exhibited a random orientation after the first pass ECAP process. The stacking fault energy and accumulation dislocation are also associated with this process. Several shear bands can be seen clearly, which is parallel to the shear direction. It concluded that the preliminary deformation by ECAP was effective to promote grain refinement due to their high equivalent strain

Synthesis and Characterisation of New {Fe2CrO} Heterotrinuclear Iron-chromium Clusters

Two new μ3-oxo trinuclear heterometallic Fe2IIICrIII complexes with furan-2-carboxylic and salicylic acids with the composition: [Fe2CrO(C4H3OCOO)6(CH3OH)3]NO3·0.5CH3OH and [Fe2CrO(C6H4(OH)COO)7(CH3OH)2]·2DMA were synthesized starting from iron(III) and chromium(III) salts mixture. The complexes structures were confirmed by elemental analysis, IR, Mössbauer spectroscopies, and X-ray analysis. The atomic absorption spectroscopy confirmed that the iron: chromium ratio is 2:1. The thermal properties of both heteronuclear complexes have been investigated in oxidizing and inert atmospheres revealing the stability of the trinuclear core up to 170 and 220°C, respectively.

Kinetic Monte Carlo Modelling of Dissolution and Passive Film Formation in Fe-Cr Alloys

<p>Stainless steels differ from iron in that chromium content allows for the formation of a passive iron-chromium oxide film which is only nanometres in thickness, offering protection from the environment. While the composition of this oxide layer has been established, the mechanism of its formation is not well understood. In particular, the threshold level of chromium for oxide formation is significantly lower then the chromium content of the alloy itself. We present a Cahn Hilliard type analytical model that relates the onset of passivation to an instability which leads to a phase segregating current above 17% Cr in a bulk alloy. Proposing that this current could lead to Cr enrichment at a surface, we compare atomistic simulations with and without a surface driven Cr current. We implemented a kinetic Monte Carlo algorithm with extensions to allow for vacancy assisted nearest neighbour migration in a body centered cubic alloy, tracking a surface, dissolution and surface passivation. We compare the time evolution of Fe dissolution rates, Cr surface enrichment and the threshold for passive film formation and find that the Cr current has a significant impact on each of these properties.</p>

Kinetic Monte Carlo Modelling of Dissolution and Passive Film Formation in Fe-Cr Alloys

<p>Stainless steels differ from iron in that chromium content allows for the formation of a passive iron-chromium oxide film which is only nanometres in thickness, offering protection from the environment. While the composition of this oxide layer has been established, the mechanism of its formation is not well understood. In particular, the threshold level of chromium for oxide formation is significantly lower then the chromium content of the alloy itself. We present a Cahn Hilliard type analytical model that relates the onset of passivation to an instability which leads to a phase segregating current above 17% Cr in a bulk alloy. Proposing that this current could lead to Cr enrichment at a surface, we compare atomistic simulations with and without a surface driven Cr current. We implemented a kinetic Monte Carlo algorithm with extensions to allow for vacancy assisted nearest neighbour migration in a body centered cubic alloy, tracking a surface, dissolution and surface passivation. We compare the time evolution of Fe dissolution rates, Cr surface enrichment and the threshold for passive film formation and find that the Cr current has a significant impact on each of these properties.</p>