Corrosion Resistance Of Amorphous Alloys Research Articles

Preparation and properties of a bulk metallic glass and high-entropy alloy composite

A composite alloy, consisting of bulk metallic glass (BMG) and high entropy alloy (HEA), was prepared by suction casting method in argon atmosphere. This BMG/HEA composite has a nominal composition of (Zr59Ni21Al20)95(Ni2.1TiAlFeCrCo0.8)5. The as-cast composite alloy possesses both good mechanical properties and high corrosion resistance. The alloy has fracture strength of 2.34 GPa under a compressive load, higher than the value of Zr59Ni21Al20 BMG. Plasticity of the composite alloy reaches 6.45%，which is also significantly improved when compared to the BMG. Moreover, the composite alloy inherits the excellent corrosion resistance of amorphous alloy. This work proves that the dual-phase composite alloy prepared by suction casting can combine the superior properties of both BMG alloy and high-entropy alloy.

Corrosion Resistance of Some Amorphous Metallic Fe–P–M (M = Si, Nb, Mo) Alloys: Effects of Composition, Structural Relaxation, Partial Crystallization, and Local Deformation

The corrosion resistance of metallic amorphous alloys (AAs) Fe80.2P17.1Mo2.7, Fe80.5P18.4Nb1.1, Fe98 –xPxSi2 (x = 14, 16, 20), Fe76.5P13.6Si4.8Mn2.4V0.2C2.5 in a 0.1 M solution of Na2SO4 (pH 6.25) and its change due to structural relaxation, nanocrystallization, and local deformation are studied. The activation of structural relaxation by photonic treatment is shown to increase the corrosion resistance of AAs. As the phosphorus content in the Fe98 ‒ xPxSi2 system decreases, the corrosion resistance of AAs decreases because of partial crystallization, which is accompanied by the formation of iron phosphides during rapid cooling of a melt, and silicon segregation at phase boundaries. The formation of local deformation zones in the near-surface layer of Fe76.5P13.6Si4.8Mn2.4V0.2C2.5 AA decreases its corrosion resistance. The niobium alloying of Fe‒P AAs is shown to be effective to decrease the corrosion rate.

Influence of Heat Treatment and Oligomeric Coatings on the Corrosion Resistance of Amorphous Alloys Based on Aluminum

By the methods of corrosion chronopotentiometry, voltammetry, and electrochemical impedance spectroscopy, we investigate the dependence of the electrochemical parameters of the corrosion of amorphous alloys of aluminum Al87.0Y5.0Ni80 , Al87.0Gd5.0Ni8.0, Al87.0Y4.0Gd1.0Ni8.0 , Al87.0Gd5.0Ni4.0Fe4.0 , and Al87.0Y4.0Gd1.0Ni4.0Fe4.0 on the temperature of treatment and deposition of oligoperoxide protective coatings on the surface. It is shown that the efficiency of the formed layer is determined by the compositions of oligoperoxide solutions and the content of rare-earth alloying additions in these alloys.

Effect of external actions on the magnetic properties and corrosion resistance of Co70.5Fe0.5Cr4Si7B18 amorphous alloy

Variations in the magnetic characteristics (specific saturation magnetization and coercive force) of Co–Fe–Cr–Si–B amorphous alloy (AA) are studied after high-pressure torsion (HPT) and heat treatment. The behavior of AA magnetic properties is analyzed with respect to structural transformations caused by external actions. The corrosion resistance of AA upon transitioning from an amorphous to a crystalline state is investigated. The established optimum annealing and HPT conditions yield a satisfactory combination of the magnetic properties and corrosion resistance of the investigated alloy.

Effect of Sub-T g Annealing on the Corrosion Resistance of the Cu–Zr Amorphous Alloys

Despite the economy of material cost and excellent toughness of Cu-based amorphous alloys, especially Cu50Zr50, their poor corrosion resistance to a chloride medium limits their widespread applications. In this study, corrosion tests were performed on the Cu50Zr50 amorphous alloy with different degrees of short-range order, which were prepared by annealing below the glass transition temperature (T g). It was found that the corrosion resistance of amorphous alloys is improved to a significant level when the alloys were heated below T g. Calorimetric studies showed that thermally activated relaxation process of created disorder, which occurs during sub-T g annealing, is responsible for the improvement in the corrosion resistance. Molecular dynamics simulations performed on the Cu–Zr amorphous alloys demonstrated that the relaxation process of the alloys is associated with the formation of energetically stable icosahedra and icosahedron-like structures. Our study highlights the effects of sub-T g annealing on the improvement in the corrosion resistance of the amorphous alloys from the viewpoint the relaxation process of the short-range orders.

Influence of Remelting Treatment on Corrosion Behavior of Amorphous Alloys

The corrosion behavior of Gd 56 Al 26 Co 18 and Sm 56 Al 26 Co 18 amorphous alloys in 0.01 mol/L NaOH solution has been researched by polarization curves, EIS technique, XRD and SEM. The free volume was also investigated by DSC technique. We find that the corrosion resistance of amorphous alloys in 0.01 mol/L NaOH solution increases after remelting. The corrosion resistance of Gd-based amorphous ribbons is better than that of the Sm-based amorphous ribbons in 0.01 mol/L NaOH solution. In addition, the amount of free volume of remelting amorphous ribbons is less than that of first-time melting amorphous ribbons.

Susceptibility of minor alloying to corrosion behavior in yttrium-containing bulk amorphous steel

Minor alloying of yttrium to bulk amorphous steels can influence their corrosion resistance significantly. The corrosion behavior was investigated by using potentiodynamic polarization measurements, Mott–Schottky analysis and X-ray photoelectron spectroscopy (XPS). It showed that, in comparison with Y-free alloy, the stability of the passive film for 0.5 at.% yttrium alloy decreased sharply, whereas enhanced with more additions of yttrium. It is noticed that the corrosion resistance was correlated to semiconductor properties of the passive film. This is understood on the basis of the yttrium-doping-induced structural defect effects in the passive films. A probable way to further enhance the corrosion resistance of amorphous alloys is suggested.

Influence of annealing on the phase transformations and corrosion resistance of amorphous alloys based on cobalt

Influence of annealing on the phase transformations and corrosion resistance of amorphous alloys based on cobalt

Change in corrosion behavior of amorphous FePC alloys by alloying with various metallic elements

Comprehensive work to examine the effect of metallic alloying elements M on the corrosion behavior of amorphous Fe M13 P7 C alloys was performed. All alloying elements except manganese are effective in increasing the corrosion resistance of amorphous alloys in various acidic and neutral solutions, regardless of anionic species, pH and oxidizability. The addition of elements more active than iron to amorphous FePC alloy decrease the corrosion rate in an active region during immersion tests, depending upon the passivation capabilities of the alloying elements themselves. When elements nobler than iron are added, the nobler is the alloying element, the higher is the corrosion resistance of amorphous Fe M13 P7 C alloys.

非晶質合金の耐食性

非晶質合金の耐食性

Corrosion behavior of amorphous and crystalline Cu 50Ti 50 and Cu 50Zr 50 alloys

Corrosion rates and anodic polarization curves of amorphous and crystallinecu 50Ti 50 and Cu 50Zr 50 alloys have been examined in various acidic, neutral and alkaline solutions. The amorphous alloys are very stable in acidic and alkaline solutions, but unstable in agressive chloride solutions. The corrosion resistance of these amorphous alloys is higher than that of the crystallized alloys. The high corrosion resistance of amorphous alloys is attributable to the high chemical homogeneity of amorphous alloys without localized crystalline defects such as precipitates, segregates, grain boundaries, etc. Metalloid elements play an important role in the corrosion behavior of amorphous alloys; the addition of phosphorus to amorphous CuTi alloy greatly increases the corrosion resistance, even in 1N HCl.

Effect of metalloidal elements on corrosion resistance of amorphous iron-chromium alloys

Corrosion and electrochemical behaviours of amorphous iron-chromium alloys containing different sets of glass-forming metalloidal elements, boron, carbon, silicon and phosphorus, have been investigated. The corrosion resistance in 0.1N H 2SO 4 increases in the order of alloys containing silicon, boron, carbon and phosphorus, and the corrosion resistance in 3% NaCl increases in the order of alloys containing boron, silicon or carbon, and phosphorus. Difference in the corrosion resistance of amorphous alloys containing various metalloids has been interpreted in terms of the difference in the formation rate of the chromium-enriched protective film on the surface of alloys.