Oxidation Kinetic and Diffusion Mechanism Study of a Zr-Based Bulk Metallic Glass Alloy

2011 ◽  
Vol 675-677 ◽  
pp. 193-196 ◽  
Author(s):  
Bin Wang ◽  
Dong Ya Huang ◽  
Zhe Chen ◽  
Nathalie Prud’homme ◽  
Vincent Ji
Keyword(s):  
Metallic Glass ◽  
Oxide Scale ◽  
Oxide Layer ◽  
Bulk Metallic Glass ◽  
Diffusion Mechanism ◽  
Oxidation Kinetic ◽  
Atomic Diffusion ◽  
Oxide Surface ◽  
Outward Diffusion ◽  
Oxidation Rates

Oxidation kinetic of a Zr55Cu30Al10Ni5 bulk metallic glass (BMG) and its crystalline counterpart were studied under dry artificial air (20% of O2 and 80% of N2) at 673 K by thermogravimetry analysis (TGA) method. According to TGA profiles, the oxidation kinetic in both amorphous and crystalline states followed a protective parabolic law. However, the oxidation rates for the amorphous alloy were obviously higher than those for the crystalline alloy. Pseudo-grazing incident X-Ray diffraction (GIXRD) has been carried out to identify the oxides nature and their crystalline structure. Tetragonal-ZrO2 dominated the oxide scale formed on both alloys (BMG and crystalline) at T = 673 K; meanwhile, a slight amount of Cu was detected on the oxide surface of studied BMG alloy. The atomic diffusion mechanism was investigated using a two-stage oxidation treatment to study oxide scale growth kinetics. The studied specimens were oxidized firstly under dry artificial air and then under 18O2 isotopic tracer gas for 1.5 hours respectively at 673 K. The evident solute penetration zone and ion diffusion characteristic through the oxide scale were determined by Cs+ secondary ion mass spectrometry (SIMS) depth profile. The results showed the mechanism of the oxide layer formation of both alloys was not only due to Oxygen ions diffusion from oxide surface to interior scale, but also to an outward diffusion of Zirconium ions from substrate to oxide layer and the ZrO2 oxide growth seemed to occur at the oxide/gas interface in our studied case.

Oxidation Behavior of Cu60Zr30Ti10 Bulk Metallic Glass

2005 ◽  
Vol 20 (6) ◽  
pp. 1396-1403 ◽  
Author(s):  
C.Y. Tam ◽  
C.H. Shek
Keyword(s):  
Metallic Glass ◽  
Oxide Layer ◽  
Bulk Metallic Glass ◽  
Photoelectron Spectroscopy ◽  
Oxidation Kinetics ◽  
Oxide Surface ◽  
X Ray ◽  
Rate Law ◽  
Cu Content ◽  
Surface Morphologies

The oxidation kinetics of Cu60Zr30Ti10 bulk metallic glass and its crystalline counterpart were studied in oxygen environment over the temperature range of 573–773 K. The oxidation kinetics, measured with thermogravimetric analysis, of the metallic glass follows a linear rate law between 573 and 653 K and a parabolic rate law between 673 and 733 K. It was also found that the oxidation activation energy of metallic glass is lower than that of its crystalline counterpart. The x-ray diffraction pattern showed that the oxide layer is composed of Cu2O, CuO, ZrO2, and metallic Cu. Cu enrichment on the topmost oxide layer of the metallic glass oxidized at 573 K was revealed by x-ray photoelectron spectroscopy while there was a decrease in Cu content in the innermost oxide layer. The oxide surface morphologies observed from scanning electron microscopy showed that ZrO2 granules formed at low temperatures while whiskerlike copper oxides formed at higher temperatures.

Atomic Diffusion of Al and Si in Cu44.25Ag14.75Zr36Ti5 Bulk Metallic Glass

2012 ◽  
Vol 510 ◽  
pp. 804-807
Author(s):  
Wei Yuan Yu ◽  
You Liang Wang ◽  
Wen Jiang Lu
Keyword(s):  
Diffusion Coefficient ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Diffusion Mechanism ◽  
Base Material ◽  
Atomic Diffusion ◽  
Diffusion Activation Energy ◽  
Metal Atoms ◽  
Secondary Ion ◽  
Diffusion Activation

Secondary ion mass spectroscopy (SIMS) has been adopted to study the diffusion of Al and Si in Cu44.25Ag14.75Zr36Ti5bulk metallic glass (BMG). It has been found that around the transition temperature of metallic glass, the relation between its diffusion coefficient and the temperature satisfy the same Arrhenius relation, which means the metallic transition has not caused change to the diffusion mechanism. In addition, the radius of Al atom is close to that of Si atom, but under the same temperature and time condition, the diffusion coefficient of Si atom in bulk metallic glass (BMG) is twice that of the Al atom, while there is not a big difference in diffusion activation energy. This is because as non-metallic element, the radius of Si atom has a strong binding force with the metal atoms in the base material, which also has a bigger diffusion coefficient.

Oxide Formation on the Bulk Metallic Glass Zr46.75Ti8.25Cu7.5Ni10Be27.5

1998 ◽  
Vol 554 ◽  
Author(s):  
M. Kiene ◽  
T. Strunskus ◽  
G. Hasse ◽  
F. Faupel
Keyword(s):  
Metallic Glass ◽  
Oxide Layer ◽  
Bulk Metallic Glass ◽  
Photoelectron Spectroscopy ◽  
Depth Profiling ◽  
Outward Diffusion ◽  
Oxide Layers ◽  
Preparation Conditions ◽  
Ti Oxides ◽  
Outermost Surface

AbstractIn this investigation depth profiling by Ar+ ion sputtering in combination with x-ray photoelectron spectroscopy was used to determine the thickness and the chemical composition of the oxide layers formed on the bulk metallic glass Zr46.75Tig8.25Cu7.5Ni10Be27.5 (V4) under different preparation conditions. The thickness of the oxide layer was in the range between 4 nm and 30 nm for samples oxidized in air at room temperature and annealed in air at 573 K for 15 hours, respectively. The oxide layers showed an enrichment of Be at the outermost surface followed by a Be, Zr and Ti rich phase. Cu and Ni are depleted within the whole oxide layer. BeO, ZrO2 and various Ti oxides were detected in the oxide layer, whereas Cu and Ni occurred only in a non-oxidized zerovalent state. Our data indicate that the oxidation is controlled by the inward and outward diffusion of the metallic components.

Improved wettability of Sn-based solder over the Cu60Zr30Ti10 bulk metallic glass surface

2009 ◽  
Vol 24 (9) ◽  
pp. 2931-2934 ◽  
Author(s):  
A. Imai ◽  
M. Katayama ◽  
S. Maruyama ◽  
H. Nishikawa ◽  
T. Wada ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Thin Layer ◽  
Oxide Layer ◽  
Bulk Metallic Glass ◽  
Glass Surface ◽  
Complete Removal ◽  
Surface Oxide ◽  
High Resistivity ◽  
Polished Surface ◽  
Surface Oxide Layer

The wettability of Pb-free Sn-based solder over the Cu-based Cu60Zr30Ti10 bulk metallic glass surface was investigated. We observed that the as-polished surface was nonwetting for the solder, which was due to the surface oxide layer of ZrOx formed in air. After complete removal of the oxide layer, a thin layer of Ag was deposited on the clean Cu60Zr30Ti10 surface. The Ag-covered Cu60Zr30Ti10 surface showed relatively high resistivity to the reoxidation even in air, and thus the wettability of the Cu60Zr30Ti10 surface for the Sn-based solder was greatly improved.

Quasicrystal Formation in a Zr-based Bulk Metallic Glass

2003 ◽  
Vol 805 ◽  
Author(s):  
L. Liu ◽  
K. C. Chan ◽  
G. K. H. Pang
Keyword(s):  
Phase Transformation ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Atomic Diffusion ◽  
Present System ◽  
Initial Formation ◽  
High Resolution Tem ◽  
Mould Casting ◽  
Copper Mould ◽  
Step Crystallization

ABSTRACTZr65Ni10Cu7.5Al7.5Ag10 bulk metallic glass with a diameter of 2 mm and a length of 50 mm was prepared by copper-mould casting. The metallic glass obtained follows two-step crystallization reactions with the initial formation of metastable quasicrystals from amorphous phase, followed by the formation of a stable intermetallic Zr2Cu from the post-formed quasicrystals. In this paper, the microprocess of the amorphous-to-quasicrystalline transformation of Zr65Ni10Cu7.5Al7.5Ag10 bulk metallic glass was studied in detail by TEM and high resolution TEM coupled with nanobeam EDX. It was found that the amorphous-to-quasicrystalline transformation in the present system does not follow the traditional nucleation/growth mechanism. Instead, it undergoes a series of inter-processes and follows the sequence of phase transformation of amorphous → FCC Zr2Ni → Tetragonal Zr2Ni → Quasicrystals. Nanobeam EDX revealed that atomic diffusion was involved in all inter-processes of the phase transformations, suggesting that the amorphous-to-quasicrystalline transformation in the present bulk metallic glass is a non-polymorphous reaction.

Spectroscopic Examination of Protein Adsorption from Seawater onto Titanium

1993 ◽  
Vol 47 (8) ◽  
pp. 1140-1151 ◽  
Author(s):  
G. T. Taylor ◽  
P. J. Troy ◽  
M. Nullet ◽  
S. K. Sharma ◽  
B. E. Liebert ◽  
...  
Keyword(s):  
Film Thickness ◽  
Oxide Layer ◽  
Electrochemical Impedance ◽  
Surface Film ◽  
Electrochemical Techniques ◽  
Oxide Surface ◽  
State Function ◽  
Transfer Resistance ◽  
Bisphosphate Carboxylase ◽  
Oxidation Rates

Several noninvasive optical and electrochemical techniques were adapted to examine partitioning of protein from seawater onto polished titanium with the use of the plant enzyme ribulose-1,5,-bisphosphate carboxylase-oxygenase (Rubisco) as a model. Protein films, varying in surface concentrations from 0.011 to 3.606 μg cm−2, were prepared by exposing polished Ti surfaces to seawater amended with 0.04–90.80 μg mL−1 of 3H-Rubisco. Mean film thickness, d, measured by ellipsometry, increased linearly over most of the range of irreversibly bound protein (Γirr = 0.011–2.491 μg cm−2). Spatial coverages of the films were more heterogeneous at low surface coverages, indicative of heterogeneous adsorption resulting in barren Ti oxide surface sites and insular protein clusters. The thickness of the underlying Ti oxide layer, also measured by ellipsometry, was highly variable and indicated that oxidation of the surface was suppressed at high protein coverages during two-hour exposures to seawater. Vibrational spectra of surface films, from submonolayer (0.03 μg cm−2) to multilayer (3.61 μg cm−2), were obtained with the use of Fourier transform infrared reflection-absorption spectrometry (FT-IRAS). Peak areas of amide I and II bands varied linearly with Γirr, permitting noninvasive measurement of protein mass at the surface. Relative intensities of the amide II/amide I bands, band composition of the amide III, and peak frequencies varied with surface concentration, indicating unfolding of adsorbed proteins. Vibrational spectroscopic and ellipsometric evidence suggests that protein structure is most altered at low surface concentrations. Electrochemical impedance spectroscopy (EIS) performed from 100 /μHZ to 100 kHz on replicate test surfaces revealed that the electrochemical behavior of the titanium/protein interface was consistent with that of a parallel RC circuit. The charge transfer resistance, Rct, of the interface varied as a two-state function of protein concentration. The Rct increased more rapidly within the monolayer domain (0.12 to 2.8 MΩ cm2) than in the multilayer domain (2.8 to 4.9 MΩ cm2), indicating that impedance to electron flow across the interface is most influenced by protein monolayer formation and is less affected by additional layers. Estimations of rates of oxidation or dissolution of the substratum were inversely proportional to protein surface concentrations. Together these techniques provide internally consistent measurements of surface film thickness, adsorbate mass, gross chemical composition, interface organization, electrical impedance, capacitance, and oxide layer thickness. These data are useful for determining the physical state of the interface, its dynamics, and the potential oxidation rates of the substratum underlying the surface film.

Quasicrystal Formation in a Zr-based Bulk Metallic Glass

2003 ◽  
Vol 806 ◽  
Author(s):  
L. Liu ◽  
K. C. Chan ◽  
G. K. H. Pang
Keyword(s):  
Phase Transformation ◽  
Metallic Glass ◽  
Bulk Metallic Glass ◽  
Atomic Diffusion ◽  
Present System ◽  
Initial Formation ◽  
High Resolution Tem ◽  
Mould Casting ◽  
Copper Mould ◽  
Step Crystallization

ABSTRACTZr65Ni10Cu7.5Al7.5Ag10 bulk metallic glass with a diameter of 2 mm and a length of 50 mm was prepared by copper-mould casting. The metallic glass obtained follows two-step crystallization reactions with the initial formation of metastable quasicrystals from amorphous phase, followed by the formation of a stable intermetallic Zr2Cu from the post-formed quasicrystals. In this paper, the microprocess of the amorphous-to-quasicrystalline transformation of Zr65Ni10Cu7.5Al7.5Ag10 bulk metallic glass was studied in detail by TEM and high resolution TEM coupled with nanobeam EDX. It was found that the amorphous-to-quasicrystalline transformation in the present system does not follow the traditional nucleation/growth mechanism. Instead, it undergoes a series of inter-processes and follows the sequence of phase transformation of amorphous→FCC Zr2Ni →Tetragonal Zr2Ni → Quasicrystals. Nanobeam EDX revealed that atomic diffusion was involved in all inter-processes of the phase transformations, suggesting that the amorphous-to-quasicrystalline transformation in the present bulk metallic glass is a non-polymorphous reaction.

scholarly journals Nanoindentation Investigation on the Size-Dependent Creep Behavior in a Zr-Cu-Ag-Al Bulk Metallic Glass

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 613 ◽  
Author(s):  
Z. Y. Ding ◽  
Y. X. Song ◽  
Y. Ma ◽  
X. W. Huang ◽  
T. H. Zhang
Keyword(s):  
Metallic Glass ◽  
Strain Rate ◽  
Bulk Metallic Glass ◽  
Creep Behavior ◽  
Creep Mechanism ◽  
Atomic Diffusion ◽  
Transformation Zone ◽  
Size Dependent ◽  
Strain And Strain Rate ◽  
Creep Deformations

Nanoindentation technology has been widely adopted to study creep behavior in small regions. However, nanoindentation creep behavior of metallic glass is still not well understood. In the present work, we investigated nanoindentation size effects on creep deformation in a Zr-based bulk metallic glass at room temperature. The total creep strain and strain rate of steady-state creep were gradually decreased with increasing holding depth under a Berkovich indenter, indicating a length-scale-dependent creep resistance. For a spherical indenter, creep deformations were insignificant in elastic regions and then greatly enhanced by increasing holding strain in plastic regions. Strain rate sensitivities (SRS) decreased with increasing holding depth and holding strain at first, and then stabilized as holding depth was beyond about 500 nm for both indenters. SRS values were 0.4–0.5 in elastic regions, in which atomic diffusion and free volume migration could be the creep mechanism. On the other hand, evolution of the shear transformation zone was suggested as a creep mechanism in plastic regions, and the corresponding SRS values were in the range of 0.05 to 0.3.

Oxidation Behavior in Super-Plastic Microforming of Zr65Cu17.5Ni10Al7.5 Bulk Metallic Glass

2011 ◽  
Vol 117-119 ◽  
pp. 1377-1382
Author(s):  
Jun Wang ◽  
Guang Lan Liao ◽  
Qiang Yu ◽  
Tie Lin Shi
Keyword(s):  
Metallic Glass ◽  
Oxide Layer ◽  
Bulk Metallic Glass ◽  
Room Temperature ◽  
Oxidation Behavior ◽  
Amorphous Structure ◽  
Liquid Region ◽  
Silicon Mold ◽  
X Ray ◽  
Super Plastic

The influence of oxidation behavior on super-plastic microforming of bulk metallic glass Zr65Cu17.5Ni10Al7.5in the super-cooled liquid region was investigated. Samples were heated in air from room temperature to 395°C, 410°C, and 430°C, respectively, and kept under each temperature for 40 minutes. The increased weight of samples and the thickness of oxide layer were measured. Subsequently, the sample was compressed under 410°C with a micro gear silicon mold. In result, the oxide layer of the gear cracked and could be easily removed; also, the X-ray diffractometer showed that the gear core below the oxide layer remained an amorphous structure. It can be concluded that the oxidation behavior of Zr65Cu17.5Ni10Al7.5does not affect the super-plastic deformation, which indicates the feasibility of super-plastic microforming process in air.

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