Synthesis, characterization and stability of amorphous alloys

In this paper the results of chemical and electrochemical synthesis of Fe-P, Fe-W and Fe-Ni amorphous powders, investigations of their structural characteristics, stability and processes of their relaxation and stabilization during heating in the temperature range of 20-1000oC are presented. .

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Crystallization of Ni-Cr-Si-B and Ni-Cr-Fe-Si-B Amorphous Alloys

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.216.35 ◽

2014 ◽

Vol 216 ◽

pp. 35-38 ◽

Cited By ~ 1

Author(s):

Cosmin Codrean ◽

Dragoş Buzdugan ◽

Ramona Lǎzar ◽

Viorel Aurel Şerban ◽

Ion Mitelea

Keyword(s):

Thermal Stability ◽

Chemical Composition ◽

Rapid Solidification ◽

Amorphous Alloys ◽

Structural Characteristics ◽

Glass Forming Ability ◽

Glass Forming ◽

Melting Temperatures ◽

Dta Analysis ◽

Thermal Stability Of

Ni based amorphous alloys with Si and B, which can also, contains Fe and Cr, prepared by rapid solidification, have low melting temperatures. This fact increases their susceptibility to be joined by welding and brazing. The glass forming ability (GFA) is conditioned also by the crystallization delay, due to certain chemical composition of the alloys. The thermal stability of these alloys was revealed by DTA analysis and structural characteristics were investigated by XRD. Applying an annealing at temperatures between 420°C and 540°C, with 30 minutes maintaining time, allowed the investigation of phase occurred during the crystallization and the estimation of the crystalline grains dimensions.

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Synthesis and characterization of nanometer-sized Ti-based amorphous powders

Journal of Materials Research ◽

10.1557/jmr.2007.0211 ◽

2007 ◽

Vol 22 (6) ◽

pp. 1754-1758 ◽

Cited By ~ 3

Author(s):

J. Jayaraj ◽

E. Fleury ◽

B.J. Park ◽

D.H. Kim ◽

W.T. Kim

Keyword(s):

Amorphous Alloys ◽

Magnetic Behavior ◽

Selective Dissolution ◽

Two Phase ◽

Simple Method ◽

Size Dependent ◽

Rapidly Quenched Alloys ◽

Identical Composition ◽

Amorphous Powders

We present a simple method for preparing nanometer-sized, Ti-based amorphous powders from the Y28Ti28Al24Co20and Y36Ti20Al24Co20two-phase amorphous alloys. The initial microstructure of these rapidly quenched alloys is composed of Ti-based, amorphous, spherical, nanometer-sized particles embedded in a Y-based amorphous matrix, with particle size dependent on the alloy composition. The Ti-based powders were extracted from the two-phase amorphous alloys through selective dissolution of the Y-rich matrix in a 0.1 M HNO3solution. The powders of size ranging between 20 and 200 nm have smooth and spherical morphology, and exhibit different magnetic behavior than the bulk alloy of identical composition.

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Electrochemical synthesis of CuSCN nanostructures, tuning the morphological and structural characteristics: From nanorods to nanostructured layers

Materials Science in Semiconductor Processing ◽

10.1016/j.mssp.2017.06.030 ◽

2017 ◽

Vol 68 ◽

pp. 226-237 ◽

Cited By ~ 6

Author(s):

Daniel Ramírez ◽

Gonzalo Riveros ◽

Katherine Álvarez ◽

Bárbara González ◽

Carlos J. Pereyra ◽

...

Keyword(s):

Electrochemical Synthesis ◽

Structural Characteristics ◽

Nanostructured Layers

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Mechanical Alloying for Preparation of Ti50Fe45Sn5 Amorphous Alloys Powder

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.480-481.104 ◽

2011 ◽

Vol 480-481 ◽

pp. 104-108

Author(s):

Ge Wang ◽

Chun Zhang ◽

Yu Ying Zhu ◽

Zhi Gang Chao ◽

Qiang Li

Keyword(s):

Mechanical Alloying ◽

Amorphous Alloys ◽

Weight Ratio ◽

Supercooled Liquid ◽

High Energy ◽

Supercooled Liquid Region ◽

Liquid Region ◽

X Ray Diffraction ◽

Typical Morphology ◽

Amorphous Powders

Ti50Fe45Sn5 amorphous alloys powder was prepared by mechanical alloying (MA) in a high-energy planetary ball mill. The non-crystallization degree was tested by X-ray diffraction (XRD). It was shown from the XRD results that a higher ball to powder weight ratio (BPR) is advantageous in preparing amorphous alloys powder. The microstructure and shape of the powder was observed by scanning electron microscope (SEM). It was shown from the SEM results that the as-milled amorphous alloys powder is flake shape and assembles together to be agglomeration structure, which is a typical morphology of amorphous powders prepared by MA. Thermodynamic properties and crystallization kinetics behavior of the as-milled amorphous alloys powder were measured by differential scanning calorimeter (DSC). The supercooled liquid region △Tx is broad (up to 119K) and the reduction glass transforming temperature Trg (0.78) is great, which shows that the as-milled amorphous alloys powder has a strong glass-forming ability and the thermal stability of the powder is excellent.

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ELECTRICAL RESISTIVITY OF COBALT-BORON LQA ALLOYS

Modern Physics Letters B ◽

10.1142/s0217984995001534 ◽

1995 ◽

Vol 09 (23) ◽

pp. 1535-1538 ◽

Cited By ~ 3

Author(s):

S. M. M. R. NAQVI ◽

S. DABIR H. RIZVI ◽

SAJIDA JAMILA ◽

SHABANA RIZVI ◽

S. MOHSIN RAZA ◽

...

Keyword(s):

Electrical Resistivity ◽

Amorphous Alloys ◽

Amorphous Matrix ◽

Arrhenius Plot ◽

Amorphous Material ◽

Activation Energies ◽

Dangling Bonds ◽

Crystalline Phases ◽

Temperature Range

Activation energies determined from Arrhenius plot for cobalt-boron liquid quenched amorphous alloys in the temperature range 40 K < T < 300 K , suggest vacancy and interstitial formation to nucleate crystalline phases in an amorphous matrix preferably at sites where dangling bonds are present. Nucleation of crystallites with preferential tetragonal or orthorhombic structures is a self-evolving process due to catalytic presence of dangling bonds in an amorphous material and that the occurrence of negative activation energies support this evidence.

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Electrochemical synthesis, morphological and structural characteristics of carbon nanomaterials produced in molten salts

Electrochimica Acta ◽

10.1016/j.electacta.2016.05.160 ◽

2016 ◽

Vol 211 ◽

pp. 343-355 ◽

Cited By ~ 21

Author(s):

Inessa A. Novoselova ◽

Sergei V. Kuleshov ◽

Sergei V. Volkov ◽

Valerii N. Bykov

Keyword(s):

Electrochemical Synthesis ◽

Molten Salts ◽

Carbon Nanomaterials ◽

Structural Characteristics

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Correlation Between Resistivity Characteristics and Electronic Structure Parameters of the Ni-Pd-P Amorphous Alloys

MRS Proceedings ◽

10.1557/proc-644-l12.1 ◽

2000 ◽

Vol 644 ◽

Cited By ~ 1

Author(s):

Mykola Babich ◽

Olesya Nakonechna ◽

Mykhailo Semen'ko ◽

Mykola Zakharenko ◽

Gennagy Yeremenko ◽

...

Keyword(s):

Amorphous Alloys ◽

Crystallization Process ◽

Level Shift ◽

Relaxation Processes ◽

Temperature Range ◽

Temperature Coefficients ◽

Localized State ◽

P Content ◽

Two Stages ◽

Kinetics Of

AbstractThe temperature dependencies of resistivity of the Ni-Pd-P-based amorphous alloys (P content was varied from 14 to 23 at. %) have been measured in a wide temperature range using the standard four-probe method. The temperature coefficients of resistivity (TCR) have been calculated. TCR value is decreased with P content increasing and becomes negative for Ni46Pd31P23 alloy. On the other hand, TCR value is increased with Pd content increasing while P content is not changed. Such behavior could be attributed to the electronic transfer effect from Ni to Pd and from P to Ni. These lead to the Fermi level shift to d-band edge and to the increasing influence of the Mott's localized state. The peculiarities caused by structural relaxation processes have been observed at the temperature range of 550 – 620 K. The relaxation process was shown to consist at least of two stages. The kinetics of the crystallization process has been analyzed using the Kissinger method.

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NANOSTRUCTURED AND BULK AMORPHOUS Zr-BASED ALLOYS PREPARED BY MECHANICAL ALLOYING AND ARC MELTING

International Journal of Modern Physics B ◽

10.1142/s021797920301817x ◽

2003 ◽

Vol 17 (10) ◽

pp. 2035-2044 ◽

Cited By ~ 3

Author(s):

S. BASKOUTAS ◽

P. LEMIS-PETROPOULOS ◽

V. KAPAKLIS ◽

Y. KOVEOS ◽

C. POLITIS

Keyword(s):

Glass Transition ◽

Transition Temperature ◽

Glass Transition Temperature ◽

Mechanical Alloying ◽

Amorphous Alloys ◽

Liquid Region ◽

X Ray ◽

Bulk Amorphous Alloys ◽

Arc Melting ◽

Amorphous Powders

We have produced powders of nanostructured and amorphous alloys as well as bulk amorphous alloys with composition Zr 64 Cu 18 Ni 10 Al 8 by mechanical alloying and by quenching arc melted melts in water cooled cooper dies, respectively. The alloys were investigated by X-ray diffraction as well as by thermal analysis in order to determine the structure and thermal properties. The mechanical alloyed amorphous powders and bulk amorphous cylinders show the same thermal and X-ray characteristics. For the amorphous powders, we find that the glass transition temperature Tg is 657 K and the crystallization temperature Tx is 752 K. For bulk amorphous alloys with the same composition prepard by arc melting and liquid quenching Tgis 655 K and the Tx is 725 K. Moreover for the bulk amorphous alloys the supercooled liquid region Δ Txg is 70 K, the reduced glass transition temperature tg is 0.557, the Lu–Liu parameter γ which represents the glass forming ability for bulk metallic glasses is 0.396 and experimentally the critical cooling rate Rc takes the value 7 K s -1.

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