Bulk amorphous Pd–Ni–Fe–P alloys: Preparation and characterization

1999 ◽  
Vol 14 (5) ◽  
pp. 2107-2115 ◽  
Author(s):  
T. D. Shen ◽  
Y. He ◽  
R. B. Schwarz
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Molar Volume ◽  
Amorphous Alloys ◽  
Composition Range ◽  
Glass Transition Temperatures ◽  
Bulk Amorphous Alloys ◽  
The Difference ◽  
Quenching Method ◽  
Chemically Selective

Bulk amorphous alloys of PdxNiyFe80−x−yP20 (25 ≤ x ≤ 60, 20 ≤ y ≤ 55, x + y ≥ 60) were prepared by a flux-melting and water-quenching method. Seven-mm diameter glassy rods of Pd40Ni40−xFexP20 (0 ≤ x ≤ 20) were studied in greater detail. For these alloys, the difference between the crystallization and glass transition temperatures ranges from 102 K for x = 0 to 53 K for x = 20. In this composition range, the reduced glass transition temperature, Trg, ranges from 0.66 to 0.57. The change in density upon crystallization ranges from 0.24 ± 0.04% for x = 0 to 1.33 ± 0.24% for x = 10. The partial molar volume of Fe in amorphous Pd40Ni40−xFexP20 alloys is significantly larger than the molar volume of (metastable) fcc Fe. This, as well as a comparison with the molar volumes of crystalline compounds, suggests chemically selective Fe–Pd bonding in these glasses.

scholarly journals Synthesis and Properties of Bulk Metallic Glasses in Pd-Ni-P and Pd-Cu-P Alloys

1996 ◽  
Vol 455 ◽  
Author(s):  
Y. He ◽  
R. B. Schwarz
Keyword(s):  
Thermal Stability ◽  
Glass Transition ◽  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Composition Range ◽  
Wide Composition Range ◽  
Upper Limit ◽  
Ternary Alloy Systems ◽  
The Difference ◽  
Thermal Stability Of

ABSTRACTBulk amorphous Pd-Ni-P and Pd-Cu-P alloy rods with diameters ranging from 7 to 25 mm have been synthesized over a wide composition range using a fluxing technique. For most bulk amorphous Pd-Ni-P alloys, the difference ΔT = Tx - Tg between the crystallization temperature Tx and the glass transition temperature Tg is larger than 90 K, while for bulk amorphous Pd-Cu-P alloys, ΔT varies from 27 to 73 K. Pd40Ni40P20 has the highest glass formability, and 300-gram bulk amorphous cylinders, 25 mm in diameter and 50 mm in length, can be easily produced. This size, however, is not an upper limit. The paper presents the glass formation ranges for both ternary alloy systems and data on the thermal stability of the amorphous alloys, as well as their specific heat, density, and elastic properties.

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

2003 ◽  
Vol 17 (10) ◽  
pp. 2035-2044 ◽  
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.

Annealing experiments on bulk amorphous alloys around the glass transition temperature

2006 ◽  
Vol 304 (2) ◽  
pp. e657-e659
Author(s):  
Antal Lovas ◽  
András Bárdos ◽  
Pavel Kamasa ◽  
Jozef Kováč ◽  
Krisztián Bán
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Amorphous Alloys ◽  
Bulk Amorphous Alloys ◽  
Annealing Experiments

Structural and Optical Properties of Li2O–NaF–ZnO–P2O5:(CdO + S) Glass System

2017 ◽  
Vol 6 (1) ◽  
pp. 108-115 ◽  
Author(s):  
Mohammed A. Algradee ◽  
A. A. Higazy ◽  
S. Wageh
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Molar Volume ◽  
Absorption Spectra ◽  
Spectral Range ◽  
Glass Matrix ◽  
Structural Changes ◽  
Quenching Method ◽  
The Fourier Transform

Glasses having composition 5Li2O-33NaF-7ZnO-55P2O5: x wt% (CdO + S) where x = 0.0, 1.0, 2.0, 3.0 and 4.0 wt%, were prepared by the melt quenching method and their amorphous nature was confirmed by X-ray diffraction technique. Variations in density (ρ), molar volume (Vm) and glass transition temperature (Tg) have been correlated with structural changes in the glass matrix. The optical absorption spectra of the polished samples were recorded in spectral range from 200 to 1000 nm at room temperature. The optical band gap (Eopt.) and Urbach energy (ΔE) were determined from the absorption spectra. These parameters (Eopt., ΔE) were found to vary depending on the composition of the glasses. The Fourier-transform Infrared (FTIR) spectra have been recorded in the spectral range from 400 to 4000 cm–1. The FTIR reveals that the addition of Cd2+ ions provide ionic cross-linking between the non-bridging oxygen of different chains and increasing the bond strength of this ionic cross-link which confirmed by decrease in the molar volume and increase in the glass transition temperature when (CdO + S) content is increased. The compositional dependences of the above properties are discussed and correlated with the structural changes in glass matrix.

A Copolymerization Modified Acrylate Resin and its Polyhedral Oligomeric Silsesquioxane Composites

2014 ◽  
Vol 887-888 ◽  
pp. 97-100
Author(s):  
Xiao Lan Hu ◽  
Xi Lan ◽  
Teng Fei Lu ◽  
Hong Shan Yang ◽  
Ying Lai Yang
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Polyhedral Oligomeric Silsesquioxane ◽  
Glass Transition Temperatures ◽  
Acrylate Copolymer ◽  
Amino Resin ◽  
Acrylate Resin ◽  
Oligomeric Silsesquioxane ◽  
Physical Blending ◽  
Better Than

An acrylate resin copolymerized with epoxy and amino resin was prepared in this paper, and its polyhedral oligomeric silsesquioxane (POSS) modified nanocomposites were fabricated via physical blending. Results showed that glass transition temperature of the acrylate copolymer was about 7.9 oC via DSC. Dispersion of nanocomposites with aminopropyllsobutyl POSS is better than those with Octalsobutyl POSS. Moreover, glass transition temperatures of the nanocomposites with POSS are close to the acrylate copolymer matrix.

Observation of Glass Transition Temperatures in Polymeric Thin Films by Wafer Curvature Measurements

1991 ◽  
Vol 239 ◽  
Author(s):  
P. H. Townsend ◽  
B. S. Huber ◽  
D. S. Wang
Keyword(s):  
Thin Films ◽  
Glass Transition ◽  
Transition Temperature ◽  
Polymer Network ◽  
Cross Linking ◽  
Positional Isomers ◽  
Glass Transition Temperatures ◽  
Thin Coatings ◽  
Polymeric Thin Films ◽  
Curvature Measurements

ABSTRACTWafer bending measurements have been used to study the glass transition temperature, Tg, of thin coatings of polystyrene and polycarbonate on Si wafers. The observed values of Tg agree with DSC and TMA measurements on bulk samples. The evolution of the substrate curvature has been used to examine the behavior of Tg in thin epoxy films and coatings derived from divinylsiloxane bisbenzocyclobutene, mixed stereo and positional isomers of 1, 3-bis(2-bicyclo[4.2.0]octa-1, 3, 5-trien-3-ylethenyl)-1, 1, 3, 3-tetramethyl disitoxane (CAS 117732–87–3). The dependence of the Tg of the epoxide coatings is studied as a function of the cross-linking. The evolution of the Tg in the benzocyclobutene coating is found to be a monotonie function of the level of conversion of the polymer network.

Formation, Mechanical and Electrical Properties of Ni-based Amorphous alloys and their Nanocrystalline Structure

2002 ◽  
Vol 740 ◽  
Author(s):  
Xiangcheng Sun ◽  
Tiemin Zhao
Keyword(s):  
Glass Transition ◽  
Transition Temperature ◽  
Glass Transition Temperature ◽  
Amorphous Alloy ◽  
Amorphous Alloys ◽  
Interaction Model ◽  
Nanocrystalline Structure ◽  
Primary Crystallization ◽  
Electron Interaction ◽  
Liquid Region

ABSTRACTA Ni-based amorphous alloy in Ni60Ti20Zr20 system was prepared by melting spinning. The glass transition temperature (Tg) was as high as about 760 K, the supercooled liquid region was quite wide, ΔTx = 50 K (ΔTx= Tx-Tg, Tx crystallization temperature), and the reduced glass transition temperature (Tg/Tm) was 0.60. The amorphous alloys exhibited a high tensile strength (of= 1015 MPa) at room temperature. The electrical conductivity obeyed a T12 law over the range of 15 K< T < 300 K, which can be explained by an electron-electron interaction model. After annealing the amorphous alloy into primary crystallization, a nanocomposites consisted of metastable Ti2Ni and Zr2Ni nanophases with size less than 15 nm embedded in the amorphous matrix was appeared.

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