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Title: Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles

Abstract

We report on intermetallic formation reactions in vapor-deposited multilayered foils of Ni/Zr with 70 nm bilayers and overall atomic ratios of Ni:Zr, 2 Ni:Zr, and 7 Ni:2 Zr. The sequence of alloy phase formation and the stored energy is evaluated at slow heating rates ({approx}1 K/s) using differential scanning calorimetry traces to 725 deg. C. All three chemistries initially form a Ni-Zr amorphous phase which crystallizes first to the intermetallic NiZr. The heat of reaction to the final phase is 34-36 kJ/mol atom for all chemistries. Intermetallic formation reactions are also studied at rapid heating rates (greater than 10{sup 5} K/s) in high temperature, self-propagating reactions which can be ignited in these foils by an electric spark. We find that reaction velocities and maximum reaction temperatures (T{sub max}) are largely independent of foil chemistry at 0.6{+-}0.1 m/s and 1220{+-}50 K, respectively, and that the measured T{sub max} is more than 200 K lower than predicted adiabatic temperatures (T{sub ad}). The difference between T{sub max} and T{sub ad} is explained by the prediction that transformation to the final intermetallic phases occurs after T{sub max} and results in the release of 20%-30% of the total heat of reaction and a delay inmore » rapid cooling.« less

Authors:
; ; ;  [1]
  1. Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland 21218 (United States)
Publication Date:
OSTI Identifier:
21538018
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 109; Journal Issue: 1; Other Information: DOI: 10.1063/1.3527925; (c) 2011 American Institute of Physics; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALLOYS; AMORPHOUS STATE; ATOMS; CALORIMETRY; COOLING; DEPOSITION; ELECTRIC SPARKS; FOILS; HEATING RATE; INTERMETALLIC COMPOUNDS; LAYERS; NICKEL; REACTION HEAT; SPUTTERING; STORED ENERGY; TRANSFORMATIONS; VAPOR DEPOSITED COATINGS; VELOCITY; ZIRCONIUM; COATINGS; ELECTRIC DISCHARGES; ELEMENTS; ENERGY; ENTHALPY; METALS; PHYSICAL PROPERTIES; THERMODYNAMIC PROPERTIES; TRANSITION ELEMENTS

Citation Formats

Barron, S. C., Knepper, R., Walker, N., and Weihs, T. P. Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles. United States: N. p., 2011. Web. doi:10.1063/1.3527925.
Barron, S. C., Knepper, R., Walker, N., & Weihs, T. P. Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles. United States. doi:10.1063/1.3527925.
Barron, S. C., Knepper, R., Walker, N., and Weihs, T. P. Sat . "Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles". United States. doi:10.1063/1.3527925.
@article{osti_21538018,
title = {Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles},
author = {Barron, S. C. and Knepper, R. and Walker, N. and Weihs, T. P.},
abstractNote = {We report on intermetallic formation reactions in vapor-deposited multilayered foils of Ni/Zr with 70 nm bilayers and overall atomic ratios of Ni:Zr, 2 Ni:Zr, and 7 Ni:2 Zr. The sequence of alloy phase formation and the stored energy is evaluated at slow heating rates ({approx}1 K/s) using differential scanning calorimetry traces to 725 deg. C. All three chemistries initially form a Ni-Zr amorphous phase which crystallizes first to the intermetallic NiZr. The heat of reaction to the final phase is 34-36 kJ/mol atom for all chemistries. Intermetallic formation reactions are also studied at rapid heating rates (greater than 10{sup 5} K/s) in high temperature, self-propagating reactions which can be ignited in these foils by an electric spark. We find that reaction velocities and maximum reaction temperatures (T{sub max}) are largely independent of foil chemistry at 0.6{+-}0.1 m/s and 1220{+-}50 K, respectively, and that the measured T{sub max} is more than 200 K lower than predicted adiabatic temperatures (T{sub ad}). The difference between T{sub max} and T{sub ad} is explained by the prediction that transformation to the final intermetallic phases occurs after T{sub max} and results in the release of 20%-30% of the total heat of reaction and a delay in rapid cooling.},
doi = {10.1063/1.3527925},
journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 1,
volume = 109,
place = {United States},
year = {2011},
month = {1}
}