Microstructural Evaluation of Dy-Ni-Al Grain-Boundary-Diffusion (GBD) Treatment on Sintered Nd-Fe-B Magnet

2010 ◽  
Vol 654-656 ◽  
pp. 2919-2922 ◽  
Author(s):  
Naoko Oono ◽  
Masato Sagawa ◽  
Ryuta Kasada ◽  
Hideki Matsui ◽  
Akihiko Kimura
Keyword(s):  
Melting Point ◽  
Grain Boundary ◽  
Eutectic Alloy ◽  
Alloy Powder ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Rich Phase ◽  
X Ray ◽  
Microstructural Evaluation

A novel GBD treatment with Dy-Ni-Al eutectic alloy powder enhanced the coercivity of the sintered Nd-Fe-B magnet plate as thick as 5mm to 1760 kA/m (22 kOe) without reducing the remanence. The results of wavelength dispersive X-ray spectroscopy (WDS) indicated that this industrially epoch-making treatment spread Dy, which is a coercivity enhancing element, from the surface to the centre of the magnet through Nd-rich phase. Microstructural observations suggested that Ni and Al, which are the melting point depressants of Nd and Dy, enabled the high diffusivity of Dy.

Grain Boundary Diffusion in Co/Cu and Co/Cr Magnetic Thin Films

1993 ◽  
Vol 313 ◽  
Author(s):  
John G. Holl-Pellerin ◽  
S.G.H. Anderson ◽  
P.S. Ho ◽  
K.R. Coffey ◽  
J.K. Howard ◽  
...  
Keyword(s):  
Thin Films ◽  
Activation Energy ◽  
Diffusion Coefficient ◽  
Grain Boundary ◽  
Photoelectron Spectroscopy ◽  
Boundary Diffusion ◽  
Magnetic Thin Films ◽  
Grain Boundary Diffusion ◽  
X Ray ◽  
Before And After

ABSTRACTX-ray photoelectron spectroscopy (XPS) has been used to investigate grain boundary diffusion of Cu and Cr through 1000 Å thick Co films in the temperature range of 325°C to 400°C. Grain boundary diffusivities were determined by modeling the accumulation of Cu or Cr on Co surfaces as a function of time at fixed annealing temperature. The grain boundary diffusivity of Cu through Co is characterized by a diffusion coefficient, D0gb, of 2 × 104 cm2/sec and an activation energy, Ea,gb, of 2.4 eV. Similarly, Cr grain boundary diffusion through Co thin films occurs with a diffusion coefficient, Do,gb, of 6 × 10-2cm2/sec and an activation energy, Ea,gb of 1.8 eV. The Co film microstructure has been investigated before and after annealing by x-ray diffraction and transmission electron Microscopy. Extensive grain growth and texturing of the film occurred during annealing for Co deposited on a Cu underlayer. In contrast, the microstructure of Co deposited on a Cr underlayer remained relatively unchanged upon annealing. Magnetometer Measurements have shown that increased in-plane coercivity Hc, reduced remanence squareness S, and reduced coercive squareness S* result from grain boundary diffusion of Cu and Cr into the Co films.

Grain boundary diffusion of Cu in TiN film by X-ray photoelectron spectroscopy

2000 ◽  
Vol 70 (4) ◽  
pp. 431-434 ◽  
Author(s):  
K.Y. Lim ◽  
Y.S. Lee ◽  
Y.D. Chung ◽  
I.W. Lyo ◽  
C.N. Whang ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Photoelectron Spectroscopy ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
X Ray ◽  
Tin Film

Grain Boundary Diffusion in NiFe/Ag Bilayer Thin Films

1994 ◽  
Vol 343 ◽  
Author(s):  
M. Gall ◽  
J.G. Pellerin ◽  
P.S. Ho ◽  
K.R. Coffey ◽  
J.K. Howard
Keyword(s):  
Grain Boundary ◽  
Photoelectron Spectroscopy ◽  
Annealing Temperature ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Before And After

ABSTRACTX-ray photoelectron spectroscopy (XPS) has been used to investigate grain boundary diffusion of Ag through 250 Å thick Ni80Fe20 (permalloy) films in the temperature range of 375 to 475°C. Grain boundary diffusivities were determined by modeling the accumulation of Ag on Ni80Fe20 surfaces as a function of time at fixed annealing temperature. The grain boundary diffusivity of Ag through Ni80Fe20 is characterized by a diffusion coefficient prefactor, D0,gb, of 0.9 cm2/sec and an activation energy, Ea,gb, of 2.2 eV. The Ni80Fe20 film microstructure has been investigated before and after annealing by atomic force microscopy and x-ray diffraction. The microstructure of Ni80Fe20 deposited on Ag underlayers remained relatively unchanged upon annealing.

Ni Grain Boundary Diffusion in Cu-Co Alloys

2015 ◽  
Vol 363 ◽  
pp. 130-132 ◽  
Author(s):  
Alexey O. Rodin ◽  
Ainur Khairullin
Keyword(s):  
Grain Boundary ◽  
Microprobe Analysis ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Triple Product ◽  
Alloying Element ◽  
X Ray ◽  
Temperature Range ◽  
Co Concentration ◽  
Co Alloys

The influence of Co as an alloying element on grain boundary diffusion (GBD) in Cu attracts particular interest due to anomalous GBD of Co in Cu. Ni as a neutral to Co and Cu element was chosen for GBD study. The triple products of Ni GBD in Cu and Cu-Co alloys (with concentration up to 2.9 wt. %) were determined in temperature range 500 – 700 °C by X-ray microprobe analysis. It was shown, that in spite of some scattering the triple product does not depend on Co concentration at all temperatures of experiments. From the obtained results it follows that Co does not change the GB structure.

GRAIN BOUNDARY DIFFUSION OF BULK INTERSTITIALS IN ALPHA-ZIRCONIUM

1990 ◽  
Vol 51 (C1) ◽  
pp. C1-691-C1-696 ◽  
Author(s):  
K. VIEREGGE ◽  
R. WILLECKE ◽  
Chr. HERZIG
Keyword(s):  
Grain Boundary ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion

Room-temperature grain boundary diffusion data measured from historical artifacts

2005 ◽  
Vol 96 (10) ◽  
pp. 1187-1192 ◽  
Author(s):  
Raymond J. Kremer ◽  
Mysore A. Dayananda ◽  
Alexander H. King
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Boundary Diffusion ◽  
Grain Boundary Diffusion ◽  
Diffusion Data
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