Nanocrystalline Ni-3.6 at.% P and its transformation sequence studied by atom-probe field-ion microscopy

Journal Article · Fri Feb 25 04:00:00 EST 2000 · Acta Materialia

DOI:https://doi.org/10.1016/S1359-6454(99)00371-7· OSTI ID:20015592

Hentschel, T; Isheim, D; Kirchheim, R; Mueller, F; Kreye, H

The transformation sequence of electroless plated nanocrystalline Ni-3.6 at.% P layers upon different heat treatments is studied by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and atom-probe field-ion microscopy (APFIM). APFIM reveals P segregation at the grain boundaries in the as-plated nanocrystalline alloy. DSC shows two heat releases upon isochronic heat treatment. During the first heat release, starting at about 136 C for a heating rate of 20 C/min, structural relaxation occurs first, followed by slight crystal growth and segregation enhancement, as shown by XRD and APFIM. Nucleation of the equilibrium phase Ni{sub 3}P starts in the transition to the second heat release. This second heat release, with a sharp onset at 417 C for heating at a rate of 20 C/min, is related to the major part of Ni{sub 3}P-phase formation and substantial grain growth. The transformation sequence is compared with the one observed on amorphous Ni-P alloys and discussed in terms of a thermodynamic model.

• Research Organization: Univ. Goettingen (DE)
• OSTI ID: 20015592
• Journal Information: Acta Materialia, Journal Name: Acta Materialia Journal Issue: 4 Vol. 48; ISSN 1359-6454; ISSN ACMAFD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALORIMETRY
CRYSTAL-PHASE TRANSFORMATIONS
MICROSCOPY
MICROSTRUCTURE
NICKEL ALLOYS
PHOSPHORUS ADDITIONS
SEGREGATION
THERMODYNAMIC MODEL
X-RAY DIFFRACTION