Nanocrystalline Ni-3.6 at.% P and its transformation sequence studied by atom-probe field-ion microscopy
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, Vol. 48, Issue 4; Other Information: PBD: 25 Feb 2000; ISSN 1359-6454
- Country of Publication:
- United States
- Language:
- English
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