Ni-P Amorphous Alloy Research Articles

The Hall effect in amorphous Ni-P alloys

The authors have measured the room-temperature Hall resistivity of electro-deposited amorphous Ni1-xPx samples for 0.15<or=x<or=0.26. The apparent Hall coefficient is observed to change sign as a function of P concentration at x approximately=0.23. The anomalous Hall coefficient was determined from the ferromagnetic saturation in the x=0.15 sample. Using recent values from the literature for the susceptibility of electro-deposited Ni-P, it it concluded that the anomalous Hall coefficient makes an insignificant contribution to the apparent Hall coefficient. The experimental results are discussed on the bases of an electronic structure calculation of Ni0.74P0.26 and it is suggested that the change in sign of the classical Hall coefficient of Ni1-xPx may be attributed to a decrease in the s-p density of states at the Fermi energy causing the d holes to begin to dominate the conductivity.

Thermal expansion and structural relaxation of microcrystalline and amorphous Ni-P alloys

Continuing former investigations on Co-P and Fe-P, the changes in length of Ni100 − xPx samples (8 ≤ x ≤ 24, x 20 totally amorphous) on continuous heating and on step-annealing were measured. As long as structural relaxation has not completed, reversible thermal expansion competes with irreversible shrinkage. This effect is considerably stronger than that observed on Co-P but nearly as large as in Fe-P. Therefore it is not directly determined by short-range order which is similar to that of Co-P but not to that of Fe-P. On the other hand, the reversible thermal expansion coefficient and its composition dependence exhibit a clear correlation with short-range order and reflect especially the peculiar structural properties of Fe-P alloys.

Experimental Arrangement for Obtaining Uniform Amorphous Ni-P Alloys by Electrodeposition

Experimental Arrangement for Obtaining Uniform Amorphous Ni-P Alloys by Electrodeposition

Crystallization Characteristics of Electrodeposited Amorphous Ni-P Alloys

Crystallization Characteristics of Electrodeposited Amorphous Ni-P Alloys

Magnetization and NMR study of amorphous Ni-P alloys in the paramagnetic concetration range

The temperature- and field-dependence of magnetization, and the 31P NMR linewidth and Knight shift of some amorphous Ni 100− x P x alloys with 18⩽ x ⩽ 22 prepared by melt-quenching and electrodeposition were studied below room temperature. Although all the alloys investigated contain magnetic inhomogeneities, the amount and nature of which depend on impurities and on the details of sample preparation, it could be established that the amorphous matrix of Ni 100− x P x alloys with x ⩾ 18 exhibit Pauli paramagnetism and the Pauli susceptibility was found to decrease rapidly with P content. From the results, a similarity of the electronic structure and the short-range order in amorphous Ni-P alloys and in the crystalline Ni 3P compound is deduced.

A Comparative Study of The Crystallization of Ni-P Amorphous Alloys Produced By Ion-Implantation And Melt Spinning.

ABSTRACTImplantation of 4OkeV P+ ions into high purity Ni was employed at room temperature to a dose of 3×10E17 ions/cm2 to produce an 1100 A thick amorphous surface alloy of Ni-14 wt% P. Commercially available melt spun metallic glass ribbons of nominal composition, Ni-il wt% P were used for comparison of crystallization behaviour studied with TEM and RBS techniques. The DTA analysis was employed to construct a TTT curve for the melt spun glass, which was then used as a guide for selecting time and temperature of crystallization of the implanted amorphous alloy. The melt implanted glass is found to be less stable and crystallizes more readily than melt spun glass of similar composition. A detailed study on nucleation and growth of crystallites, mode of crystallization and effect of surface proximity will be presented.

THE HEXAGONAL METASTABLE PHASE FORMED IN AN AMORPHOUS Ni-P ALLOY DURING CRYSTALLIZATION (Ⅲ)——HEXAGONAL POLYTYPE

By tilting the crystals formed in an amorphous Ni-P alloy during crystallization in transmission electron microscope, two further hexagonal metastable phases (a2 and a3) have been discovered. Their lattice parameter a has the same value (6.73?) as that of the previously reported hexagonal metastable phase (a1), but the values of the other lattice parameter c are 3/2 and 4 times respectively of that of the phase a1. This shows that these phases are longperiod polytype structures. Furthermore, the previously assumed F.C.C. sublattice (a=5.50?) of a1 has been found to be really metastable phase from {111} planes of which these hexagonal metastable phases are formed.

CRYSTALLIZATION PHASES IN AMORPHOUS Ni-P ALLOY

Vafaei-Makhsoos claimed to have discovered three new Ni3P phases in crystallized Ni-P amorphous alloy. By analysis of his experimental data as well as our own electron diffraction experiments, it is shown that the various electron diffraction patterns of the so-called new Ni3P phases are in fact all belonging to Ni12P5. Thus it is clear that there are seven crystallization phases in annealed amorphous Ni-P alloys: metastable fcc phase α (α=5.48?), metastable hexagonal polytypes α1,α2,α3 transformed from α, bct Ni12P5, bct Ni3P and Ni solid solution.

Electrical properties of amorphous Ni-P alloys produced by ion implantation

The resistivity temperature dependence of room-temperature-implanted ${\mathrm{Ni}}_{1\ensuremath{-}x}{\mathrm{P}}_{x}$ alloys was measured at P concentrations between $x=0.14$ and $x=0.27$, and compared to that of evaporated and electrodeposited alloys. The results are discussed in the light of previously reported channeling experiments on the same alloys. It is found that the implanted amorphous ${\mathrm{Ni}}_{1\ensuremath{-}x}{\mathrm{P}}_{x}$ systems are identical to their counterparts prepared by conventional techniques.

TDPAC-study of amorphous NiP alloy produced by ion implantation

The perturbed γ-γ angular correlation technique is applied to ion-implanted Ni 82P 18 (2.2×10 17 P/cm 2). The disorder created by P implantation is microcopically probed by the hyperfine interaction of radioactive 111Cd nuclei which strongly suggests a homogeneous amorphous layer ranging from the surface to the P implantation depth R p + ΔR p ∼ 800 A ̊ . The structural phase transitions induced by annealing up to 1000 K and the subsequent crystalline phases are discussed together with recent results on electrodeposited alloys.

無電解Ni-Pめっき膜の構造と諸性質におよぼす繰返し応力の影響

The microstructure of electroless deposited Ni-P alloys in the composition ranging from 5.3 to 7.9 mass%P has been studied by a large angle X-ray scattering method. The changes of microstructure and mechanical properties by cyclic stressing at various stress levels were examined by a X-ray scattering technique and also by a static bend test.The results obtained are as follows;(1) The microstructure of electroless Ni-P alloys containing less than about 7 mass%P is a supersaturated solid solution of fcc Ni in which an excess of P dissolves. On the other hand, the electroless Ni-P alloys containing more than about 7 mass%P are completely amorphous structure. This structure is quite similar to that of the amorphous alloys obtained by other methods such as rapid quenching and electrodeposition.(2) The amorphous Ni-P alloys prepared by the present method have some excellent properties such as good ductility and high corrosion resistance. But, these excellent properties deteriorate by cyclic stressing, particularly by tensile stressing, because of a changes in amorphous structure due to structural relaxation and local crystallization.

電析非晶質Ni-P合金の相分離挙動について

電析非晶質Ni-P合金の相分離挙動について

Effect of low-temperature annealing and deformation on the structure of metallic glasses by X-ray diffraction

The changes in the atomic structure of amorphous Pd-Si and Ni-P alloys due to low-temperature annealing, cold-rolling and isothermal creep have been studied by the conventional X-ray diffraction. The present results on the effect of low-temperature annealing were consistent with those of amorphous Fe40Ni40P14B6 alloy studied by the energy dispersive X-ray diffraction method. In addition, the present results have indicated that the effect of cold-rolling causes small changes in the structure of amorphous Pd80Si20 alloy which are qualitatively different from the structural relaxation, and the effect of annealing plays a significant contribution in the structural change during an isothermal creep test.

Nuclear-magnetic-resonance studies of amorphous Ni-P alloys

Nuclear-magnetic-resonance studies of amorphous Ni-P alloys

Magnetic properties of amorphous NiP alloys

Magnetization, NMR and coercive force measurements were performed on amorphous Ni 1− c P c alloys for concentration ranging between 0.15 and 0.25. The experimental results show that the magnetism is not of the same nature below and above some critical concentration c 0 which determines the concentration ranges: the first one (0.15 < c < 0.18) presents the characters of a weak homogeneous ferromagnetism, while inhomogeneities dominate the magnetic properties of the second one (0.18 < c < 0.25).

Amorphous Ni-P alloys prepared by ion implantation

Abstract Ion implantation of 40 keV, P+ ions into pelycrystalline Ni foils has been used to produce amorphous Ni-P alloys. The foils were subsequently investigated by electron microscopy and electron diffraction. The diffraction measurements confirm the presence of an amorphous surface layer. The ion implanted alloy is compared to similar material produced by the more usual techniques of electro deposition and vapour quenching. After annealing, the implanted layer recrystallizes into a dense, small grained structure. Equivalent results have been obtained using Co and Fe as target materials. The data suggests that ion implantation should contribute to an understanding of the production and stability of amorphous metals.

Magnetic properties of amorphous NiP alloys

An experimental study on amorphous electrodeposited Ni1−cPc alloys was performed using measurements of magnetic properties, coercive force, NMR and resistivity at low temperatures. The results show that weak ferromagnetism takes place for 0.15 < c < 0.25. Furthermore, the anomalies in the transport properties are of structural and not a magnetic origin.

Structural investigation of amorphous CoP and NiP alloys by combined X-ray and neutron scattering

Structural investigation of amorphous CoP and NiP alloys by combined X-ray and neutron scattering

Microstructure of amorphous and crystalline electrodeposited Ni-P and Co-P alloys

A new model for the microstructure of electrodeposited Ni-P and Co-P alloys is presented based upon the concept of grain boundary segregation. The model correctly explains the compositional dependence of grain size as well as other experimental data. The model also predicts an anomalous low temperature heat capacity and a low temperature resistivity minimum. Both these predictions are confirmed experimentally.