Analyse thermique des alliages amorphes de Ni-P et Ni-B

Abstract

The nickel-phosphorus and nickel-boron alloys prepared for oxidation-reduction in the liquid phase are amorphous or perfectly crystallized in their initial form. An atomic diffusion precedes the crystallization of nickel, nickel phosphides or nickel borides in the course of appropriate thermal treatment. The different stages of the structural development of the alloys were followed by DTA and X-ray diffraction. The changes in the electrical conductivities of the same alloys as a function of linearly increasing temperature confirmed the results obtained with the aid of DTA and X-ray diffraction.Les d@6ts chimiques de m~taux repr6sentent une mdthode ~ldgante et peu cofiteuse d'obtention d'alliages amorphes [1][2][3][4][5].Nous pr6parons au laboratoire par oxydo-r6duction en phase liquide des d6p6ts d'alliages binaires Ni-P (6/~ 25 % de phosphore en atomes) et Ni-B (29 et 33.5 % de bore) pulv6rulents ou sous forme de films minces.

Electron transport and kinetics of transformations in the amorphous alloy Ni66B34

“…-The nucleation frequency COcryst produced near 400 °C by the exothermal transformation has been calculated for this transformation, knowing the value of Ea cryst determined by Kissinger's method (c.f. relation (11')) [11] : the calculation gives Knowing that the apparent order y has been found to equal 2, relations (8') and (8") allow us to determine : so that :…”

“…-X-ray diffraction [2,[5][6][7][8][9], -electron microscopy and microdiffraction [4,10], -differential thermal analysis [6,8,9,11], -electrical resistivity measurement [2, 4,5,7,10,12].…”

“…In the present work we propose developing this last analytical method, to compare the results with those of differential thermal analysis (D.T.A.) [11] and to interpret them by a detailed structural study.…”

“…3.2.2 Kissinger's method [17]. -This allowed us [11] to determine, by D.T.A. on powder samples, the apparent activation energy Ea and nucleation frequency Co upon crystallization.…”

“…-Kissinger's method is applied to the exothermic D.T.A. peak, the maximum Tm cryst oi which can vary from 385 °C to 435 °C as a function of heating rate a [11].…”