|
|
Strukturní změny ve slitinách Fe91-yMo8Cu1By – srovnání vlivu difuzivit Fe a Mo
Čermák, Jiří ; Stloukal, Ivo
Partly crystallized alloys Fe91-yMo8Cu1By belong to a NANOPERM-type family with excellent soft-magnetic behavior. Molybdenum, as an alloying element, causes that the Currie temperature of both amorphous and nano-crystallized form of the alloys is close to the room temperature, which opens possibilities to numerous applications. In the present work, structure changes of three chosen alloys (y = 12, 15, 17) are investigated after several temperature treatments by TEM, XRD and DSC and diffusivity of the principal metallic components is measured in the temperature interval 548 – 773 K. It was found that bulk diffusion coefficients of Fe and Mo in relaxed amorphous state are about the same, but grain boundary diffusivity of Fe is much higher than that of Mo. Such a difference in grain boundary diffusivity may act as structure stabilizing factor.
|
|
| |
|
|
Difúze 99Mo ve teplně zpracované slitině Fe76Mo8Cu1B15
Čermák, Jiří ; Stloukal, Ivo
Ion beam sputtering by Ar+ ions was used to investigate 99Mo tracer diffusion in Fe76Mo8Cu1B15 alloy in the temperature range 548 – 648 K. The experimental samples were prepared from ribbons of Fe76Mo8Cu1B15 alloy in as quenched state q, and after pre-annealing at 683 K for 1 h (state a1) and at 743 K for 1 h (state a2). The penetration profiles were obtained using serial sectioning method and consist of two parts suggesting that two different diffusion paths are operating. The Mo short-circuit diffusivity P was evaluated using both LeClaire’s analysis and Divinski’s theory derived for transition type-A/B regime in coarse-grained materials.
|
|
| |
|
|
Difúzní studie Fe a Mo ve slitině Fe76Mo8B15Cu1
Čermák, Jiří ; Stloukal, Ivo
59Fe and 99Mo tracer diffusion in Fe76Mo8B15Cu1 alloy was studied using serial sectioning method in the temperature range 527 – 649 K. The ribbon-like samples were annealed at 695 K for 1 and 5 hours before the diffusion experiments; the volume fraction of crystalline phase was checked by the Mössbauer spectroscopy. Concentration profiles obtained by sputtering by Ar+ ions in a glow discharge show two distinct branches suggesting that two diffusion paths are operating.
|
|
|
Přístroj pro měření koncentračních profilů – Analýza výstupních dat
Čermák, Jiří ; Stloukal, Ivo
In this paper, a new modification of a commercial apparatus Edwards Coating system E306A is described that enables to perform diffusion measurements with radioactive tracers. The plan-parallel thin layers are removed by sputtering with Ar+ ions and the well defined fraction of the sputtered-off material is sequentially collected. The function of the apparatus is exemplified by the measurement of bulk diffusion coefficient of 65Zn in Fe40Ni40B20 alloy at T = 684 K.
|
|
| |
guest ::
