In this work we describe the procedure to produce alloy based on Ni-Mn-Ga which is considered to be modern magnetic material. Alloy has been synthesized bz pouring the molten Ni-Mn-Ga alloy over a porous mould made of sodium aluminate. This has then been etched away using a mixture of different acids and got porous magnetic material that exhibits so-called giant magnetic shape memory effect.
COBISS.SI-ID: 1424479
We have coated Nd-Fe-B melt spun powders, used for the production of bonded magnets via the sol-gel route by Al[sub]{2}O[sub]{3}. Topography and chemical composition of as-spun and protected ribbons was compared by Auger electron spectroscopy, X-ray photoelectron spectroscopy, secondary electron spectroscopy and electron diffraction spectroscopy. To determine the corrosion properties, we have conducted a Highly accelerated stress test, at 110 °C and 90 % humidity, followed by measuring the weight change. To confirm the effectiveness of the coated layer, magnetic properties were compared with a vibrating sample magnetometer. Al[sub]{2}O[sub]{3} coatings resulted in superior corrosion resistance and magnetic properties and thus expanding the applicability of bonded magnets to severe atmospheric conditions.
COBISS.SI-ID: 980650
We have studied the influence of Ni on the magnetocaloric effect (MCE) in Nanoperm-type amorphous materials by investigating a series of Fe84-xNixZr6B10 alloys with x=0, 2, 4 and 6. As expected, the Curie temperature increased with the amount of Ni from 427 K for x=0 to 482 K for x=6. The maximum magnetic entropy change (∆Sm(peak)) for an applied field of 1.4 T also increased, reaching a value of 1.52 J/Kkg for x=6, which is an increase of 25% compared to the Ni-free alloy. The refrigerant capacity first decreased for x=2 and then increased, reaching a maximum value of 93 J/kg (ΔH = 1.4 T) for x=6. For a 5 T field change, the value increased to 407 J/kg, which is higher than the 355 J/kg achieved with Gd5Ge1.9Si2Fe0.1. We confirmed the proposed “master curve” behavior for second-order magnetic transition (SOMT) alloys for the temperature dependence of ΔSm for different alloy compositions of the same series, which makes it easier and faster to find proper candidates for a magnetic refrigerator.
COBISS.SI-ID: 27413799