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1

The Magnetic Entropy Changes in Pb Doped Ni-Mn-Cu-Ga Alloys

Sielicki K., Zygmuntowicz J., Wróblewski R., Leonowicz M.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

823--825

EN

Effect of Pb addition on magnetocaloric properties of Ni50 Mn18,75 Cu6,25-aPbaGa25 (a = 1, 2, 3, 4, 5) alloys was investigated experimentally. The magnetic measurements conducted at low field of 4 kA/m showed that addition of Pb led to separation of the both transformation temperatures and significantly shifted the structural transition effect towards lower temperatures as well as increased the Curie temperature. The analysis of isothermal magnetic curves allowed for the calculation of magnetic entropychange (ΔSM). Although the peak values of |ΔSM| for alloys containing 4 and 5 at.% Pb, ~3 J/(kg*K) and ~1.5 J/(kg*K) respectively, are low they stretch over the structural transformation and Curie temperature, and are at least 30 K wide at half maximum height.

2

Chemical composition and phase constitution of recycled metals from computer scrap

Michalski B., Sielicki K., Leonowicz M., Szymański M., Miazga Z.

Environment Protection Engineering

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2016

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Vol. 42, nr 1

101--112

EN

Studies done on recycled products gained from computer boards have been presented. Alloys fabricated by melting of computer boards were investigated in detail. It was found that the alloy is segregated into two regions - copper and iron rich, in which other alloying elements, forming either solid solutions or intermetallic phases, are dissolved. Scale from melting and sediment from etching metals in hydrochloric acid were also studied. In the scale fluxing agents and residual of metals were gathered, whereas in the sediment some amount of noble metals was detected. Microscopic investigations and chemical composition measurements were performed on alloys from melted boards as well as on the scale and the sediment.

3

Effect of annealing on the structure and properties of Ni46.4 Mn 28.5 Ga 25.1 single crystal

Wróblewski R., Sielicki K., Leonowicz M.

Inżynieria Materiałowa

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2010

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Vol. 31, nr 3

284-286

EN

Effect of annealing at 1073 K for 12 hours on the structure, transformation temperatures and magneto-mechanical properties of Ni46.4Mn28.5Ga25.1 single crystal was studied. Slow cooling from the temperature above the B2-L21 transformation allows to eliminate phases other than martensitic and to refine the 7M martensite structure. The annealing is also a good method to control structural and magnetic transformation temperatures. Magneto-mechanical properties reveal significant change after the heat treatment. Strain in the magnetic field increases over four times after annealing in comparison to that in the as-cast state.

PL

W pracy opisano wpływ wyżarzania w temperaturze 1073 K przez 12 godzin na strukturę, temperaturę przemian oraz właściwości magneto-mechaniczne monokryształu o składzie opisanym wzorem Ni46,4Mn28,5Ga25,1. Wolne chłodzenie z temperatury powyżej przemiany B2-L21 umożliwia eliminację faz innych niż martenzytyczna oraz wpływa na poprawę struktury martenzytu modulowanego 7M (rys. 2). Obróbka cieplna jest również skuteczną metodą kontroli temperatury przemian strukturalnej i magnetycznej (tab. 1., rys. 1). Właściwości magneto-mechaniczne zmieniają się w sposób znaczący w wyniku obróbki cieplnej. Odkształcenie w polu magnetycznym po wyżarzaniu wzrasta ponad czterokrotnie w porównaniu ze stanem przed wyżarzaniem (rys. 3).

4

Aparatura pomiarowa parametrów bezpieczeństwa użytkowania

Owoc G., Sielicki K.

Nowa Elektrotechnika

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2009

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nr 5 (57)

25-29