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X-ray photoelectron spectroscopy (XPS) study of Heusler alloy (Co2FeAl) interfaced with semiconductor (n-Si) structure

Kumar Arvind, Srivastava P. C.

Materials Science Poland

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2019

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Vol. 37, No. 1

116--121

EN

Layered magnetic heterostructures are very promising candidates in spintronics in which the influences of interfaces, surfaces and defects play a crucial role. X-ray photoelectron spectroscopy (XPS) study has been performed for studying in detail the chemical state and electronic structure of Co2FeAl (CFA) Heusler alloy interfaced with Si substrates. XPS survey scan spectra have clearly shown the presence of Fe, Co and Al signal along with the signal due to Si. The presence of Co, Fe and Al signal confirms the formation of CFA alloy phase. Our XPS results support our previous study [1] on CFA/Si structure in determining the magnetic and transport properties across the interface.

2

Silicide formation on silicon by dense compression plasma treatment

Anishchik V., Uglov V., Kvasov N., Petykhou Y., Astashynski V., Kuzmitski A., Zhukowski P., Karwat C., Zhukowski P., Fedotova J.

Przegląd Elektrotechniczny

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2010

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R. 86, nr 7

311-313

EN

In the present paper the means of applying compression plasma flows (CPF) for deep metal doping of silicon, formation of single- and multiphase metal silicide as well as submicron silicide structures are discussed. The action of CPF on Fe/Si and Ni/Si systems results in the formation of silicon dendries and metal silicides á-FeSi2 and NiSi, NiSi2 respectively. Metal silicides are preferably localized between the silicon dendrites’ branches.

PL

Prezentowany artykuł omawia zastosowanie strumieniowej plazmy kompresyjnej do głębokiego domieszkowania krzemu metalem oraz powstawanie jedno- i wielofazowych krzemków metali oraz submikroskopowych struktur krzemkowych. Działanie strumieniowej plazmy kompresyjnej na układy Fe/Si oraz Ni/Si powoduje tworzenie się dendrytów krzemowych i krzemków metali odpowiednio - .-FeSi2 i NiSi.

3

The temperature - and stress fields of valves of IC engine

Jaskólski J., Krzyżak R.

Journal of KONES

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2007

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Vol. 14, No. 3

245-252

EN

The paper concerns building up one exhaust valve of composite-steel and two intake ceramics-steel valves of a hypothetical adiabatic engine. The input temperatures were computed using three diverse FORTRAN95 programs, solving a shortened optical integral equation with radiative transfer, transient differential equation while starting and switching off the engine and a rod like diff. Equation with 'progonka' (Thomas) solution. The ANSYS11 programme was fed up with the output of the programs. It turns out that, generally, a mineralogical, crystal-chemical approach to the joining of materials results in stresses known from the common metal engines. Such problems as CTE enhancing (partly hypothetical) by means of doping the anionic compounds by cationic ones, swelling of structures, compressibility versus coefficient of thermal expansion (CTE) , compatibility of crystal motifs while joining, thermal shock resistance, switching the bonds, mechanical longevity, radiation protection etc were addressed. It turns out that true nature of the temperature and stress field, especially of the exhaust valve is closer to the FORTRAN temperature computation than, e.g. From the heat film coefficients (ANSYS11).

4

Complex silumins

Pietrowski S.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 24, nr 1

101-105

EN

Purpose: The study presents the results of investigations carried out on silumins with additions of Mg, Ni, Cu, Cr, Mo and W. The silumins containing Mg, Cu and Ni are well-known and commonly used in construction of machines and equipment. Design/methodology/approach: Additions of Cr, Mo and W have not been thoroughly investigated yet. They are considered a new family of innovative cast aluminium alloys. Findings: In Al-Si systems they form silicides, like Cr3Si, Mo3Si, W3Si and intermetallic phases of Al13Cr4Si4, Al12Mo, Al12W and AlWSi. The silicides crystallise in cubic lattice of parameters similar to aluminium and silicon. Research limitations/implications: Therefore they can act as crystallisation substrates and occur as separate phases. The examinations under the microscope and X-ray microanalysis of the linear and point distribution of elements confirmed the presence of the above mentioned phases. A combination of two elements, e.g. Cr and Mo, or Cr and W, was observed to cause the formation of complex silicide layers of Mo3Si and (Cr, Mo)3Si, or Cr3Si as well as (W, Cr)3Si. Originality/value: The presence of the silicides has been indicated as a possible source of the refinement of alpha (Al) and beta (Si) phases. The precipitations of these phases and of the intermetallic phases favour a high degree of the silumins hardening. A characteristic feature is the fact that nucleation and crystallisation of the successive phases takes place at the phase boundaries formed between the previously precipitated phase and solid solution alpha. The studies carried out so far have indicated that in complex silumins at high temperatures crystallise the silicides and peritectic phases of Al12W, AlWSi, Al12Mo and Al13Cr4Si4. Phases alpha or beta are the next ones to crystallise, followed by complex eutectic alpha + beta +Al(Si, Cr, Mo, W, Fe). Further crystallise the phases of Mg2Si, Al3Ni and Al2Cu. The silumins presented here are characterised by high mechanical properties: Rp0,2=320-420MPa, Rm=400-520MPa, A5=0.5-5.0% and elevated hardness of 145-210HB. Further investigations will be carried out to optimise the chemical composition of silumins and the precipitation hardening process parameters to produce alloys characterised by optimum combination of strength, ductility and hardness.

5

Redukcja fluorowanego grafitu (CF)n w fali spalania i charakterystyka produktów reakcji

Cudziło S., Huczko A., Szala M., Bystrzejewski M.

Biuletyn Wojskowej Akademii Technicznej

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2006

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Vol. 55, nr 4

257-265

PL

Badano proces spalania mieszanin fluorowanego grafitu (CF)n z różnymi reduktorami: NaN₃, B, Ti, ZrTi, Si, CaSi₂, AlSi, TiSi, MoSi₂ i CrSi₂. Okazało się, że reakcje pomiędzy tymi substratami są dostatecznie szybkie i egzotermiczne, aby proces redukcyjnego defluorowania przebiegał w reżimie samopodtrzymującej się, wysokotemperaturowej syntezy. Wykonano pomiary ciepła reakcji oraz zbadano skład fazowy i mikrostrukturę skondensowanych produktów spalania. Obserwacje mikroskopowe ujawniły obecność rozwarstwionego grafitu we wszystkich próbkach. Nanometryczne struktury w formie włókien, prętów i krystalitów 3D także wykryto w większości produktów reakcji.

EN

Mixtures of fluorinated graphite (CF)n with different reductants, such as NaN₃, B, Ti, ZrTi, Si, CaSi₂, AlSi, TiSi, MoSi₂, and CrSi₂ were investigated. Reactions between these substrates are fast and exothermic enough to proceed in a high temperature self-sustaining regime. Heat effects accompanying the reactions were measured and the solid reaction products were analyzed. SEM observation revealed the presence of exfoliated graphite in each case. Nanostructures, like nanofibers, nanorods, nanospheres and nano-sized crystals, were also present in most of the products. Phase (XRD) and elemental composition as well as porous structure (N₂ adsorption) of chosen reaction products were also determined.

6

Wytwarzanie metodą odlewniczą wysokokrzemowych stopów Fe-C-Cr

Granat K., Pigiel M.

Archiwum Odlewnictwa

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2006

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R. 6, nr 18/2

183--188

PL

W pracy przedstawiono wyniki badań nad możliwością wytwarzania metodą odlewniczą wysokokrzemowych stopów Fe-C-Cr. Stwierdzono, że przy zachowaniu ustalonej procedury postępowania, doborze odpowiednich składników wsadu metalowego i wykorzystaniu specjalnych nomogramów możliwe jest wytwarzanie stopów o założonych właściwościach użytkowych, w których krzem sprzyja krystalizacji zwiększonej ilości twardych węglików chromu typu M7C3, a ponadto krzemków typu M5Si3 i M3Si oraz węglikokrzemków typu M7X3, M5X3 i M3X2.

EN

In the paper the results of investigations concerned with the manufacturing by the casting method of Fe-C-Cr alloys containing high silicon content were shown. It was ascertained, that by applying of the manufacturing procedure, selection of alloying elements and applying of special nomographs it is possible the manufacturing of alloys characterized by the assumed functional properties. Discussed properties are achieved according to the silicon effect on the formation of the high amount of silicon carbides of M7X3, M5X3 and M3X3 type.

7

Peculiarities of Components' Interaction in Rare Earth-Transition Metal-Silicon Systems in R(MxSi1-x)2-y Composition Region

Gladyshevsky E., Bodak O. I., Gorelenko Y. K., Yarovetz V. I.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 5

617--622

EN

The explanation of ternary compounds, forming with AlB2 structure type in the rare earth metal-transition metal-silicon systems, implements on base of analysis of the dependence of the valence-electron concentration versus the kind of the transition metals in their solid solutions in the binary compounds with AlB2, _-ThSi2, and _-GdSi2 structure types appropriate to the rare earth-silicon systems. There is shown that the silicon content (as the electron donor) during formation of the ternary compounds with AlB2 structure type is dependent on the kind of transition metal and this content is decreased in the series of the compounds with Fe, Co, Ni, and Cu consecutively. The experimental data on concentrational intervals of the stability ranges of these ternary compounds are proposed to the qualitative evaluation of the effective valency of the transition metal atoms.