Search results for "Silicide"
showing 9 items of 19 documents
Methods for Enhancing the Thermal Durability of High-Temperature Thermoelectric Materials
2013
Author's version of an article in the journal: Journal of Electronic Materials. Also available from the publisher at: http://dx.doi.org/10.1007/s11664-013-2917-0 Thermoelectric materials, for example skutterudites and magnesium silicides, are being investigated as promising materials for medium-to-high-temperature waste heat recovery in transport and in industry. A crucial aspect of the success of a thermoelectric material is its stability over time when exposed to rapid heating and cooling. In this work different aspects of the degradation of these thermoelectric materials at high temperature were examined. Initial thermal durability was studied, and several candidate coatings were evaluat…
Mechanical activation effect on the self-sustaining combustion reaction in the Mo–Si system
2001
Abstract Nanostructured molybdenum disilicide (MoSi2) was synthesized using an alternative route called MASHS (mechanically activated self-propagating high-temperature synthesis). This original process combines a short duration ball milling (MA) with a self-sustaining combustion (SHS). These two steps were investigated. The microstructure evolution of the powder mixture during mechanical activation was monitored using XRD profile analysis and TEM investigations. Short duration ball milling of (Mo+2Si) powder produces Mo and Si nanocrystallites into micrometric particles. It was demonstrated that pure α-MoSi2 with nanometric structure (DMoSi2=88 nm) could be produced via a very fast combusti…
Formation of cobalt silicide films by ion beam deposition
2006
Abstract Thin films of cobalt silicide are widely used as metallization in very large-scale integrated electronic circuits. In this study, Co ions were deposited on Si(1 1 1) wafers by a high beam current filter metal vacuum arc deposition (FMEVAD) system. Surface silicide films were formed after annealing from 500 to 700 °C for 30 min. The results show that a thin CoSi2 surface layer with both a smooth surface topography and sharp interface can be achieved by annealing at 700 °C. The CoSi phase and O contamination were observed in the samples that were annealed at lower temperatures.
Formation of cobalt silicide from filter metal vacuum arc deposited films
2006
The thermal reaction of Co film deposited on Si(111) surfaces by a high current filter metal vacuum arc (FMEVAD) system has been studied. After deposition the films were annealed over the 400-900 degrees C temperature range for 30 min. Rutherford backscattering spectrometry (RBS) was used to characterize the elemental depth distributions in the films subjected to different annealing temperatures. Ordered chemical phases were determined by glancing-incidence X-ray diffraction (GIXRD) and the morphology was determined by cross section transmission electron microscopy (TEM). The results show that the phases formed are Co2Si at 400 degrees C, CoSi + Coo at 500 degrees C, CoSi + CoSi2 at 600 deg…
Assisted self-sustaining combustion reaction in the Fe–Si system: Mechanical and chemical activation
2007
Abstract This work presents original investigations carried out to improve the activated self-propagating high-temperature synthesis (SHS) process in the Fe–Si system: different ignition modes are tested (volume heating as opposed to a local ignition source), and the use of additive is considered in order to enhance the SHS type reactivity in the Fe–Si system. When 20 wt.% of KNO 3 is added to the reactive mixture, the fast (>20 mm s −1 ), stable and self-sustaining combustion reaction produces a very fine FeSi + α-FeSi 2 structure. Infrared thermography (IR) as well as post-mortem analysis (SEM, EDXS, XRD) was used to understand the mechanism behind the chemical activation process when KNO…
Reactivity of commercial silicon and silicides towards copper(I) chloride. Effect of aluminium, calcium and iron on the formation of copper silicide
1998
Abstract The reaction of CuCl with silicon, containing Al, Fe and Ca as impurities, or with silicides (Si2Ca, Si2Fe, Si2Al2Ca, Si8Al6Fe4Ca) has been investigated in the temperature range 200–300°C. For the reaction between CuCl and commercial Si, it was found that, at 282°C, aluminium promotes the reaction between Cu3Si and CuCl while the rate of consumption of Cu3Si is greatly reduced by the presence of iron. The combined action of these two impurities leads to the formation of more copper–silicon alloy. In the presence of mixed silicides, the reaction with CuCl also leads to the formation of Cu3Si. For the quaternary Al–Ca silicide containing iron the rate of formation of Cu3Si is not inc…
The lateral variation of solid state reactions at surfaces studied by means of photoemission electron microscopy: formation of titanium silicides
2001
The alloying and oxygen reduction at titanium silicon interfaces were studied by means of photoemission microscopy. The microscopic chemical composition of the sample surface was characterised by means of imaging X-ray absorption. The silicide formation was studied at clean and oxidised silicon substrates both covered with micron-sized titanium patterns.
Combustion wave structure during the MoSi2 synthesis by Mechanically-Activated Self-propagating High-temperature Synthesis (MASHS): In situ time-reso…
2006
Abstract In situ synchrotron time-resolved X-ray diffraction experiments coupled with an infrared imaging camera have been used to reveal the combustion wave structure during the production of MoSi2 by Mechanically Activated Self-propagating High-temperature Synthesis (MASHS). The fast combustion front exhibits a form described as an ‘equilibrium structure’ where the chemical reaction is the sole major driving force. In the MASHS process, oxide-free interfaces between Mo and Si nanocrystallites enhance the reaction Mo+2Si→MoSi2. Exhaustive time-resolved investigations show a possible solid-state process in the first second of the reaction within the combustion front. If preheating is added,…
Fabrication of a Silicide Thermoelectric Module Employing Fractional Factorial Design Principles
2021
AbstractThermoelectric modules can be used in waste heat harvesting, sensing, and cooling applications. Here, we report on the fabrication and performance of a four-leg module based on abundant silicide materials. While previously optimized Mg2Si0.3Sn0.675Bi0.025 is used as the n-type leg, we employ a fractional factorial design based on the Taguchi methods mapping out a four-dimensional parameter space among Mnx-εMoεSi1.75−δGeδ higher manganese silicide compositions for the p-type material. The module is assembled using a scalable fabrication process, using a Cu metallization layer and a Pb-based soldering paste. The maximum power output density of 53 μW cm–2 is achieved at a hot-side temp…