Carbides of Low Tungsten and Molybdenum Steels

Morral, F. R.; Phragmén, Gösta; Westgren, Arne

doi:10.1038/132061b0

Cited by 16 publications

(9 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The third x-ray diffraction profile of Fig. 2(c) is typical of that for a sample of intermediate composition between the equilibrium phases Cu 3 Si and Cu 15 Si 4 .Using a calculated pattern based on an experimental study33,34 , peaks in this scan are indexed to the cubic structure of Cu 15 Si 4 . Bragg peaks identified with the Cu 3 Si are also observed in the scan ofFig.…”

mentioning

confidence: 92%

Thermodynamic and kinetic study of solid state reactions in the Cu–Si system

Chromik¹,

Neils²,

Cotts³

1999

Journal of Applied Physics

View full text Add to dashboard Cite

It has been shown that significant changes in the course of solid state reactions can be realized by decreasing length scale, temperature, or by varying parent microstructures. In the case of the formation of Cu 3 Si by interdiffusion of Cu and Si, previous research has shown that over a large temperature range reaction rates are determined by the rate of grain boundary diffusion of Cu through the growing Cu 3 Si phase. We have examined the effect of replacing crystalline Si with amorphous Si (a-Si) on these solid state reactions, as well as the effect of decreasing the temperatures and length scales of the reactions. Multilayered thin film diffusion couples of Cu and a-Si were prepared by sputter deposition, with most average composite stoichiometries close to that of the equilibrium phase Cu 3 Si. Layer thicknesses of the two materials were changed such that the modulation (sum of the thickness of one layer of Cu and a-Si), λ, varied between 5 and 160 nm. Xray diffraction analysis and transmission electron microscopy analysis were used to identify phases present in as prepared and reacted diffusion couples. Complete reactions to form a single phase or mixtures of the three low temperature equilibrium silicides (Cu 3 Si, Cu 15 Si 4 and Cu 5 Si) were observed. Upon initial heating of samples from room temperature, heat flow signals were observed with differential scanning calorimetry corresponding to the growth of Cu 3 Si. At higher temperatures (> 525 K) and in the presence of excess Cu, the more Cu rich silicides, Cu 15 Si 4 and Cu 5 Si formed. Based on differential scanning calorimetry results for samples with average stoichiometry of the phases Cu 3 Si and Cu 5 Si, enthalpies of formation of these compounds were measured. Considering the reaction of these phases forming from Cu and a-Si, the enthalpies were found to be-13.6±0.3 kJ/mol for Cu 3 Si and-10.5±0.6 kJ/mol for Cu 5 Si. The growth of Cu 3 Si was found to obey a parabolic growth law:

show abstract

mentioning

confidence: 92%

Thermodynamic and kinetic study of solid state reactions in the Cu–Si system

Chromik¹,

Neils²,

Cotts³

1999

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“… [14] and by Morral et al. [18] . Subsequently Mukherjee [17] obtained more X-ray reflections than Morral et al.…”

Section: Introductionmentioning

confidence: 90%

Experimental investigation of the Cu–Si phase diagram at x(Cu)>0.72

et al. 2011

View full text Add to dashboard Cite

Cu–Si phase equilibria have been investigated at compositions greater than 72 at.% Cu by X-ray diffraction, optical and electronic microscopy, electron probe microanalysis and differential thermal analysis.The general aspects of the phase equilibria already reported in literature have been substantially confirmed, but selected composition ranges and the nature of a few invariant equilibria have been modified. In particular stability ranges of the β, δ and η phases have been slightly modified as well as temperature and nature of the invariant equilibria related to the γ ⇄ δ transformation.Stability of the ɛ-(Cu15Si4) phase has been especially investigated concluding that it is thermodynamically stable but kinetically inhibited by nucleation difficulties which become especially effective when samples are synthesized in very high purity conditions.Crystal structure and composition ranges of the high temperature β and δ phases, despite difficulties by the non-quenchability of these phases, have been investigated by different methods including high temperature XRD.

show abstract

“…The 3-Cu 15 Si 4 crystal structure was first identified as cubic with a body centered lattice [27,29]. Subsequently Mukherjee et al [13] obtained more X-ray reflections than Ref.…”

Section: Phase Namementioning

confidence: 99%

“…Subsequently Mukherjee et al [13] obtained more X-ray reflections than Ref. [29] and concluded that the structure should be cubic but not bcc. Finally, Mattern et al [12] refined the structure according to a body centred space group, claiming however to be in agreement with Ref.…”

Section: Phase Namementioning

confidence: 99%