A thermodynamic assessment of the Co-V system

Experimental observation of magnetically induced phase separation and thermodynamic assessment in the Co–V binary system

“…CoeV binary system was calculated by Bratberg and Sundman [1] and Huang et al [10]. In their works, Co 3 V phase in CoeV binary was treated as ordered phase and stoichiometric phase, respectively.…”

“…As an important subsystem for high speed steels, tool steels, cemented carbides [1] and magnetic recording materials [2], the CoeV binary system has been experimentally and thermodynamically studied extensively [1,3e13]. The complete phase diagram for the CoeV binary system was firstly proposed by K€ oster and Schmid [3], and more works [4e13] were carried out in the decades that followed.…”

“…Until later, Inden [9] predicted its existence by calculation. Due to lack of the direct experimental data, the magnetically induced phase separation in the (aCo) phase was only estimated [1] or even ignored [10] in some thermodynamic assessments in the CoeV binary system. Therefore, it is necessary to experimentally investigate the Coerich side and to perform a precise reassessment of the CoeV binary system.…”

Phase Equilibria in Binary and Ternary Systems with Chemical and Magnetic Ordering

“…Inden [42] demonstrated that in the binary Co-V system the magnetic transformation should be of second-order nature and occur continuously above 1280 K whereas below this temperature a ''miscibility gap'' separates the ferromagnetic and paramagnetic showing the presence of tricritical points or lines associated to magnetic ordering transitions that change from second-order (dash-dotted lines) to first-order nature (solid lines). The calculated phase diagram in (a) corresponds to the thermodynamic description [51] and the isopleth in (b) to the description [9] Basic and Applied Research: Section I phase states. Consequently a tricritical point occurs at T = 1280 K. The presence of a magnetically induced ''miscibility gap'' in fcc-Co was proven experimentally [42] based on Mössbauer spectroscopy for two distinct alloys with minor addition of 57 Fe isotope, i.e.…”

“…Co 0.94 V 0.05 57 Fe 0.01 and Co 0.89 V 0.10 57 Fe 0.01 . Moreover, thermodynamic modelling of the Co-V system [51] showed that the magnetic contribution produces inflection points in the Gibbs energy curve, leading to the A1 + A1 fm ''miscibility gap'' or Nishizawa horn originated from the tricritical point at temperature 1226 K (Fig. 4a).…”