Vapor Pressure and Heat of Vaporization of Cobalt

Abstract

New vapor pressure data for cobalt have been obtained in the temperature range 1519-1926°K fromKnudsen effusion experiments. The derived third-law heat of vaporization of cobalt is 6.H298o== 101.0±0.6 kcal/mole. Plausible explanations are presented that account for the widely differing vapor pressure data and heats of sublimation published in the literature. It is shown that the evaporation coefficient for cobalt is essentially unity rather than 3X1<J4 and that the electron impact ionization cross section for cobalt is <T(Co) =4.4±1 X 10-16 cm! for 50 eV electrons.

Nucleation, Alloying, and Stability of Co–Re Bimetallic Nanoparticles on Al2O3/NiAl(110)

“…The height decrease of the particles and the loss of Co in the XPS signal in Figure c confirm that some of the Co is indeed removed from the surface. We should point out that evaporation of Co does not play a role at the temperatures employed here . Since the Re signal for Re+Co completely recovers to its intensity before Co deposition, the Re atoms do not diffuse into the substrate at 950 K. Similar behavior is observed for the Co+Re sample (Figure c, bottom panel), although at higher temperature (1080 K).…”

“…We should point out that evaporation of Co does not play a role at the temperatures employed here. 43 Since the Re signal for Re+Co completely recovers to its intensity before Co deposition, the Re atoms do not diffuse into the substrate at 950 K. Similar behavior is observed for the Co+Re sample (Figure 7c, bottom panel), although at higher temperature (1080 K). The difference in onset temperature was attributed to the higher Re content in the Co+Re sample, which likely increases the stabilizing Co−Re interaction.…”

Growth of cobalt nanoparticles in Co–Al2O3 thin films deposited by RF sputtering

“…The profile fitting of XRD pattern reveals that the 1100 °C annealed thin films consists of ∼98% fcc and ∼2% hcp phase of cobalt. In addition to transformation from hcp to fcc phase a marked reduction in the intensity of XRD peaks is observed for films annealed at and above 1000°C which may be probably attributed to volatilization of cobalt . The experimentally observed data, calculated data and the difference between the two are represented by red, black, and blue colors, respectively, in Fig.…”

A critical comparison of MINDO/3, MNDO, AM1, and PM3 for a model problem: Carbon clusters C2‐C10. An ad hoc reparametrization of MNDO well suited for the accurate prediction of their spectroscopic constants

“…35 (TDW), IR bands of species C2 to Cg had been obtained; a 1544 cm-' transition had been assigned to C5, a 2164 cm-' band to C4. Theoretical studies22,36 appeared to indicate, that the 2164 cm-' band belongs to C5 instead, and that the 1544 cm-l band is caused by the linear isomer of C4; conclusive evidence was given by Martin et al 37 42 The latter two determinations were an attempt to resolve the disagreement between second-and third-law entropies for C3 which was caused by the extremely anharmonic character of the low bending vibration." Using an augmented coupled cluster methodz7 combined with an empirical scaling procedure, Raghavachari and Binkley (RB)z6 succeeded in theoretical predictions of the binding energies for Cz to Clo that they expect to be accurate to +0.2-0.4 eV A correlated study of the potential energy surface (PES) of C3 was first carried out by Whiteside et a111.…”