Vaporization Behavior, Phase Equilibria, and Thermodynamic Stabilities of Nickel Phosphides

Abstract

The equilibrium vaporization reactions 12Ni2Pfalse(normalsfalse)=2Ni12P5false(normalsfalse)+P2false(normalgfalse) and 6.8Ni12P5false(normalsfalse)=32Ni2.55Pfalse(normalsfalse)+P2false(normalgfalse) have been studied by mass‐loss effusion in the temperature range 1237–1401 K. The results were combined with published calorimetric data for nickel‐rich samples and static phosphorus‐dissociation pressure data for phosphorus‐rich samples, with consideration of the requirements of the published phase diagram, to obtain enthalpies of formation (from red P), normalΔHnormalf0/R , and enthalpies of atomization, normalΔHnormalat0/R , respectively, in kilokelvins at 298.15K:1/4 Ni3Pfalse(normalsfalse),−5.94±0.5,54.8;1/3.55 Ni2.55Pfalse(normalsfalse),−6.65±0.5,55.2;1/17 Ni12P5false(normalsfalse),−6.73±0.5,55.1;1/3 Ni2Pfalse(normalsfalse),−6.87±0.5,54.8;1/9 Ni5P4false(normalsfalse),−6.39±0.5,53.0;1/2.22 Ni1.22Pfalse(normalsfalse),−6.32±0.5,52.9;1/2 normalNiPfalse(normalsfalse),−6.09±0.5,52.1;1/3 NiP2false(normalsfalse),−5.38±0.5,49.4;1/4 NiP3false(normalsfalse),−4.52±0.5,47.6 .

Degradation mechanisms of SOFC anodes in coal gas containing phosphorus

“…Thermodynamic parameters for nickel phosphide solid phases used in the calculations were obtained from Myers and Conti [29], which are summarized in Table 1 and are consistent with standard enthalpies of formation given more recently by Zaitsev et al [30]. A review of thermodynamic properties of various metal phosphides has been given by Schlesinger [31].…”

Determination of standard Gibbs free energy of formation for Ca2P2O7 and Ca(PO3)2 from solid-state EMF measurements using yttria stabilised zirconia as solid electrolyte

“…The decision to use the literature values of D f G (Ca 3 (PO 4 ) 2 ) and D f G (Ni 3 P) in equation (14) [2] and Ni 3 P [12, [14][15][16][17][18] were somewhat smaller than the literature value of Ca 2 P 2 O 7 [14]. From the analysis of equilibrium (I) it is evident that the stoichiometry is more favourable using Ca 3 (PO 4 ) 2 instead of Ca 2 P 2 O 7 as a reference phase.…”

The Thermodynamic Properties of Phosphorus and Solid Binary Phosphides

“…- 220 Boone and Kleppa 35 Viksman and Gordienko 218 Miodownik 216 Press et al 227 Kubaschewski et al 121 de Boer et al 100 Barin et al 4 Elliott and Gleiser formation of nickel phosphides (converted to red (V) reference state) estimated by different sources. An obvious need exists for further experimental measurements in this system.…”

“…The third vapor pressure measurement is that of Myers and Conti, who used Knudsen effusion/mass loss measurements to measure p P 2 in equilibrium with Ni 2 P/Ni 12 P 5 (1260−1362 K) and Ni 12 P 5 /Ni 5 P 2 (1400 K). For the reaction, For the reaction, Δ G ° = +60 300 J/mol at 1400 K. The Gibbs energies of formation of nickel phosphides were also estimated by Ghosh and Hess 199 and by Miodownik (quoted by Lee and Nash) .…”