Thermodynamic Investigation of the Ni-Rich Side of the Ni−P System

Abstract

Ni(P) is used in electronics as a protective layer during the soldering process. New thermodynamic information on Ni-P alloys has been obtained in the Ni-rich part (up to the molar fraction x P ) 0.40) by using a high-temperature direct drop calorimeter. The experimental trend of ∆ f H°[kJ • (mol of atoms) -1 ] of the Ni-P alloys versus composition (x P ) has been plotted and the following standard enthalpy of formation [∆ f H°( 2 kJ • (mol of atoms) -1 ] values interpolated for the Ni-rich phases: -48.0 (Ni 3 P), -55.0 (Ni 5 P 2 ), -56.0 (Ni 12 P 5 ), and -61.0 (NiP 2 ). Our results have been compared with those reported in the literature and discussed.

Thermochemistry of the nickel–phosphorus system

“…This shows that the corresponding compositions are outside the phase Ni 2 P at the temperature of 1000 K. For both temperatures, 1000 and 1123 K, the value of a P varies by about three orders of magnitude over the narrow homogeneity range of Ni 2 P, indicating the high stability of this particular phase. This is supported by the enthalpy measurements by Delsante et al [20] where the most negative value of DH f 0 in the entire NieP system was found for the compound Ni 2 P.…”

Nanoscaled Metal Borides and Phosphides: Recent Developments and Perspectives

“…Phase evolution of Cr–B (CrB and CrB 2 phases), Mo–B (MoB 2 and Mo 2 B 5 phases), Co–P alloys, Ni–P alloys, Ni 70 P 30 (main phases: Ni 2 P and Ni 12 P 5 ), and Fe 8 P , (main phase: Fe 2 P) was investigated by reactive ball milling, a solid state method that avoids the loss of P/B or M in the solvent or in the gas phase. These results at the bulk scale were oriented by the imposed stoichiometry and by thermodynamics, which predicts that some particular phases are more stable than others. , (M x M′ 1‑ x )B 2 (M, M′ = Ti, Hf, Zr, Ta, Nb) and (Ni x Co 1‑ x ) 2 P solid solutions were also obtained. In the latter case, a phase segregation was observed for high Co proportions.…”

“…These results at the bulk scale were oriented by the imposed stoichiometry and by thermodynamics, which predicts that some particular phases are more stable than others. 100,156 (M x M′ 1-x )B 2 (M, M′ = Ti, Hf, Zr, Ta, Nb) 14 and (Ni x Co 1-x ) 2 P 773 solid solutions were also obtained. In the latter case, a phase segregation was observed for high Co proportions.…”

“…Thermodynamic knowledge was improved with the publication of updated M–P phase diagrams (Rb–P, K–P, Na–P, Cs–P, Ni–P , ). Relative stabilities of different boride phases have also been investigated. ,− Among metal phosphides, the Ni–P system was particularly studied in the Ni-rich side . Heat capacity of InP was also determined .…”

“…39,150−155 Among metal phosphides, the Ni−P system was particularly studied in the Ni-rich side. 156 Heat capacity of InP was also determined. 157 Recently, first-principle studies were devoted to the phase transitions of several binary phosphides (Co−P, 158 InP, 159,160 GaP, 160 BP, 160 and AlP 160 ) and ternary phosphides such as LaFe 4 P 12 161 and Au 2 MP 2 ternary alloys (M = Pb, Tl, Hg).…”