Structural, microstructural and mechanical properties of Cr₃P₂ chromium phosphide powders

Abstract

Nanometric particles of a new chromium structure were produced by mechanical alloying of Cr₃P₂ under low nitrogen pressure. X-ray diffraction study has shown that the particles have an ordinary bcc structure of chromium (α-Cr) up to 1 h of milling but they have a new cubic chromium A15-type structure (δ-Cr), up to 2 h of milling, with a lattice parameter equal to 0.4703 ± 0.001 nm. The new structure has a Pm-3 space group with eight atoms distributed within the unit cell: 2 Cr atoms with occupancy equal to 1 in positions: 1a: 000 and 1 b: ½½½ in addition to 6 others Cr atoms with occupancy equal to 0.25 in positions: 6f: ¼ 0 ½; 6f: ½ ¼ 0; 6f: 0 ½ ¼; 6f: ¾ 0 ½; 6f: ½ ¾ 0; 6f: 0 ½ ¾. As well as the new δ-Cr A15-type phase two chromium phosphides are formed in the nanometric Cr₃P₂ alloy: an orthorhombic CrP and the monoclinic CrP₂ after 1 and 2 h of milling, respectively. Therefore, the formed phosphide records the highest density of dislocations and the lowest stacking fault probability after 2 h of milling. The mechanical properties show that the P and CrP are auxetic strong reentrant cellular structures with negative Poisson’s ratio which makes them specifically resistant.

Graphical Abstract

Keywords:

• Cr-P
• ball milling
• X-ray diffraction
• Rietveld

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Algerian Directorate for Scientific Research and Technological Development (DGRSDT). The author would like to thank Prince Sultan University too.