Influence of Fe substitution on the stability of Pr₃Pt₄ compound

ABSTRACT

The stability of the phase Pr₃Pt₄ in a series of Pr_42.9Pt_57.1-xFe_x (x = 0, 1, 2, 3) alloys was investigated by using X-ray diffraction (XRD) and differential thermal analysis (DTA). It was found that the phase Pr₃Pt₄ (3:4 phase) with Pu₃Pd₄-type structure formed in the Pr_42.9Pt_57.1-xFe_x alloy for x = 0 annealed at 1173 K for two weeks. However, the fraction of the 3:4 phase decreased rapidly with increasing x, and approached zero when x = 3. XRD and DTA results showed that the 3:4 phase decomposes gradually into the two neighboring phases PrPt (1:1 phase) and (Pr, Fe)Pt₂ (1:2 phase), and the decomposition temperature of the reaction 3:4 → 1:1 + 1:2 is shifted slightly to higher temperature with increasing x. The reason for this phase decomposition is briefly discussed by the preferential site occupation of Fe in Pr₃Pt_4.

On a examiné la stabilité de la phase Pr₃Pt₄ dans une série d’alliages de Pr_42.9Pt_57.1-xFe_x (x = 0, 1, 2, 3) en utilisant la diffraction des rayons X (XRD) et l’analyse thermique différentielle (DTA). On a constaté que la phase Pr₃Pt₄ (phase 3:4) avec une structure de type Pu₃Pd₄ s’était formée dans l’alliage Pr_42.9Pt_57.1-xFe_x pour x = 0 recuit à 1173 K pendant deux semaines. Cependant, la fraction de la phase 3:4 diminuait rapidement avec l’augmentation de x et s’approchait de zéro quand x = 3. Les résultats de XRD et DTA ont montré que la phase 3:4 se décompose graduellement en deux phases voisines PrPt (phase 1:1) et (Pr·Fe)Pt₂ (phase 1:2), et la température de décomposition de la réaction 3:4 → 1:1 + 1:2 est légèrement déplacée vers une température plus élevée avec l’augmentation de x. On discute brièvement de la raison de cette décomposition de phase par l’occupation préférentielle du site de Fe dans Pr₃Pt₄.

KEYWORDS:

• Rare-earth intermetallic
• phase stability
• site occupation
• phase transformation

Acknowledgements

This work was supported by the Guangxi Natural Science Foundation (Grant No: 2021GXNSFAA220081, Grant No: 2020GXNSFAA159071, Grant No: 2016GXNSFGA380001, and Grant No: 2015GXNSFAA139249), the National Key Research and Development Program of China (Grant No: 2016YFB0700901) and the National Basic Research Program of China (No: 2014CB643703), the National Natural Science Foundation of China (Grant No: 51161005 and Grant No: 51601044) , 2018 Guangxi higher education undergraduate teaching reform project (Grant No: 2018JGA301) and the Basic ability improvement of Middle and Young teachers in Guangxi Universities Foundation (Grant No: 2018KY0662).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Guangxi Natural Science Foundation [Grant Numbers 2021GXNSFAA220081, 2020GXNSFAA159071, 2016GXNSFGA380001 and 2015GXNSFAA139249]; National Natural Science Foundation of China: [Grant Number 51161005]; National Natural Science Foundation of China: [Grant Number 51601044]; National Key Research and Development Program of China: [Grant Number 2016YFB0700901]; National Basic Research Program of China: [Grant Number 2014CB643703].