Monitoring atomic level electronic changes in the alloying of stainless steels with Auger and photoelectron spectroscopy

Understanding the electronic changes that take place at the atomic level upon alloying is a key issue in alloy design. The Cu Kα and Al Kα excited XPS and Auger spectroscopy have been used to investigate the role of the major elements in multi component steels from the electronic structure point of view. A combination of the Auger parameter and Core-Core-Valence (CCV) Auger lines were used as the analysis method. The CCV Auger transitions studies, as a probe of the local density of states, revealed that there is some charge transfer between Fe and both Ni and Cr in the steels. However, no significant charge transfer was found between Cr and Ni. The Auger parameter studies of Cr in the steels showed that the charge transfer effect is the main factor affecting the local atomic potential at Cr sites compared to the cohesive energy related factor. It has also been demonstrated that the magnitude of the cohesive energy decreases as the Ni/Cr ratio decreases, which suggests that Ni has a significant role in increasing the cohesive energy of the steels and supports previous quantum mechanical calculations showing that the bulk modulus increases with increasing Ni concentration in Fe100−(m+n)CrmNin ternary alloys for the concentration range 13.5 ⩽ m ⩽ 25.5 and 8 ⩽ n ⩽ 24.