Interfacial Kinetic Engineering: How Far Have We Come Since Kingery's Inaugural Sosman Address?

Abstract

The manipulation of the rate of atomic transport along and across interfaces (most notably grain boundaries) remains a central theme in the control of the microstructure and properties of inorganic materials. This is known as the field of interfacial kinetic engineering (IKE). In his opening Sosman Memorial lecture in 1973, Professor Kingery proposed a set of plausible concepts that he considered to be necessary and sufficient for the interpretation of ceramic grain‐boundary phenomena, which provided a foundation for conducting IKE. This 2008 Sosman Memorial lecture provides both a retrospective assessment and a prospective viewpoint of this persistently challenging field of study. A major focus of this paper, like Kingery's Sosman lecture, is the demonstration of how new techniques of observation have led to conceptual advances. A noteworthy new concept that has emerged is that of grain‐boundary complexions. Through control of the complexions, the interface transport rate and the material performance can be engineered toward a given application requirement.

Atomistic modeling of dopant segregation in α-alumina ceramics: Coverage dependent energy of segregation and nominal dopant solubility

“…This is due to the large number of parameters such as the crystallography of an interface and the concentration and arrangement of dopants (i.e. complexion 3 ), which dictate the thermodynamic stability and mobility of the interface but are difficult to characterize simultaneously on the same interface.…”

“…More recently it has been established that dopants also have a marked effect on the structure and thermodynamic stability of grain boundaries by forming so called grain boundary complexions. 3 While it was assumed for many years that grain boundary structures control the concentration of dopants in their vicinity this represents a paradigm shift in the sense that the dopant concentration can in fact also control the structure of the grain boundary. This indicates that there is a strong interdependence between the concentration of dopants present at the interface and the interface structure.…”

“…Albeit with recent advances in experimental analysis techniques (Ref. 3 and references therein), it is still very challenging to experimentally explain and quantify the influence of dopant segregation on interfacial properties at an atomic level. This is due to the large number of parameters such as the crystallography of an interface and the concentration and arrangement of dopants (i.e.…”

“…As a result the local chemical composition of the interface is modified, 1,5 the extent depending on the exact nature of the boundary and dopant. 3 Depending on their size, concentration and arrangement, segregated dopant ions may either slow down or accelerate grain boundary transport and mobility. 3 Energy minimization techniques based on empirical interatomic potentials are used in the present work to investigate the segregation of lanthanum (La), gadolinium (Gd), ytterbium (Yb) and magnesium (Mg) dopants to nine low energy surfaces and their respective mirror twin grain boundaries of alumina.…”

“…3 Depending on their size, concentration and arrangement, segregated dopant ions may either slow down or accelerate grain boundary transport and mobility. 3 Energy minimization techniques based on empirical interatomic potentials are used in the present work to investigate the segregation of lanthanum (La), gadolinium (Gd), ytterbium (Yb) and magnesium (Mg) dopants to nine low energy surfaces and their respective mirror twin grain boundaries of alumina. This technique has previously been used for Yttrium dopants and showed segregation to be strongly dependent on the type of surface or grain boundary.…”