Formation of Ti<sub>2</sub>AuN from Au-Covered Ti<sub>2</sub>AlN Thin Films: A General Strategy to Thermally Induce Intercalation of Noble Metals into MAX Phases
Shun Kashiwaya, Chung‐Chuan Lai, Jun Lu, Andrejs Petruhins, Johanna Rosén, Lars Hultman
Abstract
Thermally induced intercalation of noble metals into non-van der Waals ceramic compounds presents a method to produce a new class of layered materials. We recently demonstrated an exchange reaction of Au with A layers of MAX phase carbides with plentiful combinations of A and M elements. Here, we report the first substitution of Al with Au in a Ti2AlN MAX phase nitride at an elevated temperature without destroying the original layered structure. These results bolster the generalization of the Au intercalation for the A elements in MAX phases with diverse combinations of M, A, and X elements. Furthermore, we propose crucial factors to achieve the exchange reaction: there should be a chemical potential for the A element to dissolve in or react with noble metals to intercalate; the noble metals should be inert to the initial metal carbides/nitrides; and it is necessary to choose the reaction temperature that allows balanced interdiffusion of the noble metals and A elements.