During thermal treatment, a series of chemical reactions took place in the CrN interlayer in the NiCrAlY/CrN/DSM11 system. The CrN phase in the interlayer was first transformed to intermediate AlN and Cr2N phases during vacuum heat treatment, and thereafter both changed to TiN phase after thermal exposure. The formation of TiN is beneficial to the suppression of elemental interdiffusion. With the good barrier ability and strong interfacial bonding, the CrN interlayer acts as an excellent diffusion barrier. (C) 2009 Elsevier B.V. All rights reserved.