The microstructure of a 26.6% chromium white iron was characterised in terms of its phase constituents after being given a three stage heat treatment. The heat treatment cycle consisted of a 1-h anneal at 800 degrees C plus a 1-h destabilisation treatment at 1025 degrees C, followed by a subsequent 1-h temper at 450 degrees C. The heat treatment cycle used in the experiment was similar to that of a commercially used heat treatment. The use of XRD and electron microscopy has revealed that secondary carbides precipitated in the microstructural matrix of the white iron are of the form (Fe,Cr)(23)C-6 and have a cubic crystal structure. The techniques have also shown that the matrix has transformed to martensite and has a 'c/a' ratio almost equal to unity. (c) 2006 Elsevier B.V. All rights reserved.