The present invention relates to a plain bearing between two parts movable with respect to each other, the first part having a first bearing element made from a first metal and the second part having a second bearing element made from a second metal of higher hardness. The first bearing element has a surface layer hardened by strain hardening. As a result of the invention, the wear between the parts can be reduced and their life can be substantially lengthened. The invention can be advantageously applied to cases in which the first part is a variable-setting diffuser blade and the second part is a gas turbine casing.