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PurposeThe purpose of this paper is to consider the corrosion properties of laser nitrided Ti‐6Al‐4V alloys that have been reported previously by several researchers.Design/methodology/approachDifferent kinds of surface nitriding methods of titanium alloys, such as plasma nitriding, ion nitriding, gas and laser nitriding, are introduced. Microstructure changes, such as phase formation and the influence of laser processing parameters in laser nitriding layers of Ti‐6Al‐4V alloys, were investigated using scanning electron microscope, transmission electron microscope, X‐ray photo‐electron spectroscopy, and X‐ray diffraction. Based on investigations presented in the literature, the effect of laser nitriding on the corrosion behavior of Ti‐6Al‐4V alloy was reviewed.FindingsBy regulating the laser processing parameter, the microstructure of the nitrided layer can be controlled to optimize corrosion properties. This layer improves corrosion behavior in most environments, due to the formation of a continuous TiNxOy passive film, which can retard the ingress of corrosive ions into the substrate and can maintain a constant value of a current density. Therefore, the laser gas nitrided specimens have a relatively noble corrosion potential and a very small corrosion current, as compared to untreated specimens.Originality/valueThis paper comprises a critical review, and its collection of references is useful. It summarizes current knowledge in laser surface treatment research.

PurposeThe present study aims to investigate the corrosion and electrical properties of the chromate conversion coatings on aluminium alloy Type 6061 in electrically bonded interfaces.Design/methodology/approachTests were carried out to obtain the optimum conditions for chromate bath composition and immersion time for standard requirement provisions such as corrosion resistance in the salt‐spray test, electrical resistance and coating quality. The applied coatings were tested electrochemically in seawater and distilled water. The protection mechanism was evaluated from Tafel and cyclic polarisation curves in the said environments.FindingsThe evaluations showed that the passive film layer contained chromate with alumina formed on the substrate. The good performance of the conversion coating in terms of its corrosion and electrical conductivity was probably due to the characteristics of this protective film.Originality/valueThe paper presents findings on the corrosion of chromate conversion films on aluminium in electrically bonded interfaces.