Fig. 1 Typical back-scattered electron images: a 0Er, b 0.20Er, c 0.56Er at 320 °C; d 0Er, e 0.20Er, f 0.56Er at 400 °C

Fig. 2 EDS element mapping analysis of 0.56Er alloys showing Er enrichment of intermetallic particles

Fig. 3 Images of intergranular corrosion tests: a 0Er, b 0.20Er, c 0.56Er at 320 °C; d 0Er, e 0.20Er, f 0.56Er at 400 °C

Fig. 4 Effect of Er content on average maximum corrosion depth in samples treated at 320 and 400 °C

Fig. 5 Images of acid salt spray solution tests in samples treated at 400 °C: a 0Er, b 0.2Er, c 0.56Er

Fig. 6 Effect of Er content on corrosion area and area density in sample treated at 400 °C

Fig. 7 a Potentiodynamic polarization curves of Al-2.6 Mg-xEr alloys in samples treated at b 400 °C, c 320 °C; d effect of Er on corrosion of Al-2.6 Mg alloy measured in terms of corrosion current density from Tafel extrapolation

Fig. 8 Images of electrochemical corrosion tests: a 0Er, b 0.20Er, c 0.56Er at 320 °C; d 0Er, e 0.20Er, f 0.56Er at 400 °C

Fig. 9 Mass loss per unit area following electrochemical corrosion tests 20 min and subsequent cleaning of corrosion products

Fig. 10 Effect of Er content on tensile strength of aluminum alloy treated at 400 °C

Fig. 11 Simultaneous effects of Er on corrosion and tensile strength of Al-2.6 Mg alloy

Fig. 12 Bright-filled TEM image of alloys annealed at 320 °C: a 0Er, b 0.56Er

Fig. 13 Bright-filled TEM images of alloys annealed at 400 °C: a 0Er, b, c 0.56Er

Fig. 14 Samples in coastal substations a before test (0 year), b after 1 year, c after 2 years