Al₂O₃ eliminating defects in the Al coating by laser cladding to improve corrosion and wear resistance of Mg alloy

Abstract

Although Al produces a solid metallurgical bonding with Mg alloy substrates, micropores or crevices in the Al coating can reduce the resistance of Mg alloy to corrosion. In this study, a composite coating with a defect-free microstructure was prepared on the AZ31 Mg alloy substrate by introducing Al 2 O 3 into the Al matrix via the method of laser cladding. On the one hand, Al 2 O 3 with thermal insulation had a low thermal expansion coefficient and was not very prone to voids during laser melting. On the other hand, Al 2 O 3 particles with a small size acted as the filler in the micropores or crevices. The Al/Al 2 O 3 coating exhibited a smaller current density (2.1 × 10 −6 A/cm 2 ) in comparison with those of bare substrate and Al coating (158.4 × 10 −6 and 3.1 × 10 −6 A/cm 2 , respectively), which was mainly ascribed to the pore-free microstructure and high resistance to corrosion of Al 2 O 3 phase. A favorable microhardness value of 95.3 HV was achieved for Al/Al 2 O 3 coating, approximately 1.8 times higher than that of Al coating (52.8 V), which was mainly ascribed to the dispersion hardening of Al 2 O 3 phase. Meanwhile, the Al/Al 2 O 3 coating significantly reduced wear volume from 2.8 mm 3 /m of Al coating to 0.4 mm 3 /m, showing great potential for weight reduction applications. K E Y W O R D S coating, corrosion, laser cladding, mechanical properties

Construction of a Robust Radiative Cooling Emitter for Efficient Food Storage and Transportation

“…The absorption/emission of the infrared light is mostly related to the Si–O–Si vibration of rare earth silicate . Besides, the Al 2 O 3 particles have high solar reflectivity, which also has potential to enhance the abrasion property of the emitter . With the synergy of the solar reflection and infrared emission, RC can be realized, while the wear resistance ensures stability during usage.…”

“…40 Besides, the Al 2 O 3 particles have high solar reflectivity, 32 which also has potential to enhance the abrasion property of the emitter. 41 With the synergy of the solar reflection and infrared emission, RC can be realized, while the wear resistance ensures stability during usage. The facile coating method (Figure 1c) empowers a scalable and low-cost solution for RC emitter.…”

Layer-by-Layer Self-Assembly Composite Coatings for Improved Corrosion and Wear Resistance of Mg Alloy for Biomedical Applications

“…Due to the merits of natural biodegradability, good processability and favorable mechanical properties etc., Mg alloys display promising biomedical applications in urinary stent, vascular stent, artificial joints, etc., [1][2][3][4][5]. It can reduce the permanent metallic implant risks of thrombosis, inflammatory responses, physical irritation, and inability to adapt to the changes and growth of defect sites [6][7][8].…”

Effects of Ultrasonic Surface Rolling Processing and Subsequent Recovery Treatment on the Wear Resistance of AZ91D Mg Alloy

“…However, the poor wear resistance of Mg alloys severely limits their applications and causes huge economic losses. In order to enhance the wear resistance of Mg alloys, some effective technologies have been proposed, such as surface coating technology [ 3 ], laser cladding [ 4 ], ion implantation [ 5 ], physical vapor deposition (PVD) [ 6 ] and surface nanocrystallization (SNC) [ 7 , 8 ]. Among the above processing methods, SNC is a simple, economical and effective method to improve the wear resistance of the material surface.…”