Amorphous Al–Mn coating on NdFeB magnets: Electrodeposition from AlCl3–EMIC–MnCl2 ionic liquid and its corrosion behavior

Ternary alloying additions and multilayering as strategies to enhance the galvanic protection ability of Al-Zn coatings electrodeposited from ionic liquid solution

“…One promising alternative approach to electrodeposition of aluminum-zinc multilayers is through use of room temperature ionic liquids. In particular, ionic liquids consisting of a mixture of AlCl 3 and 1-ethyl-3-methylimidazolium chloride (EMIC) have been successfully used to electrodeposit pure aluminum [10][11][12][13][14] as well as a wide range of aluminum alloys, including Al-Zn [15,16], Al-Mn [17][18][19][20][21][22][23][24], Al-Zr [25], and many others [26][27][28][29][30][31][32][33][34][35][36][37]. In Al-Mn, there is even prior work reporting multilayered coatings, in which the composition and microstructure were controlled between layers through modulation of deposition current density [23,24].…”

“…Conversely, many secondary alloying elements have been found to improve the properties of aluminum electrodeposits from EMIC/AlCl3 solutions. The most widely studied is Mn, which decreases grain size with increasing concentration, eventually leading to an amorphous structure in deposits with concentrations above approximately 12 at.% Mn, resulting in dramatic improvements in hardness, surface roughness, and corrosion resistance [19,[21][22][23]. Tsuda et al reported a similar effect for Zr, which was found to produce dual phase deposits with an fcc Al-Zr phase with up to 5 at.% Zr, and an amorphous Al-Zr phase with 17 at.% Zr which showed significant improvement in resistance to pitting corrosion [25].…”

Mirror-like Bright Al-Mn Coatings Electrodeposition from 1-Ethyl-3 Methylimidazolium Chloride-AlCl3-MnCl2 Ionic Liquids with Pyridine Derivatives

“…Aluminum (Al) and Al alloys exhibit excellent physical properties, especially aluminum–manganese alloys (Al-Mn). Not only do they have low density and good strength, they possess superior hardness and outstanding corrosion resistance, which has attracted much attention in the field of corrosion protection [ 1 , 2 , 3 , 4 , 5 , 6 ]. Electrodeposition is considered to be the primary technique for the preparation of metal and alloy coatings.…”

Corrosion resistance of the NdFeB coated with AlN/SiC bilayer thin films by magnetron sputtering under different environments

“…The Nd-rich and B-rich phases are easy to be corroded under corrosion media, which will result NdFeB magnets into powderlike, non-usable product [5,6]. Many efforts have been made to improve the corrosion resistance of the NdFeB, including adding alloy elements [7] and preparing protective coatings [8,9]. The alloying elements can improve the intrinsic corrosion resistance of NdFeB at the expense of magnetic properties, whereas the surface coating can improve the corrosion resistance of NdFeB and does not damage its magnetic properties obviously [10,11].…”