Electrodeposition of Manganese Alloys

Electrodeposition and characterization of sacrificial copper-manganese alloy coatings: Part II. Structural, mechanical, and corrosion-resistance properties

“…[21] This process is somewhat active and corresponds to the active region on the potentiodynamic curves. As the potential increases to Ϫ0.5 to Ϫ0.6 V SCE , an apparent passive region starts, probably due to a dehydration reaction of manganese hydroxides: [21] [1] 3Mn(OH) 2 …”

“…This process has been also proposed to account for the high corrosion resistance of Zn-Mn coatings. [39] Above 0 V SCE , the oxidation of copper may occur: [2] Cu 2 O could also provide some corrosion protection, [33] but, due to its ability to easily form complexes, it is unstable in the presence of Cl Ϫ : At higher potentials (above 0.1 V SCE ), Mn(II) and Mn(III) would further be oxidized to MnO 2 : [32] [4]…”

“…[1,2] This ductile metastable phase undergoes room-temperature recrystallization to a brittle bcc ␣ phase in a time frame of several weeks, which easily leads to cracking and flaking upon impact or abrasion and should be prevented or retarded. Cu additions to Mn, in particular, can stabilize electrodeposited Mn in its ductile form [2] and, potentially, could tune the redox potential of the alloy, thus allowing control of the dissolution kinetics.…”

“…Pure Mn coatings on steel, however, are highly reactive and exhibit a high corrosion current and quick dissolution. [1,2] Alloying of Mn with other metals such as zinc, [3][4][5][6][7][8] nickel, [9,10] iron, [11,12] chromium, [13] cobalt, [14] or tin [15] potentially enables tailoring of the corrosion potential and dissolution kinetics, improving the coating performance. Ideal sacrificial coatings should provide, in addition, suitable contact and soldering surfaces for any foreseeable application in the field and, therefore, should exhibit a low friction coefficient, low ductility, good electrical conductivity, and good solderability both at the nano-and microscale, where surface interactions will occur.…”

Electrochemical Formation of Brazing Alloys On Metal Substrates

“…The increase in temperature on the other hand, decreased the Ag in the deposit while the current density and KCN concentration were kept constant at 8 mA/cm 2 and 13 g/L respectively. This was probably due to the larger increase in the cathode current efficiency of copper [2] than Ag with increase in temperature.…”