Effect of Current Density on Deposition of Ni-Mn₃O₄ Composite Coating and its High Temperature Behavior

Abstract

The combination of electrophoresis and electrodeposition technique is an effective method to increase Mn3O4 particle content in Ni-Mn3O4 composite coatings. The effect of current density during electrodeposition process on the deposition time, surface morphology, and Mn3O4 content of the composite coating has been systematically studied. Results show that the coatings deposited at a current density of 25 mA cm−2 for 4.5 min of deposition time are most suitable. Steels with composite coatings deposited under the optimum condition are exposed at 800 °C in air for different times to reveal the thermal conversion process. The oxide scale on the samples deposited at 5 mA cm−2 and 15 mA cm−2 consists of an external (Ni,Mn,Fe)3O4 spinel layer, a middle NiO layer and an internal Mn-doped Cr2O3 layer after 100 h oxidation. Whereas NiO is non-continuous and embeds in (Ni,Mn,Fe)3O4/(Ni,Fe)3O4 spinel layer for the samples deposited at 25 mA cm−2. The scale area specific resistance (ASR) of the sample deposited at 25 mA cm−2 is lower than those of the samples deposited at 5 mA cm−2 and 15 mA cm−2 as well as uncoated steel.

Anodic and Cathodic preparation of MnO2/Co2O3 Composite Electrode Anodes for Electro-Oxidation of Phenol

“…SEM photos reveal a decent degree of surface covering, however as the current density is increased to 35 mA/cm 2 , peeling is detected on the surface of the composite coating, which is consistent with prior research [29,41,42]. As the current density increases from 25 mA/cm 2 up to 35 mA/cm 2 , the amount of Co3O4 particles slightly decreases, and the amount of MnO2 particles in the coating increases gradually [43,44].…”

Enhancement of Electrochemical Properties of Lithium Rich Li2RuO3 Cathode Material

“…They found that Cr doping increases capacity and Na doping suppresses voltage-decay. Similar doping investigations using Mg, [24][25][26] Ni, [25][26][27][28][29][30][31][32][33][34][35] Co, 28,31,36,37 and N [38][39][40] on the electrode of lithium-ion batteries have demonstrated improved electrochemical performance.…”