Effects of K2TiF6 and Electrolyte Temperatures on Energy Consumption and Properties of MAO Coatings on 6063 Aluminum Alloy

Abstract

To decrease energy consumption and improve the performance of micro-arc oxidation (MAO) films on 6063 Al alloy, a policy of K2TiF6 additive and electrolyte temperature control was adapted. The specific energy consumption relied on the K2TiF6 additive and more particularly on the electrolyte temperatures. Scanning electron microscopy demonstrates that electrolytes with 5 g/L K2TiF6 can effectively seal the surface pores and increase the thickness of the compact inner layer. Spectral analysis shows that the surface oxide coating consists of γ-Al2O3 phase. Following 336 h of the total immersion process, the impedance modulus of the oxidation film, prepared at 25 °C (Ti5-25), remained 1.08 × 106 Ω·cm2. Moreover, Ti5-25 has the best performance/energy-consumption ratio with a compact inner layer (2.5 ± 0.3 μm). This research found that the time of the big arc stage increased with the temperature, resulting in producing more internal defects in the film. In this work, we employ a dual-track strategy of additive and temperature providing an avenue to reduce the energy consumption of MAO on alloys.

Evaluation of Fracture Toughness of Plasma Electrolytic Oxidized Al2O3-ZrO2 Coatings Utilizing Nano-Scratch Technique

“…Literature review shows that PEO Al 2 O 3 -ZrO 2 coating may be produced through addition of ZrO 2 nanoparticles [2], or Zr-based salt additives such as potassium zirconium carbonate (K 2 [Zr(CO 3 ) 2 (OH) 2 ]) [14], and dipotassium hexafluorozirconate (K 2 ZrF 6 ) [7,15] into the electrolytic solution. Matykina et al [2] prepared this coating in phosphate-based and silicate-based electrolytes, which contain monoclinic ZrO 2 nano particles (m-ZrO 2 ), and observed that the phosphate-based electrolytic solution developed high-temperature forms of zirconia including tetragonal ZrO 2 (t-ZrO 2 ) and/or cubic ZrO 2 (c-ZrO 2 ).…”