Process characteristics and parameters of Anodic Oxidation by spark discharge (ANOF)

Abstract

Process characteristics and parameters of ANOF as well as that special logarithmic relation of the layer formation parameters which is valid for the spark region are discussed. By calorimetric investigation it can be shown that the greatest share of electric energy will be transformed to heat and that the current quantity of ≈ 1.1.A · s · cm−2 is characteristic for the incubation period before spark discharge during the gas — solid reaction of aluminium coating.

Electrolytic plasma processing for plating coatings and treating metals and alloys

“…In a decade, the tech nique was improved and named microarc oxidation (which seems not exactly accurate) [7]. In the 1980s, possibilities provided by the use of surface discharges for plating oxides on various metals were considered in detail by the groups of Gordienko [8,9], Markov [10], and Kurze [11][12][13]. The first attempts to use the method in industry were made at that time [14,15].…”

Spark anodizing of β-Ti alloy for wear-resistant coating

“…Recently, spark anodizing, often also referred to as plasma electrolytic oxidation [7], anodic oxidation by spark discharge [8][9][10], anodic spark deposition [11] and micro-arc oxidation, has been attracted increased attention to improve surface properties, including corrosion, friction and biocompatibility, of titanium alloys [7,[12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Sparking proceeds during anodizing due to dielectric breakdown of the anodic oxide at high voltages.…”

An Investigation of Oxide Coating Synthesized on an Aluminum Alloy by Plasma Electrolytic Oxidation in Molten Salt

“…As shown in Figure 2a,b, a typical anodizing process proceeds up to 30 V and causes the formation of a thin oxide layer that prevents further chemical reaction. At the same time, the negatively charged ions accumulate on the anode surface, forming a so-called quasi-cathode [19,20]. These ions simultaneously redistribute the voltage between electrodes in the electrolytic bath, leading to an increase in the electric field intensity between the anode and local quasi-cathode until a sufficient value for the ion diffusion process is reached through the barrier layer.…”