Effects of anodic spark oxidation by pulse power on titanium substrates

Abstract

The characteristics of the oxide layer of titanium generated by anodic spark oxidation are affected significantly by the process variables. In this study, electrochemical treatments were performed while applying a direct current, a pulse current, and a reverse pulse current during anodic spark oxidation. A mixed solution of 0.015 M DL-α-GP (DL-α-glycerophosphate disodium salt) and 0.2 M CA (calcium acetate) was used as the electrolyte. The pore size generated after anodic spark oxidation was smallest in the group exposed to the reverse pulse current followed in order by the pulse current and direct current. Anatase was the major crystal phase of the TiO 2 produced on the surfaces subjected to 280 V, and the rutile phase was additionally detected in the group subjected to 320 V. The crystals precipitated on the surface after the hydrothermal treatment were hydroxyapatite (HA) crystals that had a polygonal bar-shaped needle structure. Good activity was observed in the 320-V pulse treated group, in which very thin needle-shaped crystals were observed after immersing the samples in Hanks' solution for 4 weeks. The cell viability was increased greatly by anodic spark oxidation, and the surface roughness was also increased. It is believed that the surface treated using a pulse current has excellent characteristics, making it suitable for applications in biomaterials. Copyright

Synthesis of zirconia‐incorporated titania layer by microarc oxidation for biomedical applications

“…[7][8][9][10] MAO generates a thick, hard, and adherent titania (TiO 2 ) layer over titanium and its alloys, which is generally composed of anatase and rutile forms of TiO 2 . [11][12][13] Furthermore, adjusting the composition of the electrolyte utilized in the MAO process can create a broad range of altered composition, morphology, and microstructure of the TiO 2 layer. In recent years, research efforts have focused on enhancing the bioactivity and/or antimicrobial activity of the TiO 2 layer via adding chemicals containing Ca/P and/or Ag into the electrolyte, respectively.…”

“…Among the surface modification processes, microarc oxidation (MAO) is an attractive technical solution for titanium‐based materials because of its suitability for complex geometries and relatively low heat input, which does not alter the microstructure and/or mechanical properties of the substrate . MAO generates a thick, hard, and adherent titania (TiO 2 ) layer over titanium and its alloys, which is generally composed of anatase and rutile forms of TiO 2 . Furthermore, adjusting the composition of the electrolyte utilized in the MAO process can create a broad range of altered composition, morphology, and microstructure of the TiO 2 layer.…”

Influence of hydrothermal exposure on surface characteristics and corrosion behaviors of anodized titanium

“…[14] As to the electric conditions, the anodization voltage plays an important role in modulating surface properties of anodic oxide layers. [15][16][17] According to the applied voltage, the anodization method can be classified into two types: (i) treating the specimen with a voltage lower than the breakdown voltage to fabricate thin and compact oxide layers [15] and (ii) treating the specimen with a voltage higher than the breakdown voltage to fabricate thick and porous oxide layers. [16,17] For the anodization of titanium in 1 M phosphoric acid solution, the breakdown voltage is about 150 V. [18,19] Although the preparation and characterization of anodized titanium have been intensively reported, reports on the structure and property evolution of anodized titanium in harsh environments were seldom.…”

Influence of incremental rate of anodising current on roughness and electrochemical corrosion of oxide film on titanium alloy Ti–10V–2Fe–3Al

“…Moreover, electrical parameters determine the thickness, surface morphologies and microstructure of anodic coatings. 8 Although several studies have been carried out to evaluate the effect of electrical parameters on the growth of anodic films following pulse anodic oxidation, 9,10 these studies have not paid much attention to the method of imposing the anodic current.…”