title: Incorporation of ZrO2 particles in the oxide layer formed on Mg by anodizing: Influence of electrolyte concentration and current modes.
abstract: OBJECTIVE
  The objectives of the present study are to ascertain, particle incorporation during the initial stages of microarc oxidation (MAO), feasibility of increasing the level of particle incorporation through manipulation of process variables and, the use of MgO-ZrO2 composite coatings either as a pre-treatment or as a post-treatment for MAO coated Mg.
  
  
  METHODS
  Anodic oxide coatings were prepared using 0.3M NaOH+15g/l ZrO2 and 3M NaOH+15g/l ZrO2 at 10V under direct current, pulsed current (PC) unipolar and PC bipolar modes. MAO coatings were prepared using 5g/l NaOH+15g/l Na2SiO3 at 250V under direct current mode for 2min.
  
  
  RESULTS
  The study reveals that it is possible to incorporate ZrO2 particles in the anodic oxide layer, suggesting such a possibility during the initial stages of MAO. When the MgO-ZrO2 composite coating is used as a pre-treatment, it helps to reduce the size and density of the pores of the MAO coatings and increased the corrosion resistance. When it is used as a post-treatment, lamellar shaped Mg(OH)2 with a very high surface area is formed on the surface, which would be beneficial to impart a better bioactivity and to facilitate immobilization of biomolecules.
authors.affiliation: Department of Dental Biomaterials and Institute of Biodegradable Materials, Institute of Oral Bioscience and School of Dentistry (plus BK21 program), Chonbuk National University, Jeonju 561-756, South Korea. Electronic address: tsnsn@rediffmail.com.
authors.forename: T S N
authors.initials: TS
authors.lastname: Sankara Narayanan
authors.affiliation: Department of Dental Biomaterials and Institute of Biodegradable Materials, Institute of Oral Bioscience and School of Dentistry (plus BK21 program), Chonbuk National University, Jeonju 561-756, South Korea. Electronic address: lmh@chnbuk.ac.kr.
authors.forename: Min Ho
authors.initials: MH
authors.lastname: Lee
mesh_terms: D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010316:Particle Size; D013499:Surface Properties; D015040:Zirconium / Q000737:chemistry*
chemical_list: D004573:Electrolytes; D010087:Oxides; D015040:Zirconium; D008274:Magnesium; C028541:zirconium oxide
keywords: Anodizing; Biomedical applications; Composite coatings; Corrosion resistance; Interfacial reactions; Microarc oxidation; Particle incorporation; Post-treatment; Pre-treatment; Surface modification