title: Synthesis and corrosion study of zirconia-coated carbonyl iron particles.
abstract: This paper describes the surface modification of micrometer-sized magnetic carbonyl iron particles (CI) with zirconia from zirconium(IV) butoxide using a sol-gel method. Zirconia shells with various thicknesses and different grain sizes and shapes are coated on the surface of CI particles by changing the reaction conditions, such as the amounts of zirconia sol, nitric acid, and CI particles. A silica adhesive layer made from 3-aminopropyl trimethoxysilane (APTMS) can be introduced first onto the surface of CI particles in order to adjust both the size and the shape of zirconia crystals, and thus the roughness of the coating. The microanalyses on these coated particles are studied by field-emission scanning electron microscopy (FE-SEM) and X-ray-diffraction (XRD). Accelerated acid corrosion and air oxidation tests indicate that the coating process dramatically improved oxidation and acid corrosion resistances, which are critical issues in various applications of CI magnetic particles.
authors.affiliation: Department of Chemical Engineering, University of Rochester, Gavett Hall 206, Rochester, NY 14627-0166, United States.
authors.forename: Rui
authors.initials: R
authors.lastname: Shen
authors.forename: Shai N
authors.initials: SN
authors.lastname: Shafrir
authors.forename: Chunlin
authors.initials: C
authors.lastname: Miao
authors.forename: Mimi
authors.initials: M
authors.lastname: Wang
authors.forename: John C
authors.initials: JC
authors.lastname: Lambropoulos
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Jacobs
authors.forename: Hong
authors.initials: H
authors.lastname: Yang