Improving anticorrosion performance of hydroxyapatite via controlling exposed crystal surface and applications

• Published in: Journal of alloys and compounds Vol. 845; p. 156290
• Main Authors: Guo, Xiao-Jiao, Yuan, Xiao-Yu, Zhao, Si-Rui, Liu, Jin-Ku, Xue, Xi-Zi, Xue, Ya-Nan
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 10.12.2020; Elsevier BV
• Subjects: Anion exchange; Anion exchanging; Anticorrosion; Coating effects; Corrosion prevention; Corrosion rate; Crystal facet; Crystal surfaces; Exposure; Hydroxyapatite; Rectangular plates; Shielding; Tetracalcium phosphate; Anion exchange; Anticorrosion; Crystal facet; Hydroxyapatite
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2020.156290

The relationship between crystal facet and anticorrosion performance is studied by controlling the microstructure of hydroxyapatite (HAP). HAP in shape of rectangular plate exposing (002) facets promotes it exerting anticorrosion activity. The displacement reaction occurs between OH− groups on (002) facet and corrosive Cl−, which reduces the corrosion rate. At the same time, anion exchange forms a stable chlorapatite to further enhance shielding effect of coatings. Moreover, self-supporting mechanism is proposed to explain the conversion between tetracalcium phosphate (TTCP) and HAP is benefited to making up for HAP consumed in the anticorrosion process. The rectangular plate-like HAP also prolongs the diffusion path of corrosive substances. Therefore, HAP with bare (002) facet raises the impedance by 110.3% compared with common HAP with exposed (300) facet. This research provides a direction for reducing the consumption and effective use of materials in the coatings industry. [Display omitted] •HAP with exposed (002) facet by adjusting synthesis is obtained to promote anticorrosion activity.•Anion exchange between OH- on (002) facet and Cl- reduces corrosion rate.•The chlorapatite formed through ion displacement improves shielding performance.•Self-supporting mechanism of conversion from TTCP to HAP is proposed.•This study provides reference for reducing consumption and effective use of materials.