In Vitro Behavior of Plasma Sprayed Hydroxyapatite Coatings Related to their Chemical and Microstructural Characteristics

Magnesium (Mg) and its alloys are promising candidates for biodegradable bio-implants. However, the excessive corrosion in the physiological environment and subsequent decline in the mechanical integrity of Mg and its alloys have limited their utility as biomaterials. In the present study, an attempt has been made to improve the corrosion resistance of Mg alloy ZK60 plasma sprayed with tantalum (Ta)-reinforced hydroxyapatite coating. The experiment was conducted with three varied levels, i.e. 10, 20 and 30 weight percent (wt%) of Ta-content in hydroxyapatite coating. The coatings were characterized and in vitro corrosion behaviour was investigated by electrochemical measurements in Ringer's solution along with the analysis of surface properties. The corrosion resistance of the Mg alloy increased with the incremental increase in Ta reinforcement in hydroxyapatite coating. An increase in the protection efficiency was analysed for the Ta-reinforced hydroxyapatite coatings (∼10%, 18% and 23% for hydroxyapatite-10Ta, hydroxyapatite-20Ta and hydroxyapatite-30Ta, respectively) as compared to the pure hydroxyapatite coating. The hydroxyapatite coating effectively increased the surface hardness of the Mg alloy and Ta reinforcement further enhanced it. Surface roughness decreased with the incremental increase in Ta-content in hydroxyapatite coating. Wettability analysis revealed the hydrophilic nature of pure hydroxyapatite and Ta-reinforced hydroxyapatite coatings. The results of the study suggest that the proposed Ta reinforcement in hydroxyapatite is potentially important for biodegradable Mg bio-implants.

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In vitro andin vivo biological responses of plasma-sprayed hydroxyapatite coatings with posthydrothermal treatment

Journal of Biomedical Materials Research Part A ◽

10.1002/jbm.a.31246 ◽

2007 ◽

Vol 83A (2) ◽

pp. 263-271 ◽

Cited By ~ 29

Author(s):

C. Y. Yang ◽

T. M. Lee ◽

C. W. Yang ◽

L. R. Chen ◽

M. C. Wu ◽

...

Keyword(s):

Biological Responses ◽

Hydroxyapatite Coatings ◽

Plasma Sprayed

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In Vitro Assessment of Hydroxyapatite and Si-Substituted Hydroxyapatite Coatings under Different VPS Conditions

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.396-398.345 ◽

2008 ◽

Vol 396-398 ◽

pp. 345-348 ◽

Cited By ~ 5

Author(s):

Qian Tang ◽

Roger Brooks ◽

Serena Best

Keyword(s):

Input Power ◽

Precipitation Method ◽

Human Osteoblast ◽

Lower Plasma ◽

Plasma Gun ◽

Vacuum Plasma ◽

Hydroxyapatite Coatings ◽

Phase Pure ◽

Plasma Sprayed

Hydroxyapatite and silicon-substituted hydroxyapatite powers were prepared in-house through a wet precipitation method and then vacuum plasma sprayed onto Ti-6Al-4V discs. Two plasma gun input powers were employed, 37 kW and 40 kW. All coatings were nearly phase pure, except small traces of impurities (TTCP, -TCP and CaO). Coatings prepared under the lower plasma gun input power had lower crystallinity. In vitro studies showed that human osteoblast-like cells attached and spread very well on all coated discs. Among the four kinds of discs, SiHAC37 was the most supportive to cell growth.

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In-vitro Investigation of Air Plasma-Sprayed Hydroxyapatite Coatings by Diffraction Techniques

Residual Stresses 2016 ◽

10.21741/9781945291173-82 ◽

2016 ◽

Keyword(s):

Air Plasma ◽

Hydroxyapatite Coatings ◽

In Vitro Investigation ◽

Plasma Sprayed

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Higher in-flight particle velocities enhance in vitro tribological behavior of plasma sprayed hydroxyapatite coatings

Tribology International ◽

10.1016/j.triboint.2016.08.006 ◽

2016 ◽

Vol 103 ◽

pp. 496-503 ◽

Cited By ~ 8

Author(s):

N.W. Khun ◽

Z. Li ◽

K.A. Khor ◽

J. Cizek

Keyword(s):

Tribological Behavior ◽

Hydroxyapatite Coatings ◽

Particle Velocities ◽

Plasma Sprayed

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Near-surface in vitro studies of plasma sprayed hydroxyapatite coatings

Powder Diffraction ◽

10.1154/1.3583181 ◽

2011 ◽

Vol 26 (2) ◽

pp. 138-143 ◽

Cited By ~ 8

Author(s):

T. P. Ntsoane ◽

M. Topic ◽

R. Bucher

Keyword(s):

Body Fluid ◽

Quantitative Phase Analysis ◽

X Rays ◽

Near Surface ◽

Tetracalcium Phosphate ◽

Early Stages ◽

Opposite Trend ◽

Hydroxyapatite Coatings ◽

Plasma Sprayed

Coatings of plasma sprayed hydroxyapatite (HAp), incubated in simulated body fluid for periods varying from 1 to 56 days, were characterized using conventional laboratory X rays. Quantitative phase analysis, employing TOPAS software, showed an opposite trend in the two main phases of the coating, viz., HAp and tetracalcium phosphate (TTCP). The former increased within the first 7 days of incubation whilst the latter decreased during the same period; both phases stabilized with further incubation. The crystallinity of the coatings exhibited a trend similar to that of HAp i.e., an increase in the early stages of incubation stabilization with further incubation. Results of residual stress determined with Bruker’s D8 Discover and analyzed with LEPTOS software, showed both the normal stress tensor components, σ11 and σ22, to be tensile, relaxing significantly in the early stages of incubation before stabilizing with further incubation.

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