Production of biocompatible coatings by atmospheric plasma spraying

Lugscheider, E.; Weber, Th.; Knepper, M.; Vizethum, F.

doi:10.1016/0921-5093(91)90594-d

Cited by 41 publications

(20 citation statements)

References 2 publications

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“…Plasma spraying is one of the most widely used methods for the fabrication of biomedical hydroxyapatite (HA) coatings, and it is generally agreed that HA decomposes partially during air plasma spraying [1][2][3][4][5]. The coating process results in structural alterations of HA including: (i) the formation of amorphous calcium phosphate; (ii) a loss of OH À groups; and (iii) the formation of secondary calcium phosphate phases [2].…”

Section: Introductionmentioning

confidence: 99%

Surface nanocrystallization of hydroxyapatite coating

Chen

et al. 2008

Acta Biomaterialia

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Section: Introductionmentioning

confidence: 99%

Surface nanocrystallization of hydroxyapatite coating

Chen

et al. 2008

Acta Biomaterialia

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“…However, due to the high temperatures of plasma jet, the degradation of HA is inevitable during spraying, which involves the formation of tetracalcium phosphate (TTCP), tricalcium phosphate (TCP) and calcium oxide. In addition, due to the rapid cooling of sprayed particles, amorphous calcium phosphate (ACP) also forms in HA coatings [3][4][5][6][7][8]. Crystalline HA is a very stable phase in body fluids, but the other phases, particularly the ACP, have higher dissolution rates.…”

Section: Introductionmentioning

confidence: 99%

Study on the influence of plasma spray processes and spray parameters on the structure and crystallinity of hydroxylapatite coatings

Zhao

Bobzin

Ernst

et al. 2006

Materialwissenschaft Werkst

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Hydroxylapatite (HA) is one of the most important materials for human hard tissue implants. Until now, HA coatings are widely deposited on implants using atmospheric plasma spraying (APS). Due to the decomposition of HA and formation of amorphous phase during spraying, the crystallinity of APS coatings is usually below 70 %, although coarser spray powders such as one with a size distribution of -150 +45 lm are used. In this study a finer HA powder -80 +50 lm was sprayed using both a conventional APS process and the new "microplasma spraying" (MPS) process. The coatings were characterized in terms of their microstructure and crystallinity. It was found that the spray parameters influenced strongly the coating structure and phase composition. Despite the smaller particles, the HA content of APS coatings could be increased from 27 % to 72 % only by changing the spray parameters. Higher HA contents up to over 85 % could be obtained by microplasma spraying. It was found that textured coatings could form under certain conditions during both spray processes.Keywords: hydroxylapatite, coating, microplasma spraying, crystallinity Hydroxylapatit (HA) zählt zu den wichtigen Biowerkstoffen für Implantate zum Hartgewebeersatz. Bislang wird die Beschichtung der Implantate mit HA meist mittels atmosphärischen Plasmaspritzverfahren durchgeführt. Aufgrund der Zersetzung von HA und Bildung einer amorphen Phase beim Spritzen liegt die Kristallinität einer APS-Schicht normalerweise unter 70 %, selbst wenn gröbere Spritzpulver mit einer Kornfraktion im Bereich von -150 + 45 lm verwendet werden. Im Rahmen dieser Arbeit wurde ein feineres Pulver -80 +50 lm sowohl mittels APS-Verfahren als auch mittels des neuen Mikroplasmaspritzverfahrens (MPS) gespritzt. Die Schichten wurden im Bezug auf ihre Mikrostruktur und Kristallinität untersucht. Es wurde festgestellt, dass die Spritzparameter sowohl die Schichtstruktur als auch die Phasenzusammensetzung der Schicht stark beeinflussen. Trotz der kleineren Spritzpartikel konnte der HA-Gehalt der APS-Schicht durch Variation der Spritzparameter von 27 % bis auf 72 % erhöht werden. Mittels des MPS Verfahrens konnte ein höherer HA-Gehalt bis über 85 % erzielt werden. Unter bestimmten Spritzkonditionen entstand eine Texturstruktur in der Schicht sowohl beim APS als auch beim MPS.

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“…x~as teilweise sogar zu einem unerwª Freiliegen der Metalloberfl[iche fi.ihrte [11,12,14,15]. Diese Implantate wurden mit dem bislang eingesetzten konventionellen Plasmaspritzverfahren unter Umgebungsluftbedingungen beschichtet (APS: atmosph/irisches Plasmaspritzen) [ 13] …”

Section: Hydroxylapatitkeramikbeschichunclassified

Tierexperimentelle Testung einer unter Niederdruckbedingungen gespritzten Hydroxylapatitkeramikbeschichtung

Kettner

Jänicke

Schmitz

1997

Mund Kiefer GesichtsChir

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Implants that were coated with hydroxyapatite ceramic (H-A.C.) under atmospheric condition in vivo often showed local areas of delamination. By applying the H-A.C. coating using the vacuum plasma spraying (VPS) technique, the mechanical characteristics of the coating was decidedly improved. We used a standardized rabbit model to compare a coating produced by this new technique with an implant conventionally plasma sprayed under atmospheric condition (APS). Cylindrical implants, 6 x 4 mm in size with a region flattened to a depth of 800 microns, were inserted into distal rabbit femurs underneath the patella. The flattened surfaces were coated with either a 150-micron APS-H-A.C. layer or a 150-micron VPS-H-A.C. layer plasma sprayed on an underlying 50-micron porous titanium layer. The animals were killed after 84 or 365 days. After 84 days histomorphologic evaluation revealed that more than 86% of each surface was covered with mature bone, while the VPS-H-A.C. coating demonstrated an almost two times greater tensile strength than the APS-H-A.C. coating. After 365 days both coatings showed a bony coverage of more than 94%. Again the tensile strength testing revealed much higher values for the VPS-H-A.C. coating. This study demonstrates that after 84 days as well as after 365 days in vivo, the VPS-H-A.C. coating had a significantly greater load capacity than an H-A.C. coating applied under atmospheric condition, and an equal affinity for bone.

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Production of biocompatible coatings by atmospheric plasma spraying

Cited by 41 publications

References 2 publications

Surface nanocrystallization of hydroxyapatite coating

Surface nanocrystallization of hydroxyapatite coating

Study on the influence of plasma spray processes and spray parameters on the structure and crystallinity of hydroxylapatite coatings

Tierexperimentelle Testung einer unter Niederdruckbedingungen gespritzten Hydroxylapatitkeramikbeschichtung

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