Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Experiment Videos

Thermal processing of hydroxyapatite for coating production

K A Gross1, C C Berndt

  • 1Department of Materials Science and Engineering, State University of New York at Stony Brook, 11794-2275, USA.

Journal of Biomedical Materials Research
|March 10, 1998
PubMed
Summary

This study examines how thermal processing affects the composition of hydroxyapatite coatings used in medical implants. The researchers found that high temperatures during coating production lead to changes in the material’s structure. These changes are caused by the removal of certain chemical components, like hydroxyl and phosphate groups, and by the speed at which the material cools. The study shows that these factors influence the formation of new phases, such as amorphous and oxyapatite, as well as calcium-rich compounds like tetracalcium phosphate. The findings suggest that controlling thermal conditions during coating production could help preserve the original hydroxyapatite content, which is important for the coating’s performance and compatibility with surrounding tissues.

Related Concept Videos

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

RF magnetron-sputtered coatings deposited from biphasic calcium phosphate targets for biomedical implant applications.

Bioactive materials·2018
Same author

Morphology and gelation of thermosensitive chitosan hydrogels.

Biophysical chemistry·2005
Same author

Changes in the innate immune response of Atlantic salmon, Salmo salar L., exposed to experimental infection with Neoparamoeba sp.

Journal of fish diseases·2005
Same author

Influence of ferrous iron incorporation on the structure of hydroxyapatite.

Journal of materials science. Materials in medicine·2005
Same author

Dissolution and mineralization of sintered and thermally sprayed hydroxy-fluoroapatites.

Journal of materials science. Materials in medicine·2005
Same author

Encapsulation of apatite particles for improvement in bone regeneration.

Journal of materials science. Materials in medicine·2004

Area of Science:

  • Materials science for biomedical applications
  • Bioceramics in orthopedic and dental implants
  • Thermal processing of ceramic coatings

Background:

Hydroxyapatite coatings are widely used in biomedical applications to improve implant integration with surrounding tissues. However, the effectiveness of these coatings depends on their chemical and structural stability during thermal processing. Prior research has shown that hydroxyapatite can undergo phase transformations when exposed to high temperatures. Yet, the exact mechanisms of these transformations during coating processes remain unclear. This uncertainty limits the ability to optimize coatings for long-term performance. Understanding how thermal conditions affect phase evolution is essential for improving coating quality. No prior work has resolved how specific thermal parameters influence the formation of secondary phases. This gap motivated the current investigation into phase transformations during hydroxyapatite coating production. The study aims to clarify the relationship between processing conditions and final coating composition.

Purpose Of The Study:

Keywords:
biomedical coatingsthermal spray processhydroxyapatite compositionphase evolution in ceramics

Frequently Asked Questions

Phase transformations are caused by preferential removal of hydroxyl and phosphate groups and the high cooling rate during thermal spraying.

This removal leads to a calcium-rich melt, promoting the formation of tetracalcium phosphate and calcium oxide.

High cooling rates influence phase formation by affecting melt viscosity and decomposition of hydroxyapatite.

X-ray diffraction was used to identify and track the evolution of different phases in the coatings.

Related Experiment Videos

The study aimed to examine how thermal processing affects the phase composition of hydroxyapatite coatings. Specifically, the researchers wanted to determine how phase transformations occur during plasma spraying. They focused on identifying the chemical and structural changes that arise from thermal exposure. The goal was to understand the factors that lead to the formation of secondary phases. This knowledge could help improve the design of biomedical coatings. The study also sought to propose a model for phase distribution within the coating layers. The findings could inform better processing strategies to preserve hydroxyapatite content. The motivation stems from the need to enhance coating performance and tissue compatibility.

Main Methods:

The researchers used plasma spraying to apply hydroxyapatite coatings onto substrates. They then analyzed the coatings using X-ray diffraction and elemental analysis techniques. These methods allowed them to track the evolution of different phases during processing. The study focused on identifying the chemical changes that occur at high temperatures. They examined how the melt composition shifts during thermal exposure. The cooling rate was also considered as a key variable in phase formation. The analysis included tracking the removal of hydroxyl and phosphate groups. The results were used to propose a model of phase distribution within the lamellae.

Main Results:

The study found that phase transformations in hydroxyapatite coatings are driven by two main factors. First, the preferential removal of hydroxyl and phosphate groups alters the melt composition. This leads to the formation of amorphous and oxyapatite phases. Second, the high cooling rate during thermal spraying influences phase evolution. Further heating results in a less viscous melt, promoting the decomposition of hydroxyapatite into tricalcium and tetracalcium phosphate. The removal of phosphate during flight increases calcium content in the melt. This favors the formation of tetracalcium phosphate and calcium oxide. A proposed model illustrates how these phases are distributed within the coating layers. The findings suggest that controlling thermal conditions can help preserve hydroxyapatite content.

Conclusions:

The authors suggest that coating processes should aim to minimize the removal of hydroxide and phosphate during thermal treatment. This could help maintain higher hydroxyapatite content in the final coating. The study shows that phase transformations are influenced by melt composition and cooling rates. The proposed model provides insight into how different phases form within the coating layers. The findings indicate that tricalcium and tetracalcium phosphate form when the melt becomes less viscous. The presence of these phases may affect coating performance and tissue attachment. The study supports the need for better control of thermal parameters during coating production. The authors emphasize that preserving hydroxyapatite content is crucial for optimal coating performance.

Failed At:

2026-07-14T07:37:20.025645+00:00

Further heating produces a less viscous melt, facilitating decomposition into tricalcium and tetracalcium phosphate.

The model shows how amorphous, oxyapatite, and calcium-rich phases are distributed within the lamellae of the coatings.