Hydroxyapatite Coatings by Pulsed Laser Deposition A pathway for improving the performance of orthopedic and dental implants Andreece Richardson Department of Physics University of Alabama at Birmingham Orthopedic and Dental Implants Typically made of Titanium Alloys Good corrosion and fatigue life Acceptable biocompatibility Deposition of a coating of a material known as Hydroxyapatite on titanium implants Improves bioactivity Improves biocompatibility Hydroxyapatite is an important component of human bone! What type of material is Hydroxyapatite? Ceramic material Main mineral constituent of bone and teeth Bone and teeth – 50 wt.% mineral (mainly Hydroxyapatite) – 50 wt.% organic molecules + water (collagen, mucopolysaccharides) and water A great way of depositing Hydroxyapatite: Pulsed Laser Deposition Substrate Vacuum chamber Gaseous plume Excimer laser Target UV-transparent window Pulsed Laser Deposition is a Great Technique Versatile technique for preparing a wide range of thin films and multi-layer structures Can work under controlled gas ambient Allows deposition of different coatings by changing the parameters of deposition Gives researchers the opportunity to discover novel coatings with long-term stability Pulsed Laser Deposition Mixed Argon and Water Pathway Deposition Experiments Sam Laser Rep. Ambient Sub. Target-Sub. ple Fluence Rate (mTorr) Temp. Distance (J/cm2) (Hz) (C) (cm) #1 10 30 200 600 4.9 Ar/H2O* #2 4 30 300 600 7.5 Ar/H2O* #3 4 30 300 550 7.5 Ar/H2O* #4 4 30 300 500 7.5 Ar/H2O* #5 4 30 500 600 7.5 Ar/H2O* * X-Ray Diffraction Results Besides Hydroxyapatite #5: 500 mTorr; Water at 50 °C (Ca5(PO Substrate: 600°C 4)3(OH)) There are other Sample #5 Calcium Phosphate Ceramics: #4: 300 mTorr; Water at RT - Tricalcium phosphate Sample #4 Intensity (arb. units) Substrate: 500°C ) ) (Ca3(PO4 2 Sample #3 - Tetracalcium phosphate * #3: 300 mTorr; Water) at RT (Ca4P2O9 Sample #2 Substrate: 550°C - Amorphous hydroxyapatite * Sample #1 #2: 300 mTorr; Water at RT (211) (112) Substrate: 600°C (002) (210) (300) HA target (102) (202) #1: 200 mTorr; Water at RT Substrate: 600°C 20 25 30 35 2Theta Conclusion We have found good conditions for depositing Hydroxyapatite by Pulsed Laser Deposition: 500 mTorr Ar/Water; Water at 50 °C Substrate: 600°C Acknowledgments Thanks to Two Outstanding Mentors Hyunbin Kim and Dr. Renato Camata!
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