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  • An example of an hip replacement made of titanium an HA coating.
  • Explain the process of deposition
  • The actual machine we made the deposition with. Show were the laser hits the chamber.
  • Explain importance of this pathway and how we would not be able to get HA without this pathway Explain what is shown. First just pure Argon Because water will form oxide layer Oxide layer makes the adhesion strength weak Don’t turn on mixed water and Argon until we start firing the laser
  • Explain the five experiments Why we decreased laser Fluence changes in ambient pressure temperature the change in distance Meaning of astricks * Ar/H 2 O ambient created by bubbling Ar gas through deionized water kept at room temperature. ** Ar/H 2 O ambient created by bubbling Ar gas through deionized water heated to 50  C.  
  • * Although the spectrum of sample #1 shows a few clear diffraction peaks indicating crystalline material, a broad amorphous-like background is observed in the scan. *strongest peak obtained from sample #1 (indicated by an asterisk in the figure) cannot be ascribed to HA. It is likely due to the presence of tetracalcium phosphate in the coating. *sample #2 shows more crystalline peaks. The feature associated with tetracalcium phosphate (*) is still present, as is the amorphous band. However, sample #2 shows clear evidence of the presence of crystalline HA. * For samples #3 and #4, however, lower temperatures were used and these samples were dominated by amorphous material as can be seen in Fig. 2. *Results for samples #1 and #2, suggested that a higher water content should be used to achieve HA growth. Also, measurements on samples #3 and #4 demonstrated that the substrate temperature must be maintained at 600  C for the formation of crystalline material. Based on this information we deposited sample #5 using a higher ambient pressure (500 mTorr) and a substrate temperature of 600  C. In addition, a new method was used to increase the water content in the argon carrier gas. In this case Ar gas was bubbled through deionized water heated to 50  C while previously the water was kept at room temperature. These factors led to the deposition of a good quality HA coating. Figure 2 shows that this HA film displays all the peaks of the HA target. There is evidence, however, that some tetracalcium phosphate is still present in the film.
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    1. 1. Hydroxyapatite Coatings by Pulsed Laser Deposition Andreece Richardson Department of Physics University of Alabama at Birmingham A pathway for improving the performance of orthopedic and dental implants
    2. 2. Orthopedic and Dental Implants <ul><li>Typically made of Titanium Alloys </li></ul><ul><li> Good corrosion and fatigue life </li></ul><ul><li> Acceptable biocompatibility </li></ul><ul><li>Deposition of a coating of a material known as Hydroxyapatite on titanium implants </li></ul><ul><li> Improves bioactivity </li></ul><ul><li> Improves biocompatibility </li></ul><ul><li>Hydroxyapatite is an important component of human bone! </li></ul>
    3. 3. What type of material is Hydroxyapatite? <ul><li>Ceramic material </li></ul><ul><li>Main mineral constituent of bone and teeth </li></ul><ul><li>Bone and teeth </li></ul><ul><ul><li>50 wt.% mineral </li></ul></ul><ul><ul><li>(mainly Hydroxyapatite) </li></ul></ul><ul><ul><li>50 wt.% organic molecules + water </li></ul></ul><ul><ul><li>(collagen, mucopolysaccharides) and water </li></ul></ul>
    4. 4. A great way of depositing Hydroxyapatite: Pulsed Laser Deposition
    5. 5. Pulsed Laser Deposition is a Great Technique <ul><li>Versatile technique for preparing a wide range of thin films and multi-layer structures </li></ul><ul><li>Can work under controlled gas ambient </li></ul><ul><li>Allows deposition of different coatings by changing the parameters of deposition </li></ul><ul><li>Gives researchers the opportunity to discover novel coatings with long-term stability </li></ul>
    6. 6. Pulsed Laser Deposition
    7. 7. Mixed Argon and Water Pathway
    8. 8. Deposition Experiments Sample Laser Fluence (J/cm 2 ) Rep. Rate (Hz) Ambient (mTorr) Sub. Temp. (  C) Target-Sub. Distance (cm) #1 10 30 200 Ar/H 2 O* 600 4.9 #2 4 30 300 Ar/H 2 O* 600 7.5 #3 4 30 300 Ar/H 2 O* 550 7.5 #4 4 30 300 Ar/H 2 O* 500 7.5 #5 4 30 500 Ar/H 2 O** 600 7.5
    9. 9. X-Ray Diffraction Results #1: 200 mTorr; Water at RT Substrate: 600 °C #2: 300 mTorr; Water at RT Substrate: 600 °C #3: 300 mTorr; Water at RT Substrate: 550 °C #4: 300 mTorr; Water at RT Substrate: 500 °C #5: 500 mTorr ; Water at 50 °C Substrate: 600 °C Besides Hydroxyapatite (Ca 5 (PO 4 ) 3 (OH)) There are other Calcium Phosphate Ceramics: - Tricalcium phosphate (Ca 3 (PO 4 ) 2 ) - Tetracalcium phosphate (Ca 4 P 2 O 9 ) - Amorphous hydroxyapatite
    10. 10. Conclusion We have found good conditions for depositing Hydroxyapatite by Pulsed Laser Deposition: 500 mTorr Ar/Water; Water at 50 °C Substrate: 600 °C
    11. 11. Acknowledgments Thanks to Two Outstanding Mentors Hyunbin Kim and Dr. Renato Camata!