High-speed preparation of biocompatible ceramic coatings by laser CVD

本研究采用金属有机化学气相沉积和激光增强化学气相沉积技术制备了CaTiO_3、α-TcP和HAp等钙基氧化物薄膜。研究了制备条件对薄膜的晶相、微观结构和沉积速率的影响。采用化学气相沉积法制备了CaTiO3膜、α-TCP膜和HAp膜。6周后，CaTiO_3薄膜表面完全覆盖磷灰石，表面光滑；3天后，CaTiO_3薄膜表面复杂；2周后，α-TCP膜表面完全覆盖；6h后，CaTiO_3薄膜表面光滑。磷灰石主要形成在微孔中，这表明除了陶瓷薄膜的本征骨电导率外，表面形貌对磷灰石的形成速度有显著影响。在较高的沉积速度下，也可以获得HAP和α-TCP薄膜。激光功率(P_L)对Ca-P-O薄膜的晶相有显著的影响：在P_L=200W时，α-TCP在宽条件下形成，在P_L=150W时，在高温下形成α-TCP，在低温下形成HAP，在P_L=100W时，在宽条件下形成主相。任何薄膜都表现出致密的微结构。沉积速率随前驱体浓度、沉积温度、激光功率和腔室总压(P&lt；TOT&gt；)的增大而增大，在P_L=200W、P_&lt；TOT&gt；=0.6kPa时，沉积速率达到最大值，达到1200μm/h。结果表明，采用化学气相沉积法制备了CaTiO3、α-TcP和HAp薄膜，阐明了制备条件对薄膜晶相、微观结构和沉积速率的影响。用化学气相沉积法制备的CaTiO3、α-TcP和HAp薄膜在伪体溶液中显示出较高的磷灰石形成率，具有良好的骨传导性。

In the present study, calcium base oxides, e.g. CaTiO_3, α-TCP and HAp films were prepared by metalorganic chemical vapor deposition (MOCVD) and laser enhanced CVD (LCVD). Effects of preparation conditions on the crystal phase, microstructure and deposition rate were investigated. Furthermore, the bone conductivity and biocompatibility were evaluated by the formation behavior of apatite on those films in a Hanks'' solution.CaTiO_3, α-TCP and HAp films were obtained first by MOCVD. Apatite wholly covered the surface of CaTiO_3 films with a smooth surface after 6 weeks, CaTiO_3 films with a complicated surface after 3 days, α-TCP films after 2 weeks and HAp films after 6 hours. The apatite predominantly formed at the micro-sized hollows, indicating significant effect of surface morphology on the apatite formation rate except of the intrinsic bone conductivity of the ceramics films.HAp and α-TCP films were obtained also by LCVD at a high deposition rate. Laser power (P_L) showed significant effect on the crystal phase of Ca-P-O films: at P_L=200W α-TCP formed in wide conditions, at P_L=150W α-TCP formed at high temperatures and HAp formed at low temperatures, at P_L=100W HAp in a main phase formed in wide conditions. Any film showed a dense microstructure. The deposition rate increased with increasing the precursor concentration, deposition temperature, laser power and total pressure in chamber (P_<tot>), showing the highest value of 1200μm/h at P_L=200W and P_<tot>=0.6 kPa. Apatite formed on the Hap films prepared by LCVD in Hanks'' solution after 6 hours.In a summary, it is confirmed that CaTiO_3, α-TCP and HAp films can be prepared by chemical vapor deposition, and the effects of preparation conditions on the crystal phase, microstructure and deposition rate were clarified. The CaTiO_3, α-TCP and HAp films prepared by CVD were proved to have excellent bone conductivity by revealing high apatite formation rate in pseudo body solutions.