CAJ | 학술논문

使用碳酸钙(CaCO3)和二水磷酸氢钙(DCPD,CaHPO4·2H2O)混合粉末在纯钛表面利用激光熔覆的法制备羟基磷灰石HA,Ca5(PO43(OH)涂层,研究CaCO3和DCPD的质量比对涂层相组成和微观组织的影响.研究发现,CaCO3和 DCPD之间的反应不仅在涂层中生成结晶度较高的HA,同时还生成了一定量的磷酸四钙(TTCP,Ca4P2O9),α-磷酸钙(α-TCP,α-Ca3(PO4)2),β-磷酸钙(β-TCP,β-Ca3(PO4)2)和焦磷酸钙(Ca2P2O7),且各相的含量与混合粉末的钙磷原子比有较大关系.HA只有在混合粉末的钙磷原子比大于1.54 的情况下才能生成,其含量随钙磷原子比的升高而缓慢增加;当混合粉末的钙磷原子比达到2.0时,涂层中的HA的含量达到25%(质量分数),同时涂层中还存在大量的TTCP,因此制备的涂层需要进行一定的后续热处理以增加其中HA的含量.由于制备过程中粉末之间的反应会生成大量的气体,因此制备的涂层均为多孔结构,其中用钙磷原子比为2.0的混合粉末制备的涂层中,孔隙的尺寸在100～300μm之间.粉末钙磷原子比还能影响涂层的结合强度、孔隙率和裂纹数量.随钙磷原子比的升高,涂层的结合强度和孔隙率随之下降,裂纹数量逐渐增加.
사용탄산개(CaCO3)화이수린산경개(DCPD,CaHPO4·2H2O)혼합분말재순태표면이용격광용복적법제비간기린회석HA,Ca5(PO43(OH)도층,연구CaCO3화DCPD적질량비대도층상조성화미관조직적영향.연구발현,CaCO3화 DCPD지간적반응불부재도층중생성결정도교고적HA,동시환생성료일정량적린산사개(TTCP,Ca4P2O9),α-린산개(α-TCP,α-Ca3(PO4)2),β-린산개(β-TCP,β-Ca3(PO4)2)화초린산개(Ca2P2O7),차각상적함량여혼합분말적개린원자비유교대관계.HA지유재혼합분말적개린원자비대우1.54 적정황하재능생성,기함량수개린원자비적승고이완만증가;당혼합분말적개린원자비체도2.0시,도층중적HA적함량체도25%(질량분수),동시도층중환존재대량적TTCP,인차제비적도층수요진행일정적후속열처리이증가기중HA적함량.유우제비과정중분말지간적반응회생성대량적기체,인차제비적도층균위다공결구,기중용개린원자비위2.0적혼합분말제비적도층중,공극적척촌재100～300μm지간.분말개린원자비환능영향도층적결합강도、공극솔화렬문수량.수개린원자비적승고,도층적결합강도화공극솔수지하강,렬문수량축점증가.
Hydroxyapatite coatings were fabricated on Ti substrates by laser cladding (LC) using mixed powders of CaCO3 and dicalcium phosphate dihydrate (DCPD, CaHPO4·2H2O). The effect of the mass ratio of CaCO3 to DCPD on phase and microstructure formation of the coatings was investigated. The reactions between CaCO3 and DCPD can produce high crystallized hydroxyapatite (HA, Ca5(PO4)3(OH)) in the coatings as well as tetracalcium phosphate (TTCP, Ca4P2O9), α-tricalcium phosphate (α-TCP, α-Ca3(PO4)2), β-tricalcium phosphate (β-TCP, β-Ca3(PO4)2) and Ca2P2O7. The Ca/P molar ratio (CMR) of the mixed powders (CMRP) has a great influence on the contents of the phases in the coating. HA can be produced in the coating only when the CMRP is higher than 1.54, and its content increases slowly as the CMRP increases. The coating contains only about 25wt% HA when CMRP reaches 2.00, and there exists large amount of TTCP in the coating. So a post heat treatment with furnace cooling is recommended to increase the amount of HA in the coating. All the coatings have porous structures because the reactions between the powders produce lots of gases during LC. The pore size in the coating fabricated by the powders with CMR equal to 2.00 is about 100-300 μm. CMRP also has a great influence on the bond strength, porosity and cracks of the coatings. Along with the increase of the CMRP, the bond strength and porosity decrease, whereas the number of cracks increases.