Ma Fengcang

Effects of Growth Parameters on the Morphology of CNTs/Cu Composite Powder Prepared Using Cr/Cu Catalyst by Chemical Vapor Deposition

Abstract Based on the in-situ polymerization and chemical vapor deposition method (CVD), the synthesis method of CNTs/Cu composite powder was developed by Cr/Cu catalyst via CVD. The crystal phase and micro morphologies of the as-synthesized materials were characterized using scanning electron microscopy (SEM) and Raman spectrum as well as transmission electron microscopy (TEM), respectively. The results show that the superior quality and well-crystallized CNTs/Cu composite powder can be produced by CVD using 10wt% Cr/Cu catalyst at growth temperature as low as 1073 K, for growth time of 30 min and under mixture gas of H 2 /C 2 H 4 with a flow rate of 2450/300 mL/min.

预处理工艺对铜基材表面化学镀Ni-P-PTFE复合涂层的影响

研究铜基预处理工艺过程中不同除油温度和酸洗时间对Ni-P-PTFE复合涂层的微观结构和力学性能的影响.首先对H70黄铜进行不同工艺的预处理，然后在基体上先镀Ni-P层，最后化学镀Ni-P-PTFE复合涂层.通过控制预处理过程中除油温度和酸洗时间，利用扫描电子显微镜（SEM）、X射线衍射仪（XRD）、纳米压痕仪和HSR-2M摩擦磨损试验机对涂层的微观结构和力学性能进行表征和测试.结果表明：不同除油温度和酸洗时间对Ni-P-PTFE复合涂层的微观组织、涂层硬度和摩擦因数均有较大的影响.当除油温度为70℃、酸洗时间为4 min时，可在基材上得到润滑性和硬度等综合性能优良的Ni-P-PTFE复合涂层，涂层硬度达到5.16 GPa，摩擦因数为0.135.

β-TCP/PLLA复合材料的制备与降解性能

采用溶液共混法制备不同β-磷酸三钙（β-tricalcium phasphate，β-TCP）质量分数的复合材料，并将纯聚左旋乳酸（PLLA）和复合材料置于模拟体液中降解3个月，用万能材料试验机测试纯PLLA和复合材料的弯曲强度、拉伸强度和弯曲模量，用扫描电子显微镜（SEM）观察其断面形貌.结果表明：少量β-TCP的加入可以使复合材料弯曲强度和拉伸强度增大，随着β-TCP的进一步加入，复合材料的弯曲强度和拉伸强度均减小，而复合材料的弯曲模量随着β-TCP的加入逐渐增大；降解后不同β-TCP含量的复合材料的弯曲强度均有所降低，但降幅不同，所有复合材料在前6周弯曲强度衰减较快，第6~12周强度衰减趋缓；纯PLLA体外降解时，弯曲强度衰减明显快于β-TCP/PLLA复合材料；第12周时复合材料的弯曲强度仍有17.8~32.4 MPa，高于松质骨的（11.5±2.1）MPa，满足松质骨骨折内固定器的要求.

Effects of Acidic MAO Electrolytes on the Coatings of Ti Alloy and the Proliferation of Osteoblast

Titanium oxide coatings are prepared by using Micro-arc oxidation method on the Ti-6Al-4V in 5% H2SO4 and 10% H3PO4 electrolytes. MG63 cells are grown in coculture on oxide films for different times to evaluate the cell proliferation ability of various films. The morphologies, phase component and roughness of coatings are characterized by means of SEM, XRD and roughness instrument. The results show that the pore diameter of micro-arc oxidation films increase with the increment of voltage and the biggest pore diameters are 239.2 nm and 2.398 μm in H2SO4 and H3PO4 respectively. The films consist of rutile and / or anatase phases with porous structures are formed on Ti-6Al-4V after oxidizing in H2SO4, while amorphous titanium with matrix phase is produced in H3PO4. The samples treated in H2SO4 solution exhibit a more significant effect on the cell proliferation compared with H3PO4 as the OD value of the samples treated in H2SO4 increase with voltage represents the greater quantity of cells, but in H3PO4 the OD value is the highest under the lowest voltage at the same time.