Li Xiang, Huang Jie, Edirisinghe Mohan
Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK.
J Mater Sci Mater Med. 2008 Apr;19(4):1545-51. doi: 10.1007/s10856-007-3303-3. Epub 2007 Nov 8.
Electrohydrodynamic atomisation (EHDA) spraying of a hydroxyapatite (HA) suspension consisting of nano-particles (nHA) has been used to produce a HA coating comprising of nanostructured surface topography. In EHDA the suspension is jetted from a needle under an electric field. Obtaining the stable cone-jet mode of EHDA is critical to improve the quality and optimise the morphology of HA coatings, therefore a systematic investigation of the effects of several key processing parameters, such as suspension flow rate, applied voltage and distance between the needle and substrate, and needle size was carried out in this work. The HA coatings processed under different spraying parameters were compared and then scored according to uniformity and microstructural integrity. It was found that all of these parameters had a very significant influence on the morphology of nHA coating prepared. Under an optimised processing condition, where a needle orifice diameter of 300 microm, kept at a distance of 20 mm from the substrate, a flow rate of 20 microL/min, and the applied voltage kept within 4.3 kV and 5.2 kV, a uniform nHA coating was obtained. This is a crucial step forward in obtaining advanced nano-hydroxyapatite coatings of high quality for biomedical applications by using EHDA spraying.
利用电液动力雾化（EHDA）技术对由纳米颗粒（nHA）组成的羟基磷灰石（HA）悬浮液进行喷雾，已用于制备具有纳米结构表面形貌的HA涂层。在EHDA过程中，悬浮液在电场作用下从针管中喷出。获得EHDA的稳定锥射流模式对于提高HA涂层的质量和优化其形态至关重要，因此，本研究对几个关键工艺参数的影响进行了系统研究，这些参数包括悬浮液流速、施加电压、针管与基底之间的距离以及针管尺寸。对在不同喷涂参数下制备的HA涂层进行了比较，并根据均匀性和微观结构完整性进行评分。结果发现，所有这些参数对制备的nHA涂层的形态都有非常显著的影响。在优化的工艺条件下，即针孔直径为300微米，与基底保持20毫米的距离，流速为20微升/分钟，施加电压保持在4.3 kV至5.2 kV之间，获得了均匀的nHA涂层。这是通过使用EHDA喷涂技术获得用于生物医学应用的高质量先进纳米羟基磷灰石涂层的关键一步。
