Fine coatings of bio-seramics with using well controlled thermal plasmas

利用基于新设计的强制收缩型直流等离子体射流发生器的可控热等离子体反应器，研究了其在先进材料精细加工中应用的可行性，主要是羟基磷灰石（HAP）功能梯度涂层（FGC）的制备。研究结果如下：1.研制了由双波长光学系统和选通ICCD相机组成的像分光系统。该系统可以测量喷射粒子的二维温度分布和参数。讨论了喷射喷涂粒子参数与薄膜质量的关系.研究了不同喷涂条件下Ti-HAP FGC薄膜的制备。通过控制喷涂工艺条件，可以很好地控制FGC薄膜的结合强度、维氏硬度、c轴取向和孔隙率。对HAP涂层进行了模拟体液实验，发现涂层表面有磷灰石生成.研究了一种制备含多壁碳纳米管的碳纳米纤维的连续合成方法。使用催化剂粉末（Fe、Ni）比单独使用CH_4/H_2混合气体更能提高CNFs的产量.等离子喷枪是一种新型的双阳极等离子喷枪，它能在各种工作条件下长时间产生稳定的高功率等离子射流。利用这种方法，在空气层流等离子体射流作用下，以钛粉为原料，直接有效地合成了金红石型和金红石型混合的TiO_2粉体。

With the use of the well-controlled thermal plasma reactor based on the newly designed forced constricted type dc plasma jet generator, application feasibility for advanced materials fine process is studied, mainly functionally graded coatings (FGC) of hydroxyapatite (HAP). Findings are as follows:1. The image spectroscopic system composed of a double wavelength optical system and the gated ICCD camera has been developed. This system can measure two dimensional temperature distribution and parameters of injected spraying particles. Relationship between parameters of injected spraying particles and quality of prepared films is discussed.2. Preparation of Ti-HAP FGC films are studied under various spraying conditions. The adhesion strength, the Vickers hardness, c-axis orientation and the porosity of prepared FGC films are well controlled with spraying conditions. Simulated body fluid test of HAP coatings is also discussed and apatite is newly formed on the surface of the coatings.3. A continuous synthesis method to produce carbon nanofibers (CNFs) including multi-walled carbon nanotubes is studied. CNFs production using catalyst powders (Fe, Ni) is more enhanced compared to that using only CH_4/H_2 gas mixtures.4. Plasma spray gun has been newly designed as dual anode type plasma spray gun which can generate stable and high power plasma jets for a long time at various operating conditions. Using this, under laminar plasma jets in the air, TiO_2 powders with anatase and rutile types mixtures are directly and effectively synthesized from raw Ti powders.