The influence of plasma power on liquid precursor decomposition in suspension plasma spray (SPS) is studied with optical emission spectroscopy (OES). The precursors consist in a suspension of titania nanoparticles (TiO₂) in water. The precursor decomposition was observed through the emission of the titanium element and of the TiO molecule, from which temperature and density maps were plotted. The resulting coating phase and microstructure were determined with X-ray diffraction and scanning electron microscopy, respectively. OES results have been corelated to the microstructure and phase composition of the TiO₂ coatings at three different powers. The aim of this study is to bring a new understanding of the precursor decomposition inside the plasma and to fathom the effect of the power on microstructure and phase. Results show that OES temperature maps alone are insufficient to understand the SPS process; atomic and molecular species densities maps are of prime importance.

利用发射光谱法 (OES) 研究了等离子体功率对悬浮等离子体喷雾 (SPS) 中液体前驱体分解的影响。前体由二氧化钛纳米颗粒（TiO ₂）在水中的悬浮液组成。通过钛元素和 TiO 分子的发射观察前体分解，从中绘制温度和密度图。分别用 X 射线衍射和扫描电子显微镜测定所得涂层相和微观结构。OES结果与TiO _{2的微观结构和相组成相关}三种不同功率的涂层。本研究的目的是对等离子体内的前体分解产生新的认识，并了解功率对微观结构和相的影响。结果表明，仅 OES 温度图不足以理解 SPS 过程；原子和分子物种密度图是最重要的。