The effect of relative humidity on the decomposition reaction of zinc dialkyldithiophosphate (ZDDP) additive under boundary lubrication regime has been investigated using Raman spectroscopy and atomic force microscopy (AFM). The ZDDP tribofilms were formed using the pin-on-disc tribometer at 30 and 90% relative humidity, which was controlled using a custom-made humid chamber. The results suggest that relative humidity does not change only the length of the phosphate chains but also their affinity towards the available cations. At low relative humidity, zinc pyrophosphate to polyphosphate chains were formed compared to predominantly shorter iron orthophosphate chains at high relative humidity. In addition, relative humidity altered the structure of the mature tribofilm. At low relative humidity, the tribofilm had a patchy structure with average thickness of 140 nm and fractal dimension of 2.17. However, at high relative humidity, the tribofilm had a thin dendritic structure with average thickness of 85 nm and fractal dimension of 2.34. This means that the structure is more complex with a larger number of nesting self-similar structures at all scales. This is significant in making the transition from descriptive towards quantitative information of the tribofilm structure.

利用拉曼光谱和原子力显微镜研究了相对湿度对二烷基二硫代磷酸锌（ZDDP）添加剂在边界润滑条件下的分解反应的影响。ZDDP摩擦膜是使用圆盘式摩擦计在30％和90％的相对湿度下形成的，相对湿度使用定制的潮湿室进行控制。结果表明相对湿度不仅改变了磷酸酯链的长度，而且改变了它们对可用阳离子的亲和力。在较低的相对湿度下，与在较高的相对湿度下显着较短的正磷酸铁链相比，焦磷酸锌到聚磷酸锌的链形成了。另外，相对湿度改变了成熟的摩擦膜的结构。在较低的相对湿度下 摩擦膜的片状结构平均厚度为140 nm，分形维数为2.17。然而，在较高的相对湿度下，摩擦膜具有较薄的树枝状结构，平均厚度为85 nm，分形维数为2.34。这意味着在所有尺度上都有大量嵌套自相似结构的结构会更复杂。这对使摩擦膜结构从描述性信息过渡到定量信息具有重要意义。