I performed XPS depth profiling to investigate surface chemistry and compositional gradients through thin films. Controlled sputtering and peak fitting enabled evaluation of oxidation states and chemical uniformity. This analysis provided insight into surface and near-surface stability after processing 

The image illustrates variation of oxidation as we go from thin film surface to depth. Equipment-Themo Scientific Al k-alpha

I used XPS to analyze surface chemistry following electrochemical corrosion testing. XPS measurements revealed oxidation and passivation behavior of alloy surfaces exposed to corrosive environments. These results complemented electrochemical data and supported interpretation of corrosion mechanisms. 

The image illustrates oxidation state checking after corrosion of high entropy alloy.