Compositional changes between free coatings and surface coating layers during mechanochemical process, An IR-based chemometric analysis

By mid-IR analysis, mixtures of stearic acid, a paraffinic compound and a fluorinated compound were analyzed using attenuated total reflection (ATR) spectroscopy and reflection–absorption infrared spectroscopy (RAIRS). The precision of the partial least square (PLS) models created for each of these two techniques were compared in order to work out a quality control process of the mixtures which are involved in mechanochemical coating technology. We obtained a good relationship between spectral data and concentration with ATR spectroscopy. However, RAIRS spectroscopy allows to observe the affinity of long-chain organic acids for steel surfaces, and to determine the actual composition of coatings.