The interactions between oxidised tantalum and methylene diphenyl diisocyanate (MDI) have been investigated by X‐ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectrometry (ToF‐SIMS). Thin (approximately 2 nm) and thick layers of polymeric MDI were deposited on tantalum; one set was cured at 200°C, the other dried at ambient temperature (20°C). The thick layers serve as a characteristic pMDI layer, and thin layers contain information relating to the nature of interfacial bonding. By careful fitting of the N1s region contributions relating to interfacial bonding have been established. All spectra show an N^δ+ contribution indicative of acid–base bonding; in the case of the thick films, this is of an intermolecular nature whereas in the thin films, the more intense contribution is a result of such forces between pMDI and substrate. This is confirmed by ToF‐SIMS. A lower binding energy component at ca 396 eV on the air‐dried thin layer of pMDI is the result of a formal reaction between pMDI and tantalum yielding a nitride‐like species in the N1s spectrum.

中文翻译：

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亚甲基二苯基二异氰酸酯和钽在热交换器中的界面化学研究

X射线光电子能谱（XPS）和飞行时间二次离子质谱（ToF-SIMS）已研究了氧化钽与亚甲基二苯基二异氰酸酯（MDI）之间的相互作用。聚合物MDI的薄层（约2 nm）和厚层沉积在钽上；一组在200℃下固化，另一组在环境温度（20℃）下干燥。厚层用作特征性的pMDI层，而薄层则包含有关界面键合性质的信息。通过仔细拟合N1s区域，已经建立了与界面结合有关的贡献。所有光谱均显示^Nδ+指示酸碱键的贡献；在厚膜的情况下，这是分子间性质，而在薄膜中，更强烈的贡献是pMDI和底物之间的这种作用的结果。这已由ToF-SIMS确认。pMDI的风干薄层上约396 eV处较低的结合能成分是pMDI和钽之间正式反应的结果，在N1s光谱中产生类氮化物。