Do any of you can tell me how can I find out if the film is cohesive or adhesive? What analysis techniques that can be used to detect if the film adhesive or cohesive?
Analyze the surface composition of the fractured interfaces. A cohesive failure will result in both surfaces having comparable chemistry to the bulk film because the film remains behind on the substrate surface. Alternatively, the substrate will fail, in which case both surfaces have comparable chemistry to the bulk substrate. javascript:In adhesive failure, the chemistries of the two interfaces will each be closer to their respective bulk materials.
Techniques to perform the analysis include the alphabet list of surface spectroscopies. I would recommend XPS and possibly EDS (or EDXA). With polymer films, I would suggest ATR-FTIR.
I am not going to answer the above question instead using this forum, I am asking another question from you.
I want to study the Adhesion and adhesion mechanism of Shape Memory Alloy films on Titanium alloys (metal substrate). Can you recommend me some method or article especially by using the indentation one to calculate the mechanism or work of adhesion for this system.
@Q A Mateen: I cannot recommend anything specifically. This is outside my direct area of expertise. My general recommendation is however for you to do a literature search in sources such as Web of Science, IEEE, Chem Abstracts, or Science Direct using the terms you have in your question.
Adhesive failure means covering 100% area at failure (1 adherend only), Cohesive failure means covering 200% area (covering both adherends). There is also mixed failure (between 100 and 200%). In an adhesive failure the failure is in the interface while in a cohesive failure the failure is within the adhesive not in the interface.
You can find it out by using SEM + EDAX. First do SEM+EDAX on the clean adherend then on the pure adhesive and then on both adherends and compare. FTIR can also help
Scratch or nanoscratch (depending on the thickness of the film) could be used in addition to spectroscopic techniques. These type of tests could demonstrate the adhesion/cohesion characteristics of the films, actually, you can calculate the loads for coating delamination (indicates the adhesion features of the film) and the loads for film cracking (related to cohesion features). Tribological tests such as reciprocating wear test plus image analysis could also aids to determining wear mechanism, which is related to the adhesion/cohesion of the film.