Sharif Digital Repository

Coatings are used in order to prevent wear, corrosion, thermal gradient reduction, surface strength improving and many other applications in industries. One of the common applications of coatings, is to prevent wear and surface abrasion. Hardness and friction coefficients are two parameters that determine the wear properties of a coating. Determining these parameters in very thin films is only possible by nanoindentation and nanoscratch tests. Surface hardness, young modulus and fracture toughness can be obtained using nanoindentation and friction coefficient is calculated from nanoscratch.
Finite element method is widely used for simulating the nanoindentation and nanoscratch... 

Nanocrystalline materials have received increasing attention during the last decades. Polycrystalline structures with grain sizes less than 100 nm are referred as nanocrystalline (NC). Their mechanical properties differ significantly from polycrystalline structures. As an example, hardness and wear resistance of nanocrystalline structures are higher than those of polycrystalline structures. With the reduction of grain size, hardness increases based on the Hall–Petch relation. However, at the very small grain sizes the Hall–Petch relation breaks down and a fundamental shift takes place in hardening mechanism. Molecular dynamics (MD) simulation offers a powerful method for the investigation of... 

Today, in order to reach atomic scale resolution, novel nanolithography methods, known as unconventional nanolithography, have been presented, since conventional methods, including photolithography and scanning beam lithography are fundamentally unable to fulfill this need. In this work, a specific type of unconventional lithography, known as scanning probe lithography, is presented. Scanning probe lithography takes advantage of the interactions between a very sharp probe and the sample in nanoscale distances to control this distance, and hence enable the modification of the sample using this sharp probe. In mechanical scanning probe lithography, the probe is used mechanically to change the... 

Nowadays, metal-organic frameworks have received a lot of attention due to their properties and characteristics such as controllable structure, high specific surface area and the tunable porosity size and have found many applications. One group of metal-organic frameworks are zeolitic imidazolate frameworks which ZIF-8 is a member of this family, and many studies have been conducted on it. In the present study, ZIF-8 nanocomposite coating was applied to the plain carbon steel substrate by synthesis at room temperature and immersion method, and its corrosion behavior and mechanical properties were investigated. The effect of Mercaptobenzothiazole (MBT) inhibitor on corrosion behavior and...