Introduction To explain nanocrystalline materials, the concept of “nano” should have been explained first. Nanostructures are relatively new and interesting topics to study, they are found on a scale between 0 and 100 nanometers (1 nanometer, nm equals 10-9 meters). There are some types of nanostructured materials such as lamellar (one-dimensional), filamentary (two-dimensional), and crystallite (three-dimensional). If the grains of the material are made up of crystals, then they are called the term “nanocrystalline materials”. In this case, nanocrystalline materials have grains that are typically <100 nm in size. An example of SnO2 nanocrystalline material is imaged with STM as shown in Fig. 1 [1] and SEM image of nanocrystalline diamond thin films as shown in Fig. 2. [2]Fig. 1. STM image of nanocrystalline SnO2 [1]Fig. 2. SEM image of nanocrystalline diamond thin films. [2]There are numerous superior properties in nanocrystalline materials that are actually very useful and promising for future work and applications. The reason for the superior properties is that nanocrystalline materials have a very large number of atoms at the grain boundaries that are on the nanoscale. Some of the properties that can be improved and increased by producing nanocrystalline materials instead of coarse-grained materials are higher strength, higher hardness, higher diffusivity, higher mechanical properties and so on [3]. This is why humans have been studying this topic for a very long time and since then a lot of information has been known about nanocrystalline materials and their properties. Of course there are still many other things that people cannot yet learn or study, however, according to the results of current work, it can be said that the very promising future for nanocrystalline materials is near. Nanocrystalline materials have