Interfacial imperfections:

Interfacial imperfections exist at an angle among any two faces of a crystal or crystal form. These imperfections are found at domain boundaries, free surfaces, grain boundaries or interphase boundaries. Free surfaces are interfaces among solids and gases. Domain boundaries refer to interfaces while electronic structures are different on either side causing every side to act differently while the similar atomic arrangement exists on the both sides. Grain boundaries exist among crystals of similar lattice structure that possess different spacial orientations. Polycrystalline materials are made up of several grains that are separated through distances classically of various atomic diameters. At last, interphase boundaries exist among the regions where materials exist in different phases that are BCC further to FCC structures.