## 10 Influence of Coating on Electrical Steel  
Researchers are actively working to improve the performance of electrical steels through several approaches. These include advancements in secondary recrystallization techniques [72], the precise control of grain orientation [11], increasing electrical resistivity, gauge reduction [79], and gaining a deeper understanding of the magnetic domain structure [102]. These efforts aim to optimize the magnetic and electrical properties of electrical steels, making them more efficient and suitable for a wide range of applications in the electrical and electronics industries [103]. Among these approaches, utilizing effective stress coatings has shown promising results in minimizing losses and magnetostriction [82]. During transformer manufacturing, steel sheets are typically under stress-free conditions, but compressive stress can develop during the process, leading to increased magnetostriction. By applying coatings that induce tensile stress on the steel, the compressive stress can be counterbalanced. Coatings play a crucial role in reducing power losses. By manipulating the surface roughness or varying surface stress through coatings, overall power loss can be significantly decreased [83]. Studies have shown that improving surface roughness can reduce power losses by 30-40% [84]. Coatings play a crucial role in minimizing eddy current losses in electrical steels through various mechanisms. By providing insulation resistance, coatings effectively reduce the flow of eddy currents, which are electric currents induced in a material via changing magnetic fields. Additionally, coatings help to decrease hysteresis and anomalous losses by enhancing surface roughness. The rougher surface introduced by the coating alters the magnetic domain structure, leading to reduced energy losses during magnetization cycles. Moreover, coatings can introduce beneficial tensile stress to a substrate, further optimizing a material's magnetic properties and enhancing its overall performance [43]. In this way, coatings contribute significantly to the efficiency and effectiveness of electrical steels in various electrical and electronic applications. Moreover, the application of tensile stress through coatings to a steel sheet can bring further benefits. Also, this process helps eliminate surface closure domains, which results in a narrowing of domain wall spacing and reduces anomalous loss. Additionally, by removing supplementary structures, the coercivity of the magnetic material can be reduced, leading to an improvement in hysteresis loss [82]. Several techniques are available for applying coatings to steel sheets, each with its own unique advantages. These methods include sol-gel processes, chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma spraying, wet coating, printing, electroless plating, and electrochemical plating. The corresponding coatings are designed to possess specific properties to meet the desired requirements for electrical steels. These properties include insulation resistance, which prevents the flow of an electric current; heat resistance; chemical resistance to withstand harsh environments; it possessed the capability to be easily punched, simplifying the processing of the material; weldability for joining; corrosion resistance to prevent degradation; burn-out characteristics; and resistance to compression. The thickness of the coating, surface roughness, and scratch resistance are also crucial factors to consider when applying coatings to ensure optimal performance [104]. For example, a 1 \(\upmu\)m thick titanium carbide (TIC) coating deposited via chemical vapor deposition on 0.23 mm thick GOES effectively reduced losses to 0.586 W/kg [105]. The coating primarily reduces eddy current loss, while hysteresis loss remains unaffected. Combining the effects of surface roughness and tensile stress, [PERSON] et al. [106] achieved a loss of 0.6 W/kg.