## 1 Introduction  
The rising global demand for marine resources and enhanced transportation capabilities has driven extensive research into innovative materials specifically tailored for marine applications, including platforms, pipelines, and essential connection components. These developments aim to address the unique challenges of the marine environment, ensuring the reliability and longevity of critical infrastructure. The corrosion of metals remains a major concern across diverse sectors, affecting not only the structural integrity and lifespan of materials, but also posing environmental hazards by introducing contaminants into ecosystems and creating potential health risks for workers. Among various types of corrosion, microbiologically influenced corrosion (MIC) stands out as a significant issue, particularly in aquatic environments [1]. MIC results from the activity of microorganisms that form biofilms on material surfaces, which alter the local electrochemical environment and accelerate corrosion through oxygen concentration gradients and differential aeration cells [2; 3]. Additionally, microbial metabolic byproducts can further intensify material degradation, leading to faster structural failure [4]. As MIC contributes to substantial economic losses worldwide, with corrosion costs representing a considerable portion of industrial maintenance budgets [5], addressing MIC is critical. Effective management strategies not only extend the service life of assets, but also protect environmental and human health, making MIC mitigation a priority in corrosion science. High-entropy alloys (HEAs), first conceptualized by [PERSON] et al. [6], mark a paradigm shift in alloy design by incorporating multiple principal elements in near-equiatomic ratios. This unique composition confers a high configurational entropy, promoting single-phase solid solutions rather than complex intermetallics, which are typical in conventional alloys. Due to their distinctive microstructures, HEAs exhibit exceptional properties, such as enhanced hardness, wear resistance, and corrosion resistance, making them suitable for protective coatings in demanding environments like marine applications [6; 7]. HEAs are generally classified into three main categories based on their phase structures: single-phase, multi-phase, and amorphous or nano-crystalline. Single-phase HEAs, which often adopt face-centered cubic (FCC), body-centered cubic (BCC), or hexagonal close-packed (HCP) structures, offer a balance between ductility and toughness, as shown in studies by [PERSON] et al. [7] and [PERSON] et al. [8]. Multi-phase HEAs, on the other hand, can exhibit combined FCC and BCC phases, enhancing their strength and hardness due to phase boundary strengthening effects [9]. Amorphous or nano-crystalline HEAs present high corrosion and wear resistance due to their lack of crystalline boundaries, which makes them particularly suitable for coating applications in marine environments [8]. High-entropy alloy (HEA) coatings are gaining attention for their ability to enhance the corrosion resistance and durability of various metals, particularly under harsh conditions. While HEA coatings share the same fundamental composition principles as bulk HEAs, they involve distinct fabrication techniques suited for their thin-film structure [10]. This structural difference not only influences mechanical properties but also alters failure mechanisms compared to bulk HEAs [11; 12]. HEA coatings offer several benefits over bulk HEAs, particularly in reducing costs and improving practicality. Due to the complex composition of HEAs and the challenges of alloying elements with widely varying melting points, bulk HEAs often require extensive post-processing, making them costly to produce [13; 14; 15]. HEA coatings, on the other hand, use less material and can be produced more economically using energy-efficient processes, making them more practical for industrial applications [16].