Advances in Solid-State Boriding of AISI 304, 316, and 316L Stainless Steels: Progress and Challenges

Boriding, or boronizing, is a thermochemical surface treatment that enhances the hardness, wear resistance, and corrosion properties of austenitic stainless steels such as AISI 304, 316, and 316L, which are widely used in biomedical, nuclear, and chemical applications despite their inherent limitations in tribological performance. This review synthesizes over 60 peer-reviewed articles to examine recent advances in solid-state boriding technologies, specifically powder-pack and paste boriding methods, highlighting their mechanisms, process parameters, and impacts on tribological integrity, mechanical properties, and corrosion mitigation. Key classifications of boriding operations are discussed, including physical and chemical processes, with emphasis on overcoming diffusion barriers posed by high Cr and Ni content in these steels. The review details the compositions of boriding agents, schematic configurations for practical implementation, and comparative advantages of paste boriding over powder-pack methods, such as selective application and energy efficiency. Challenges, including oxidation risks, inconsistent layer formation, and process optimization, are critically analyzed alongside progress in achieving boride layers (FeB and Fe2B) with superior hardness exceeding 2000 HV. The findings underscore boriding's potential to extend component service life in demanding environments, while identifying gaps for future research to enhance industrial scalability and environmental sustainability.