镀锌板无铬钝化技术的研究进展OA

Due to their excellent corrosion resistance,galvanized steel sheets are widely utilized across various industrial sectors,including construction,automotive manufacturing,home appliances,and electrical power.This protective performance can be further enhanced through passivation treatments.However,although traditional chromate passivation offers remarkable corrosion protection due to its self-repairing capability and high chemical stability,it poses significant risks to both human health and the environment,as hexavalent chromium is classified as a highly toxic and carcinogenic substance.Consequently,the development of efficient and environmentally friendly chromium-free passivation technologies as alternatives to chromate has become a prominent and urgent research challenge in the field of surface engineering and materials protection.The work aims to review the recent research progress in chromium-free passivation technologies for galvanized steel sheets,systematically categorizing existing systems into three main types of inorganic passivation,organic passivation,and organic/inorganic composite passivation.The film formation mechanisms and anticorrosion properties of inorganic systems such as molybdates,rare earth salts(e.g.,cerium and lanthanum salts),titanium salts,and silicates,as well as organic systems including silanes,tannic acid,and acrylic resins,are examined in detail,highlighting their respective advantages and intrinsic limitations. Current researches indicate that individual passivation systems whether purely inorganic or purely organic still exhibit limitations in terms of corrosion resistance,film compactness,adhesion,and self-healing capability.For instance,while molybdate-based inorganic films may provide good barrier properties,they often suffer from micro-defects,limited thickness uniformity,and lack long-term stability under aggressive environmental conditions.Rare earth salt passivation films can inhibit cathodic reactions but are prone to cracking upon drying.Organic films,such as those based on silanes or tannic acid,on the other hand,can offer flexibility,excellent adhesion to the metal substrate,and compatibility with subsequent coatings,but they may not achieve the same level of robust and enduring protection as chromate treatments,particularly in terms of barrier performance against corrosive media like chloride ions.These shortcomings highlight the pressing need for more advanced strategies to meet the stringent durability and safety requirements of modern industrial applications. In this context,organic/inorganic composite passivation technology has emerged as a highly promising and intensively investigated approach.By leveraging synergistic effects at the molecular or nanoscale level,these composite systems effectively combine the superior barrier function and mechanical hardness of inorganic phases with the interfacial bonding strength,film-forming ability,and functional tunability of organic components.This integration significantly enhances the integrity,density,and overall protective performance of the passivation film,effectively sealing micro-pores and reducing the penetration pathways for corrosive agents.Furthermore,the composite films often exhibit improved compactness,strong chemical adhesion to the galvanized steel substrate,and in some cases,self-healing properties through the incorporation of corrosion inhibitors,thereby offering a viable and sustainable pathway toward replacing conventional chromate-based treatments.Finally,the key challenges currently facing the field of chromium-free passivation for galvanized steel are critically discussed,and future research directions are proposed,emphasizing the need for a deeper understanding of interface chemistry and synergistic mechanisms,the development of novel multifunctional composite formulations with enhanced self-healing capabilities,and the translation of these technologies into scalable,cost-effective,and eco-friendly manufacturing processes suitable for industrial implementation.