In the pursuit of greener and more efficient technologies, a team of researchers from the China Academy of Machinery Wuhan Research Institute of Materials Protection Co., Ltd., and the Haixi (Fujian) Institute has made significant strides in understanding the alkaline nickel-free normal temperature sealing process. Their study, published in *Cailiao Baohu* (which translates to *Materials Protection*), sheds light on the critical factors influencing the performance of this environmentally friendly sealing technology, with profound implications for the energy sector.
The research, led by TAO Ming and colleagues, systematically investigated various parameters affecting the sealing quality of alkaline nickel-free processes. These parameters included pH, temperature, time, surfactants, fluoride ions, and process management variables such as aging temperature, aging time, and aluminum ion impurities. The findings revealed that pH and temperature are the most influential factors. “When the pH value fell below 8 or the temperature dropped below 25 ℃, the sealing quality deteriorated rapidly,” noted TAO Ming, emphasizing the precision required in maintaining optimal conditions.
The study employed an online rapid dye spot test to evaluate sealing quality, further verified through a phosphochromic acid weight loss test following nitric acid pre-immersion. The results highlighted the critical role of precise process control. For instance, when the ambient temperature was below 15 ℃, the sealing film aging process was incomplete, leading to a weight loss of the sealed pores exceeding 60 mg/dm² after 24 hours of aging. This underscores the need for stringent environmental controls in the production process.
The optimal sealing process control parameters were determined to be a fluoride ion concentration of 0.4～0.6 g/L, a pH value of 8.2～8.6, a sealing temperature of 32～35 ℃, and a sealing time of 1.2～1.3 min/μm. These findings are crucial for industries aiming to adopt nickel-free sealing technologies, as they provide a clear roadmap for achieving high-quality sealing performance.
The commercial impacts of this research are substantial, particularly for the energy sector. As the demand for energy-efficient and environmentally friendly technologies grows, the development of nickel-free sealing processes becomes increasingly important. “Special attention should be paid to the introduction of aluminum ions into the oxidation tank during production management, resulting in turbidity of the bath solution and the formation of sealing ash on the sealed surface,” warned LIU Xiaohui, one of the co-authors. This insight is vital for manufacturers looking to avoid costly production issues and maintain high-quality standards.
The research not only advances our understanding of the alkaline nickel-free sealing process but also paves the way for future developments in the field. By providing a comprehensive analysis of the influencing factors, this study offers a foundation for further innovation and optimization. As the energy sector continues to evolve, the adoption of such technologies will be crucial in meeting sustainability goals and enhancing operational efficiency.
In summary, the study by TAO Ming and colleagues represents a significant step forward in the development of energy-efficient and environmentally friendly sealing technologies. Their findings, published in *Cailiao Baohu*, offer valuable insights for manufacturers and researchers alike, shaping the future of the energy sector and beyond.