【Ten Years of Rapid Development in Chemical Engineering Equipment】Project initiation for 1778-2022: Research on long-lasting protective materials for extreme environments in deep-sea applications

The development timeline for this project is 3 years. Among these, within 1 year of the project’s completion period: research will be conducted on two-dimensional layered materials for deep seas, fiber-reinforced, toughened, long-lasting pressure-resistant composite materials and protective coatings; research will also focus on self-healing intelligent protective coatings for deep-sea use as well as underwater anti-corrosion maintenance materials. Additionally, studies will explore the mechanisms of strong coupling damage and accelerated failure in materials designed to function in complex and extreme environments such as those found at seafloor hydrothermal vents, where hydrogen sulfide and microorganisms are present. Evaluation criteria: Salt spray resistance life of deep-sea anti-corrosion coating > 5000 hours, compressive strength ≥ 60 MPa, adhesion ≥ 55 MPa. The self-healing anti-corrosion material has an elongation at break >300% and a tensile strength >15 MPa. Deep-sea sacrificial anode materials maintain a current efficiency of ≥85% in deep-sea environments at depths of 10,000 meters. Two years after the project’s completion: The technology of combining anti-corrosion coatings with sacrificial anodes for deep-sea environments at depths of over 10,000 meters was developed; long-lasting protection coatings and sacrificial anode materials suitable for deep-sea use were created, enabling long-term protection of deep-sea equipment across different depths and sea areas throughout its entire lifespan. Additionally, intelligent monitoring and corrosion early-warning technologies for deep-sea protection materials were developed. Evaluation criteria: The pressure resistance strength of the anti-corrosion coating for deep-sea use should be ≥100 MPa, and its adhesion strength should be ≥65 MPa. The self-healing anti-corrosion material has an elongation at break >300%, a tensile strength >20 MPa, and its self-healing strength reaches 80% within 3 hours. Deep-sea sacrificial anode materials maintain a current efficiency of ≥90% in deep-sea environments at depths of 10,000 meters. 3 years after the project completion: achieve monitoring of microbial corrosion in deep seas, establish a database of microorganisms responsible for corrosion in deep-sea environments, conduct research on in-situ testing and evaluation techniques at depths of 10,000 meters, develop in-situ verification techniques for use in real sea conditions, and create a technical framework for evaluating long-term protective materials used in deep seas as well as assessing their lifespan. Evaluation criterion: Salt spray life of deep-sea anti-corrosion coating > 10,000 hours. 3 to 5 strains of typical deep-sea corrosion microorganisms were isolated. Achieve the deployment and recovery of functional protective materials for depths of 10,000 meters, with sea-based performance evaluation tests at such depths lasting ≥90 days. A pilot-scale production platform for thousand-ton-class high-strength, tough, pressure-resistant, and anti-corrosion materials has been established, enabling 1–2 demonstration applications in deep-sea engineering. Tan Weimin, manager of the Innovation and Digitalization Department at Changzhou Coating Institute, said that the successful implementation of this plan will effectively improve the technical level of protective coating materials for deep-sea equipment and facilities in China, change the current situation of lagging behind in the development of such coatings through independent research, and better meet the needs of various marine activities in China, including deep-sea scientific research and oil and gas field development, thereby contributing to the realization of the strategy to build a strong maritime nation.

According to Tan Weimin, as the **deep-sea energy strategy advances, it has become urgent to accelerate research on deep-sea materials technology and address the issue of corrosion in materials used for deep-sea equipment. In recent years, the Changzhou Coating Research Institute has been continuously researching marine heavy-duty anti-corrosion coating technologies, with a focus on addressing the anti-corrosion challenges encountered in deep-sea oil and gas exploration and development. By leveraging research projects initiated by China National Offshore Oil Corporation, such as those related to the study of typical coating systems for offshore engineering and the development of supporting materials, as well as research on new anti-corrosion coating systems for offshore platforms, the institute has carried out valuable investigations into coating preparation under high-pressure conditions in deep seas and the mechanisms behind coating failure. At the same time, research on the relationship between coating structure and performance in deep-sea environments was conducted in connection with CNOOC’s \"Deep Sea No.1\" project, providing corrosion protection technology support for this vital national asset. In 2022, Changzhou Coating Research Institute set out to address the technical challenges related to the development of long-lasting protective materials for use in deep-sea environments. It jointly submitted an application for the **Key R&D Program “Task Assignment via Public Call” – Deep-Sea Special Project: Long-Lasting Protective Materials for Extreme Environments and Their Engineering Applications** with institutions such as the Ningbo Institute of Materials Technology and Engineering under the Chinese Academy of Sciences, Tianjin University, and the 725th Research Institute of China State Shipbuilding Corporation. (Tu Jie)

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Corrosion protection of materials is very important for ships.