Our country has completed the corrosion test of deep-sea materials at a depth of 10,000 meters.
Recently, China completed the world's first 537-day continuous deep-sea material corrosion test at a depth of 10,000 meters. This test was led by the 725 Institute of China State Shipbuilding Corporation and the actual operation water depth was approximately 11,000 meters. It set a world record for the longest duration of such tests of the same kind. The in-situ deep-sea test technology has achieved a key leap from "full coverage of depth" to "full coverage of cycle".
This experiment was conducted in the 10,000-meter deep-sea area, where the environment was extremely harsh. The static water pressure exceeded 110 MPa, equivalent to the weight of 2,000 African elephants on a 1-square-meter area. It also faced low temperatures, high salinity, and extremely low oxygen levels. It was called the "limiting survival" challenge in the field of deep-sea engineering. To this, the research team overcame three major world-class technical difficulties: First, they broke through the technology of high-precision positioning at the 10,000-meter level and the deployment and recovery in complex sea conditions, achieving accurate deployment, reliable stay, and complete recovery of the device in the deep-sea environment; Second, they constructed a long-lasting composite seal and ultra-low power consumption power supply management system to realize continuous in-situ monitoring of corrosion electrochemical parameters for 537 days in the extreme 10,000-meter environment; Third, they constructed a corrosion protection technology system composed of high-pressure-resistant and anti-permeation coatings and deep-sea-specific sacrificial anodes, solving the problem of long-term safe operation and protection of deep-sea equipment.
The success of this long-term test is not only a breakthrough in a single technical record, but also marks that China is shifting from being a "participant in the rules" to a "standard setter" in this field. "Liao Zhicai, deputy director of the 725 Research Institute of China State Shipbuilding Corporation and the executive director of the National Key Laboratory for Marine Corrosion and Protection, said, "The 537-day in-situ measured data obtained from this test can not only provide a direct basis for the material performance evolution of deep-sea equipment without calculation, but also optimize the corrosion margin design of deep-sea equipment and get rid of the predicament of excessive thickness and potential thinness. Moreover, it can also provide core boundary conditions for the improvement of protection processes and full life cycle life prediction of long-term equipment such as underwater scientific observation, deep-sea oil and gas production, and deep-sea resource exploitation."
Liao Zhicai proposed: "We have developed five or six types of coatings this time, laying the foundation for the research and development of coating systems at various depths in the future. When conducting corrosion protection for deep-sea oil extraction and deep-sea mining equipment, the corresponding coating systems can be selected."
Sun Mingxian, the deputy chief engineer and researcher of the 725 Research Institute of China Shipbuilding Industry Corporation, introduced: "Our institute has independently developed a deep-sea simulation test device with a depth of over 10,000 meters. It achieves the 10,000-meter pressure through a pressure vessel, and controls parameters such as salinity and pH value through the control system to simulate the actual seawater conditions in the deep sea. This indoor simulation test device has already been put into use and will meet the increasing test demands."
It is reported that currently, research institutions such as the Ningbo Institute of Materials Technology, Northeastern University, Beijing University of Science and Technology, and Tianjin University are all using this device to evaluate test data, screen and develop new products such as protective materials suitable for deep-sea environments. (Chen Hongyi)
