In the early hours of today, China's manned submersible "Fendouzhe" (Striver) successfully completed its 100th dive to depths exceeding 10,000 meters in the Challenger Deep of the Mariana Trench, setting a new record for the longest continuous underwater operation time in a single dive (14 hours and 20 minutes). The core guarantee for this historic breakthrough was the first comprehensive installation of "Ultra-High Pressure Resistant Fluorosilicone-Graphene Composite Seals" on its critical hydraulic systems and viewports. Jointly developed by CSSC No. 725 Research Institute and Tsinghua University, these seals achieved zero leakage and zero creep under extreme static pressure of 115 MPa (approximately 1150 atmospheres) and deep-sea low temperatures, marking that China's core basic materials for deep-sea equipment have completely eliminated dependence on imported products. According to the project's technical lead, the 10,000-meter deep-sea environment features extreme conditions of "high pressure, low temperature, and strong corrosion." Traditional rubber seals are prone to failure due to the "extrusion effect" under long-term high pressure, while ordinary fluoroelastomers tend to harden and lose elasticity at low temperatures. The R&D team innovatively constructed a microstructure of a "3D Graphene Skeleton Reinforced Fluorosilicone Matrix": utilizing the high modulus characteristics of graphene sheets to build a physical barrier against high-pressure medium penetration, while retaining the excellent flexibility of the phenyl-fluorosilicone rubber backbone across a wide temperature range of -60°C to 200°C. Laboratory simulation data showed that after soaking under 120 MPa pressure for 3,000 hours, the composite material exhibited a volume compression rate of only 0.8% and maintained a rebound rate of over 98%, far surpassing the performance of top-tier international counterparts. The chief designer of "Fendouzhe" stated in a video link: "The successful application of this seal has solved the 'stranglehold' problem restricting the long-term residence of China's deep-sea equipment, allowing the submersible to dare to 'set up camp' on the seabed for refined scientific exploration." It is reported that this technological achievement has been included in the promotion catalog of the National "14th Five-Year Plan" Major Special Project for Deep-Sea Science and Technology. In the future, it will be widely applied in key fields such as deep-sea oil and gas extraction equipment, underwater data centers, and transoceanic communication cable joints, aiding China's construction of a maritime power as it moves into the deep blue.
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