A method for improving the hydrostatic pressure testing of the compressive strength of solid buoyancy materials used at full ocean depth

The current optimized synthesis methods for solid buoyancy materials used in manned submersibles at full ocean depth fail to meet the safety factor requirement of 1.5 specified in China Classification Society rules. To address this issue, this study proposes a novel method for enhancing the compressive strength and safety margin of such materials using hydrostatic pressure to screen hollow glass microspheres and eliminate those with low compressive strength. The as-prepared solid buoyancy material is free of surface cracks and has a water absorption rate of <0.1% after a 24-h hydrostatic pressure test at 175 MPa, satisfying the required safety performance standards for buoyancy materials used at full ocean depth. This study highlights the feasibility of using hydrostatic pressure testing to enhance the compressive strength and safety of solid buoyancy materials for full-ocean-depth applications, paving the way for the development of more advanced and reliable buoyancy materials for deep-sea exploration.