Design, Preparation, and Experiment of the Titanium Alloy Thin Film Pressure Sensor for Ocean Depth Measurements

In response to the poor adaptability of several water depth pressure sensors to the marine environment, a seawater depth pressure sensor using a titanium alloy thin film as a sensing element has been proposed. Sensors with two measuring ranges have been designed based on factors such as sensitivity, nonlinearity, and the impact of seawater corrosion. The results indicate the maximum stress on the sensor occurs at the edge of the diaphragm. In addition, the chamfer at the edge of the diaphragm increases from R0.2 to R1.2, and the maximum tensile and compressive strains decrease accordingly. After adding convex islands to the sensors, both nonlinearities and sensitivities decrease. By increasing the diameter and thickness of the elastic element's diaphragm, the effect of seawater corrosion on nonlinearity and sensitivity can be reduced. Sensors with two full-scale ranges were prepared and withstood 30 days of seawater corrosion experiments. The results indicate that the actual sensitivities and nonlinearities of sensors in two measurement ranges are close to the theoretical values. After the experiment, the sensitivity of the sensors with two measuring ranges remained unchanged. This study provides an important basis for the design of titanium alloy thin film pressure sensors and marine environmental adaptability analysis.