Ring-Core Fluxgate Sensor for High Operation Temperatures up to 220 °C

Area of Science:

• Geophysics
• Sensor Technology
• Materials Science

Background:

• Fluxgate sensors are essential for geophysical magnetic field surveys.
• High-temperature stability is a critical requirement for sensors in applications like deep drilling.
• Existing sensors often face limitations in prolonged high-temperature operation.

Purpose of the Study:

• To develop and characterize a fluxgate sensor capable of stable operation at temperatures up to 220°C.
• To investigate the high-temperature performance and magnetic characteristics of a novel sensor design.
• To understand the influence of temperature on sensor output and magnetic properties.

Main Methods:

• Design and fabrication of an accordant ring-core type fluxgate sensor.
• Utilized an Fe-based nanocrystalline magnetic core, PEEK structural components, and epoxy resin wrapping.
• Employed a broadband short-circuited working mode for enhanced stability.
• Characterized sensor performance by evaluating impedance, hysteresis, permeability, and sensitivity at temperatures up to 220°C.

Main Results:

• The developed fluxgate sensor demonstrated stability up to 220°C.
• Achieved a sensitivity of approximately 24 kV/T at 25°C.
• Exhibited an acceptable temperature coefficient of 742 ppm/°C across the tested temperature range.
• Detailed analysis of magnetic characteristic variations and their impact on sensor output.

Conclusions:

• The novel fluxgate sensor design offers high-temperature stability suitable for demanding geophysical applications.
• The material selection and working mode are key to achieving thermal consistency.
• The sensor's performance characteristics provide valuable data for high-temperature magnetic field surveying.