Choosing between a ceramic and a sputtering thin film pressure sensor usually depends on whether you prioritise cost and chemical resistance (Ceramic) or precision and long-term stability (Sputtering Thin Film).
While both measure pressure by detecting the deformation of a diaphragm, they differ significantly in construction, performance, and durability.
Comparison Overview
| Feature | Ceramic Pressure Sensor | Sputtering Thin Film Sensor |
|---|---|---|
| Manufacturing | Printed thick-film resistors on a ceramic base. | Metal resistors deposited via vacuum ion sputtering. |
| Bonding | Chemical/Glass frit bond (less stable). | Atomic-level bond (virtually permanent). |
| Accuracy | Good (\pm 0.5\% to 1.0\% FS). | Excellent (\pm 0.1\% to 0.25\% FS). |
| Durability | High chemical & corrosion resistance. | High resistance to vibration & shock. |
| Sealing | Requires O-rings (potential leak point). | All-welded (no O-rings, no leaks). |
| Cost | Generally lower / economical. | Higher due to the complex vacuum process. |
1. Ceramic Pressure Sensors
Most ceramic sensors use thick-film technology. Conductive and resistive pastes are silk-screened onto a ceramic diaphragm (usually Alumina, Al_2O_3) and then fired at high temperatures.
- How it Works: Pressure deforms the ceramic diaphragm, changing the resistance of the printed Wheatstone bridge.
- Best For: Harsh chemical environments. Because ceramic is nearly inert, it can handle aggressive fluids (acids, brackish water) that would corrode stainless steel.
- The “O-Ring” Weakness: Ceramic cannot be welded to metal. Therefore, these sensors must use an elastomer O-ring to seal the sensor to the housing. Over time, these seals can age, leak, or be attacked by chemicals.
2. Sputtering Thin Film Sensors
These sensors represent a “high-tech” approach. Instead of printing a paste, individual atoms of metal are “sputtered” onto a stainless steel diaphragm in a vacuum chamber.
- How it Works: This creates an atomic bond between the sensing film and the diaphragm. There are no glues or organic materials that can “creep” or degrade over time.
- Best For: High-performance industrial and automotive applications. They are famous for long-term stability; if you calibrate it today, it will likely still be accurate years later.
- Extreme Robustness: Because the diaphragm is typically stainless steel and can be laser-welded to the sensor body, there are no O-rings. This makes them “leak-proof” and highly resistant to intense vibration or pressure spikes.
Which one should you choose?
- Choose Ceramic if: You are on a budget, or you are measuring “dirty” or highly corrosive liquids that would eat through stainless steel.
- Choose Sputtering Thin Film if: You need “set and forget” reliability, high accuracy, or if the sensor will be subjected to heavy vibration (like on an engine block) or frequent pressure shocks (hydraulic systems).
