Material selection is crucial for pressure sensor production because the chosen materials can significantly impact the sensor’s performance, durability, and resistance to various environmental factors.

Different materials have varying properties such as corrosion resistance, strength, and stiffness, which makes them suitable for specific operating conditions.

The selection of materials should consider the type of sensing element used in the pressure sensor. For example, some pressure sensors use a strain gauge to measure pressure. In this case, the material used to make the strain gauge must be durable and resist mechanical fatigue, so it doesn’t deform over time from repeated loads. Other pressure sensors may use a piezoelectric or capacitive element to sense pressure, where material properties such as dielectric constant, resistivity, and thermal expansion coefficients become critical.

Today, I’d like to provide insights into choosing the proper and qualified materials for pressure sensor sensing elements, PCB, Filled Fluid, O-Rings, Cable and Wires, Housing and Wetted parts as below.

Material of Sensing element

There are several types of materials commonly used for sensing elements, including:

Silicon:

Silicon is the most common material used for pressure sensor sensing elements. It is used in piezoresistive and capacitive pressure sensors. Silicon has excellent mechanical properties, high sensitivity, and good long-term stability. However, silicon is sensitive to temperature changes, and its performance can degrade under harsh environmental conditions.

Stainless steel:

Stainless steel is a popular material for sensing elements in harsh environments due to its excellent corrosion resistance, durability, and strength. It is commonly used in strain gauge pressure sensors, where the sensing element is bonded to a metal diaphragm.

Ceramic:

Ceramic sensing elements are used in capacitive and thick-film pressure sensors. They offer good chemical resistance, and temperature stability, and are suitable for harsh environments. However, ceramics can be brittle and may not be ideal for high shock or vibration applications.

Metal foil strain gauges:

Metal foil strain gauges are often used in bonded strain gauge pressure sensors. They provide good stability and can withstand high pressures, but their sensitivity is lower than silicon-based sensors.

MaterialProsCons
Silicon- High sensitivity- Sensitive to temperature changes
- Good long-term stability- Not ideal for harsh environments
- Suitable for small pressure ranges
Stainless Steel- Excellent corrosion resistance- Lower sensitivity compared to silicon
- High durability and strength- Heavier and bulkier
- Suitable for high pressure ranges
Ceramic- Good chemical resistance- Brittle and less suitable for high shock
- Temperature stabilityor vibration applications
- Suitable for harsh environments- Lower sensitivity compared to silicon
Metal Foil Strain Gauges- Good stability- Lower sensitivity compared to silicon
- Can withstand high pressures- Less suitable for small pressure ranges

When selecting the material for a pressure sensor sensing element, you need to consider factors such as the pressure range, sensitivity requirements, operating temperature, and environmental conditions (e.g., corrosion, shock, vibration). Each material has its advantages and drawbacks, so the choice will depend on the specific requirements of your application.

Material of pcb

It’s essential to pay attention to the choice of material for the PCB (printed circuit board) when designing a pressure sensor, as it can impact the performance, reliability, and overall quality of the sensor. Here’s a comparison of some common PCB materials:

Ceramic thick film pressure sensor-eastsensor

MaterialProsCons
FR-4 (Standard)- Widely available- Limited thermal performance
- Low cost- Not ideal for high-frequency applications
- Good mechanical and electrical properties
Polyimide- Excellent thermal performance- Higher cost
- Suitable for high-temperature environments- More difficult to process
- Flexible, ideal for flex PCB applications
PTFE (Teflon)- Excellent for high-frequency applications (RF, microwaves)- High cost
- Low dielectric constant and loss tangent- More difficult to process
- Good thermal performance
Rogers (Laminates)- Good thermal performance- Higher cost
- Excellent for high-frequency applications- Limited availability
- Low dielectric constant and loss tangent

When choosing a PCB material, consider factors such as your pressure sensor’s operating temperature, frequency, and mechanical stress requirements.

For example, if your sensor is used in high-temperature environments or requires high-frequency performance, you might choose a material like polyimide or PTFE. However, if cost is a significant concern and the sensor operates within standard temperature ranges, FR-4 may be a suitable option. Always weigh the pros and cons of each material based on the specific requirements of your pressure sensor application.

MaterialThermal Conductivity (W/m·K)Dielectric ConstantLoss TangentTg (Glass Transition Temperature) (°C)Cost (Relative)
FR-4 (Standard)0.8 - 1.54.3 - 4.80.02 - 0.025130 - 170Low
Polyimide0.5 - 0.63.4 - 4.40.002 - 0.02250 - 260Medium
PTFE (Teflon)0.2 - 0.32.1 - 3.00.0009 - 0.0015NAHigh
Rogers0.8 - 1.53.0 - 10.20.0013 - 0.0037280 - 390High

Remember that the specific values can vary depending on the manufacturer and grade of the material. When selecting a PCB material for your pressure sensor, consider factors like thermal conductivity, dielectric constant, loss tangent, and the glass transition temperature (Tg) in addition to the cost. Choose a material that best suits the requirements of your specific application.

Material of filled fluid

Fluid-filled pressure sensors are often used when dealing with high levels of vibration, shock, or when temperature compensation is necessary. They can also provide better long-term stability and help reduce the effects of mechanical stress. Here is a table comparing common fluid materials used in fluid-filled pressure sensors:

Material of pressure sensor-filled fluidEastsensor

Fluid MaterialViscosity (cP)Temperature Range (°C)Compatibility with MaterialsProsCons
Silicone Oil10 - 100-50 to 200Most metals, elastomers, and plasticsWide temperature range, good chemical resistance, low toxicityCan become contaminated or leak
Mineral Oil10 - 100-10 to 150Most metals, elastomers, and plasticsLow cost, good lubrication, wide availabilityLess chemically stable than silicone oil, narrower temperature range
Inert Gases (e.g., Nitrogen)Varies-200 to 200Most metals, elastomers, and plasticsNon-reactive, can handle extreme temperatures, no risk of leaksRequires a sealed system, may cause measurement inaccuracies if pressure changes
Fluorocarbon-based Oils100 - 1000-40 to 280Most metals, some elastomers and plasticsExcellent chemical resistance, wide temperature rangeHigher cost, limited material compatibility
Glycol-based fluids30 - 200-40 to 120Most metals, elastomers, and plasticsGood lubrication, low cost, biodegradableLimited temperature range, can absorb moisture

Material of O-ring

O-rings are used in pressure sensors to create a tight seal between components and prevent the ingress of contaminants, moisture, or other substances that could compromise the sensor’s performance. O-rings are typically required in applications where the sensor is exposed to harsh environments, high pressures, or corrosive media.

Material of pressure sensor-O-Ring-Eastsensor

Here’s a table comparing various O-ring materials, their pros, and cons:

TypeMaterialTemperature RangeHighlight FeaturesSuitable IndustriesLimitations
Nitrile (NBR)Acrylonitrile Butadiene-40°C to +120°CGood chemical and oil resistanceAutomotive, industrial, hydraulicsPoor resistance to ozone and UV light
Silicone (VMQ)Silicone elastomer-60°C to +225°CExcellent temperature resistanceElectronics, aerospace, automotivePoor tensile strength, tear resistance
Fluorocarbon (FKM/Viton)Fluorinated hydrocarbon-20°C to +200°CExcellent chemical and heat resistanceAutomotive, aerospace, chemicalNot suitable for low temperatures
Ethylene Propylene (EPDM)Ethylene Propylene diene monomer-55°C to +150°CExcellent ozone, UV, and weather resistanceAutomotive, water systems, HVACPoor resistance to oils and fuels
Neoprene (CR)Polychloroprene-40°C to +120°CGood resistance to ozone, UV, and weatherRefrigeration, automotive, marineModerate chemical and temperature resistance
Polyurethane (AU/EU)Urethane elastomer-30°C to +100°CExcellent abrasion and tear resistanceHydraulic systems, automotivePoor resistance to high temperatures
Perfluoroelastomer (FFKM)Fully fluorinated elastomer-20°C to +330°CExceptional chemical and heat resistanceSemiconductor, chemical, aerospaceHigh cost, limited low-temperature performance
Hydrogenated Nitrile (HNBR)Hydrogenated Acrylonitrile Butadiene-40°C to +150°CImproved ozone, UV, and chemical resistance compared to NBRAutomotive, oil and gas, industrialLimited resistance to polar solvents, strong acids

Material of Cable and Wires

First, let’s clarify the difference between wires and cables in the context of pressure sensors:

  • Wires: A wire is a single, flexible, cylindrical conductor that transmits electricity. It is typically made of a metal core (usually copper or aluminum) and an insulating material to cover and protect the core.
  • Cables: A cable consists of multiple wires or conductors bundled together, usually with an insulating or protective outer layer. Cables can transmit electrical signals or power, and their construction allows for more complex connections and greater durability in various environments.

Click for more details about the pressure sensor cable

Material of pressure sensor-Cable -wires-Eastsensor

Now, let’s look at the materials used for wires and cables:

TypeMaterialProsConsLimitationsCommon ApplicationsModel Types/Examples
WireCopperHigh electrical conductivity (5.96×10^7 S/m), good flexibility, solderableHeavier, less resistant to corrosion than aluminumSusceptible to corrosion in certain environmentsPower transmission, data transmission, electronicsAWG, THHN, THWN
WireAluminumLightweight, good electrical conductivity (3.77×10^7 S/m), cost-effectiveLess flexible, less solderable, prone to oxidationOxidation, less flexible, difficult to solderPower transmission, overhead lines, automotiveAA, AAAC, ACSR
Insulation (Wire/Cable)PVC (Polyvinyl Chloride)Economical, flexible, flame retardant, good insulating propertiesNot ideal for high temperatures or extreme environmentsLimited temperature range (-40°C to 105°C), not suitable for harsh environmentsGeneral-purpose wiring, automotive, building wiringUL 1015, UL 1007
Insulation (Wire/Cable)PTFE (Teflon)Excellent chemical resistance, wide temperature range (-196°C to 260°C), flame retardantHigher cost, stiffer than PVCHigher cost, stiffer than other insulation materialsHarsh environments, aerospace, chemical processingMIL-W-16878, Type E
Insulation (Wire/Cable)SiliconeGood temperature range (-60°C to 180°C), flame retardant, flexibleLower mechanical strength, more expensive than PVCLower mechanical strength, higher costHigh-temperature applications, medical equipmentUL 3239, UL 3302
Insulation (Wire/Cable)PE (Polyethylene)Lightweight, good dielectric properties, resistant to moistureLower temperature range (-65°C to 80°C), less flexible than PVCLimited temperature range, less flexible than PVCTelecommunications, low voltage applicationsPE-89, PE-39
Insulation (Wire/Cable)FEP (Fluorinated Ethylene Propylene)Excellent chemical resistance, wide temperature range (-200°C to 205°C), flame retardantHigher cost, stiffer than PVCHigher cost, stiffer than other insulation materialsHarsh environments, aerospace, chemical processingUL 1330, UL 1659

Material of Housing & Wires when Package

For good checking, please find below table comparing different materials used for wire, housing, and pressure sensor packaging

ComponentMaterialProsConsLimitationsSuitable IndustriesExamples
WireCopperHigh electrical conductivity (5.96×10^7 S/m), good flexibility, solderableHeavier, less resistant to corrosion than aluminumSusceptible to corrosion in certain environmentsPower transmission, data transmission, electronicsAWG, THHN, THWN
WireAluminumLightweight, good electrical conductivity (3.77×10^7 S/m), cost-effectiveLess flexible, less solderable, prone to oxidationOxidation, less flexible, difficult to solderPower transmission, overhead lines, automotiveAA, AAAC, ACSR
HousingStainless SteelCorrosion-resistant, high strength, durable, good temperature resistanceHeavier, more expensive than plasticHeavier, more expensive than other materialsOil and gas, food and beverage, marine, chemicalSS 316, SS 304
HousingAluminumLightweight, corrosion-resistant, cost-effectiveLower strength than stainless steel, prone to oxidationProne to oxidation, lower strength than stainless steelAutomotive, aerospace, electronics, general-purpose6061, 7075
HousingPlasticLightweight, cost-effective, good chemical resistanceLower strength and temperature resistance than metalsLower strength, limited temperature resistanceConsumer electronics, automotive, general-purposeABS, Polycarbonate
Pressure Sensor PackagingCeramicGood chemical resistance, stable at high temperatures, electrical insulationBrittle, more expensive than some metalsBrittle, more expensive than some metalsOil and gas, automotive, aerospace, chemicalAlumina, Zirconia
Pressure Sensor PackagingStainless SteelCorrosion-resistant, high strength, durable, good temperature resistanceHeavier, more expensive than plasticHeavier, more expensive than other materialsOil and gas, food and beverage, marine, chemicalSS 316, SS 304
Pressure Sensor PackagingPlasticLightweight, cost-effective, good chemical resistanceLower strength and temperature resistance than metalsLower strength, limited temperature resistanceConsumer electronics, automotive, general-purposeABS, Polycarbonate

Material of Wetted Parts

Wetted parts are the components of a pressure sensor that come into direct contact with the process media (liquid, gas, or vapor). Choosing the right material for wetted parts is crucial for ensuring the sensor’s accuracy, reliability, and longevity.

Here are some common materials for wetted parts and factors to consider when selecting them:

Stainless Steel (e.g., SS 316, SS 316L, SS 304)

  • Pros: Corrosion-resistant, durable, good strength, good temperature resistance
  • Cons: Heavier and more expensive than some other materials
  • Suitable for: Oil and gas, food and beverage, marine, chemical industries

Hastelloy (e.g., Hastelloy C276)

  • Pros: Excellent corrosion resistance, especially to acidic and chloride environments, good strength, high temperature resistance
  • Cons: More expensive than stainless steel
  • Suitable for: Chemical, petrochemical, oil and gas, wastewater treatment industries

Monel (e.g., Monel 400)

  • Pros: Good corrosion resistance, especially to reducing media, good strength, high temperature resistance
  • Cons: More expensive than stainless steel, less resistant to oxidizing environments than Hastelloy
  • Suitable for: Marine, chemical, petrochemical, oil and gas industries

Tantalum

  • Pros: Outstanding corrosion resistance, high temperature resistance, biocompatible
  • Cons: Expensive, limited availability
  • Suitable for: Chemical, pharmaceutical, medical industries

Ceramic (e.g., Alumina, Zirconia)

  • Pros: Good chemical resistance, stable at high temperatures, electrical insulation
  • Cons: Brittle, more expensive than some metals
  • Suitable for: Oil and gas, automotive, aerospace, chemical industries

PTFE (Polytetrafluoroethylene)

  • Pros: Excellent chemical resistance, non-stick properties, good electrical insulation
  • Cons: Limited temperature and pressure range, lower mechanical strength compared to metals
  • Suitable for: Food and beverage, chemical, pharmaceutical industries

When choosing a material for wetted parts, consider the following factors:

  • Chemical compatibility: Ensure the material is resistant to the process media.
  • Temperature range: Choose a material that can withstand the expected temperature range of the application.
  • Pressure range: Select a material with adequate strength to withstand the pressure range.
  • Cost: Balance the material cost with the desired performance and reliability.
  • Regulatory requirements: Comply with industry-specific regulations (e.g., FDA, NSF) if necessary.
MaterialProsConsSuitable IndustriesLimitations
Stainless Steel (e.g., SS 316, SS 316L, SS 304)Corrosion-resistant, durable, good strength, good temperature resistanceHeavier and more expensive than some other materialsOil and gas, food and beverage, marine, chemical industriesCost, weight
Hastelloy (e.g., Hastelloy C276)Excellent corrosion resistance, especially to acidic and chloride environments, good strength, high temperature resistanceMore expensive than stainless steelChemical, petrochemical, oil and gas, wastewater treatment industriesCost
Monel (e.g., Monel 400)Good corrosion resistance, especially to reducing media, good strength, high temperature resistanceMore expensive than stainless steel, less resistant to oxidizing environments than HastelloyMarine, chemical, petrochemical, oil and gas industriesCost, oxidation resistance
TantalumOutstanding corrosion resistance, high temperature resistance, biocompatibleExpensive, limited availabilityChemical, pharmaceutical, medical industriesCost, availability
Ceramic (e.g., Alumina, Zirconia)Good chemical resistance, stable at high temperatures, electrical insulationBrittle, more expensive than some metalsOil and gas, automotive, aerospace, chemical industriesBrittleness, cost
PTFE (Polytetrafluoroethylene)Excellent chemical resistance, non-stick properties, good electrical insulationLimited temperature and pressure range, lower mechanical strength compared to metalsFood and beverage, chemical, pharmaceutical industriesTemperature and pressure range, mechanical strength

Material of pressure sensor-Eastsensor

Summary

In conclusion, the selection of materials for pressure sensors is highly dependent on the specific application, industry, and environmental conditions. Understanding each material’s properties, advantages, and limitations is essential to ensure the pressure sensor performs optimally and maintains a long service life.

Different pressure sensor applications require materials with different properties. For instance, sensors used in environments with high humidity, saltwater corrosion, or exposure to harsh chemicals require materials that can withstand chemical attack and resist degradation.

Therefore, material selection for pressure sensor production is vital to ensure that the sensor can meet its intended use for an extended period, offer high measurement accuracy, good repeatability, and reliability. The wrong material selection can lead to sensor failure, lower accuracy, reduced lifespan, and even safety risks due to chemical corrosion, deformation of the measurement component, or even material fatigue.