Tantaline® Treated Thermowells



Thermowells protect sensitive temperature measuring probes from corrosive fluids and conditions handled by special equipment found in many industries. Tantalum is recognized as the most corrosion resistant metal commercially available. Tantalum can be applied by the proprietary Tantaline ® treatment process to produce a robust and cost effective option for threaded, flanged, Van Stone and sanitary thermowells. Tantaline® treatment provides superior corrosion resistance in hot acids and chlorinated compounds. This has been shown to extend equipment service life and reduce maintenance costs in Chemical, Pharmaceutical, Oil & Gas, Semiconductor, and Mining industries.


The Chemical Vapor Deposition (CVD) process used by Tantaline® produces a thin, uniform, tantalum layer that conforms to complex geometries and adheres to the base metal part through diffusion bonding. The typical 50 micron thick layer is thermally conductive which minimizes sensor error while maintaining excellent chemically compatibility in wide range of corrosive fluids. The robust, metallurgically bonded layer can withstand high pressure and erosion corrosion conditions found in pipelines, vessels, and process equipment.

These features result in enhanced thermowells that can be offered as a substitute for ones made from exotic alloys with more economical pricing and shorter lead-times.


Types of thermowells suitable for Tantaline® treatment:

Connection Type:
  • Thread
  • Flanged
  • Van Stone
  • Sanitary


Shank Type:
  • Straight
  • Tapered
  • Stepped


Chemical Processing Hot acids, wet and dry chlorine, sulfur compounds, sour gases containing H2S compounds Piping systems, tanks, distillation columns, cracking units, incinerators and waste treatment systems
Oil & Gas Acid gases (CO2, H2S, SO2) in vapor phase, ammonia (NH3), hydrogen cyanide (HCN), and amine derivatives Pipelines, storage vessels, compression systems, emission control, exploration/extraction, hydrocarbon cracking and treating units
Pharmaceutical Oxidizing agents (hydrogen peroxide, bromine, chlorine) Fermentation tanks, sterilization units and separators
Semiconductor Strong HCl etchants, corrosive Nital (alcohol + nitric acid), byproducts of Silicon deposition process Wafer processing units, deposition systems, cleaning and waste treatment systems
Mining Strong acid leaching (HPAL), partial oxidation (POX), extraction Mineral extraction units

Key Technical Information

Stainless Steel, Hastelloy®*, Inconel®**, Zirconium, and Titanium thermowells are susceptible to Stress Corrosion Cracking (SCC) and pitting under certain conditions especially hot acids. Tantaline® treated thermowells offers the following beneficial characteristics:

  • Integrity is verified through manufacturing QC testing in concentrated HCl at 60⁰ C for 48 hours
  • Chemically resistant to SCC and pitting in many aggressive media and environments.
  • Tantalum layer remains passivated and inert to corrosion under high temperature (>200° C) acidic conditions including concentrated HCl and H2SO4.***
  • Superior corrosion resistance against wet, dry chlorine atmospheres and other chlorinated environments.
Tantalum HCl Corrosion Resistance
*Hastelloy® is a registered trademark of Haynes International
**Inconel® is a trademark of Special Metals Wiggin Limited
***FJ, H. (n.d.). Properties of Tantalum for Applications in the Chemical Process Industry