Protection Sheath Material Ceramics

Materials specification for temperature sensor protection sheaths

Our temperature sensors are specifically designed for many different types of harsh and reducing atmosheres and therefore we supply protection sheaths suitable for each application. Here is a list of datasheets for the materials that we supply and use. This list is available as a PDF. Click on the material names for more information.

Recrystalised Alumina (Alsint)
A pure and tough ceramic exhibiting hardness and vacuum tightness. Excellent in oxidising and reducing atmospheres. Fair thermal shock resistance. Used with R, S and B thermocouples.

Basic Composition	Al 2O 3 99.7%
Temperature Limits	1750 ° C
International Standards	DIN VDE 0335 C799
Density	3.9 g/cm³
Melting Range	2072
Specific Heat
Coefficient of Expansion	8 x10^-6 / ° C
Thermal Conductivity	26 W/m ° C
Peak Sensors Colour Code

Aluminous Porcelain (Pythagoras)
Good thermal shock resistance. Used with J, K, N and E conductors.

Basic Composition	Al 2O 3 60%
Temperature Limits	1500 ° C
International Standards	DIN VDE 0335 C610
Density	2.6 g/cm³
Melting Range
Specific Heat
Coefficient of Expansion	6 x10^-6 / ° C
Thermal Conductivity	2 W/m ° C
Peak Sensors Colour Code

Sillimanite 60
Very good thermal shock resistance. Porous.

Basic Composition	Al 2O 3 73 to 75%
Temperature Limits	1600 ° C
International Standards	DIN VDE 0335 C530
Density	2.35 g/cm³
Melting Range
Specific Heat
Coefficient of Expansion	5.7 x10^-6 / ° C
Thermal Conductivity	1.4 W/m ° C
Peak Sensors Colour Code

Silicon Carbide (Clay Bonded)
Excellent thermal shock resistance. Tends to have a thick wall to improve strength. A porous material that usually has a lining refractory for platinum sensors. High thermal conductivity. Not suitable for highly oxidising atmospheres.

Basic Composition	SiC 70 – 90 %
Temperature Limits	1400 ° C
International Standards
Density	2.4 g/cm³
Melting Range
Specific Heat
Coefficient of Expansion	5.0 x10^-6 / ° C
Thermal Conductivity	28.0 W/m ° C
Peak Sensors Colour Code

Silicon Carbide (Recrystalised)
Excellent thermal shock resistance. A porous material that usually has a lining refractory for Platinum sensors. High thermal conductivity.

Basic Composition	SiC 99%
Temperature Limits	1600 ° C in oxidising atmosphere, 2000 ° C in protected atmosphere
International Standards
Density	2.6 to 2.7 g/cm³
Melting Range
Specific Heat
Coefficient of Expansion	4.5 x10^-6 / ° C
Thermal Conductivity	30.0 W/m ° C
Peak Sensors Colour Code

Syalon 101
A strong and thermal shock resisting material for use in molten metals with little wetting or dross build up. Good in molten aluminium or salt baths. Fairly expensive.

Basic Composition	Silicon Nitride, Aluminium Oxide
Temperature Limits	1000 ° C (1250 ° C in controlled conditions)
International Standards
Density	3.26 g/cm³
Melting Range
Specific Heat
Coefficient of Expansion	3.2 x10^-6 / ° C
Thermal Conductivity	16.7 W/m ° C
Peak Sensors Colour Code

Quartz
Low coefficient of expansion, High thermal shock resistance.

Basic Composition	SiO 2
Temperature Limits	1500 ° C (Then flows under own weight)
International Standards
Density	2.2 g/cm³
Melting Range	1683 ° C
Specific Heat	670 J/Kg ° C
Coefficient of Expansion	5.5 x10^-7 / ° C
Thermal Conductivity	1.4 W/m ° C
Peak Sensors Colour Code

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Mild Steel	4C54, Ferritic, 446 SS	Platinum Grain Stabilised
321 SS	Sanicro 31 HT®	Hastelloy C276
310 SS	Alloy 600 (Inconel®)	Kanthal AF, Kanthal APM
316 SS	Alloy 800 HT (Incoloy®)	Recrystalised Alumina (Alsint)
353 MA®	Platinum 10% Rhodium	Aluminous Porcelain (Pythagoras)
253 MA®	Kanthal Super	Silicon Carbide (Clay Bonded)
Pyrosil	Sillimanite 60	Silicon Carbide (Recrystalised)
Platinum	Quartz	Monel 400
Cast Iron	Brass	Hastelloy B2
Syalon 101	Platinum 10% Rhodium Grain Stabilised

Protection Sheath Material Datasheets

Materials specification for temperature sensor protection sheaths