Measurement of high temperatures, higher than 1000 C, using ceramic based thermocouples is actually a well known process. In order to do this successfully the resistance wires throughout the thermocouple need to be insulated and protected.
The use of Ceramic materials to safeguard the platinum based wire is a method that has been used for many years, as a result of exceptional heat resistant properties of the materials. The thermocouple is easily the most popular heat measurement implement and it is useful for measuring the temperature inside of a furnace, typically getting used to the melting or heat therapy for metal or indeed for manufacturing ceramic products.
The ceramic components in the typical thermocouple device would be the outer protection tube that may be subjected to the furnace. Occasionally multiple tubes are employed inside the other person to supply the amount of insulation and protection required.
Ceramic insulators (Tubes with 2 or maybe more core holes through them) can also be employed to isolate the several wires that go to the bi-metallic joint with the head which is the point from where sens0rs temperature is measured.
The typical materials used for that tube is a 99.7% alumina material, impervious tube, which happens to be attached typically to your metal thermacouple head, containing a terminal block that is utilized in order to connect to some standard wire towards the instrumentation. In a less demanding heat atmosphere a mullite tube may be used as a cheaper alternative, which can work sufficiently around 1600 ‘oc. The mullite tube can also be an impervious tube and contains 60% alumina content.