STEP 1. SCS’s luminescent sensor can be applied in two different ways:
- Thermal History Paint (THP) The sensor powder is mixed with a water-based binder and simply applied through air spraying. The application cost and time are lower.This technology is demonstrated up to 1,000 °C.
- Thermal History Coating (THC) The sensor powder is applied through industrial atmospheric plasma spray (APS) so that it can withstand longer exposure times (up to at least 4,500 h) The temperature range currently extends up to 1,400 °C. See the full range of THP and THC embodiments offered by SCS here
An exceptional material that records temperature
What we make here is what we call a ‘smart material’. We can know after it gets hot, even if it is not hot anymore, how hot it was in the past.
The component is installed and operated at high temperatures, for example in an engine test. The sensor will undergo a physical transformation from amorphous to crystalline which depends on the maximum temperature of operation. The degree of crystallinity affects the luminescence.
STEP 3. SCS had developed its own compact and automated measurement system which comprises:
- Optical systems: the luminescence is excited using a laser. After each pulse, the phosphorescence decay emitted by the sensor material is logged by a photo detector. This is fitted to an exponential equation and the lifetime decay is recorded. The lifetime decay is correlated to the past temperature of exposure.
- Automated measurement by device. Automated measurement of complex geometries such as turbine blades, is possible by attaching SCS’s laser probe to a gantry system and placing the component on a rotary table. This newly developed system allows measurements of a blade aerofoil in just 2.5 h with a spatial resolution of 2 mm. The results can be integrated in a CAD model for quick use by designers.
An objective and automated read-out
This is our instrumentation box. It contains laser, detector and our data acquisition system. The software is responsible to analyse this data and get us the temperature of the sample that we are measuring.
*NEW* Prototype Robotic Arm to speed-up temperature measurements
Since June 2018 Sensor Coating Systems is using robotic arm technology for measuring temperatures. After several months development under an InnovateUK co-funded project, SCS has customised a robotic arm prototype ready for operation. This latest development will assist SCS in speeding up measurements by an estimated factor of 10 to 20 and carrying out measurements on irregular surfaces where access is difficult for other systems.