TY - JOUR
T1 - Development of an optical thermal history coating sensor based on the oxidation of a divalent rare earth ion phosphor
AU - Yáñez-González, Álvaro
AU - Ruiz-Trejo, Enrique
AU - Van Wachem, Berend
AU - Skinner, Stephen
AU - Beyrau, Frank
AU - Heyes, Andrew
N1 - “This is an author-created, un-copyedited version of an article accepted for publication in Measurement Science and Technology. The publisher is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/0957-0233/27/11/115103.”
PY - 2016/11/30
Y1 - 2016/11/30
N2 - The measurement of temperatures in gas turbines, boilers, heat exchangers and other components exposed to hot gases is essential to design energy efficient systems and improve maintenance procedures. When on-line measurements, such as those performed with thermocouples and pyrometers, are not possible or inconvenient, the maximum temperatures of operation can be recorded and measured off-line after operation. Although thermal paints have been used for many years for this purpose, a novel technique based on irreversible changes in the optical properties of thermographic phosphors, can overcome some of the disadvantages of previous methods. In particular, oxidation of the divalent rare earth ion phosphor BaMgAl10O17:Eu (BAM:Eu) has shown great potential for temperature sensing between 700 °C and 1200 °C. The emission spectra of this phosphor change with temperature, which permits to define an intensity ratio between different lines in the spectra that can be used as a measurand of the temperature. In this paper, the study of the sensing capabilities of a sensor coating based on BAM:Eu phosphor material is addressed for the first time. The sensitivity of the intensity ratio is investigated in the temperature range from 800 °C to 1100 °C, and is proved to be affected by ionic diffusion of transition metals from the substrate. The use of an interlayer made of zirconia proves efficient in reducing ionic diffusion and coatings with this diffusion barrier present sensitivity comparable to that of the powder material.
AB - The measurement of temperatures in gas turbines, boilers, heat exchangers and other components exposed to hot gases is essential to design energy efficient systems and improve maintenance procedures. When on-line measurements, such as those performed with thermocouples and pyrometers, are not possible or inconvenient, the maximum temperatures of operation can be recorded and measured off-line after operation. Although thermal paints have been used for many years for this purpose, a novel technique based on irreversible changes in the optical properties of thermographic phosphors, can overcome some of the disadvantages of previous methods. In particular, oxidation of the divalent rare earth ion phosphor BaMgAl10O17:Eu (BAM:Eu) has shown great potential for temperature sensing between 700 °C and 1200 °C. The emission spectra of this phosphor change with temperature, which permits to define an intensity ratio between different lines in the spectra that can be used as a measurand of the temperature. In this paper, the study of the sensing capabilities of a sensor coating based on BAM:Eu phosphor material is addressed for the first time. The sensitivity of the intensity ratio is investigated in the temperature range from 800 °C to 1100 °C, and is proved to be affected by ionic diffusion of transition metals from the substrate. The use of an interlayer made of zirconia proves efficient in reducing ionic diffusion and coatings with this diffusion barrier present sensitivity comparable to that of the powder material.
KW - phosphorescence
KW - temperature measurement
KW - thermal history sensor
KW - thermal paints
KW - gases
KW - energy efficiency
KW - thermographic phosphors
UR - http://www.scopus.com/inward/record.url?scp=84992381840&partnerID=8YFLogxK
U2 - 10.1088/0957-0233/27/11/115103
DO - 10.1088/0957-0233/27/11/115103
M3 - Article
AN - SCOPUS:84992381840
VL - 27
JO - Measurement Science and Technology
JF - Measurement Science and Technology
SN - 0957-0233
IS - 11
M1 - 115103
ER -