On the thermal sensitivity and resolution of a YSZ:Er3+/YSZ:Eu3+ fluorescent thermal history sensor

Abstract

This paper deals with the problem of thermal history analysis of high temperature components for applications such as furnaces, nuclear reactors and jet engines. It focuses on fluorescent thermal history sensors, which exhibit permanent changes in their luminescence properties when exposed to high temperature. These changes can then be quantitatively evaluated to determine the temperature of exposure from a previous thermal event. The main objective of this paper is to investigate the thermal sensitivity and the thermal resolution of a yttria-stabilized zirconia (YSZ) Er 3+-doped phosphor produced by a solgel route and combined with a thermal history insensitive YSZ:Eu 3+ reference, which was selected for its high sensitivity to thermal history above 1173 K. In particular, the interest of this YSZ:Er 3+ /YSZ:Eu 3+ sensor is discussed in the view of the physical properties of sol-gel deposited YSZ coatings, the selection of an appropriate excitation wavelength and the practical measurement of coatings fluorescence properties. The sensitivity and the resolution of two thermal history measurement fluorescence methods, based on intensity ratios and lifetime analysis, were determined and compared. A comparison is also made with standard non-contact temperature measurement methods such as infrared thermography and thermochromic paints.

Surface temperature condition monitoring methods for aerospace turbomachinery: exploring the use of ultrasonic guided waves

“…This shows an improvement over temperature sensitive paints, which can only be used for short term (∼5 minutes) engine tests. The processes behind the optical changes that are caused by temperature are explained by Rabhiou et al [30], followed by experimental results that show a Y 2 SiO 5 :Tb phosphor suitable for use up to 1000 • C, with potential for further development to extend the upper temperature limit to 1400 • C. A resolution comparison between thermal paints/temperature indicating paints, pyrometry, and thermal history sensors is given by Amiel [31] in Table 2. Pyrometry methods provide the highest resolution (0.3 • C), followed by thermal history sensors (1-5 • C), and finally temperature sensitive paints (10-100 • C).…”

Measurements of turbine blade temperature in an operating aero engine using thermographic phosphors

“…Temperature sensitivity by itself is not a good predictor of temperature measurement precision because the signal-tonoise ratio (ratio of signal mean to standard deviation) also has a large effect on measurement precision. An estimate of temperature measurement precision can then be given by the noise equivalent temperature difference (NETD) [15,20],…”

Understanding the power of luminescence ratiometric thermal history indicators driven by phase transitions: the case of Eu3+ doped LaVO4

“…7,8 The response to such demands is thermal history sensors, which have spawned a new field of research. 5,7,[9][10][11][12][13][14][15][16][17] In general, this type of sensor should be able to determine temperature based on irreversible changes in its properties. Thermal history paintings are a wellknown instance of such sensors.…”