IOP Conference Series: Earth and Environmental Science PAPER • OPEN ACCESS Measurement of thermal expansion coefficient of rock minerals using XRD and its implications to thermal damage mechanism To cite this article: Zhaoyang Ma et al 2021 IOP Conf. Ser.: Earth Environ. Sci. 861 072021 You may also like - Longitudinal force measurement in continuous welded rail with bi-directional FBG strain sensors Ping Wang, Kaize Xie, Liyang Shao et al. - Experimental results for nulling the effective thermal expansion coefficient of fused silica fibres under a static stress Chris J Bell, Stuart Reid, James Faller et al. - High Performance ZrNbAl Alloy with Low Thermal Expansion Coefficient Yun-Kai Zhou, , Xing Zhang et al. View the article online for updates and enhancements. This content was downloaded from IP address 113.163.220.135 on 20/04/2023 at 03:04 11th Conference of Asian Rock Mechanics Society IOP Conf. Series: Earth and Environmental Science 861 (2021) 072021 IOP Publishing doi:10.1088/1755-1315/861/7/072021 Measurement of thermal expansion coefficient of rock minerals using XRD and its implications to thermal damage mechanism Zhaoyang Ma1; Guanglei Zhang2; Ranjith Pathegama Gamage1*; Chengpeng Zhang3* Deep Earth Energy Laboratory, Building 60, Monash University, Melbourne, Victoria 3800, Australia. 1 2 Department of Earth Science and Engineering, Imperial College London, London SW7 2BP, UK 3 State Key Laboratory of Coal Mine Disaster Dynamics and Control, Chongqing University, Chongqing, 400044, China. Abstract. The measurement of thermal expansion coefficient (TEC) of rocks is of vital importance to various geotechnical engineering applications, such as high-level radioactive waste disposal, enhanced geothermal energy exploitation, ultra-deep borehole stability, liquid nitrogen storage, etc. However, previous researchers mainly focused on the thermal expansion coefficient of various rocks, instead of the constituent minerals. In this manuscript, we measured the both temperature-dependent volume and linear thermal expansion coefficients of two rockforming minerals (quartz and albite) using both high-temperature X-ray diffraction (XRD) as well as low-temperature XRD. It is found that there exist strong anisotropic linear thermal expansion coefficients of the two minerals, which can provide strong reference for the relevant engineering applications and numerical simulations. 1. Introduction Thermal stresses induced during the heating or cooling of rocks cause fracture and fragmentation, which is of vital importance to various geotechnical engineering applications, such as high-level radioactive waste disposal, enhanced geothermal energy exploitation, ultra-deep borehole stability, etc. Rocks are inherently heterogeneous and they are polycrystalline with various anisotropic mineral aggregates. Generally, thermal stresses can be generated due to the following reasons: (1) thermal expansion (contraction) coefficient mismatch between different phases (grains) (2) anisotropic thermal expansion (contraction) coefficient of individual phase (3) thermal gradient (heating or cooling rate) (4) phase change and/or structural chemical reactions (5) temperature-dependent elastic modulus of each individual phase (6) composition, distribution and orientation of individual grains (7) presence of crack or fracture (8) previous maximum temperature (9) presence of water (moisture content) (10) pressure [1] (11) thermal cycling (temperature history). Take granite for instance, it consists of three major mineral constituents, namely, quartz, feldspar and mica. The thermal expansion coefficient of these three dominant minerals is of great difference. For each single phase, there exists a distinct anisotropic linear thermal expansion coefficient, which is relatively less studied. Thermal expansion coefficient (πΌπΌ) indicates the percentage of material expands or contracts with temperature changes. Under a constant pressure, volumetric thermal expansion coefficient (πΌπΌππ or π½π½) is defined by the variations of volume by a differential temperature change (βππ) and it is normally described as the following relationship: πΌπΌππ = 1 ππππ ( ) ππ ππππ ππ where ππ is the volume at a temperature ππ under a constant pressure ππ. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd 1 11th Conference of Asian Rock Mechanics Society IOP Conf. Series: Earth and Environmental Science 861 (2021) 072021 IOP Publishing doi:10.1088/1755-1315/861/7/072021 Similarly, the linear thermal expansion coefficient is defined as: πΌπΌππ = 1 ππππ ( ) ππ ππππ ππ Accurate thermal expansion coefficients of rock-forming minerals are of great essence to the clarification of the equation of state of the earth’s interior [2] and it is emphasized that most serious error in the calculation of thermodynamic functions arises from the uncertainty of thermal expansivity at high temperature [3]. In most cases, rocks are assumed to be homogeneous and isotropic for the convenience of analysis. Only a few studies focused on the thermal expansion coefficient measurement of rock minerals. For instance, Jay [4] measured the lattice parameters of quartz from 18 to 730 β using the high-temperature Debye-Scherrer method and it was found that thermal expansion coefficients in both axial direction of the hexagonal unit cell increased from 18 to 580 β and both axes apparently decreased in length from 580 to 730 β. Ackermann and Sorrell [5] measured the thermal expansion coefficient of quartz using high-temperature X-ray diffractometry from 22 to 1400 β. It was found that the expansion was zero from 574 to 1000 β and decreased from 1000 to 1400 β. The maximum volume thermal expansion coefficient was 100±20 × 10−5 /degree between 572 and 574 β. In addition, they [6] measured the thermal expansion of both single-crystal quartz and quartz powder using the highly sensitive dilatometer apparatus. It was found that the expansion coefficient characteristics were identical with X-ray diffractometer measurement below 560 β . Single-crystal quartz reached a maximum volume thermal expansion coefficient 250× 10−5 /degree between 571 and 573 β while the quartz powder reached a maximum volume thermal expansion coefficient 150× 10−5 /degree between 571 and 576 β. Richter and Simmons [7] measured the thermal expansion coefficient of several igneous rocks from 25 to 550 β and they found that the measured thermal expansion coefficient is a function of crack porosity, heating rate, previous maximum temperature as well as mineralogical composition and preferred crystal orientation. In their study, they only measured the linear thermal expansion coefficient of rock core along the long dimension of the sample only, and the volume expansion was assumed to be three times the linear expansion coefficient. In addition, the anisotropy of expansion was not investigated. The experimental volume expansion coefficients of the rocks and calculated value using the Turner’s formula and the input value for the Turner’s calculation is from [7]. Alvaro, Angel et al. [8, 9] measured the unit cell volume of quartz using the high-temperature single-crystal X-ray diffraction from 294K to 872K. 2. Temperature Calibration In this manuscript, the thermocouple measurements were calibrated using the lattice parameter changes for magnesium oxide (MgO) as a function of the temperature. We measured the XRD pattern of MgO with the change of temperature, as shown in figure 1. It can be found that there is an obvious peak shift of MgO in the temperature range between room temperature and 1200 β. Figure 2 demonstrated the calibrated temperature of MgO with the set temperature and it can be found that the two curves fit very well, which indicates the accuracy of temperature. 2 11th Conference of Asian Rock Mechanics Society IOP Conf. Series: Earth and Environmental Science 861 (2021) 072021 IOP Publishing doi:10.1088/1755-1315/861/7/072021 Intensity (A.U.) 1200 °C 1100 °C 1000 °C 900 °C 800 °C 700 °C 600 °C 500 °C 400 °C 300 °C 200 °C 100 °C 30 °C 41 42 43 2θ (degree) 44 45 Figure 1. MgO-high-temperature from room temperature to 1200 β Calibrated temperature (οC) 1200 HTK Calibrated temperature using MgO Linear fitting of tempeture 1000 800 600 400 y = a + b*x -10.55255 ± 3.67413 1.02643 ± 0.0052 0.99986 0.99972 0.99969 Equation Intercept Slope Pearson's r R-Square (COD) Adj. R-Square 200 0 0 200 400 600 800 Set temperature (oC) 1000 1200 Figure 2. The HTK calibrated temperature using MgO 3. XRD experimental results for quartz and albite 3.1 Thermal expansion coefficient and unit cell parameters of quartz Figure 3 demonstrates the XRD pattern of quartz from room temperature to 1200 β and figure 4 shows the magnification of XRD pattern of quartz from room temperature to 1200 β. Linear and volume expansion coefficients are calculated using the following equation: πΌπΌππ = 1 βππππ 1 + ππππ βππ where the suffix ππ represents a, b, c (each crystallographic axis) and π£π£ (volume). The unit cell parameters of quartz under various temperatures were gained using the Rietveld method and the results are shown in Table 1. 3 11th Conference of Asian Rock Mechanics Society IOP Conf. Series: Earth and Environmental Science 861 (2021) 072021 IOP Publishing doi:10.1088/1755-1315/861/7/072021 1200°C 1000°C 600°C Quar tz Intensity (A.U.) 800°C 30°C 20 25 30 35 40 45 2θ (degree) 50 55 60 Figure 3. XRD pattern of quartz from room temperature to 1200 1200°C Intensity (A.U.) 1000°C 800°C 600°C 30°C 25 26 27 28 2θ (degree) 29 30 Figure 4. Magnification of XRD pattern of quartz from room temperature to 1200 β Table 1. Relationship of unit cell parameters of quartz with various temperatures Set Temperature (β) 30 60 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 Calibrated temperature (β) 30.432 60.864 101.44 152.16 202.88 253.6 304.32 355.04 405.76 456.48 507.2 557.92 608.64 659.36 710.08 760.8 811.52 Unit cell Volume (Å3) 112.997 113.13 113.317 113.569 113.841 114.133 114.455 114.803 115.194 115.645 116.212 117.203 118.032 118.027 118.012 117.992 117.973 Unit Cell Volume error 0.0012 0.001 0.0009 0.0009 0.001 0.0013 0.001 0.0011 0.0014 0.0014 0.0013 0.0019 0.0018 0.0018 0.0011 0.0016 0.0013 4 a (Å) Error of a c (Å) Error of c 4.9134 4.915654 4.918826 4.923111 4.927676 4.932559 4.93795 4.943732 4.950275 4.957828 4.967182 4.983595 4.997388 4.997536 4.99748 4.997404 4.997257 0.00002299 0.00001813 0.00001666 0.00001594 0.000018 0.00002422 0.00001722 0.00001938 0.00002614 0.00002224 0.00002298 0.00003551 0.00003069 0.00002897 0.00001614 0.00002594 0.00002155 5.404704 5.406116 5.408062 5.410651 5.413549 5.416709 5.420121 5.423896 5.428004 5.432687 5.438776 5.44908 5.457351 5.456792 5.456229 5.455496 5.454927 0.00002789 0.00002369 0.00002655 0.00002269 0.00002417 0.00002825 0.00003026 0.00003268 0.00003047 0.00004227 0.00003027 0.0000433 0.00004623 0.00005055 0.00003419 0.00004672 0.00003838 11th Conference of Asian Rock Mechanics Society IOP Conf. Series: Earth and Environmental Science 861 (2021) 072021 850 900 950 1000 1050 1100 1150 1200 862.24 912.96 963.68 1014.4 1065.12 1115.84 1166.56 1217.28 117.947 117.921 117.899 117.876 117.856 117.835 117.817 117.798 0.0012 0.0017 0.0021 0.0015 0.0013 0.0017 0.0014 0.0016 4.997015 4.996836 4.996665 4.996482 4.996339 4.996121 4.99601 4.995864 IOP Publishing doi:10.1088/1755-1315/861/7/072021 0.0000193 0.00003286 0.00003852 0.00002703 0.00002134 0.00002793 0.00002658 0.00002707 5.46 Unit Cell-c (Å) 5.00 Unit Cell-a (Å) 0.00003698 0.00003534 0.00004706 0.00003817 0.00003759 0.00004893 0.00002752 0.00004141 Unit Cell a change with temperature 5.47 Unit Cell c change with temperature 5.02 5.45 4.98 5.44 4.96 5.43 4.94 5.42 4.92 4.90 5.45425 5.453431 5.452801 5.452133 5.451528 5.451025 5.450411 5.449864 5.41 0 200 400 600 800 Temperature (°C) 1000 1200 5.40 Figure 5. Unit cell parameters change of quartz from room temperature to 1200 β Figure 5 shows the unit cell parameters change of two directions of quartz (namely, a and c). There exists an obvious variation of unit cell parameters near the phase change temperature (namely, 573 β). The quartz πΌπΌ − π½π½ transition is marked by a kink in the unit cell parameters, as shown in the above figures. From the above curves, we can find that quartz has a steep, nonlinear expansion curve until is transition temperature and a slight contraction exists beyond the transition temperature. 3.2 Thermal expansion coefficient and unit cell parameters of albite Similarly, figure 6 demonstrates the XRD pattern of albite from room temperature to 1200 β and figure 7 shows the magnification of XRD pattern of albite from room temperature to 1200 β. The unit cell parameters of albite under various temperatures were gained using the Rietveld method and the results are shown in Table 2. Figure 8 shows the unit cell parameters change of three directions of albite and figure 9 demonstrates the unit cell angle variation of albite with temperature. Figure 10 shows the both the volume and linear thermal expansion coefficient of albite with the calibrated temperature and it can be seen that there exists a strong anisotropic thermal expansion coefficient of albite and both the volume and linear thermal expansion coefficient of albite increases with the temperature. 5 11th Conference of Asian Rock Mechanics Society IOP Conf. Series: Earth and Environmental Science 861 (2021) 072021 IOP Publishing doi:10.1088/1755-1315/861/7/072021 Intensity (A.U.) 500 °C 300 °C A l bi te 950 °C 700 °C 30 °C 20 40 60 80 2θ (degree) 100 Figure 6. XRD pattern of albite from room temperature to 950 β 950 °C Intensity (A.U.) 700 °C 500 °C 300 °C 30 °C 27.0 27.5 28.0 2θ (degree) 28.5 29.0 Figure 7. Magnification of XRD pattern of albite from room temperature to 950 β Table 2. Relationship of unit cell parameters of albite with various temperatures Set temperature (β) 30 100 150 200 250 300 350 400 450 500 550 600 650 700 750 800 850 900 950 Calibrated temperature (β) 30 101.008 151.728 202.448 253.168 303.888 354.608 405.328 456.048 506.768 557.488 608.208 658.928 709.648 760.368 811.088 861.808 912.528 963.248 Volume (π΄π΄Μ3 ) 664.938 666.167 667.03 668.001 668.877 669.882 670.88 671.912 673.02 673.905 675.013 675.949 677.007 678.091 679.136 680.172 681.371 682.629 683.925 a (Å) b (Å) c (Å) 8.143125 8.151428 8.157127 8.163595 8.169331 8.175948 8.182209 8.188472 8.195641 8.201536 8.208406 8.214505 8.221115 8.22804 8.23472 8.241806 8.250021 8.258159 8.266808 12.79024 12.79433 12.79744 12.80085 12.80423 12.80755 12.81216 12.8164 12.82044 12.82384 12.82798 12.83135 12.83528 12.83933 12.84418 12.84739 12.85182 12.85653 12.86114 7.160918 7.161221 7.161281 7.161787 7.162122 7.163084 7.163663 7.1647 7.165916 7.166494 7.167861 7.168712 7.169874 7.171152 7.171764 7.17293 7.174199 7.175586 7.177362 6 α (°) 94.24636 94.2226 94.19119 94.16269 94.13197 94.09352 94.05622 94.00687 93.96167 93.90932 93.85375 93.79725 93.74332 93.6799 93.61521 93.55089 93.47926 93.40101 93.31534 β (°) 116.6172 116.567 116.5319 116.4983 116.4682 116.4387 116.4107 116.383 116.3553 116.3329 116.3056 116.2819 116.254 116.2304 116.2066 116.1839 116.1627 116.1356 116.1153 γ (°) 87.74094 87.73409 87.72876 87.71893 87.70934 87.69948 87.68577 87.68124 87.67019 87.663 87.65198 87.63967 87.62926 87.61681 87.60656 87.59337 87.58058 87.57001 87.56183 11th Conference of Asian Rock Mechanics Society IOP Conf. Series: Earth and Environmental Science 861 (2021) 072021 8.28 8.24 7.178 12.86 a b c 8.26 IOP Publishing doi:10.1088/1755-1315/861/7/072021 7.176 12.85 7.174 12.84 8.22 8.20 8.18 7.172 12.83 7.170 12.82 7.168 7.166 12.81 8.16 12.80 8.14 12.79 0 200 400 600 800 1000 7.164 7.162 7.160 1200 Calibrated temperature (°C) Figure 8. Variation of unit cell parameter of albite (length) with the calibrated temperature 94.4 94.2 116.6 94.0 116.5 93.8 116.4 α β γ 93.6 93.4 93.2 87.76 116.7 200 87.72 87.70 87.68 87.66 87.64 87.62 116.3 87.60 116.2 116.1 0 87.74 400 600 800 Calibrated temperature (°C) 1000 87.58 87.56 87.54 1200 Figure 9. Variation of unit cell parameter of albite (angle) with the calibrated temperature 3.1 1.65 6.0 Volume thermal expansion*10^-5 Linear thermal expansion a*10^-5 Linear thermal expansion b*10^-6 Linear thermal expansion c*10^-7 3.0 1.60 2.9 5.6 25 20 1.55 5.4 5.2 15 2.8 1.50 2.7 5.0 1.45 4.8 10 4.6 5 2.6 1.40 2.5 5.8 0 200 400 600 800 Calibrated temperature (°C) 1000 4.4 0 1200 Figure 10. Volume and linear thermal expansion coefficients of albite with the calibrated temperature 4. Conclusions: In this study, the relationship between the rock mineral thermal expansion coefficient and temperature was established. The unit cell parameters (a, b, c, πΌπΌ, π½π½, πΎπΎ and V) were refined using the Rietveld method. For quartz, there exists an obvious variation of unit cell parameters near the phase change temperature (namely, 573 β) and quartz has a steep, nonlinear expansion curve until is transition temperature and 7 11th Conference of Asian Rock Mechanics Society IOP Conf. Series: Earth and Environmental Science 861 (2021) 072021 IOP Publishing doi:10.1088/1755-1315/861/7/072021 a slight contraction exists beyond the transition temperature. For albite, there exists a strong anisotropic thermal expansion coefficient and both the volume and linear thermal expansion coefficient of albite increases with the temperature. This study if of vital importance to the relevant geotechnical engineering, such as high-level radioactive waste disposal, enhanced geothermal energy extraction, etc. In addition, the accurate measurement of thermal expansion coefficients of these rock minerals can provide baselines for the numerical simulation. 5. Acknowledgement We appreciate the help from Jisheng Ma to carry out the high-temperature XRD tests and its postprocessing. The first author would like to acknowledge the financial support provided by the China Scholarship Council (No. 201706420055). In addition, this work is funded by various projects, namely, China Postdoctoral Science Foundation (No. 2020 M673142), Chongqing Science and Technology Bureau Foundation (No. cstc2020jcyj-bsh0059), Chongqing Human Resources and Social Security Bureau Foundation (No. cx2019100), Chongqing Science and Technology Bureau Foundation (No. cstc2020jcyj-zdxm0122) and National Natural Science Foundation of China (No. U19B2009). 6. References [1]. Sweet, J.N., Pressure effects on thermal conductivity and expansion of geologic materials. 1979, Sandia Labs., Albuquerque, NM (USA). [2]. Suzuki, I., Thermal expansion of periclase and olivine, and their anharmonic properties. Journal of Physics of the Earth, 1975. 23(2): p. 145-159. [3]. Jay, A., The thermal expansion of quartz by X-ray measurements. Proceedings of the Royal Society of London. Series A, Containing Papers of a Mathematical and Physical Character, 1933. 142(846): p. 237-247. [4]. Thirumalai, K. and S. Demou, Effect of reduced pressure on thermalβexpansion behavior of rocks and its significance to thermal fragmentation. Journal of Applied Physics, 1970. 41(13): p. 5147-5151. [5]. Ackermann, R. and C.A. Sorrell, Thermal expansion and the high–low transformation in quartz. I. High-temperature X-ray studies. Journal of Applied Crystallography, 1974. 7(5): p. 461-467. [6]. Richter, D. and G. Simmons. Thermal expansion behavior of igneous rocks. in International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts. 1974. Elsevier. [7]. Clark, S.P., Handbook of physical constants. Vol. 97. 1966: Geological Society of America. [8]. Johnson, B., A. Gangi, and J. Handin. Thermal cracking of rock subjected to slow, uniform temperature changes. in 19th US Symposium on Rock Mechanics (USRMS). 1978. American Rock Mechanics Association. [9]. Friedman, M. and B. Johnson. Thermal cracks in unconfined Sioux quartzite. in 19th US Symposium on Rock Mechanics (USRMS). 1978. American Rock Mechanics Association. 8