Thermomechanical Analysis of Illite From Füzérradvány

Abstract

Young's modulus of green illite from Füzérradvány (Hungary) was measured in-situ in the temperature interval 20 °C -1100 °C and auxiliary analyses DTA, TG and TDA, XRD and EGA, were also performed. It was found that a removal of the physically bound water (20 °C -250 °C) sets illite crystals closer, which leads to a significant increase of Young's modulus from its initial value of 7 GPa to the maximum 12 GPa at 300 °C. Young's modulus slightly decreases in the temperature interval of dehydroxylation of illite (300 °C -800 °C), and which then reaches up to 45 GPa at 1100 °C, increasing exponentially as a consequence of the sintering above 800 °C.

Mechanical properties of illite‐based ceramics with controlled porosity studied by modern in situ techniques

“…Therefore, it allows to study the properties of illite in a relatively pure form, devoid of the influence of other phases such as kaolinite, quartz, and feldspars, which are typically present in natural clays in considerably high quantities. There are only a limited number of works investigating this material and these studies focus primarily on the thermo‐physical properties of illite …”

“…There are only a limited number of works investigating this material and these studies focus primarily on the thermo-physical properties of illite. 2,15,16,[18][19][20][21][22][23][24][25][26][27][28] Moreover in this work, a controlled porosity was introduced into IRC using a sacrificial template method, thus obtaining sample sets with various degrees of porosity. Mechanical properties of IRC and their dependence on the level of porosity were investigated using conventional compression tests combined with modern in situ acoustic emission (AE) and digital image correlation (DIC) techniques, which proved to be particularly effective for the examination of deformation dynamics, investigated up to now mostly in porous or dense metallic and composite materials, see Refs.…”

The influence of heat on elastic properties of illitic clay Radobica

“…As far as we know, Young's modulus of the green ceramic sample was measured during heating only for porcelain mixture, 6) for heat-proof stove ceramics 7) and for almost pure illite. 8) Some common features can be observed in a development of Young's modulus: 1) a loss of the remainders of the physically bound water from pores increases the Young's modulus of the green ceramic mass in a significant measure. For example, Young's modulus of the green porcelain mixture increases ³30%; 6)8) 2) no significant changes of Young's modulus were observed in the dehydroxylation region; 8) 3) ¡ ¼ ¢ transformation of quartz at 573°C, which is characterized with intensive expansion and sharp decrease of Young's modulus of quartz grains in the ceramic mixture, 9) does not influence elastic properties of the green ceramic sample during its heating; 7),10) 4) sintering, which starts at ³700°C, increases the Young's modulus.…”

“…8) Some common features can be observed in a development of Young's modulus: 1) a loss of the remainders of the physically bound water from pores increases the Young's modulus of the green ceramic mass in a significant measure. For example, Young's modulus of the green porcelain mixture increases ³30%; 6)8) 2) no significant changes of Young's modulus were observed in the dehydroxylation region; 8) 3) ¡ ¼ ¢ transformation of quartz at 573°C, which is characterized with intensive expansion and sharp decrease of Young's modulus of quartz grains in the ceramic mixture, 9) does not influence elastic properties of the green ceramic sample during its heating; 7),10) 4) sintering, which starts at ³700°C, increases the Young's modulus. 6), 11) In addition to direct observating the influence of heat on the mechanical properties during heating, a commonly used way how to find these relationships is the measurement of the mechanical properties after firing.…”

“…8) A consequence of the expansion and mass loss of the sample is a decrease in the bulk density. The values of Young's modulus pass through very flat minimum between 400 and 800°C.…”