Thermochemistry and phase stability of the polymorphs of yttrium tantalate, YTaO4

First‐principles study of thermophysical properties of polymorphous YTaO4 ceramics

“…Moreover, the high-temperature phase transformation of YTaO 4 was studied using the first-principles calculation method by Feng et al 28 and their results showed that it was a second-order ferroelastic phase transition from the T to M phase transition. Furthermore, the thermochemistry and phase stability of the polymorphs YTaO 4 were investigated using complementary high-temperature analysis methods proposed by Lepple et al 29 and their enthalpies of formation, heat capacities, and heat contents were measured, and the stability of the T phase was confirmed up to its melting point of 2090℃. The mechanical properties of polymorphous YTaO 4 at room temperature with M and M' phases were explored by Wu et al 30 who found a relationship between the mechanical properties and their chemical bonding strength using nanoindentation technology combined with first-principles calculations.…”

“…The phase transition temperature of YTaO 4 is approximately 1430℃, and the M' to T phase transition occurs during the heating process, while the T to M phase transition proceeds from high temperature to low temperature. 29 Only M phase is mostly obtained by conventional sintering method.…”

“…Studies o derived SiC ceramic 25 and SiC/SiC c shown that porosity decreases and mecha prove with the increasing number of PIP show that increasing pyrolysis temperatu tration of SiC fillers in polycarbosilane improved mechanical properties in two-d SiC (C/SiC) composites fabricated using Starting with pyrolysis of a "cured prepreg-based composite, each processin process involves infiltration of a precera porous ceramic preform followed by a py which the polymer is converted into ceram cess modeling is focused on these two ste Modeling of infiltration of liquids in well-studied subject, especially in the where it is used to model seepage of wa soils and rocks. 29,30 The physics of resin under pressure is similar to the seepage pr lar approaches have been used also to mod into a mold containing fiber mats. 23,[31][32][33][34][35][36][37][38] T in these cases to determine the resin flow ing times corresponding to different infilt Preceramic polycarbosilane polymers as precursors to make ceramic fibers 10,3 trix.…”

“…[55] In Equation ( 16), the hardness of polymorphous YTaO 4 at high temperatures is related to its modulus and melting point. According to the YO 1.5 -TaO 2.5 phase diagram, 29,56 the melting point of YTaO 4 is 2090℃, and H V (300) is obtained by the models of Chen and Tian. This parameter is regarded as the initial input value for the hardness at high temperatures.…”

“…Modeling of infiltration of liquids in porous media is a well-studied subject, especially in the field of hydrology where it is used to model seepage of water through porous soils and rocks. 29,30 The physics of resin flow into a mold under pressure is similar to the seepage problem and so similar approaches have been used also to model the flow of resin into a mold containing fiber mats. 23,[31][32][33][34][35][36][37][38] The models are used in these cases to determine the resin flow front and mold filling times corresponding to different infiltration conditions.…”