Interaction of multicomponent disilicate (Yb0.2Y0.2Lu0.2Sc0.2Gd0.2)2Si2O7 with molten calcia-magnesia-aluminosilicate

Abstract

Environmental barrier coating (EBC) materials that are resistant against molten calcia-magnesia-aluminosilicate (CMAS) corrosion are urgently required. Herein, multicomponent rare-earth (RE) disilicate ((Yb0.2Y0.2Lu0.2Sc0.2Gd0.2)2Si2O7, (5RE)2Si2O7) was investigated with regard to its CMAS interaction behavior at 1400 °C. Compared with the individual RE disilicates, the (5RE)2Si2O7 material exhibited improved resistance against CMAS attack. The dominant process involved in the interaction of (5RE)2Si2O7 with CMAS was reaction-recrystallization. A dense and continuous reaction layer protected the substrate from rapid corrosion at high temperatures. The results demonstrated that multicomponent strategy of RE species in disilicate can provide a new perspective in the development of promising EBC materials with improved corrosion resistance.

Water vapor and CMAS corrosion tests of Y2SiO5/Si thermal and environmental barrier coating

“…At 1300 C, the reaction speed began to accelerate. The thickness of the reaction layer at different reaction times was consistent with previous studies, indicating the validity of the data [26][27][28][29][30].…”

“…It can be summarized from the variation of the elemental proportions shown in Figure 7 that Ca and Si in CMAS continuously permeate into Y 2 SiO 5, leading to the formation of a reaction zone between melted CMAS and Y 2 SiO 5 . This reaction zone can effectively stop the mutual diffusion of elements in CMAS and Y 2 SiO 5 [ 27 , 28 , 29 ]. Therefore, Y is not capable of diffusing into the reaction zone and the CMAS layer, and Mg and Al are only detected in the CMAS layer.…”

“…The amount of Si also decreases to a certain degree in the Y 2 SiO 5 layer.It can be summarized from the variation of the elemental proportions shown in Figure7that Ca and Si in CMAS continuously permeate into Y 2 SiO 5, leading to the formation of a reaction zone between melted CMAS and Y 2 SiO 5 . This reaction zone can effectively stop the mutual diffusion of elements in CMAS and Y 2 SiO 5[27,28,29]. Therefore, Y is not capable of diffusing into the reaction zone and the CMAS layer, and Mg and Al are only detected in the CMAS layer.Figure8displays the phase composition of the mixture of Y 2 SiO 5 and CMAS powders at a weight ratio of 1:1 after heating at 1300 C for 30 min and 4 h, respectively.…”

Discovery of orthorhombic perovskite oxides with low thermal conductivity by first-principles calculations

“…Meanwhile, the decreased thermal conductivity is demanded in order to continuously improve the protective effect of the TBCs and maintain the long-life service of the gas turbine engines safely. Therefore, searching for new materials with low thermal conductivities is one focus in the ceramic field [4][5][6][7][8].…”

Significantly improved corrosion resistance of high‐entropy rare‐earth silicate multiphase ceramics against molten CMAS

“…High‐entropy RE silicates, referring to a multiprincipal solid solution consisting of four or more RE components, have attracted wide attention due to its outstanding molten CMAS corrosion resistance and lower thermal conductivity 15,16 . Wang et al 17 . prepared a high‐entropy RE disilicate (5RE 0.2 ) 2 Si 2 O 7 (RE = Yb, Y, Lu, Sc, and Gd) and found that the high‐entropy RE disilicate exhibited a good molten CMAS corrosion resistance, and the thickness of the apatite reaction layer was only 25 μm after corrosion at 1400°C for 20 h. Wang et al 13 .…”