Effect of LiYO₂ on the synthesis and pressureless sintering of Y₂SiO₅

Abstract

Y 2 SiO 5 has potential applications as a high-temperature structural ceramic and environmental/thermal barrier coating. In this work, we synthesized single-phase Y 2 SiO 5 powders utilizing a solid-liquid reaction method with LiYO 2 as an additive. The reaction path of the Y 2 O 3 /SiO 2 /LiYO 2 mixture with variation in temperatures and the role of the LiYO 2 additive on preparation process were investigated in detail. The powders obtained by this method have good sinterability. Through a pressureless sintering process, almost fully dense Y 2 SiO 5 bulk material was achieved with a very high density of 99.7% theoretical.

Thermal properties of single-phase Y2SiO5

“…Details of the preparation can be found in our previous work. 25 Fig. 1(a) presents the microstructure of the thermal etched surface of Y 2 SiO 5 material via heating to 1300 • C with a rate of 10 • C/min, holding for 30 min, and then cooling to room temperature with a rate of 15-20 • C/min.…”

“…But these data are indispensable for selection of Y 2 SiO 5 as candidate for both high-temperature structural components and coatings. In our previous paper, we successfully synthesized singlephase Y 2 SiO 5 powders (X2-Y 2 SiO 5 , here after written as Y 2 SiO 5 for brevity) from Y 2 O 3 and SiO 2 powders, 25 and evaluated its mechanical properties. 26 Y 2 SiO 5 has low Young's modulus but high damage tolerance, which endow the promising coating applications of Y 2 SiO 5 from the view of mechanical properties.…”

Mechanical properties and damage tolerance of Y2SiO5

“…Details of the preparation procedure can be found in our previous work. 21 Microstructure observation of the thermal etched specimens was performed in a SUPERA 35 scanning electron microscope (SEM, LEO, Oberkochen, Germany) equipped with an Oxford energy dispersive X-ray spectroscope.…”

“…21 In this paper, the mechanical properties of single-phase bulk Y 2 SiO 5 ceramic including elastic moduli, hardness, strength and fracture toughness were measured. Since the performances of a material are intimately correlated with its structure, here the relationship between the crystal structure and mechanical properties of Y 2 SiO 5 was investigated in detail.…”

Preparation of Y2Si2O7/ZrO2 Composites and Their Composition – Mechanical Properties – Tribology Relationships

“…One important approach is to develop novel composites that combine the merits of two end materials. Yttrium silicates, or ternary Y–Si–O oxides, including Y 2 Si 2 O 7 , Y 2 SiO 5 , and Y 4.67 (SiO 4 ) 3 O, have attracted the attention of material scientists due to their potential applications as high‐temperature structural materials or environmental coatings on ceramic matrix composites . Y 2 Si 2 O 7 in particular has some interesting properties, such as high‐melting point (1775°C), machinability, and stability in oxidizing and hot corrosive environments .…”