ZrB2–SiC based composites for thermal protection by reaction sintering of ZrO2+B4C+Si

Abstract

Synthesis and sintering of ZrB 2 -SiC based composites have been carried out in a single-step pressureless reaction sintering (PLRS) of ZrO 2 , B 4 C, and Si. Y 2 O 3 and Al 2 O 3 were used as sintering additives. The effect of ratios of ZrO 2 /B 4 C, ZrO 2 /Si, and sintering additives (Y 2 O 3 and Al 2 O 3 ), was studied by sintering at different temperatures between 1500 and 1680 ℃ in argon atmosphere. ZrB 2 , SiC, and YAG phases were identified in the sintered compacts. Density as high as 4.2 g/cm 3 , micro hardness of 12.7 GPa, and flexural strength of 117.6 MPa were obtained for PLRS composites. Filler material was also prepared by PLRS for tungsten inert gas (TIG) welding of the ZrB 2 -SiC based composites. The shear strength of the weld was 63.5 MPa. The PLRS ZrB 2 -SiC composites exhibited: (i) resistance to oxidation and thermal shock upon exposure to plasma flame at 2700 ℃ for 600 s, (ii) thermal protection for Cf-SiC composites upon exposure to oxy-propane flame at 2300 ℃ for 600 s.

Preparation and mechanical characteristics of fine‐woven cloth and punctured felt preform Cf/C‐SiC‐ZrC composite

“…Silicon carbide (SiC) and zirconium carbide (ZrC) are commonly used ceramic matrix and/or coating due to their high melting points and insensitivity to oxidation at elevate temperatures. 5,23,24 The carbon/ceramic composites have already been proved to possess good service reliability in the high-temperature oxidation environment. 14,25 For instance, the boron element could work at 1073 K 26 and the silicone element can be operated at temperatures over 1973 K. 1,25,27 The adhesive joint properties of fine-woven punctured preform composite with a needled preform composite and Cu-W alloy, as well as the ablation behavior of such composite, have been discussed by our research group.…”

“…All these failure mechanisms have been widely discussed for the fiber reinforced composites, especially for those with short fibers or 2.5D needled fabrics. Silicon carbide (SiC) and zirconium carbide (ZrC) are commonly used ceramic matrix and/or coating due to their high melting points and insensitivity to oxidation at elevate temperatures 5,23,24 . The carbon/ceramic composites have already been proved to possess good service reliability in the high‐temperature oxidation environment 14,25 .…”

Sol-gel derived porous ultra-high temperature ceramics

“…Ultra-high temperature ceramics (UHTCs) are a class of nonmetallic and inorganic materials that have melting point over 3000 ℃ and are typically borides, carbides, and nitrides of early transition metals (e.g., Zr, Hf, Nb, Ta) [1][2][3][4][5][6][7][8]. Due to the combination of series of excellent physical and chemical properties, such as high hardness, good high-temperature stability, and excellent solid-phase stability, UHTCs are considered as promising candidate materials for high-temperature structural applications, including engines, hypersonic vehicles, plasma arc electrode, cutting tools, furnace elements, and high-temperature shielding [7,[9][10][11][12][13]. UHTCs are difficult to densify without sintering additives and external pressure.…”

Effect of Y3Al5O12 Addition on The Microstructural Evaluation And Mechanical Properties of Spark Plasma Sintered ZrB2-SiC Composites

“…Recently, yttrium and aluminium based additives including Al2O3, Y2O3 have been successfully used to improve the sinterability of ZrB2, forming a liquid phase or removal of surface oxides. In addition to sinterability, it has been stated that these additions played an important role for improving mechanical properties and oxidation resistance [13][14][15][16][17][18][19][20]. YAG gel coated ZrB2-SiC composites were prepared by pressureless sintering by He et all [15].…”