Pressure‐less joining of C/SiC and SiC/SiC by a MoSi₂/Si composite

Abstract

A MoSi2/Si composite obtained in situ by reaction of silicon and molybdenum at 1450°C in Ar flow is proposed as pressure‐less joining material for C/SiC and SiC/SiC composites. A new “Mo‐wrap” technique was developed to form the joining material and to control silicon infiltration in porous composites. MoSi2/Si composite joining material infiltration inside coated and uncoated C/SiC and SiC/SiC composites, as well as its microstructure and interfacial reactions were studied. Preliminary mechanical strength of joints was tested at room temperature and after aging at service temperatures, resulting in interlaminar failure of the composites in most cases.

Joining of Cf/SiC Ceramic Matrix Composites: A Review

“…It is well known that it is very di cult to form di usion between C f /SiC composites owing to the strong covalent bond and the poor deformation ability of the SiC in C f /SiC composites, thus resulting in a weak bonding strength of direct bonding joint (Figure 2(b)). erefore, second-phase materials with plastic deformability, such as Ag-Cu-Ti [30,49], Ti-Zr-Be [50], Ni [31,51,52,55], calciaalumina (CA) glass-ceramic [54], Ti 3 SiC 2 [16,36,55,56] and Si resin [57], and MoSi 2 [58], were widely reported to be used for the joining of C f /SiC composites. ese kinds of joining are known as indirect bonding method, always including using metal ller or nonmetal ller.…”

“…Nonmetal llers, such as MAX ceramic [16,36,55,56,63], ceramic precursors [64], Si resin [57], and MoSi 2 [58], are also reported to be used in the selfjoining of C f /SiC composites (as listed in Table 5).…”

“…Moreover, the Si-O-C ceramics infiltrating into the pits can form tiny "pins," thus increasing the shear strength of the joints. Gianchandani et al [58] reported that a MoSi 2 /Si composite obtained in situ by reaction of silicon and molybdenum at 1450°C in Ar flow is proposed as pressure-less joining material for C f /SiC composites.…”

Residual thermal stress of SiC/Ti3SiC2/SiC joints calculation and relaxed by postannealing

“…On the other hand, joining SiC itself without joining materials by hot‐pressing usually should be very high temperature because of the high covalent bonding character and low self‐diffusivity of SiC. Therefore, the development of a reliable joining technique and well‐controlled joining layer are critical for the potential nuclear applications of SiC materials …”

“…Therefore, the development of a reliable joining technique and well-controlled joining layer are critical for the potential nuclear applications of SiC materials. [6][7][8] Spark plasma sintering (SPS) technology is an efficient technique to fabricate ultra-high temperature ceramics at low temperatures compared to conventional sintering methods. Recently, SPS has been widely used to join monolithic SiC and ceramic matrix composites due to the electric filed can accelerate solid state diffusion in the joining layer.…”