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Issues and advances in SiCf/SiC composites development for fusion reactors

“…The 'in situ' displacement reaction joints performances have also been reported [4]: in this case, the joining layer consists of a complex compound such as Ti x Si y C z + SiC. Recently, the use of Si-Ti and SiCr eutectics has been proposed for brazing of SiC and SiC f /SiC composites [60]. The joints obtained by means of these brazing alloys showed high pure-shear strengths (up to 80 MPa).…”

“…Recently the feasibility of a high thickness-tight coating has been proved (up to 200 lm) [58] but this process is time consuming and expensive. The possibility to use glass ceramic coatings and Si-Cr or Si-Ti eutectics [59,60] is under investigation. In particular the first offers a materials which can be in a non-brittle state at the operating temperatures, while the second offers an excellent sealing capability.…”

Issues of low activation brazing of SiCf/SiC composites by using alloys without free silicon

“…The samples joined by using CrSi 2 exhibited a shear strength of 64 ± 5 MPa. Table 1 shows a comparison of the shear strength of joints obtained in our previous activities [10], i.e., Si-16 Ti and Si-18Cr at.% joints, and the current ones.…”

“…Si-16Ti and Si-18Cr at.% eutectic alloys have been already studied in a previous activity [9,10] and they were found to satisfy the requirements of a fusion relevant brazing technique such as low neutron activation, suitable brazing temperature, good wettability and compatibility with the composite. Conversely, both the alloys have a pure Si phase and the neutron induced swelling of pure silicon, which is different from that of SiC [11], can in principle limit their use in a fusion reactor environment.…”

Compatibility of SiC with static liquid LiPb at 800°C

“…Therefore an efficient densification or sealant is needed for blanket applications. The possibility to use glass ceramic coatings and Si-Cr or Si-Ti eutectics [19,20] is under investigation. The coating on the SiC f /SiC composites which contains Al 2 O 3 and a small quantity of SiO 2 as the seal coat was tested.…”