SCORPION achievements in the 1st & 2nd reporting periods:
WP1 – Processing of bulk proof-of-concept (PoC) materials
• Grain boundary (GB) engineered & doped SiC were produced by SPS. SiC GB decoration by rare-earth (RE)-silicates/garnets and various oxides was successful.
• High-purity RE-silicates/garnets were produced by pressureless sintering; the samples were pulverised and densified via SPS.
• Porous SiC ceramics (uniform/gradient porosity) were produced & characterised.
• State-of-the-art CVD/CVI & LPS SiC/SiC composites were produced.
WP2 – Deposition of PoC coatings
• RE-silicate coatings were made by magnetron sputtering from compound & elemental targets.
• RE-garnet coatings were made by pulsed laser deposition from compound targets.
• The coatings were characterised with various techniques (XRD, ERDA, SEM/EDS).
WP3 – Joining of PoC materials & testing of joints
• Pressure-less joining of SiC/SiC composites was achieved with the help of localised laser heating; the candidate joining materials were RE-silicates/garnets.
• Joining SiC by fibre-reinforced preceramic polymers has been achieved.
• The joint quality was controlled by computed tomography (CT), SEM/EDS.
WP4 – Characterization of PoC materials & joints
• RE-silicates/garnets (bulk samples & coatings) & doped SiC were characterized by SEM/WDS, XRD, FIB, STEM/EELS.
WP5 – Cladding/coolant interaction tests
• The hydrothermal stability of RE-silicates/garnets was tested in autoclave (360°C, 187 bar, PWR water with 1000 ppm B & 2 ppm Li).
• All materials showed negligible weight changes; minor weight loss was observed in 2 samples with small fractions of residual SiO2.
• The steam oxidation resistance of RE-silicates/garnets was assessed:
o Isothermally at 1200°C for 1 h – negligible weight change.
o Isothermally at 1600°C for 1 h – negligible weight change except from 1 sample with residual SiO2.
• The steam oxidation resistance of GB engineered & doped SiC was assessed during slow transient heating to 1600°C – small weight change except from few samples that reacted with the sample holder.
WP6 – Ion/proton irradiation campaigns
• RE-silicates/garnets were in situ ion irradiated in the TEM (600 keV Kr+, 350-1000°C) – despite the harsh test conditions, all materials behaved well (@800°C, crystallinity was retained to >40 dpa).
• Porous SiC appeared stable under in situ ion irradiated in the TEM (600 keV Ar+, RT & 350-1000°C).
• Synergistic proton irradiation/aqueous corrosion tests (5.4 MeV p+, 320°C, 48 h, PWR water with 3 ppm H2) showed better performance for RE-silicates/garnets than CVD SiC.
WP7 – Advanced PIE of BR2-irradiated SiC-based ATF cladding materials
• Hot transport of BR2-irradiated SiC-based claddings from SCK CEN to JRC is ongoing.
WP8 – Predictive modelling activities
• The thermodynamic stability of coating materials was assessed by:
o screening of the entire periodic table, and
o development of CALPHAD databases for 2 ternary systems comprising RE-oxides, Al2O3 and SiO2.
• In-service damage evolution in SiC/SiC composites was simulated by a phase field model with cohesive voxels.
• Stress generation in SiC/SiC composites due to radiation swelling was simulated.
WP9 – Dissemination, communication & training
Four Workshops were organised:
• Workshop on application-driven coating methodologies
• Workshop on multiscale engineering of advanced materials
• Workshop on advanced manufacturing methods for materials frontiers
• Workshop on modelling-enabled material development
