Unlubricated fretting wear of a hard B12(C,Si,B)3–SiC composite reactively sintered from B4C with Si aids

The fretting wear behaviour of a hard B 12 (C,Si,B) 3 –SiC composite fabricated by reactive spark plasma sintering (SPS) at only 1400 °C from B 4 C with 20 vol% Si aids was evaluated under 1-N and 5-N loads without lubrication against three ceramic materials of different hardness (diamond, Al 2 O 3 and borosilicate glass). The results were compared with those of B 4 C monoliths SPS-ed at 1400 °C and 2000 °C. First, the B 12 (C,Si,B) 3 –SiC composite exhibited lower wear under the 1-N load than under the 5-N load, and its specific fretting rate (SFR) increased with decreasing hardness of the counterpart, which was attributed to greater damage of the latter causing rougher contacts with more abundant wear debris. Nevertheless, the composite demonstrated excellent fretting resistance, having undergone very mild two-body abrasion against diamond (SFR = 10 −7 –10 −8 mm 3 /(N·m)) and very mild or mild three-body abrasion against Al 2 O 3 (SFR = 10 −7 mm 3 /(N·m)) and borosilicate glass (SFR = 10 −6 mm 3 /(N·m)). Second, owing to its fully dense, fine-grained duplex microstructure and high hardness (28.7 ± 0.8 GPa), the B 12 (C,Si,B) 3 –SiC composite exhibited a significantly higher fretting resistance than the porous B 4 C monolith SPS-ed using the same cycle and slightly higher fretting resistance than the well-densified, super-hard (35.6 ± 0.8 GPa) B 4 C monolith SPS-ed at 2000 °C, with the added advantage of requiring a substantially lower SPS temperature. • The fretting wear of a reactively sintered B 12 (C,Si,B) 3 –SiC composite was investigated in friction pairs with three other ceramics. • Fretting wear of the B 12 (C,Si,B) 3 –SiC composite is very mild or mild, and occurs by two- or three-body abrasions depending on the counter-part. • The B 12 (C,Si,B) 3 –SiC composite wears at a higher specific fretting rate the softer the ceramic counter-part. • Comparatively, the B 12 (C,Si,B) 3 –SiC composite is more resistant to fretting than its reference B 4 Cs sintered at the same and higher temperatures.