Fig. 4: Morphology and composition of worn surfaces.
From: Near-zero-wear with super-hard WB4 and a self-repairing tribo-chemical layer
SEM images and the corresponding EDS elemental mapping of the worn surfaces of WB4-βB/WC tribo-pair after different friction cycles. The arrow points to the ball’s sliding direction during friction. a The worn surface after 1.25 × 104 cycles. b The worn surface after 5 × 104 cycles. c the worn surface after 1 × 105 cycles. d High-magnification SEM image of the worn track and the corresponding elemental mapping.
