Fig. 9From: Friction characteristics between metal tool and wood impregnated with phenol formaldehyde (PF) resin during exposure to high pressureOptical micrographs of metal tool surface before and after friction coefficient (μ) measurement at 140 °C for phenol formaldehyde (PF) resin concentrations of 0, 30 and 50 % at each stem displacement (D). The triangles indicate gel-like adherentsBack to article page