A number of composite samples were fabricated using woven carbon fibre plies, epoxy resin and (with the exception of a control sample) a surfacing veil. The properties of these samples was then tested using a pin-on-disk tribometer* which is used to measure friction and wear, and the measured coefficient of friction was plotted against time. The graphs for both the best performing sample (26g/m² aramid surfacing veil) and worse (control - no surfacing veil) are shown below. The data indicates that the inclusion of the aramid veil significantly increases the time taken for the wear test to progress through the sample. The coefficient of friction stays low and it takes 5 times as long for the friction to plateau out to the same value as the control sample. Essentially, this indicates that the use of a surfacing veil means that the level of friction experienced is lower and therefore significantly less material is worn away.
The samples were then inspected to visually assess the damage to the surface and underlying reinforcement. A range of different surface veils were trialled including; 10 & 17g/m² glass, 8 & 17g/m² polyester and 14 & 26g/m² aramid. Of these, the aramid veils performed best with evidence of just surface fibre damage (rather than breakage for glass & polyester) and, in the case of the 26g/m2 aramid, no exposure of the carbon weave. In all samples except the control, the carbon weave remained undamaged. Images of the best and worst performing samples post-test are below.
Control Sample (Without OPTIVEIL) - surface fibre breakage and carbon weave exposed & damaged.
With OPTIVEIL 26 g/m² Aramid Veil - no surface fibre breakage and carbon weave is not exposed or damaged.
*The tribometer parameters used were: ball diameter 6mm, wear radius 5mm, load 10N, speed 240 rpm and a duration of 4000 cycles.