A new approach to the estimation of surface free energy based on Vickers microhardness data

A relation between surface free energy (sigma(MHV)) and Meyer's lines cut-values has been established using Vickers microhardness (MHV) method and empirical physical laws. This relation allows the calculation of sMHV only from MHV data. The parameters required are Meyer's lines cut-values and the mean value of diagonal length of the impression at different loads applied (d(mean)(real)). Our study of 12 samples of ultra high molecular weight polyethylene (PE-UHMW) showed that the new approach is applicable when the slope value of Meyer's lines equals 2 (i.e. n = 2). A gamma-(60)Co source was used for the irradiation of 11 samples ( one of the samples investigated is un-irradiated) at room temperature in air. Doses of 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000 and 1500 kGy were applied. The values of sMHV obtained are in a good agreement with the literature. The dependence of sMHV on the dose applied strictly corresponds to the radiation effects theory. MHV was measured at seven different loads -0.0123, 0.0245, 0.049, 0.098, 0.196, 0.392, 0.785 N at a loading time of 30 s.