The 18 O + 10 B within the bombarding energy range of 29,0 Mev < E LAB < 72,0 Mev, covering the 5° angular range. For this purpose, a high resolution position sensitive ionization chamber has been developed and constructed. Experimental results compared to model predictions and experimental systematics found in the literature allows to reject compound nucleus limitation to the fusion cross section up to energies as high as five times the coulomb barrier. Statistical model fits to the residues elementary distributions reveal a quite difuse partial fusion cross section in the angular momentum space. Systematic analysis of fusion barrier height (VB) and radius for neighbouring nuclei point out the importance of the nuclear matter diffuseness in the competition between the fusion and quasi-direct process. Calculations within this framework were performed.