Treatment of aluminum surfaces by depositing thin films of AIN

Full text This paper presents the experiences of hardening heads aluminum pistons used in a internal combustion engine, via sputtering in the magnetic field (Magnetron Sputtering), obtained under different conditions of heat extraction, to allow assessment of adherence and variations in the microstructure of the substrate (piston). The evaluation of thin film of aluminum nitride was performed by testing microhardness Vickers and microscopic analyzes (XRD, SEM and OM) which facilitated the confirmation of the status of thin film adhesion and a considerable increase in surface hardness. Crystals with macroscopic dimensions and different crystallographic orientations were identified. Some sections showed an increase in hardness significantly higher than others, due to the fact that the piston heads are rough and having varied relief. Surfaces showed improvements in housing stress and hardening that can function as a protective barrier to the formation of cracks on the surfaces. References: [1] BRIEN, V; MISKA, P; BOLLE, B; PIGEAT, P. Columnar growth of ALN by r.f magnetron sputtering: Role of the {1013} planes, Journal of Crystal Growth, 307, 2007, p. 245-252. [2] FIGUERO, A, U; SALAS, O; OSEGUERA, J; Deposition of AlN on Al substrates by reactive magnetron sputtering, Surface & Coatings Technology 200, p. 1768-1776, 2005. [3] LOEHMAN, Ronold E. Characterization Of Ceramics, Butterworth-HeinemannM and Manning Publications Co, 1992, 295 p. (author)