Ensaios de aderência de esquemas de pintura pelo método de tra？？o (pull-off): Avalia？？o de fatores que influenciam os resultados

the measurement of coatings adherence by the pull-off test, according to the astm d 4541 or iso 4624 standards has been extensively used in the anticorrosive protection assessment. by this methodology, the pull-off strength value is obtained as well as the nature of the failure is evaluated. however, some important inherent factors from the test influence its results. so, in this paper, it is presented the achievements of a study in which four different laboratories worked together in the evaluation of the adherence, by means of the pull-off test, of three coating systems, each one having a particular physical-chemical characteristic. it was investigated the influence of different substrate thickness (3 mm and 9 mm) and of different equipments in the adherence measurement by the pull-off method. it was shown that, regardless the equipment used, when it was used the 3 mm thick substrates the values of the pull-off strength were lower than the cases when the thicker substrates were used. it was also observed that different equipments can lead to very different results.