Studio tribologico di rivestimenti per migliorare la resistenza ad usura di componenti per attuatori idraulici

The service life of a hydraulic actuator is influenced by the sliding wear resistance of some of its steel components. In order to prolong the service life, and / or to extend the range of stresses in which the actuator can operate, a study on tribological coatings, alternative to those currently employed, was conducted. Both thick thermal spray coatings and thin PA-CVD diamond-like carbon (DLC) coatings (consisting of hydrogentated amorphous carbon, a-C:H) were taken into consideration. DLC coatings were deposited onto plasma-nitrided steel by a duplex process. In a first step of the work, the most promising candidate coatings/treatments were ranked on the basis of laboratory dry sliding tests. Subsequently, bench test were carried out on the best coated components, so as to validate and assess the tribological performance. The results of this study allowed the identification of a new combination of coatings and surface treatments, which can prolong at least 5 times the life of the hydraulic actuator