MODIFICATION OF THE SURFACE OF TOOLOX44 STEEL BY ION IMPLANTATION BY PLASMA IMMERSION: MICROSTRUCTURAL EVOLUTION AND HARDNESS INCREASE

Surface engineering has played a central role in the development of materials by improving their application in severe conditions, such as metal forming and cutting operations, in which high contact stresses and cyclic loads accelerate the wear mechanisms to which they are subjected. In this context, the present work investigated the surface modification of Toolox 44 steel by the process of ion implantation by plasma immersion (3IP), with emphasis on its microstructure, crystalline phases and mechanical properties. Some samples were treated and characterized by Vickers microhardness tests, metallographic analysis and X-ray diffraction. The results showed that the 3IP treatment induces structural modifications more distributed at depth, characterized by a higher density of crystalline defects, microdeformations and compressive residual stresses, without the formation of a thick composite layer. This microstructural difference resulted in a considerable increase in the surface hardness of the samples (~889 HV), attributed to the synergistic action of the mechanisms of hardening by defects, fine precipitation and continuous structural gradient. In addition, the absence of abrupt interfaces suggests greater mechanical stability and lower susceptibility to failures such as cracks or delamination. From a technological point of view, compared to the most used surface treatments in this segment, this process has additional advantages, including lower processing temperature and reduced treatment time, expanding its potential for industrial applications. Thus, the results demonstrated that 3IP constitutes an advanced and efficient approach to surface engineering, offering an optimized combination of hardness and structural integrity, relevant for tools subjected to repetitive load operating conditions.