Eventos Anais de eventos
COBEM 2023
27th International Congress of Mechanical Engineering
Effect of anisotropy of zirconia pins produced by additive manufacturing on the wear resistance.
Submission Author:
Giovanna Rubo de Rezende , SP
Co-Authors:
Giovanna Rubo de Rezende, Carlos Fortulan, Italo Leite de Camargo
Presenter: Giovanna Rubo de Rezende
doi://10.26678/ABCM.COBEM2023.COB2023-0982
Abstract
The additive manufacturing (AM) of ceramics has been widely studied. Like other groups of materials, ceramics produced by this process carry strong anisotropy. Many of the ceramic applications are due to its hardness, which gives it high wear resistance. In the case of zirconia ceramics, their application is also due to their fracture toughness. The aesthetic appeal of zirconia ceramic motivated its use in dentistry as prosthetic crowns and orthodontic brackets. Anisotropy is an important aspect to be considered in the AM design and fabrication of ceramic pieces. It has been observed that this property interferes with the mechanical behavior of the parts, and its interference in flexural strength has been extensively studied. However, the influence of anisotropy in parts subject to wear, such as aesthetic orthodontic zirconia brackets, has been poorly explored. This type of orthodontic accessory undergoes shear frictional force resulting from the passage of an orthodontic wire made of metallic alloys through the bracket slot. Thus, the work aims to evaluate the influence of the layer deposition direction on the wear resistance in order to find which one offers better contribution to the optimization of the production of this type of bracket. Based on the above, pins produced by AM (in parallel and perpendicular layer deposition directions) were subjected to shear forces. A “pin-on-disk” wear test was carried out following the ASTM G99–05 standard, using the equipment with a normal load of 10 N and a sliding speed of 0.1 m/s. The wear resistance of pins is classically represented by equations that directly involve hardness and fracture toughness, and can be used for an indirect assessment of fracture toughness relative to the adhesion between layers. Preliminary results have shown that the thickness and adhesion of the layers, as well as the relative movement direction (parallel or perpendicular to the produced layers), influence the wear resistance of the printed pins. The data agrees with the pre-existing results relating to resistance to flexion, showing that pins manufactured perpendicularly to the shear force are more resistant. At the end of the study, if these data are confirmed, it can be concluded that the deposition of layers perpendicular to the action of the steel wire should be the option of choice in the production of orthodontic brackets in zirconia ceramics.
Keywords
cerâmica de zircônia, manufatura aditiva, Anisotropia, desgaste
