Characterization and development of alumina toughened zirconia-zirconium diboride (ATZ-ZrB2) composites for automotive industry

Today, the need for materials with higher physical, chemical and mechanical properties is increasing day by day. In the production of these materials, high-tech materials and productions come into play when traditional methods and raw materials used are insufficient. Advanced technological materials are used in many industrial fields such as aviation, military, energy, communication and automotive industries. The growing needs of the industry have made it necessary to develop new high performance materials. As a result, the rate of usage of polymer, ceramic and composites in the engineering applications has increased. The most important feature of the high-tech materials is that the raw materials used in the production of these materials are made of artificial particles obtained with high purity and nano-sized granules. Zirconia (ZrO2) is one of the most remarkable materials of high technology ceramics. With its high wear resistance, toughness, hardness and biocompatibility, Zirkonya has entered into advanced technological ceramics with its physical and mechanical properties. Zirconia, which is used in the automotive industry, has a high hardness value although it has high toughness values. This value is not suitable for high load applications. To overcome these limitations, zirconia must be reinforced with rigid reinforcements. For this, high hardness TiB2 and ZrB2 are used. At this point, ZrB2 is the subject of our thesis. ZrB2, which is ultra high temperature ceramic (UHTC), is preferred in the production of reinforced composite materials in industrial applications in recent years due to its superior properties. For this purpose, in order to obtain a ceramic composite which can meet the needs of the automotive sector in terms of both toughness and hardness value, in this study, zirconia-Zirconium diboride (ATZ-ZrB2) ceramic composite production was performed. For the production of ATZ-ZrB2 composite material in equal molar amounts of Mg-Y-TZP (3 mol% Y2O3 and 8 mol% MgO) mixture, 1% Alumina (Al2O3) by weight and 0,5%- 1% - 1.5%- 2% by weight ZrB2 powders were added. In order to ensure homogeneity of the prepared mixture, the binders were added and mixed in the alcohol environment in the planetary mill. The resulting powder mixture was separated from the drying, sieving and shaping (uniaxial press and CIP) steps, followed by binder removal and sintering at the determined temperature values. Density, hardness-toughness, XRD and SEM analyzes of the samples were performed. According to the results, ATZ-ZrB2 composite production with desired mechanical properties was realized. It is concluded that this composite material produced can be used in industrial applications such as friction in automotive sector and construction or coating of parts with high temperature. Keywords: Tetragonal Polycrystalline Zirconia, ZrB2, ATZ-ZrB2 composite, High-tech ceramics.