Research On The Dry Sliding Tribological Behavior Of Alumina/Titania Ceramic

In this paper, four kinds of composite powders including microstructured Al₂O₃/TiO₂ powders, nanostructured Al₂O₃/TiO₂ powders, nanostructured Al₂O₃/TiO₂/ZrO₂/CeO₂ powders and plasma treated nanostructured Al₂O₃-TiO₂-ZrO₂/CeO₂ powders were chosen respectively to prepare four Al₂O₃/TiO₂ composite ceramics through spark plasma sintering (SPS), refered to as ME, NN, NS and NP ceramic, respectively. Then microstructures, mechanical properties and dry sliding tribology were investigated.XRD results showed that ME and NN ceramics were composed ofα-Al₂O₃ and Al₂TiO₅, besides those two phases, t-ZrO₂, CeTi21O38 and Ce₂Zr₂O₇ were also found in NS and NP ceramics attributed to addition of ZrO₂ and CeO₂. SEM results showed that the microstructure of NN, NS and NP ceramics were finer compared to ME ceramic with coarse grains. The mechanical properties of NN were better than ME, especially fracture toughness and hardness. Compared to NS ceramic, NP ceramic exhibited a better mechanical properties as a result of its densified and fine microstructure which were produced by plasma treating.Sliding wear tests showed that wear volumes of these four ceramics increased with increasing normal load in the condition of 400r/min and 600r/min, ME ceramic exhibited lower wear volume than NN, and NP exhibited lower wear volume than NS. In the condition of 800r/min and 20N, the third body layer in the worn surface of NN ceramic was very thin, the third body layer of other three ceramics were about 30⁵0μm. The third body layer of ME ceramic was densified and compacted compared to NS and NP ceramics. EDS analyse showed that the percent of Ti in the third body layer in the worn surface of ME was extremely high, nevertheless the percent of Ti in the third body layer in the worn sub-surface was similar as other ceramics.Wear mechanisms of NN, NS and NP ceramics were intergranular fracture, grain pull-out could be found in the NP ceramic. In the ME, NS and NP ceramics, plastic deformation existed. EDS analyse showed that oxidization and material transfer appeared on the worn surfaces. Plowing on the worn surfaces of NS and NP ceramics formed at lower velocity 400r/min.When the NS and NP ceramics were taken sliding wear tests at different velocities and normal loads, the critical condition for mild and severe wear of them was specific wear rate equal to 10^-5mm³/Nm. Then severe wear prediction was tested based on the lateral crack model (LCM), the difference between prediction data and experimental data of NS and NP ceramics were little under most wear conditions.