Tribological Influences of CuO Into 3Y-TZP Ceramic Composite in Conformal Contac

The aim of the study was to investigate the friction and wear phenomena of 3 mol % yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) ceramics with the inclusion of copper oxide (CuO) in large area conformal contact geometry. The pin-on-disk tribometer was used to conduct the dry sliding test using CuO/3Y-TZP as pin and alumina as counter surface. The coefficient of friction (μ) for CuO-added 3Y-TZP was decreased by ∼38% compared to pure 3Y-TZP due to formation of protective tribo film to the substrate. In addition, the experiments also showed that the specific wear rate (k) was reduced by ∼54% with the inclusion of CuO in to 3Y-TZP matrix. The different phases of the zirconia, copper, and yttria as well as the phase transformation before and after sliding test were identified by X-ray diffraction (XRD) analysis. Field emission scanning electron microscopy (FESEM) and energy dispersive X-ray (EDS) analysis revealed the existence of CuO in the patchy layers in the worn-out surface of the tested CuO/3Y-TZP sample leading to lower coefficient of friction and improve the wear resistance against alumina counterface in conformal contact geometry. Severe wear mechanism was the dominating factor due to the local plastic deformation of the large number of asperities since the pair of contact was conformal

Tribological property enhancement of 3Y-TZP ceramic by the combined effect of CaF2 and MgO phases

Calcium fluoride (CaF2) often provides enhanced lubricating properties into ceramic composites when combined with other metal oxides to form some lubricating substrate. Present work unveils the superiority of small amount of CaF2 (1 wt%) as solid lubricant with the addition of metal oxide such as magnesium oxide (MgO) into 3 mol% yttria stabilized tetragonal zirconia polycrystals (3Y-TZP) ceramic matrix. With addition of 0.5 wt% MgO in CaF2/3Y-TZP ceramic composite, the mean coefficient of friction (μ) was down to ∼42% and the subsequent wear rate (k) was reduced to ∼31% as compared to pure 3Y-TZP due to the presence of smooth tribo layer at the contacting interfaces. The tribological tests were performed against a hard-abrasive silicon carbide (SiC) counter surface under dry sliding condition. The wear mechanisms and elemental distributions in the worn surface were studied by field emission scanning electron microscopy (FESEM) coupled with energy dispersive X-ray (EDS) setup. X-ray diffraction (XRD) analysis was carried out to identify different phases present in test specimens as well as in wear track. The presence of chemical states in the tribo layer was investigated by means of X-ray photoelectron spectroscopy (XPS) analysis

Tribological investigation of MgO/Al2O3 ceramic composite with the inclusion of nano CuO in dry abrasive wear test

This paper aims to investigate the tribological influence of nano sized (~50 nm) copper oxide (CuO) into the magnesium (MgO) based alumina (Al2O3) ceramic composite in a hard-abrasive sliding condition. Sliding wear test was performed to find the frictional and wear behavior of the specimens against abrasive silicon carbide (SiC) interface by means of a rotary pin-on-disk tribometer. Nano CuO added specimen significantly diminished both friction coefficient and wear rate by ~42.94% and ~38.30%, respectively as compared to base MgO/Al2O3 specimen. Mending effect of nano CuO by providing a smooth layer was expected to be the main lubricating mechanism against rough abrasive wear surface. Delamination and two body abrasion were the predominant wear mechanism which was investigated using field emission scanning electron microscopy (FESEM) coupled with energy dispersive x-ray spectroscopy (EDS). Different phases of the compounds were identified by x-ray diffraction (XRD) analysis

Tribological Property Investigation of Self-Lubricating Molybdenum-Based Zirconia Ceramic Composite Operational at Elevated Temperature

Three mol% yttria-stabilized tetragonal zirconia polycrystals (3Y-TZP) with 0.5 wt% of magnesium oxide (MgO) and 6 wt% of molybdenum (Mo) were prepared by the pressureless sintering process, and the friction and wear behavior of the ceramic composite were studied against the alumina disc. Tribological tests were carried out both at room temperature as well as at an elevated temperature (500 °C). The result revealed that a substantial reduction of ∼50% in the friction coefficient and ∼31% reduction in the wear rate were achieved while 6 wt% Mo was added into the 3Y-TZP matrix operational at 500 °C. No significant tribological influence was observed with the addition of Mo at the normal operating temperature. The minimum coefficient of friction and low specific wear rate were achieved because of the formation of MoO3 in between the mating surfaces at elevated temperature. The worn surfaces were characterized by means of field emission scanning electron microscopy (FESEM). The formation of MoO3 phases was identified by wear debris analysis which was performed with the help of X-ray photoelectron spectroscopy (XPS)