An Effective Approach of Nanoscale CaF₂ Addition into ZTA Composite to Enhance Tribological Characteristics in Dry Sliding

ABSTRACT

This work was carried out to establish a noble technique to enhance tribological characteristics of zirconia toughened alumina (ZTA) ceramic composite by adding 10 wt% nano CaF₂ (∼50 nm) via chemical co-precipitation method. Result of the tribological tests, carried out using ball-on-disk tribo-pair in dry sliding, showed a considerable improvement in coefficient of friction up to ∼55% and the wear rate ∼35% in CaF₂/ZTA composite as compared to pure ZTA composite fabricated via chemical processing route followed by hot pressing. In the later stage, a similar CaF₂/ZTA ceramic composite was fabricated by traditional physical mixing process of commercial CaF₂ and ZTA powders followed by hot pressing using the same parameters and the tribological performances were compared. The specimen fabricated via chemical route possessed better responses in terms of tribo-mechanical behaviors as compared to the specimen fabricated via traditional mixing. Various phases of the composites were examined by X-ray diffraction. Elemental distribution and the worn surface were characterized by energy dispersive X-ray analysis and field emission scanning electron microscopy, respectively.

GRAPHICAL ABSTRACT

Keywords:

• Nano CaF₂/ZTA synthesis
• Powder mixing
• Tribological characterization
• Mechanical characterization