# Effect of Nano-TiO2 Addition on Some Properties of Pre-Alloyed CoCrMo Fabricated via Powder Technology

## TL;DR

This study examines how adding nano-TiO2 affects the properties of CoCrMo alloys made using powder technology, focusing on porosity, hardness, and wear behavior.

## Contribution

The paper introduces the effect of varying nano-TiO2 concentrations on the mechanical and wear properties of pre-alloyed CoCrMo fabricated via powder metallurgy.

## Key findings

- Adding 1 wt% nano-TiO2 improved wear resistance, but higher concentrations increased porosity and reduced density.
- Microhardness slightly increased with 5 wt% nano-TiO2, reaching 348 HV.
- Adhesive wear was the main mechanism, with limited abrasive wear and oxidation observed.

## Abstract

The CoCrMo alloys are progressively utilized as biomaterials. This research is dedicated to studying the consequence of (1, 3, and 5) wt% nano-TiO2 addition on the porosity, microstructure, microhardness, and wear behavior of pre-alloyed CoCrMo powder produced by powder metallurgy (PM). Microstructural features were examined using SEM, SEM mapping, and XRD. Wear behavior was assessed through pin-on-disk tests performed under dry sliding conditions at varying loads and durations. Porosity increased with the addition of nano-TiO2, from 15.26 at 0 wt% reaching 25.12% at 5 wt%, while density decreased from 7.16 to 6.33 g/cm3. Microhardness exhibited a slight improvement, attaining 348 HV at 5 wt%. SEM and XRD analyses confirmed partial particle separation after sintering and identified the TiO2 reinforcement as rutile. Wear tests revealed that adding 1 wt% nano-TiO2 enhanced wear resistance, whereas extended sliding durations resulted in increased wear rates. Adhesive wear was the predominant mechanism, accompanied by limited abrasive wear, oxidation, and plastic deformation.