Nano-TiO2 reinforced CoCr matrix wear resistant composites and high-temperature tribological behaviors under unlubricated condition

Gongjun Cui,Sai Li,Ziming Kou,Guijun Gao,Huiqiang Liu,Yanping Liu

doi:10.1038/s41598-020-63918-4

Gongjun Cui, Sai Li + Show 4 more

Open Access

https://doi.org/10.1038/s41598-020-63918-4

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Journal: Scientific Reports	Publication Date: Apr 22, 2020
Citations: 6	License type: open-access

Affiliation: Taiyuan University of Technology

Abstract

The CoCrMo matrix composites with nano-TiO2 particle (2 wt.%, 4 wt.% and 6 wt.%) were fabricated by using a powder metallurgy technique (P/M), and the nano-TiO2 content was optimized in matrix. The microstructures, mechanical and high-temperature tribological properties of the synthesized composites were systematically studied. Friction and wear behaviors were studied by using a disk-on-ball tribo-tester sliding against Si3N4 ceramic ball from room temperature (23 oC) to 1000 oC in air. TiO2 obviously strengthened the hardness and high-temperature wear resistance of composites. It was attributed to the high load-carrying capacity of matrix, in-situ formed high-temperature solid lubricants and stable oxides film on the wear tracks. 4 wt.% TiO2 was the critical threshold at which there was a transition of tribological properties over a broad temperature range. The composite containing 4 wt.% nano-TiO2 exhibited the most reasonable high-temperature friction coefficient and wear rate at all testing temperatures. At different testing temperatures, the composites showed different wear mechanisms.

Highlights

The CoCrMo matrix composites with nano-TiO2 particle (2 wt.%, 4 wt.% and 6 wt.%) were fabricated by using a powder metallurgy technique (P/M), and the nano-TiO2 content was optimized in matrix
With the increasing power of engines, there is a strong need for the materials with the good tribological properties over a broad temperature range
Wear resistance of materials only depends on the metal oxides on the surface of wear tracks at elevated temperatures, and oxidation causes the degradation of materials[4,17]

Summary

Introduction

The CoCrMo matrix composites with nano-TiO2 particle (2 wt.%, 4 wt.% and 6 wt.%) were fabricated by using a powder metallurgy technique (P/M), and the nano-TiO2 content was optimized in matrix. TiO2 particle is a potential reinforcement for Co matrix high-temperature wear resistant materials. The wear resistant cobalt matrix composite reinforced by TiO2 is rarely done at elevated temperatures.

Results

Conclusion