Wire Electrical Discharge Machining, Mechanical and Tribological Performance of TiN Reinforced Multiscale SiAlON Ceramic Composites Fabricated by Spark Plasma Sintering

Sergey Grigoriev,Sergey Fedorov,Anna Okunkova,Yuri Pristinskiy,Anton Smirnov,Pavel Peretyagin,Marina Volosova

doi:10.3390/app11020657

Sergey Grigoriev, Sergey Fedorov + Show 5 more

Open Access

https://doi.org/10.3390/app11020657

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Abstract

An effective approach for preparing electrically conductive multiscale SiAlON-based nanocomposites with 10 wt.% and 20 wt.% of titanium nitride was developed. Fully dense samples were obtained by spark plasma sintering (SPS) at 1700 °C and 80 MPa for 30 min. The morphology of nanocomposites was observed using scanning electron microscopy and the effects of TiN particles on the mechanical properties and electrical resistivity were studied. It was found that the addition of 20 wt.% TiN increased the hardness and fracture toughness compared to the commercial ceramic analogue TC3030. Meanwhile, the presence of TiN particles reduced the flexural strength of the nanocomposites due to the shrinkage difference between TiN particles and ceramic matrix during cooling, which led to tensile residual stresses and, consequently, to changes in strength values. In addition, the electrical resistivity of nanocomposites decreased with the increase of TiN content and reached 1.6 × 10−4 Ω∙m for 20 wt.% amount of second phase, which consequently made them suitable for electrical discharge machining. In addition to enhanced mechanical and electrical properties, under identical conditions, SPS-sintered multiscale nanocomposites exhibited a higher wear resistance (more than about 1.5-times) compared to the commercial sample due to their higher toughness and hardness.

Highlights

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.Because of their exceptional thermomechanical and tribological characteristics, silicon nitride-based materials are used in several applications such as cutting tools, ball bearings, sealing elements, and engine components [1–4]
It was found that the addition of 20 wt.% titanium nitride (TiN) increased the hardness and fracture toughness compared to the commercial ceramic analogue TC3030
The presence of TiN particles reduced the flexural strength of the nanocomposites due to the shrinkage difference between TiN particles and ceramic matrix during cooling, which led to tensile residual stresses and, to changes in strength values

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Acikbas et al found that the addition of titanium nitride (TiN) into SiAlON matrix can enhance fracture toughness at room temperature. They reported that TiN presence did not have any adverse effect on densification, phase assemblage, or solid solution parameter [14–16]. It is advisable to use electrochemical processing methods, such as electrical discharge machining (EDM) This method makes it possible to avoid labor-intensive and expensive operations while maintaining high workpiece quality. Sun et al reported that a SiAlON composite with 30 wt.% addition of TiN showed a decrease in wear rate and a lower friction coefficient compared to the material without TiN due to the enhancement of heat-conducting properties, mechanical properties, and the tribo-chemical reaction [38,39]. The purpose of this work, was to describe and analyze the behavior of the electromechanical and tribological properties of three multi-material composites, namely pure α/β SiAlON ceramics, as well as the same ceramic with 10 wt.% and 20 wt.% TiN as reinforcement and as the electroconductive phase

Composites Production

Tribological Behavior

Results and Discussion