The Property Characterization of α-Sialon/Ni Composites Synthesized by Spark Plasma Sintering.

Adedayo Sheriff Adeniyi,Tahir Irfan Khan,Akolade Idris Bakare,Muhammad Ali Ehsan,Abbas Saeed Hakeem,Anwar Ul-Hamid,Amir Azam Khan,Bilal Anjum Ahmed,Faheemuddin Patel

doi:10.3390/nano9121682

Abstract

This study investigates the effect of micron-sized nickel particle additions on the microstructural, thermal, and mechanical property changes of α-sialon ceramic composites. The α-sialon/Ni composites were synthesized with an increasing amount of Ni (10–40 wt.%) using the spark plasma sintering technique and nanosized alpha precursors at a relatively low synthesis temperature of 1500 °C with a holding time of 30 min in each case. The density of the samples increased with the increase in Ni content of up to 15 wt.% and, with the further increase in Ni content, it became almost constant with a slight decrease. Furthermore, thermal conductivity and thermal expansion properties of Ni-sialon composites improved slightly with the inclusion of 10 wt.% Ni. The addition of Ni to α-sialon matrix resulted in a decrease in the hardness of the composites from HV10 21.6 to HV10 16.3, however the presence of Ni as a softer interfacial phase resulted in a substantial increase in the fracture toughness of these composites. Fracture toughness was found to increase by approximately 91% at 40 wt.% Ni addition.

Highlights

Engineering applications require the use of materials that exhibit high strength, toughness and hardness, exceptional thermal performance, high resistance to oxidation, wear, and corrosion
Silicon nitride (Si3N4) is a ceramic material that has been extensively used in areas requiring exceptional mechanical properties at elevated temperature, such as gas turbine engine parts [1]
Difficulty in sintering silicon nitride material led to the development of sialon materials, where Si3N4 structure is modified by replacing a fraction of the silicon (Si) and nitrogen (N) with aluminum (Al) and oxygen (O) [1,2]

Summary

Introduction

Engineering applications (such as turbine components, ball bearings, and hard cutting tools) require the use of materials that exhibit high strength, toughness and hardness, exceptional thermal performance, high resistance to oxidation, wear, and corrosion. Silicon nitride (Si3N4) is a ceramic material that has been extensively used in areas requiring exceptional mechanical properties at elevated temperature, such as gas turbine engine parts [1]. Al2O3 [26], ZrO2 [27], as well as sialon- [17] based ceramics, have been sintered using SPS technique. This technique, when compared to conventional sintering techniques, is used to develop ceramics with high densification and better thermal and mechanical properties. Our goal was to investigate the effect of increasing Ni metal content on the microstructure, densification, mechanical, and thermal properties of α-sialon ceramic in order to evaluate their viability for industrial applications, such as gas turbine engine parts

Materials and Methods

Ni Ni

Findings

Sample IDs