Fabrication of TiN/Si₃N₄ Ceramics by Spark Plasma Sintering of Si₃N₄ Particles Coated with Nanosized TiN Prepared by Controlled Hydrolysis of Ti(O‐i‐C₃H₇)₄

Abstract

TiN‐coated Si3N4 particles were prepared by depositing TiO2 on the Si3N4 surfaces from Ti(O‐i‐C3H7)4 solution, the TiO2 being formed by controlled hydrolysis, then subsequently nitrided with NH3 gas. A homogeneous TiO2 coating was achieved by heating a Si3N4 suspension containing 1.0 vol% H2O with the precursor at 40°C. Nitridation successfully produced Si3N4 particles coated with 10–20 nm TiN particles. Spark plasma sintering of these TiN/Si3N4 particles at 1600°C yielded composite ceramics with a relative density of 96% at 25 vol% TiN and an electrical resistivity of 10−3Ω·cm in compositions of 17.5 and 25 vol% TiN/Si3N4, making these ceramics suitable for electric discharge machining.

Microstructure and mechanical properties of TiN/Si3N4 nanocomposites by spark plasma sintering (SPS)

“…The present authors have reported that TiN/Si 3 N 4 based nanocomposites with excellent mechanical properties and conductivity can be processed through a chemical route and sintered by SPS [10,11]. However, due to the complexity * Corresponding author.…”

The effect of different sintering additives on the electrical and oxidation properties of Si3N4–MoSi2 composites

“…conductive composites, this can facilitate machining of these composites into complex shapes by the more economical electrical discharge machining (EDM). 4 Various Si 3 N 4 composites with addition of an electroconductive secondary phase, such as TiN, 3 TiB 2 , 5 TaN, 6,7 TiC 8 and MoSi 2 , 9,10 have been studied. Among them, Si 3 N 4 -MoSi 2 composites are of special interest.…”

Si<SUB>3</SUB>N<SUB>4</SUB>–TiN Nanocomposite by Nitration of TiSi<SUB>2</SUB> and Consolidation by Hot Pressing and Spark Plasma Sintering

“…That is why the TiN content is usually limited to 25-40 vol% (37-52 mass%), i.e., amount necessary to form TiN continuous conductive three-dimensional network and improve toughness and room-temperature strength characteristics without significant decrease in oxidation resistance. [1][2][3][4][5][6][7][8][9][10][11][12] Methods used in the preparation of Si 3 N 4 -TiN composite materials are mainly based on using mechanical mixtures of initial components. These methods cannot provide a homogeneous distribution of titanium nitride in the silicon nitride matrix, a necessary condition of the continuous three-dimensional TiN network in the Si 3 N 4 , as well as sufficient electric conductivity.…”

“…13 The hot pressing (HP), pressureless sintering and gaspressure sintering in a nitrogen atmosphere are usual methods for the Si 3 N 4 -TiN ceramic consolidation. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] These methods generally provide high density; however, require the temperatures of 1750 C to 1800 C which result in the formation of coarse-grained structure. 2-6 9-12 Avoiding a high-temperature processing stage, i.e., achieving a finegrain microstructure may lead to enhancement of the functional properties.…”