Preparation and mechanical properties of Si₃N₄ nanocomposites reinforced by Si₃N₄@rGO particles

Abstract

A new type of reduced graphene oxide‐encapsulated silicon nitride (Si3N4@rGO) particle was synthesized via an electrostatic interaction between amino‐functionalized Si3N4 particles and graphene oxide (GO). Subsequently, the Si3N4@rGO particles were incorporated into a Si3N4 matrix as a reinforcing phase to prepare nanocomposites, and their influence on the microstructure and mechanical properties of the Si3N4 ceramics was investigated in detail. The microstructure analysis showed that the rGO sheets were uniformly distributed throughout the matrix and firmly bonded to the Si3N4 grains to form a three‐dimensional carbon network structure. This unique structure effectively increased the contact area and load transfer efficiency between the rGO sheets and the matrix, which in turn had a significant impact on the mechanical properties of the nanocomposites. The results showed that the nanocomposites with 2.25 wt.% rGO sheets exhibited mechanical properties that were superior to monolithic Si3N4; the flexural strength increased by 83.5% and reached a maximum value of 1116.4 MPa, and the fracture toughness increased by 67.7% to 10.35 MPa·m1/2.

10 years of research on toughness enhancement of structural ceramics by graphene

“…Conversely, GO is commonly fabricated by Hummers’ method, giving stable aqueous suspensions of platelets with a thickness of less than 5 nm. The functional groups in GO sheets allow the formation of strong bonds with defects present in the matrix and enable GO sheets to interact with positively charged ceramic particles [ 46 ]. These conditions create stronger interfaces for a better load transfer [ 31 ].…”

“…Adapted from [ 58 ], no permission required. Δ K IC / K 0 reported for basic bulk composites in recent years, separated by matrix type ( b ) oxides [ 11 , 12 , 22 , 31 , 32 , 59 – 62 ], ( c ) nitrides [ 15 – 17 , 41 , 46 , 63 – 67 ] and ( d ) carbides [ 19 – 21 , 25 , 27 , 28 , 68 – 71 ]. Materials already reported in Figure 2 a have been included in black colour.…”

Mechanical Properties of WC-Si3N4 Composites With Ultrafine Porous Boron Nitride Nanofiber Additive

“…In the aforementioned results, the fracture mode identified in the results can be noticeable. In general, Si 3 N 4 ceramics are known for catastrophic fracture, and thorough fracture of Si 3 N 4 grains with clean edge is observed (a fine image of fracture of Si 3 N 4 grains is provided in Riley (2000), Ii et al (2004), Klemm (2010), Zhou et al (2014), and Hu et al (2019). However, different cases of tears and scratches emerge on the Si 3 N 4 grains in the composites with UPBNNF, as shown in Figure 5, which means fractures of Si 3 N 4 occur partly under a given load.…”

A novel method of strong and tough Si3N4 ceramic from the particle‐stabilized foam

“…Si 3 N 4 ceramics have excellent comprehensive properties, such as high strength, high hardness, wear resistance, oxidation resistance, thermal shock resistance, and chemical corrosion resistance, which is considered one of the most promising industrial structural ceramics. [1][2][3][4][5] However, the inherent brittleness of Si 3 N 4 ceramics also limits the reliability of applications where brittle fractures occur at the crack propagation, resulting in catastrophic damage. Therefore, improving the fracture toughness of Si 3 N 4 ceramics remains one of the most critical issues.…”