Preparation of Si₃N₄-YAG mixtures for the spark plasma sintering method

Abstract

In order to obtain ceramics based on Si3N4 with improved physical and mechanical properties, methods of creating composites for their subsequent consolidation by the spark plasma sintering method were investigated. Four different methods of producing mixtures based on the Si3N4 and Al5Y3O12 (YAG) precursor were considered in order to obtain a homogeneous distribution of the YAG sintering additive on the surface of the Si3N4 particles. It is shown that the YAG and Y-Si-Al-O-N phases are formed by co-precipitation, deposition in a gelatin matrix and Pecini methods. The spray drying method does not lead to the formation of the YAG phase. This may indicate a high homogeneity of the YAG coating on the surface of the Si3N4 particles, preventing the growth of crystalline particles.

Spark Plasma Sintering of Si3N4 Ceramics with Y2O3–Al2O3 (3%–10% wt.) as Sintering Additive

“…There are increasing requirements for the powder mixtures as a factor determining the homogeneity and physical and mechanical properties of the ceramic samples. Codeposition methods provide high mixing homogeneity and are used to prepare the mixtures despite the process complexity [17,[34][35][36].…”

Phase homogeneity of Si3N4-based ceramic materials produced by spark plasma sintering

“…The role of initial material was played by industrial powder of Si 3 N 4 (purity 99.6%, 90 wt% α-Si 3 N 4 + 10 mass% β-Si 3 N 4 , average particle size < 5 µm, Alfa Aesar, Germany). The Y 2 O 3 −Al 2 O 3 sintering additive (with a mole ratio of 3:5) was introduced into the Si 3 N 4 initial powder in the form of precursor in an amount of 5 and 10 mass % (specimens ë 1 and 2, respectively) expressed as oxide [8].…”