Spark Plasma Sintering of fine-grained YAG:Nd+MgO composite ceramics based on garnet-type oxide Y2.5Nd0.5Al5O12 for inert fuel matrices

• Published in: Materials chemistry and physics Vol. 226; pp. 323 - 330
• Main Authors: Alekseeva, L.S., Orlova, A.I., Nokhrin, A.V., Boldin, M.S., Lantsev, E.A., Chuvil'deev, V.N., Murashov, A.A., Sakharov, N.V.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15-03-2019; Elsevier BV
• Subjects: Ceramic composites; Ceramics; Chemical precipitation; Composite materials; Diffusion; Diffusion rate; Fine-grained structure; Garnet; Grain boundaries; Grain boundary diffusion; Magnesium oxide; Nanoparticles; Plasma sintering; Residual stress; Spark plasma sintering; Stress distribution; Garnet; Spark plasma sintering; Ceramic composites; Fine-grained structure; Diffusion
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2019.01.045

Applicability of Spark Plasma Sintering has been studied for production of high-density (98.6–99.5%) composite ceramics Y2.5Nd0.5Al5O12 (YAG:Nd) – x MgO (x = 5, 10, 20 vol %). Powder YAG:Nd-MgO compositions have been obtained by precipitation of the MgO phase from Mg(NO3)2 water solution of magnesium nitrate onto the surface of garnet nanoparticles YAG:Nd. It has been demonstrated that the intensity of sintering fine-grained YAG:Nd-MgO composites is governed by volume diffusion at low temperatures and by grain boundary diffusion at high temperatures. Faster sintering at low temperatures is caused by formation of MgAl2O4 spinel particles and internal stress fields that are manifested as broadening and shifting of garnet peaks in the sintered composites.
•Ultrafine-grained Y2.5Nd0.5Al5O12 (YAG:Nd) powders obtained by co-precipitation.•Powder obtained by precipitation of the MgO phase from Mg(NO3)2 water solution.•YAG:Nd + (5, 10, 20) vol% MgO high-density ceramics obtained by SPS.•Compression fields of internal stresses form in composites during SPS.•Sintering rate is governed by the diffusion in the lattice and in grain boundary.