Microstructure and properties of mullite–ZrO2 ceramics with silicon nitride additive prepared by spark plasma sintering

About the author

Gaida Sedmale, Dr. habil. chem. (1989), associated professor and leading researcher Faculty of Material Science and Applied Chemistry, Riga Technical University. She is the author of more than 200 scientific publications in the field of glass and ceramic chemistry and technology and more than 50 Latvian and Russian patents describing glass and ceramic materials, as well as co-author or author of teaching books in branch of ceramic and silicate materials. For last 20 years her scientific interests include new high-temperature and traditional ceramic materials, as well as at present she is involved in the mineral raw materials, mainly illite clay of Latvia, researches.

Address: PaulaValdena Str.3, LV‑1048, Riga, Latvia

Phone: +371 67089257, Fax: +37167615765

E-mail: [email protected]  

 

About the author

Ilmars Zalite, Dr.sc.ing.(1992), leading researcher, Institute of Inorganic Chemistry, Riga Technical University, More than 35 years has experience in powder metallurgy, plasma chemistry and technology. Current research interest is in synthesis of refractory compounds and research of ceramic materials on their basis

Publicity: 108 scientific papers, 115 communications and proceedings, 8 investions and 6 patents.

Member of Latvian Materials Research Society and German Society of Materials, has State Premium (1980) and Premium of the Latvian Academy of Sciences (1985).

Address: Paula Valdena Str.3, LV‑1048, Riga, Latvia

E-mail: [email protected]  

 

About the author

Ints Steins, M. Sc. (1983.) researcher, Institute of Inorganic Chemistry, Riga Technical University. Up to 30 years has experience in the powder metallurgy, plasma chemistry and technology. Is the author or co-author of more than 45 scientific papers in this branch.

Address: Paula Valdena Str.3, LV‑1048, Riga, Latvia

E-mail: [email protected]  

 

About the author

Gundars Mezinskis, is a professor and head of the Department of Silicate, High Temperature, and Inorganic Nanomaterials Technology, and director of the Institute of Silicate Materials at the Riga Technical University of Latvia. He received his PhD and Dr.habil.Sc.eng. degree accordingly in 1981 and 1998, respectively. G.Mezinskis is a recognized expert in characterization of ceramic and glass like materials by scanning electron and atomic force microscopies. His main research interests are in sol-gel technology application for synthesis of glass-like and ceramic materials, and thin film coatings. He is the author or co-author of more than 120 scientific papers, 3 inventions (former USSR), and 8 patents.

Address: Paula Valdena Str.3, LV 1048, Riga, Latvia

Phone: +371 67089141, Fax: +371 67089107

E-mail: [email protected]  

 

Journal Reference

Ceramics International, Volume 42, Issue 3, 15 February 2016, Pages 3745–3750. 

Gaida Sedmale1, Ints Steins2,Ilmars Zalite2,Gundars Mezinskis1

Show Affiliations
  1. Riga Technical University, Institute of Silicate Materials, Valdena Str. 3, LV1048 Riga, Latvia
  2. Riga Technical University, Institute of Inorganic Chemistry, Valdena Str. 3, LV1048 Riga, Latvia

Abstract

The process of densification and development of the microstructure of mullite–ZrO2/Y2O3 ceramics from mixture of Al2O3, SiO2, ZrO2 and Y2O3 by gradually adding of α–β Si3N4 nanopowder from 1 to 5 wt% by traditional and spark plasma sintering were investigated by means of differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM), and some ceramic and mechanical properties. The processes of DTA for all samples are characterised by a low-pitched endo-effect, when gradual mullite formation and noticeable densification at temperatures of 1200–1400 °C is started. It is testified by shrinkage and density both for traditionally and by SPS-sintered samples. The influence of the Si3N4 additive on the density characteristics is insignificant for both sintering cases. For SPS samples, the density reaches up to 3.33 g/cm3, while for traditionally sintered samples, the value is 2.55 g/cm3, and the compressive strength for SPS grows with Si3N4 additives, reaching 600 N/mm2. In the case of traditional sintering, it decreases to approximately 100 N/mm2. The basic microstructure of ceramic samples sintered in a traditional way and by SPS is created from mullite (or pseudo-mullite) crystalline formations with the incorporation of ZrOgrains. The microstructure of ceramic samples sintered by SPS shows that mullite crystals are very densely arranged and they do not have the characteristic prismatic shape. The traditional sintering process causes the creation of voids in the microstructure, which, with an increasing amount of Si3N4 additive, are filled with mullite crystalline formations.

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