IntroductionAt the present time, YAG is the most widely-used laser material. It is important to synthesize yttrium aluminum garnet (Y3Al5O12,YAG) ceramics with high transparency. In order to produce laser ceramics with high... [ view full abstract ]
Introduction
At the present time, YAG is the most widely-used laser material. It is important to synthesize yttrium aluminum garnet (Y3Al5O12,YAG) ceramics with high transparency. In order to produce laser ceramics with high performance, it is fundamental to synthesize the powders with good dispersity and small particle size, additionally without hard-agglomeration. Solution combustion synthesis (SCS), which is based on the high energy reaction between the metal nitrates and reducing agent, is a promising method for fabrication of YAG nanopowders.
In the work the relationship between the reaction path with three various reducing agents added in stoichiometric amounts on the morphology of the obtained YAG nanopowder was investigated.
Methods
The thermal behavior of reaction mixture (metal oxide precursors and reducing agent) was studied. DSC/TG measurements were realized by using Netzsch STA 449C F1 Jupiter (Netzsch Gerätebau GmbH, Germany). The TG/DSC measurements were carried out from ambient temperature to 1000 ºC with a heating rate of 10ºC/min under 50 ml/min argon flow.
The microstructure of YAG nanopowders was analyzed by scanning electron microscopy (Nova NanoSEM 200, FEI Company).
Results
Urea, glycine and citric acid were tested as reducing agent for fabrication of YAG. In Fig. 1-3 the results of thermal analysis of the reaction mixture are presented. Fig. 4 show SEM images of the microstructure of YAG nanopowder. The powders obtained in the SCS reactions are highly agglomerated. The solidity, size and structure of the agglomerates depend on the process conditions and the type of fuel used.
Discussion
Solution combustion synthesis (SCS) involves the redox reaction of metal nitrates with reducing agent (urea, glycine, citric acid), where metal oxide precursor is obtained. During the reaction nitrates oxidize reducing agent to form metal oxide and non-toxic gaseous products. Depending on the used reducing agent the course of reaction and ignition temperature are different . These parameters affect the morphology and purity but also dispersibility of the YAG powders.
Acknowledgement
This work was funded by the Polish Ministry of Science and Higher Education.
