Heating method and wet-chemical methods such as sol-gel, co-precipitation, hydrothermal, spray drying [6] have been reported for preparation of zirconia powder.
Many of these methods need several operational steps, but, a novel method called
“mechanochemical method” [7] has the potential to synthesize zirconia powder at low
temperature.
Mechanochemical methods can induce structural and chemical changes in solid-state [8], and it enables us to synthesize ultrafine powders [9]. In this process,
chemical precursors undergo reaction, either during milling or subsequent heat
treatment, to form a nanocrystalline composite consisting of ultrafine particles. The
ultrafine powder is then recovered by removing the salt through a washing operation.
This technique has successfully been used to synthesize a wide variety of materials
including transition metals, sulfides and oxides [10]. Advantages in mechanochemical
method are shortening of reaction times, reduction in crystallizing temperature, with
control of average particle size through the use of inert diluents [11].
Mechanochemical method of synthesis is performed in milling devices. Mill and the milling is a key operation for nanostructured materials preparation. Most of
unique properties of nanoparticles depend not only on their nanodimension but also
on dispersity. During dry milling the adhesive forces grow with decreasing particle
size and cyclic stressing leads to recombination of newly created particles into
unstable aggregates, or even into stable agglomerates. Since soluble salt can disperse
the agglomeration, such as, LiCl, NaCl and CH3COONa [12].
The main purpose of this paper is to introduce the mechanochemical process for synthesizing zirconia fine powder from a mixture of ZrOCl2.8H2O and Li2CO3.
ZrOCl2.8H2O is not harmful material in comparison with ZrCl4. LiCl has been used as
a soluble salt which plays a significant role to control particle size and agglomerated
size of the product.