v parsa - Faculty of physic, ShahroodUniversity of Technolo gy,mailbox ۳۶ ۱۹۹۹۵۱۶۱,shah rood, Iran
h Haratizad eh - Faculty of physic, ShahroodUniversity of Technolo gy,mailbox ۳۶ ۱۹۹۹۵۱۶۱,shah rood, Iran
a Yoo sefi - Par-e-Taavousresearch institute, Mashhad glaze company, mailbox ۵۳۹۵/۹۱۳۷۵,mashhad, Iran

Zircon ia is an im ortant cera mic material and is used in medical and industry for a variety of applications.It is known that the main cr ystal phases of ZrO۲ are cubic (c), tetragonal (t ) and mono clinic (m).The m onoclinic phase is ther modynamic ally stable up to ۱۱۰۰ ° C, the tetragonal phase exists in the temperature range ۱۱۰۰–۲۳۷۰ °C and the cubic phase is found above ۲۳۷۰°C [۲].Zircon ia has som e unique properties su ch as high ionic conductivity, fr acture toug hness, strength and low thermal conductivity .These attractive propertie s are due to the stabili zation of tetragonal and cubic phases at room te mperature.Mate rials and m ethods:In this investigation we synth esis nanopa rticles of zirconia and stabilization tetragonal phase of zirc onia at roo m temperatu re by three different methods such as precipitation method , wet milling method, dry milling m ethod. In t hismethods zirconia po wder and yttria powder are as starting materials. yttria use a s stabilizations agent.In precipitation and wet m illing methods startin g material added to ethanoland this precipitation solventmixed I nprecipitationmethod b y magnetic mixture but In wet milling methoditmixed b y planetary mill with alumina balls for ۵h. In both methodsprecipitation solven tdriedwith microwave.

Zirconia, Precipitation, Milling, Crystallite size.