Synthesis of zirconia n anoparti cles in presence of citric acid or starch as emulsifier

The zirconium o xide nanoparticles (zirconia) are known as conductive or semi-cond uctive metal oxides. Zirconia exhibits several cr ystalline modifications: monoclinic, tetragonal, cubic and rh ombic. The martensitic transformation from t he tetragonal to the monoclinic stru cture has great import ance in cer amic and catalytic applications of zirconia. Ultrafine zirconia particles have been synthesi zed via vari ous method s such as sol–gel proc essing, chemical vapor synthesis, p recipitation from inorganic salt solutions, mic rowave plasma synthesis and etc [۱] . Zirconia’s most natura lly occurring form, wit h a monoclin ic crystallin e structure, is the rare mineral baddeleyite. Th e high tem perature cu bic crystalline form, also called cubic zirconia (CZ), is rarely found in nature as mineral tazheranite (Zr,Ti,Ca)O ۲ and a do ubtful mineral arkelite [۲ ].Mate rials and m ethods:Samples were pre pared by d rying of a solution of Z rO(NO۳)۲· ۲H۲O in pre sence of organic emulsifier of citric acid or st arch. The materials were calcined a t ۶۰۰oC an d subsequently at ۹۰۰oC for ۵ h b y a heating rate of ۱۰ °C/min from room tem perature. The samples were charac terized by F T-IR spectroscopy, XRD and TG/D TA.

کلیدواژه ها:

Emul sifier ، Nano particle ، Starch ، Citric Acid ، Thermal decomposition.