【正文】 IR spectra and UV–visible absorption spectrum of the produced ZrO2 nanopowders which are obtained by these three process ing routes at different calcination temperatures from 120 to 1200 ? C. 2. . Experimental Materials and processing The materials used in the present work were, zirconyl chlo ride ZrOCl2 Zhang et al., 2022。 Teterycz et al., 2022。 Jiang et al., 2022。 Piticescu et al., 2022). The chemical precipitation (CP) method is a suitable low cost technique for the mass production pared with the other mentioned technique. The main drawback is that the particle size is not small and has in wide size distribution. Microemulsion re?ned precipitation (MRP) gives better chem ical homogeneity with controlling the particle size and size distribution. Citrate gel bustion (CGC) technique is used to obtain highly uniform size and shape controlled nanopar ticles. ZrO2 has three polymorphic phases。 Noh et al., 2022。 Roy and Ghose, 2022。 Chatterjee et al., 1992。 Yashima et al., 1994。 Juarez et al., 2022。 Fang et al., 1997。 Ward and Ko, 1993。 Djuricic et al., 1995。 Lee et al., 1999。 2022 Elsevier . All rights reserved. doi:? 3 j o u r n a l o f m a t e r i a l s p r o c e s s i n g t e c h n o l o g y 1 9 5 ( 2 0 0 8 ) 178–185 179 such as FischerTropsch synthesis, methanol synthesis and hydrodesulfurization have been reported to proceed with higher activity and selectivity than with conventional sup ports (Jung and Bell, 2022). It is well known that zirconia is a low absorption materials usable for coating in the nearUV (300 nm) or IR (～ 8 m) regions. Typical applica tions include nearUV laser and dielectric mirror designs. In addition, about 95% of ferrule, the most important part of the optical ?ber connector is now made from zirconia ?ne ceramics. It is known that high quality of the ceramic is based on the excellent performance of zirconia powder (5). Preparing a ?ne and an agglomerate free zirconia powder is the ?rst and perhaps the most important step in obtaining a sintered zirconia ceramic of desirable microstructure and therefore mechanical properties. Various chemistrybased novel approaches have been taken for the preparation of zirco nia powders including coprecipitation, hydrothermal, sol gel, sonochemical method, microemulsion and thermal de position processing (Ma et al., 2022。 Kongwudthiti et al., 2022). Zir conia catalyzes the hydrogenation of ole?ns, isomerization of ole?ns and epoxides and the dehydrations of alco hols. When zirconia is used as support, various reactions Corresponding author. Tel.: +20 2 5010642/213。 畢業(yè) 論文 外文資料翻譯 題 目 熱處理對三種不同途徑生產(chǎn)的 納米粉氧化鋯晶體結(jié)構(gòu)和形態(tài)的影響 學(xué) 院 材料科學(xué)與工程 專 業(yè) 材料科學(xué)與工程 班 級 學(xué) 生 學(xué) 號 指導(dǎo)教師 二〇一 三 年 三 月 二 一 日 2 j o u r n a l o f m a t e r i a l s p r o c e s s i n g t e c h n o l o g y 1 9 5 ( 2 0 0 8 ) 178–185 journal homepage: Effect of thermal treatment on the crystal structure and morphology of zirconia nanopowders produced by three different routes . Rashad ? , . Baioumy Central Metallurgical Research and Development Institute, . Box 87, Helwan, Cairo, Egypt article Article history: info abstract Zirconia ZrO2 nanopowders have been successfully prepared via three processing routes, namely, conventional precipitation (CP), citrate gel bustion (CGC) and microemulsion re?ned precipitation (MRP). The formed zirconia particles were characterized using Xray diffraction analysis (XRD), scanning electron microscope (SEM), Fourier transformer infrared (FTIR) spectroscopy and UV–visible absorption spectrum. The results showed that the CP route led to the formation of tetragonal ZrO2 phase with low crystallinity at 700 ? C and the formed tetragonal phase was transformed to monoclinic ZrO2 phase at temperatures ranged Received 24 May 2022 Received in revised form 22 April 2022 Accepted 23 April 2022 Keywords: Zirconia Synthesis Crystal structure Nanoparticles Characterization from 1000 to 1200 ? C. The CGC route led to formation of monoclinic phase without presence tetragonal phase species in the temperatures range from 1000 to 1200 ? C. In contrast, MRP technique led to the formation of tetragonal phase with high crystallinity pared with the other processing at 700 ? C and the produced tetragonal phase was inverted to cubic phase by increasing the calcination temperatures from 1000 to 1200 ? C. SEM showed that the morphology of the produced zirconia nanopowders changed according to synthesis routes and thermally treated temperatures. 169。 2022 Elsevier . All rights reserved. 1. Introduction Advanced ceramics known as ?ne ceramics are a diverse group of inanic oxides such as zirconia, alumina, tita nia and nonoxides like silicon carbide, boron carbide and silicon nitride. These materials are drawing attention as high technology materials because of their superior mechan ical, thermal, electrical, chemical and optical properties. Zirconia ?ne ceramics have an impressive bination of properties such as high strength, hardness, toughness, corrosion resistance, low coef?cient of friction and bio patibility. Nearly 80% of produced zirconia in the world is used in conventional applications such as refractories, pig ments, glazers, opaci?ers, abrasives, etc. The everincreasing numbers of ceramics applications have resulted in devel oping of advanced technologies to process nanopowders zirconia (Galgali et al., 1995). The advanced applications of zirconia nanopowders are including transparent opti cal devices, electrochemical capacitor electrodes, oxygen sensors, fuel cell