02293nas a2200253   4500008004100000022001400041245009300055210006900148260013000217300001200347490000700359520135300366653001101719653004001730653001901770653001401789653001801803100002201821700001901843700001801862700002201880700002001902856011701922       2006                        eng d  a1226-086X00aDielectric properties of BaTiO3 ceramics prepared from powders with bimodal distribution0 aDielectric properties of BaTiO3 ceramics prepared from powders w  aA-803 TWIN BLDG, 275-3, YANGJAE-DONG, SEOCHO-KU, SEOUL 137-130, SOUTH KOREAbKOREAN SOC INDUSTRIAL ENGINEERING CHEMISTRYcJUL  a584-5880 v123 a<p>BaTiO3 (BT) powders having bimodal distribution were synthesized successfully through a simple classical solid-state reaction route using cheap BaCO3 and TiO2 as starting materials. These powders were further processed in the form of green pellets to obtain dense BT ceramics having densities of similar to 94 similar to 96 % after sintering in air at 1350 and 1400 degrees C/4 h in air. The room temperature dielectric constant (epsilon(RT)) of similar to 1500 at 1 KHz frequency was increased to : 10000 at a Curie temperature (T-C) similar to 126 degrees C, showing a very sharp transition from a polar tetragonal to a non-polar cubic structure. The dielectric loss factor (tan 6) was similar to 1.5 %. SEM studies revealed the presence of dense microstructures having a distribution of smaller grains (size: 2 similar to 3 gm) surrounded by larger grains (&gt;= 35 mu m). The ferroelectric hysteresis loop measurements on these samples gave values of spontaneous polarization (P-s) of similar to 12.0 mu C/cm(2), a coercive field (E-C) of similar to 2 similar to 2.5 kV/cm, and a dielectric strength (E-b) of similar to 48.0 kV/cm. DC-resistivity as high as 1.5 x 10(9) Omega-cm was obtained in these samples. All these results are quite comparable with reported ferroelectric/dielectric data and are discussed elaborately in this paper.</p>10aBaTiO310adielectric-ferroelectric properties10aMicrostructure10aSintering10astoichiometry1 aDeshpande, S., B.1 aPotdar, H., S.1 aPatil, M., M.1 aDeshpande, V., V.1 aKhollam, Y., B.  uhttps://library.ncl.res.in/content/dielectric-properties-batio3-ceramics-prepared-powders-bimodal-distribution-002296nas a2200289   4500008004100000022001400041245011600055210006900171260006900240300001200309490000800321520129400329653001301623653002301636653001101659653001401670100001901684700001901703700002801722700001801750700002501768700001901793700002101812700002301833700001901856856013101875       2010                        eng d  a0254-058400aSimple chemical co-precipitation/calcination route for the synthesis of simulated synroc-B and synroc-C powders0 aSimple chemical coprecipitationcalcination route for the synthes  aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcOCT  a695-6990 v1233 a<p>A simple chemical co-precipitation/calcination route was developed for the synthesis of simulated synroc-B and synroc-C powders using mostly nitrate salts as starting chemicals and 20% ammonia solution as precipitant. In this route, a mixed solution containing Al-nitrate, Ca-nitrate, Ba-nitrate, zirconyl nitrate and titanyl nitrate in the molar proportion required for synroc-B is added to dilute ammonia solution to precipitate these cations in the form of their hydroxides at room temperature by maintaining pH approximate to 10.5 during precipitation. Formation of a major fluorite phase with minor amounts of anatase, rutile and hollandite phases is observed in the powder obtained after calcination in air at 750 degrees C. Multiphase crystalline synroc-B matrix containing hollandite, perovskite, zirconolite, and rutile phases is obtained after sintering the heat treated powder in the form of pellets at 1230 degrees C for 4h in air. Similarly, pure synroc-C phases with 14 and 20% simulated waste loadings were synthesized following the same synthesis protocol. These pre-treated powders with a high surface area of similar to 25 m(2) g(-1) gave sintered ceramics having density of similar to 90% for 14 and 20% waste loadings. (C) 2010 Elsevier B.V. All rights reserved.</p>10aCeramics10aChemical synthesis10aOxides10aSintering1 aPotdar, H., S.1 aVijayanand, S.1 aMohaideen, Kamal, Khaja1 aPatil, K., R.1 aJoy, Pattayil, Alias1 aMadhavan, Raja1 aKutty, K., V. G.1 aAmbashta, Ritu, D.1 aWattal, P., K.  uhttps://library.ncl.res.in/content/simple-chemical-co-precipitationcalcination-route-synthesis-simulated-synroc-b-and-synroc-0