Thermal Analysis of Some Barium and Strontium Titanyl Oxalates

Abstract

The electrical resistivity of well sintered BaPbOs ceramics was measured from -50" to 100°C (Fig. 3). The electrical resistivity at 25°C was 8.3 X ohm-cm, and the temperature coefficient of resistivity was +O. 15%',l0C indicating typical metallic conduction. IV. ConclusionThe solid-state reaction of BaC03 and PbO to form Ba-Pb03 was studied by DTA, TGA, and X-ray analysis. Formation of BaPbOs started at 600°C which WAS in agreement with previous analyses. The formation of BaPb03 9 A 7 \ X6 2.8 3.0 3.2 3.6 3.8 4.0 4.2 +Yl@ 2 The thermal decompositions of BaTiO (czO4)z .-4Hz0, BaTiO (OH)zCz04.2Hp0, SrTiO ( C~0 4 ) 2 . -4H20, and SrTiO(OH)YCz04.Hz0 were investigated using TGA, DTA, and effluent gas analysis. The stoichiometry of the decompositions is discussed and it is proposed that a reduced state of titanium is formed as an intermediate.

Preparation of BaTiO3Thin Films Using Glycolate Precursor

“…Some authors have proposed that the solution-derived metal organic precursors, such as a citrate salt, BaTi (C H O ) 6H O (14), an oxalate salt, BaTiO(C O ) 4H O (15), and a neodecanoate-based precursor (16), decompose to form a finely divided mixture of BaCO and TiO , which subsequently reacts to form BaTiO on heating at 600-700°C in air. Recently Rajendran and Rao reported the citrate precursor barium bis(citrate)oxotitanate(IV) citrate heptahydrate (17), which decomposes to form not the mixture of BaCO (19) used barium acetate and titanium isopropoxide for the deposition of thin films by a dipping technique.…”

Formation mechanism of barium titanate by thermal decomposition of barium titanyl oxalate

“…(1): [2][3][4][5][6]. An example is the appearance of BaCO 3 and TiO 2 as intermediate phases, where some researchers proposed the formation of these as intermediate phases [2,4,6,[7][8][9][10][11][12][13], while others denied [1,3,[14][15][16]. Although there are some reports on the decomposition mechanism of BTO [3,6,7,9,10,[13][14][15][16], the model proposed by Gopalakrishnamurthy et al in 1975 is generally accepted [3], which can be divided into the following 5 steps:…”

“…The oxalate route co-precipitates barium titanyl oxalate tetrahydrate (BTO: BaTiO(C 2 O 4 ) 2 Á4H 2 O) as a precursor for BaTiO 3 , according to Eq. (1): [2][3][4][5][6]. An example is the appearance of BaCO 3 and TiO 2 as intermediate phases, where some researchers proposed the formation of these as intermediate phases [2,4,6,[7][8][9][10][11][12][13], while others denied [1,3,[14][15][16].…”

IR and thermal studies on lanthanum zirconyl oxalate

“…The zirconates of the alkaline earths and rare earths have found considerable importance in ceramics. The preparation of various mixed oxides in pure and homogeneous form could be achieved by thermal decomposition of mixed metal oxalate salts [1,2]. Zirconium is reported to form anionic oxalato zirconates with bivalent metal cations [3], and the thermal decomposition of such complex salts makes an interesting study.…”