Microwave Fast Sintering of Double Perovskite Ceramic Materials

Abstract

The book chapter mainly deals with the microwave sintering of high quality crystals of La MMnO M = Ni or Co ceramics. Double perovskite La MMnO M = Ni or Co ceramics with average particle size of ~ nm were manufactured using microwave sintering at °C for min in N atmosphere for the first time. The morphology, structure, composition, and magnetic properties of the prepared compacts were characterized using X-ray diffraction XRD , scanning electron microscopy SEM , transmission electron microscopy TEM , energy-dispersive X-ray spectroscopy EDX , infrared spectroscopy IR and FTIR , and physical properties measurement system PPMS . The corresponding dielectric property was tested in the frequency range of kHz MHz and in the temperature range of K, and the ceramics exhibited a relaxation-like dielectric behavior.Keywords: ceramics, microwave sintering, microstructures, XPS, multiferroic properties . IntroductionMicrowave sintering MWS is emerging and an innovative sintering technology for processing of ceramic materials and is commonly related with volumetric and uniform heating. MWS is one of the exciting new fields in material science with vast potential for preparation of novel and/or nanostructured ceramics/materials. Microwave heating has some important benefits Microwave sintering has developed in recent years as a promising technology for faster, cheapest and most environmental-friendly processing of a wide variety of materials, which are regarded as significant advantages over conventional sintering procedures. Microwave radiation/heating for sintering of ceramic constituents has recently appeared as a newly motivated scientific approach [ ].Microwave sintering approach has unique advantages over conventional sintering methods in many respects. The essential difference in the conventional and microwave sintering processes is in the heating mechanism Figure . In microwave heating, the materials themselves absorb microwave energy and then transform it into heat within the sample volume and sintering can be completed in shorter times. In microwave sintering, the heat is generated internally within the test sample due to the rapid oscillation of dipoles at microwave frequencies [ ]. The contribution of diffusion from external sources is lesser. The internal and volumetric heating makes the sintering rapidly and uniformly. The heat generated through conventional heating is generally transferred to the sample via radiation, conduction, and convention [ ]. This process takes longer duration for sintering the materials and causes some of the constituents to evaporate. This may lead to modify the desired stoichiometry and grain. Figure .Comparison of heating mechanism in microwave and conventional sintering methods. Advanced Ceramic Processing 2In contrast, microwave energy is transferred directly to the material through molecular interaction with an electromagnetic field. Microwave heating is more effective than conventional methods in terms of the usage of energy, produces higher temperature homogeneity, and...

A Review of Microwave-Assisted Sintering Technique

“…Double perovskite La 2 MMnO 6 (M = Ni, Co) was successfully prepared by Matli et al using the microwave sintering technique. The obtained material exhibited improved magnetic and dielectric properties with a reduced sintering time in comparison to conventionally obtained products [21].…”

Characteristics of Conventional and Microwave Sintered Iron Ore Preform

“…Figure 1 a,b depicts the differences in the working principles of the CS ( Figure 1 a) and MWS ( Figure 1 b) methods, demonstrating that conventional sintering has a slower heating rate than microwave sintering. When compared to CS, microwave sintering offers the following advantages: (i) volumetric and uniform heating, (ii) faster sintering resulting in reduced sintering time, (iii) better temperature control, (iv) improved properties, and (v) minimum energy consumption [ 6 , 7 ]. A survey revealed that iron ore powder is sintered at a high temperature.…”

Structural, electronic and magnetic investigations on PLD based La2Ni1-xFexMnO6 disordered thin films

“…gives rise to 180° ferromagnetic interactions between Ni 2+ (d 8 ,S=1) and Mn 4+ (d 3 , S=3/2) ions governed by Kanamori-Goodenough rules [17]. Recent studies show the microwave sintering effect on properties of La2NiMnO6 [18], effect of A site (Ba) substitution effect on structural, magnetic and vibrational properties of La2NiMnO6 double perovskite [19,20,21], effect on electric and dielectric properties of B site (Mg) doping on La2NiMnO6 [22], high transition temperature and short ferromagnetic ordering in La2FeMnO6 [23]. The substituted La2NiMnO6 composition properties were engineered to make it potential candidate for applications.…”