Studies on thermal and structural properties of glasses as sealants for solid oxide fuel cells

Recent developments in the preparation, characterization and applications of glass- and glass–ceramic-to-metal seals and coatings

“…Some compositions of glasses employed as sealants in SOFC are summarized in Table 2, and selected properties are provided in Table 3. Table 3 continued Glass code Metals commonly employed as interconnects in fuel cell designs include various austenitic and ferritic stainless steels, for example, Fe20Cr and FeCrAlY alloys, in addition to Ni-based superalloys, as summarized in [59][60][61][62][63][64][65][66][67][68][69][70][71][72][73][74], together with some BaO-free silicate glasses [74][75][76][77][78][79][80][81][82][83][84][85][86][87][88][89]. Low-silica and silica-free borate-based compositions have also been reported [90][91][92][93].…”

Effect of A2O3 (A=La, Y, Cr, Al) on thermal and crystallization kinetics of borosilicate glass sealants for solid oxide fuel cells

“…The field strength of Al 3+ which act as intermediate is highest and due to this it holds the glass matrix tightly. Because of this fact it requires higher activation energy for crystallization as compared to the Y 3+ cation followed by La 3+ which has the least value of field strength [20]. Moreover, Al 2 O 3 addition in glass is well known to prevent the crystallization and control the viscosity of the glasses [21].…”

Effects of lanthanum-to-calcium ratio on the thermal and crystalline properties of BaO–Al₂O₃–B₂O₃–SiO₂ based glass sealants for solid oxide fuel cells

“…In this study, the optimum composition of GC9 glass is 34BaO4.5Al 2 O 3 9.5B 2 O 3 34SiO 2 1ZrO 2 5La 2 O 3 12CaO, and the T g , T s , T c , and CTE of the glass are 652, 745, 865°C, and 9.48 © 10 ¹6 K ¹1 , respectively. The crystalline phase of the bulk GC9 glass after crystallization is mainly Ba 3 La 6 (SiO 4 ) 6 . In addition, the interfacial adhesion compatibility of GC9 glass seals has been evaluated by joining the seals with interconnect and PEN plate under a sealing condition at 850°C for 4 h. The results indicated that the GC9 glass at La/Ca ratio of 0.833 possesses the adequate thermal and crystalline properties, and thus the glass is suitable for use as sealant in SOFC sealing at around 800°C.…”

“…Besides, it was found that the appearance of GC9 glass specimen with La/Ca ratio of 1.4 transformed from transparent to opaque due to the devitrification after annealing at 750°C for 4 h. Although the T c of the GC9 glass with the La/Ca ratio of 1.4 is 784°C, it still undergoes crystallization during the annealing at 750°C. The T c of the GC9 glass with the La/Ca ratio of 0.833 is 865°C, therefore the crystallization peak is inconspicuous after annealing at 750°C for 4 h. Notably, according to the XRD analysis, the crystalline phase of crystallized GC9 glass is mainly single phase, 44),46) Ba 3 La 6 (SiO 4 ) 6 , with a hexagonal lattice. The characteristics of the crystalline phase of Ba 3 La 6 (SiO 4 ) 6 , according to JCPDS No.…”

“…4), 5) Recently, the studies on the glass or glass-ceramic for using on SOFC, such as novel glass system development, sealing mechanism delineation, new packaging process employment, as well as evaluation on long term stability and compatibility have been intensively investigated. 6)16) The aluminum-borosilicate glass usually yields a CTE matching that of other SOFC stack components when it contains an amount of barium oxide, and thus the BaOAl 2 O 3 B 2 O 3 SiO 2 system glasses can be used as high-temperature sealants for SOFC. 17)24) For instance, Lara et al 25), 26) reported that the CTE of ROBaOSiO 2 system glasses are in the range of 8.512 © 10 ¹6 K ¹1 .…”