Low-temperature sintering and microwave dielectric properties of Mg3B2O6-LMZBS composites

Abstract

The Mg 3 B 2 O 6 ceramics with lithium magnesium zinc borosilicate (LMZBS) glass were prepared at a lower sintering temperature. The effects of the glass addition on the densification, phase development, microstructure and microwave dielectric properties of the Mg 3 B 2 O 6 ceramics were investigated. The addition of LMZBS glass improved the densification and lowered the sintering temperature of Mg 3 B 2 O 6 ceramics from 1,300 to 950°C. X-ray diffraction patterns showed that Mg 3 B 2 O 6 transformed into Mg 2 B 2 O 5 and a new phase, Li 2 ZnSiO 4 , crystallized from the glass phase. Because of the high dielectric performance of these phases, Mg 3 B 2 O 6 mixed with 55 wt% LMZBS sintered at 950°C for 3 h had e r = 6.8, Q 9 f = 50,000 GHz, and s f = -64 ppm/°C at 7.28 GHz. The chemical compatibility of ceramic-glass composites with Ag was also investigated for LTCC.

Three‐phase borate solid solution with low sintering temperature, high‐quality factor, and low dielectric constant

“…As shown in Figure 1E, the composite ceramics synthesized in this experiment provided both excellent dielectric and sintering properties when compared with other ceramics. 7,8,[17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] Figure 2A-D presents the XRD patterns of all the samples processed at the same temperature (950°C). A single ZBO phase (JCPDS#37-1486) was formed for the samples with x = 0.00 and 0.05 and increasing the Mg 2+ content resulted Since the densification temperature of ZBO is 925°C, the increasing density for the sample with x = 0.05 sintered at 900°C should be attributed to the decreasing densification temperature due to lattice distortion, and the decreasing density value for the same sample sintered at 925-975°C can be ascribed to the over-sintering.…”

Effect of magnesium source on the fabrication of kotoite Mg3B2O6 ceramic

“…3D flower‐like magnesium borate, Mg 3 B 2 O 6 , was synthesized with high purity by precipitation reaction, despite the powder X‐ray data showed poorly crystalline product . Moreover, Mg 3 B 2 O 6 was also synthesized via solid‐state reaction of MgO with 11 wt.% excess of H 3 BO 3 at 1573 K (1300°C) for 2 hours, but unreacted MgO was also detected in the XRD pattern as impurity …”

“…12 The single phase of Mg 3 B 2 O 6 , typical for ceramics with large grains (500-1000 lm), have microwave dielectric properties with high Qxf values (˃200 000 GHz). 6,13 The synthesis of magnesium borate can be implemented in different synthetic methods, such as the high temperature solid-state synthesis route, 6,14 the solvothermal method, 15 the microwave solid-state method, 16 precipitation reaction, 10 and the sol-gel technique. However, in the processing of Mg 3 B 2 O 6 , the synthesis of pure kotoite form of magnesium borate is crucial, the most important problem is the formation of suanite form of magnesium borate, Mg 2 B 2 O 5 , and magnesium oxide, MgO besides kotoite form of magnesium borate.…”

“…10 Moreover, Mg 3 B 2 O 6 was also synthesized via solid-state reaction of MgO with 11 wt.% excess of H 3 BO 3 at 1573 K (1300°C) for 2 hours, but unreacted MgO was also detected in the XRD pattern as impurity. 14 In summary, the kotoite form of magnesium borate, Mg 3 B 2 O 6 , has been synthesized by various methods and in most of these scientific studies, magnesium orthoborate was not obtained with high purity. Owing to this reason, the aim of this study is to determine true conditions of synthesis of Mg 3 B 2 O 6 with high purity, and to point out the effect of magnesium source on the fabrication of pure Mg 3 B 2 O 6 through the solid-state reactions of boric acid with various magnesium sources such as magnesium oxide, magnesium carbonate, magnesium sulfate, and magnesium nitrate, because the quality of the final product could be dependent on the nature of the starting materials.…”

Synthesis, structural characterization, and photoluminescence properties of Eu3+‐doped Mg3‐xEux(BO3)2 phosphor

“…The synthesis of undoped magnesium borates can be implemented in different synthetic methods, for example, the high temperature solid‐state synthesis method, the solvothermal method, the microwave solid‐state method, precipitation reaction, and the sol‐gel method. Although the kotoite form of magnesium borate, Mg 3 (BO 3 ) 2 , has been prepared by various methods, Eu 3+ ‐doped magnesium borate has been only synthesized via hydrothermal and simple precipitation methods.…”