Ultra-low sintering temperature ceramic composites of CuMoO4 through Ag2O addition for microwave applications

Abstract

The present paper presents ceramic composites with ultralow sintering temperature of 500 ̊C with densification of 96 % by adding small amount (0.5, 1 and 2 wt.%) of Ag2O to CuMoO4 by simple mixing method. The effect of Ag2O addition on the structure, microstructure, sintering and thermal as well as microwave dielectric properties of CuMoO4 is also studied. The reduction in the sintering temperature is due to the formation of trace amount (1.4%) of copper silver molybdate (Cu2Ag2(MoO4)3) as observed from Rietveld refinement analysis as well as backscattered SEM image. Doping has very little influence on the structure and coefficient of thermal expansion that is about 4.7-5.2 ppm/C. The composites sintered at 500 ̊C exhibit relative permittivity of about 8-9, quality factor (Qf) of 26000-37000 GHz at 12 GHz, temperature coefficient of resonant frequency of-31-33 ppm/C and are compatible with Al electrode. The present work results in obtaining welldensified ultralow temperature cofired ceramic composites at low sintering temperature without much structural change and good thermal properties but with different dielectric properties by small doping. These composites can be used as low cost candidates for wide range of microwave applications like multilayer packages and substrates owing to the low energy required during processing and hence can pave way to the advancement of electronic materials.

Ultra-Low-Temperature Cofired Ceramic Substrates with Low Residual Carbon for Next-Generation Microwave Applications

“…However, the small peak at around 400 °C observed in the DSC of the CMOA tape was due to the formation of a new compound, Cu 2 Ag 2 (MoO 4 ) 3 , because of the reaction of Ag obtained by the decomposition of Ag 2 O with CMO and was expected to melt around 500 °C, as we have reported earlier. 17…”

“…These studied ceramics also exhibited good chemical compatibility with aluminum, which can be used for embedded electrodes. 16,17 Hence, our present work is an attempt to transform these ULTCC materials into ULTCC substrates by tape casting using an environmentally benign slurry composition and postprocessing techniques such as multilayer lamination, screen-printing, and cofiring, together with an investigation of their microstructural, dielectric, and thermal characteristics.…”

A Temperature-Responsive Copper Molybdate Polymorph Mixture near to Water Boiling Point by a Simple Cryogenic Quenching Route

“…The high purity oxides were mixed in an ethanol medium for 12 h and the mixture is then dried followed by calcination at 550 °C/12 h and sintering at 650 °C/4h, as has been reported in our previous works. 42,43 The nominal CMO polymorph mixture was prepared by cryogenic quenching of crystalline CuMoO4 ceramic using liquid nitrogen, as shown in figure 3. The polymorph mixture was obtained by cooling -CuMoO4 using liquid nitrogen.…”

LTCC and Bulk Zn4B6O13–Zn2SiO4 Composites for Submillimeter Wave Applications

“…The requirements for such new materials include a low dielectric constant to minimize the signal propagation delay, a low dielectric loss to ensure frequency selectivity and to restrict power consumption, and a low sintering temperature to enable the use of multilayer LTCC/ULTCC (low/ultralow temperature cofired ceramics) technology. Along with the modification of materials with a low dielectric constant, such as silica, borosilicate glasses, cordierite, mullite, forsterite, diopside, willemite, and aluminates [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ], which have been well-known for decades, less popular ceramics have been explored recently, such as borates, tungstates, molybdates, vanadates, and phosphates [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ]. The use of ceramic-ceramic or glass–ceramic composites is an effective way to tailor microstructure, electric, and thermal properties of functional materials for microwave substrates.…”