No abstract

No abstract

This paper deals with the critical aspects of sintering of crystallizable glass+ceramic system, which is a critical part of low‐temperature‐cofired ceramics (LTCC) process. Densification studies clearly revealed the influence of filler's nature especially at lower glass contents (≤70 vol%) and lower sintering temperatures. In this temperature range, marked improvement in density was observed in the order cordierite>fused silica>mullite>alumina. The decisive role played by wetting of glass on filler has been demonstrated using heating microscopy and wetting studies. However, densification was not influenced by the nature of filler at higher glass contents (>70 vol%) and at higher sintering temperatures. This is because in this range of glass content viscous flow of glass dominates the wetting behavior. This paper brings out the salient features responsible for the sintering behavior of anorthite glass+ceramic LTCC composition.

We report successful identification and preparation of a glass composition in the CaO–Al2O3–SiO2 phase diagram with a judicious choice of fluxes that met all dielectric, electrical, and thermal property requirements for low‐temperature cofired ceramic (LTCC) applications. The glass composition sintered at 900°C attains good density (2.45 g/cc) and does not precipitate any crystalline phase. However, when this glass powder is sintered at the same temperature in the presence of 30 vol% cordierite, crystallization of the anorthite phase is observed, which improves the properties of the composite for LTCC application.

Nickel manganite based negative temperature coefficient (NTC) thermistor compositions are extensively used as thermal sensors in a wide range of products and devices. Ni 0.701 Mn 1.823 Cr 0.35 Fe 0.07 Si 0.056 O 4 NTC thermistor composition was prepared through solid state route. The tape casting slurry composition was optimized to get defect free ceramic tapes. Chip thermistors were prepared from these NTC tapes by optimizing the process parameters. The prepared chip thermistors were encapsulated in borosilicate glass to form Chip-in-Glass thermal sensors with high material constant and excellent reliability.