Abstract:
Sillimanite is a naturally occurring mineral with an orthorhombic structure. A suitable concentration of tape casting slurry with a pseudoplastic nature has been formulated using sillimanite (Al2SiO5) (filler) and organic additives. The green tape has a tensile strength of 1.5 MPa. The Al2SiO5 (5 layers) hightemperature co-fired ceramic (HTCC) tape sintered at 1500 C shows a dielectric constant (er) of 4.59 with a loss tangent (tand) of 0.0008 at 5 GHz. The mineral has a coefficient of thermal expansion of 4.3 ppm/ C. The low cost Al2SiO5 tape from natural sources can be a suitable option for low er HTCC substrate applications.
