Atmospheric ageing of nanosized silicon nitride powders

Studies on Atmospheric Ageing of Nanosized Silicon Nitride Powders

Ageing of nanosized silicon nitride powder produced by the vapor phase reaction of silicon tetrachloride and ammonia has been studied in argon gas, in dry air and in air of 80% humidity, respectively, for 3 to 540 days. No remarkable changes were observed either in the bulk or the surface properties on storage in argon gas for 90 days. However, samples stored in dry air and humid air, respectiv...

Pattern Photoresist Silicon Silicon Nitride Silicon Photoresist Silicon Nitride Silicon Etch Nitride Remove Photoresist

In this proposal we seek to establish a porous silicon based etching process in the WTC microfabrication laboratory. The new process will allow us to etch high aspect ratio holes through a wafer. Holes like these are important for decreasing the dead volume of connections between micro and macro systems and for increasing the complexity of micro-fluidic systems. At the present time, the minimum...

Air-plasma spraying colloidal solutions of nanosized ceramic powders

Coatings prepared from nanosized powders were obtained by spraying ethanol-based colloidal solutions into a plasma plume. The powders investigated included 40 nm γ -Al2O3, 75 nm 8 wt% Y2O3-ZrO2, and 750 nm 25 wt% CeO2-ZrO2. Spray distances from approximately 50 to 63 mm were required to achieve significant coating deposition. As observed in the TEM, the typical lamella morphology of air plasma ...

Silicon Nitride and Silicon Carbide

MICROSTRUCTURAL STUDY OF SILICON NITRIDE WHISKERS PRODUCED BY NITRIDATION OF PLASMA-SPRAYED SILICON LAYERS

plasma-sprayed silicon layers have been used to produce silicon nitride layers with fibrous microstructure which optimizes fracture toughness and strength. SEM examination of the specimens shows that the surface is covered by fine needles and whiskers of Si3N4.In order to study the oxygen contamination effect as well as other contaminants introduced during spraying and nitridation processes, su...