NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
formation of porous surface layers in reaction bonded silicon nitride during processingMicrostructural examination of reaction bonded silicon nitride (RBSN) has shown that there is often a region adjacent to the as-nitrided surfaces that is even more porous than the interior of this already quite porous material. Because this layer of large porosity is considered detrimental to both the strength and oxidation resistance of RBSN, a study was undertaken to determine if its formation could be prevented during processing. All test bars studied were made from a single batch of Si powder which was milled for 4 hours in heptane in a vibratory mill using high density alumina cylinders as the grinding media. After air drying the powder, bars were compacted in a single acting die and hydropressed.
Document ID
19800067404
Document Type
Conference Paper
Authors
Shaw, N. J.
(NASA Lewis Research Center Cleveland, OH, United States)
Glasgow, T. K.
(NASA Lewis Research Center Cleveland, Ohio, United States)
Date Acquired
August 10, 2013
Publication Date
October 1, 1979
Subject Category
NONMETALLIC MATERIALS
Meeting Information
Fall Meeting(New Orleans, LA)
Distribution Limits
Public
Copyright
Other