Open AccessEnhanced thermal capacity aerogels summary report for FY 1993
Author(s) -
Lawrence W. Hrubesh,
Paul R Coronado,
J.F. Poco
Publication year - 1993
Language(s) - English
Resource type - Reports
DOI - 10.2172/142544
Subject(s) - aerogel , anhydrous , oxidizing agent , materials science , carbon fibers , sintering , nitrogen , composite material , chemical engineering , chemistry , organic chemistry , composite number , engineering
In a continuation of work done previously, the authors have fabricated a set of silica aerogels and then chemically modified their internal surfaces for the purpose of inhibiting the effects of sintering at high temperatures. They performed surface nitridation of silica aerogels, i.e., the replacement of surface oxygen atoms with nitrogen atoms, by reacting ammonia gas with the silica surfaces at elevated temperatures. After pre-oxidizing the aerogels, they exposed three sets of samples to anhydrous ammonia gas under different processing conditions. Each set contained silica aerogels of three different densities, 0.07 g/cc, 0.16 g/cc, and 0.29 g/cc. The treated samples, together with companion untreated reference samples, were sent to NASA Ames Research Laboratory for high temperature testing. They also fabricated two carbon aerogel cylinders, 7 cm diameter x 1.5 cm thick. These samples were also delivered to NASA Ames Research Laboratory for high temperature tests