In-situ densification of combustion synthesized coatings

✍ Scribed by Jan A. Puszynski; Shuxia Miao; Bjarni Stefansson; Sunil Jagarlamudi

• Publisher: American Institute of Chemical Engineers
• Year: 1997
• Tongue: English
• Weight: 820 KB
• Volume: 43
• Category: Article
• ISSN: 0001-1541
• DOI: 10.1002/aic.690431321

✦ Synopsis

Dense intermetallic and ceramic (alumina based) coatings can be formed in situ during simultaneous combustion synthesis and densification in the field of centrifigal forces. Both microstructure and composition of alumina-based coatings formed during alumino-thermal reduction of oxides can be altered by an introduction of additives such as ZrSiO,, SO,, Na,CrO,, and carbon. The activation energy and frequency factor for the Ni-A1 reacting system consisting of equal atomic amounts of Ni and A1 powders with an average particle size of 5 p m were measured using a nonisothermal technique, which were equal to 1.05 X 10' J/mol and 1.017 X lo8 s-', respectively. A mathematical model of in-situ densification of a single-phase combustion product (NiAl) in the field of centrifugal forces was developed and explored.