Investigation of a New Class of Disordered Inorganic Materials
Abstract
A new class of high temperature metastable oxides (Cerablak(Trademark)) based on aluminum phosphate composition was investigated under this program. The study included further understanding the sol-gel synthetic procedure, the structural evolution of the material from the precursor state to the calcined form, extensive microstructural and spectroscopic characterization of powders, and development of coatings targeted toward Air Force applications. Evidence collected showed that the thermal stability limit for the material is above 1400 deg C in air and the stability is enhanced by the amount of excess aluminum present beyond the 1:1 stoichiometric aluminum phosphate composition. While much of the structural details are still unknown, the presence of Al-O-Al bonds in the amorphous network appears to play an important role in extending the metastability. The hypothesis for the extended metastability has been attributed to low mobility of atoms in the amorphous network which resists crystallization. Thin, dense, and pore-free films were easily deposited on various metal, alloy, and ceramic substrates by a simple dip-coating process. The low mobility of oxygen was demonstrated through pronounced evidence of oxidation protection of stainless steel coupons coated with Cerablak(Trademark). The study also included synthesis of Cerablak(Trademark) in various forms, determination of key properties and investigating its applicability to specific Air Force applications.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 2001
- Accession Number
- ADA396446
Entities
People
- Kimberly A. Steiner
- Sankar Sambasivan