Review on Thermal Stability and Bonding Analysis of Alumina Powder for High-Temperature Applications using TGA and FTIR

Aluminum oxide (oxide Al₂O₃), or alumina, is one of the most critical and widely used ceramic oxides in hightemperature mechanical applications. This is due to its reliable mechanical properties, thermal stability, and chemical resistance. Alumina has various polymorphs and transition sequences from the metastable polytypes of γ, δ, θ, and κ to the stable α-phase can lead to a defining step in application performance. Recent developments (2020-2025) in alumina powder synthesis, thermal characterization and bonding have been organized in this review with emphasis on the use of Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR). The first technique addressed an understanding of powder thermal processing incorporating dehydration, decomposition, phase stability with TGA. The second technique addressed an understanding of Al–O bonding vibrations in the forms of structural and hydroxyl group vibrational modes with FTIR to develop a dimensional understanding of bonding transformations during calcination. These analyses have been integrated to provide an understanding of how different powder synthesis routes (sol–gel, hydrothermal, combustion and additive manufacturing) affect thermal transport, microstructural evolution and the associated mechanical behaviour of alumina powders. Other factors influencing densification and reliability of the ceramic including dopants, sintering atmosphere and conditions are summarized.The review discusses the challenges of spectral overlaps, ephemeral identification, and scaling to commercial production, and connects them to future opportunities in multi-technique in situ analysis, computational modeling, and sustainable processing approaches to optimize alumina powders for next-generation aerospace, energy, and refractory applications.