1. Enhancing the ignitability of the Al–TiO2–B2O3 powder mixture through intensive vibratory ball milling (C:P12).
- Author
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Daskalakis, Evangelos, Scott, Andrew, and Jha, Animesh
- Subjects
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POWDERS , *BALL mills , *ALUMINUM oxide , *SIZE reduction of materials , *DIFFERENTIAL thermal analysis , *IGNITION temperature - Abstract
Alumina-TiB 2 is a hard ceramic composite with applications in aviation, aerospace and wear resistant tools. It can be manufactured in-situ through a highly exothermic aluminothermic self-sustaining reaction from the starting materials of Al, TiO 2 and B 2 O 3. In this paper, the effect of vibration ball milling on the particle size reduction and the reactivity enhancement of the Al–TiO 2 –B 2 O 3 powder mixture is examined by XRD, SEM, EDS, DTA and particle analysis techniques. Measures for combating the stoichiometric inconsistencies deriving from the tendency of B 2 O 3 to absorb atmospheric water, giving boric acid H 3 BO 3 , are implemented. Characterisation of the milled samples display Al microparticles with d(0.9) below 64 μm, coated with nano-particles of TiO 2 and B 2 O 3 , with particle sizes up to 600 nm. Differential thermal analysis reveals that ignition is feasible for all of the milled mixtures, unlike the un-milled one. It also presents that extensive milling results in a reduction in the ignition temperature of the reactant mixture to 925 °C for the 5 h-30Hz milled sample, from the previous 982 °C recorded for the 1 h–20Hz milled sample. The in-situ synthesised Al 2 O 3 –TiB 2 matrix deriving from the 5 h-30Hz milled sample, gives less of the unwanted Al 5 BO 9 phase and improved skeletal and bulk densities, by 0.15 g/cc and 0.1 g/cc respectively, compared to the respective composite deriving from un-milled reactants powder mixture. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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