In situ studies of aluminium oxide break-up at flux-free brazing conditions
|Coordinator||GRÄNGES SWEDEN AB|
|Funding from Vinnova||SEK 499 000|
|Project duration||November 2018 - February 2020|
|Venture||Research infrastructure - utilisation and collaboration|
|Call||Research infrastructure - utilisation and collaboration: Industrial pilot projects for neutron and photon experiments at large scale research infrastructures - 2018|
|End-of-project report||2018-04410_Gränges.pdf (pdf, 139 kB)|
Purpose and goal
The development of a stable process for the aluminium oxide (Al2O3) break-up in nitrogen atmosphere with the use of magnesium (Mg) is today a challenge. It is important to use the correct amount of Mg for a successful Al2O3 break-up, where too much Mg would build up a film of magnesium oxide (MgO). Through synchrotron radiation-based XPS of the Al2O3 break-up process close to real process conditions it may be possible to determine the condition required for Mg initiated oxide break-up in nitrogen atmosphere, which would facilitate flux-free controlled atmospheric brazing of aluminium.
Expected results and effects
By following the changes in the XPS spectra for oxygen (O), aluminium (Al), and magnesium (Mg) it has been possible to track the kinetics of the Mg initiated break-up process of Al2O3. The project has provided new perspectives regarding the Mg initiated Al2O3 break-up and further analysis of the data expects to identify the necessary conditions for flux-free brazing of aluminium in nitrogen atmosphere. The project has also demonstrated the benefit of using XPS for industrial relevant challenges.
Planned approach and implementation
Heat treatments of rolled aluminium sheet samples have been performed in nitrogen atmosphere at temperatures up to 550 °C. While the samples were under heat treatment the composition of the surface oxide were analyzed through X-ray photoelectron spectroscopy (XPS). The heat treatments were performed in 1 mbar nitrogen, which is enough to avoid magnesium evaporation while the XPS intensity remains good. The experiments were performed at HIPPIE and SPECIES at the synchrotron radiation facility MAX IV in Lund. Data treatments and analysis were, and still are, performed at Gränges R&I.