A new approach to flux deposition for brazing aluminium by low pressure cold spraying

This paper presents the results of study on the possibility of Nocolok flux deposition to aluminium substrates using the low-pressure cold gas spraying (LPCS) method. An innovative method of applying flux in the form of a powder without organic adhesive additives was proposed, allowing strict control of the deposited material. The influence of the flux powder feeding rate (PFR – 4.5 g/min, 6.3 g/min and 8.5 g/min) on the efficiency of the brazing process of AA3003 aluminium alloy plates was investigated. The results of energy dispersive spectrometry (EDS) analysis of the deposited flux coatings are presented for various process parameters. The wettability tested by spreading the B-AlSi12 filler metal on flux-covered aluminium substrates increased significantly with increasing PFR – the contact angle decreased from 21.0° to 4.6°. Microstructure analysis confirmed the high quality of the brazed joints, which were devoid of braze incompatibilities.