Fabrication of cold sprayed Al-intermetallic compounds coatings by post annealing

A cold spray coating technique for thick Al coating with finely dispersed intermetallic compounds was tested by post annealing. The powder composition of Al:Ni and Al:Ti was fixed at 75:25 wt.%. The hard Ni and Ti powders have been successfully coated with the soft metal of Al at low gas pressure condition. Also, the Ni and Ti particles were embedded in the Al matrix. In the post annealing of coatings, the intermetallic compounds were observed in the cold sprayed Al–Ni and Al–Ti composites coatings. Above 450 °C of post annealing temperature, the Al3Ni and Al3Ni2 phases were observed in the cold sprayed Al–Ni coatings. The Ni particles in the Al matrix were fully consumed via compounding reaction with Al at the 550 °C of the annealing temperature. In the case of Al–Ti coatings, the Ti particles still existed in the Al matrix up to 630 °C of annealing temperature.