Meanwhile, in terms of drivers, the Swiss team are retaining the services of Marcus Ericsson, but are replacing Pascal Wehrlein with the services of Charles Leclerc.
Ericsson's future had been in doubt, with Ferrari-backed Italian Antonio Giovinazzi also a candidate under the new partnership. The Italian auto manufacturer is making a return to the sport after 30-years to sponsor the team.
The white-and-red scheme, reflecting Alfa Romeo's colours, marks a move away from the predominantly blue livery which Sauber has run since 2015.
"So it's a great pleasure announcing Charles Leclerc and Marcus Ericsson will be our official drivers", said Marchionne, administrator for Fiat who own Alfa Romeo and Ferrari.
Giovinazzi will be the reserve driver instead, taking part in Friday practice sessions. The title sponsorship deal means the team will be called Alfa Romeo Sauber F1 and the multi-year partnership comes with technical and commercial benefits.
"I think obviously we're starting from quite far behind because we had a hard season, but I think we have the potential to take a good step forward".
Leclerc had always been tipped for one of the Sauber seats after storming to the Formula 2 title, finishing 72 points ahead of Artem Markelov.
"For now I'm a Ferrari fan, but if Alfa Romeo Sauber do well that would of course be very welcome", Marchionne said.