I have an electrical connector made of zinc-aluminum alloy (exact mixture unknown) that I would like to braze to a steel tube. Can this be done, what kind of material(s) would work for this application?
Zinc/aluminium alloys are not uncommon in die cast parts and it should be possible to braze/solder. You would need a filler rod designed for 'white metal' or 'multi-metal' filler and the appropriate flux.
Having said that brazing/soldering unusual materials is often a bit tricky as you need to judge the temperature of both parts within a fairly narrow window with little in the way of visual clues and the low melting point of zinc means they you have to be very gentle with the heat.
Personally I would look at a mechanical connector as the first choice for something like this, even if it involves brazing or welding an intermediate bracket, stud etc to the steel.
Mechanical connection is the first choice. I would have said brazing is too hot for any aluminum alloy , but checking a reference I was surprised. There is a loop hole; somehow, using aluminum /silicon fillers ( no copper) can still be caused "brazing". However the steel must be coated with aluminum or copper first. So , mechanical or solder are the main options.