altho AIX is NOT free. here is some FREE advice.
www.WE-dont-do-warez.edu
People work had to put together OS's and what not. AIX cost $$ please support those who provide you with a way to find a JOB.
at least you dont have to worry about licenseing tho. since 4.3 aix no longer uses licenses.
despite that. I highly doubt you have a risk machine to run it on. If you had that you wouldnt be here asking for installation media.