We are interested in purifying 50 g amount of stearyl amine by preparative HPLC.

What kind of stationary phases would be feasible?

and secondly would the compound's basic corrosive properties demand for equipment built of special inert materials or can we use conventional equipment made from stainless steel and PTFE ?

You should be able to do this by several methods. One would be reversed-phase chromatography with a volatile buffer such as ammonium carbonate or acidic acid. Or you can use normal-phase chromatography using something in which the sample is well soluble (maybe methylene chloride) and a polar additive like methanol with a silica column. There is no reason to worry about the equipment. That's what stainless steel is made for.