Unti friction coating

You haven't given enough info to give a definitive answer. For example, if the normal pressure is quite low and you're looking only for a couple hundred cycles, hard coat anodize might work as an expediency. Frankly, aluminum sliding on aluminum is an awful design and I'd change that if I could. But, let's say you have no choice. In that case, I'd put a ceramic coating (flamespray) on both parts.

There is a possibility to use a PTFE doped hard coating friction coefficient is 0.04.

The plants doing the hard coating (at least some of them) do the doping as well. I thing it is the best choice for you since the price is not excessive and the thermal load is the same as for hard coating.

Many industries including the firearms manufacturers have found that electroless nickel plating provides a slick, low friction, wear resistant coating on aluminum.

Rulon material, made by Saint-Gobain Polymer Products, bonded to one of the pieces and lubricated is a standard method used in machine tools.

I forgot to mention a nickel plating as well with imbedded PTFE. I am not sure but i think magnaplate does it. I used the hard coating with PTFE but not the nickel. I had very good results.