Plain Bearing Material Problem

I have designed a small rotating assembly that runs at only 0 - 150 RPM with very very minimal load, it has a Stainless Steel (303) 3.0mm Dia shaft and a brass (CZ121) bearing. When first assembled this it has a very smooth running action and very little stiction, but after a few days of use the bearings begin to squeek and seize. Can anyone tell me if there any problems with stainless and brass as a bearing assembly or point me in the right direction for information on suitable material pairs for bearings.
Simon

Need to specify that this is in an environment where lint can collect and gum up the works, so he wants to stay away from lubricants if possible (from a thread in comp.cad.solidworks).
Mark 'Sporky' Stapleton Charlotte, NC
SGM Design Ltd wrote:
  Quoted Text Here  

  Quoted Text Here  
with
a
The following may be of use. Although most of it is concerned with lubricated bearings. http://www.cda.org.uk/megab2/costeff/tn45/index.htm

  Quoted Text Here  
I assume it is a sleeve bearing? if so the copper in the brass and nickel in the stainless steel form are soluable in each other over thier whole range of compositions (Monel, cuppernickel, etc.) The extra sulfur in a T303 stainless can sometimes help - in this case not.
Try a polymer sleeve bearing to sun with a T303 shaft - such as polyproplene. Using a brass bearing with carbon steel shaft would be OK if lubricated. Wear (tribology) is a branch of science without any general rules - one must all ways experiment or depend on historic solutions. A different design (such as a roller bearing) may be a quicker / better solution.
Ed

Yes this is a plain bearing, one at each end of the shaft. Does this mean that I should rule out using phosphor bronze bearings (95% Copper - 5% Tin)

Phosphor bronze is better used with hard shafts and lubricated. If you want to improve on brass you could try a leaded bronze or gunmetal, but for low loads a polymer might be better. If you want to use metal you could try a sintered bearing material, these would probably work but can be expensive.
  Quoted Text Here