John,
Firstly, the platelets could have been generated by surface fatigue pitting from a bearing race (inner or outer) and you might likely see large spall marks on the affected surface. Particles are laminar and appear to have a "jagged" edge on one side and a somewhat "smoother" on the other. Striation and particle discoloration marks are also visible therefore likely advanced wear. Gear wear generally generate 1:1:1 ratio particles but it depends heavily on the wear / failure mode.
That said, it might just as well be the flipside of the coin but it goes to show that you should not try and evaluate a whole system on one particle, the composition of the filter pad residue i. e. the entire story must be viewed e. g. how many of this size, what are the other types of platelets, contamination ...
Wear debris is very effective if approached in a logical and not a one sample tells you everything approach. This is possibly the single biggest pitfall of most programs. You get the guys who try to shock the daylights out of maintenance by attaching a photo of the biggest and baddest particle to the report when it is in actual fact a once off - eventually this tactic start to have the reverse effect.
What I am getting at is - stick to a wholistic approach - one particle has never been able to tell you everything.
Stefan
