Hi everyone,
I am looking for a used XRF machine for oil debris analysis. New prices are over the moon.

To detect the difference between gear and bearing steel it seems the Cr % is the way to go. Any thoughts ?

What happens if the sample has 90 gear particles and 10 bearing particles, will it read a Cr value close to gear steel ?

What options do I have to answer the source question with certainty ?

Cheers

John

john1947,

Used XRF analyzers are not cheap either, if you can find one. You would have to have a lot of samples to be analyzed in order to economically justify such purchase.

Your concept of tracking chrome is fine. However, chrome is only one component of gear and bearing metallurgy profiles. Knowing the ratio of other metals present would aid in the process of identifying the source of metals found in oil.

The cheapest solution would be to perform a visual observation of a gear and bearing when Cr reaches level of concern. This process could be used to develop a historical data.

Hi John,
Thank you for your reply.

I did find a used desk top unit for A$30k but have not taken up the offer yet.

XRF cannot see the lighter elements and carbon in particular is virtually not detectale, so %c which does vary significantly cannot be measured.

Other elements like Ni, Mo, Mn appear in small % in both gears and bearings so without a sample of each gear in the box it's difficult.

The other problem is that debris analysis is a comparision of the "counts" for each trace elements compared to iron, so you need to radiate the sample for ages to get the low particle counts up for a significant comparision to iron for each sample.

Then with that % for each metal sample you compare the sample trace element %, and very quickly you cant tell the difference between say the Mn level in each sample which is only around 0.05%.

This all has to be done on a particle by particle basis so you can only do the big ones.

Doing a filter pad won't tell you a thing as 90% may be gear steel and the rest a bearing but the Cr% will look like gear steel.

So if anyone out there knows of a desk top unit please contact me.

Cheers

John