Got some alloys tested with an XRF gun

[dtknowles]

How come my alloys have Si and P in them.

Alloy A - 92% Pb, 4% Sb, 2% Sn, 1/2% Cu, 1/2% P and 1% Si
Alloy B - 93% Pb, 1.5% Sb, 1/2% Sn, 1/2% Cu, 1% P and 3.5% Si
Alloy C - 94% Pb, 1% Sb, 2.5% Sn, 1/2% P and 2% Si

Tim

[ulav8r]

sand with phosphorus in it?????

[kevin c]

I’m no expert, but I’d think the surface of the sample being tested needs to be clean, as does the cover over the xrf sensor.

BNE describes how he scrapes the surface of the sample where he tests it. I’d guess he also cleans the sensor of his lab grade xrf instrument.

So if the sensor or sample surface are dirty, the reading will include the contaminants as well as the sample every time.

[truckjohn]

Yep. Dirt/contamination. Commercial alloys are way below 0.001% on impurities unless you are buying off spec/reject material. We would typically machine a surface clean before reading. Any sort of dirt or contamination will throw off your readings.

[dtknowles]

These are not commercial alloys. They are range scrap that are enhanced with solder, copper, COWW, type metal, etc. They are fluxed with wood chips. The sample ingots are not contaminated but they were not scraped, they were shiny. I have a small ingot mold that makes 2 oz. rounds. I don't think it is the gun because zinc, aluminum and steel samples were tested at the same time and don't show the Si and P.

Tim

[fc60]

Greetings,

The last batch of "mystery" metal I had analyzed offered good results.

I cast a one pound ingot with no writing on it. i.e LYMAN, SAECO, RCBS, etc.

I then took a coarse rasp and filed the surface clean and smooth.

The resulting surface fit the X-ray tester well and produced good results.

The first time, I did not do this and got Silicon in the test result. Likely due to the fact the metal was range salvage.

Cheers,

Dave