XRF examination of an early Viking Age sword (Petersen type B)

Lee · 17th October 2025, 06:00 PM

OK, this is clearly amateur science stuff with all of the limitations that implies, but even so some conclusions may be drawn.

Phosphorus is ten or more times greater in the readings from the central flats of the blade than on the bevels or edges (red arrows in the previous post.) Bands of pattern-welding are expected in a Petersen type B sword and phosphoric iron appears lighter in color and is known to have been used in the layered, twisted rods employed in pattern-welding to increase visual contrast.

Calcium (blue arrows above), on the other hand, is significantly greater at the edges and bevels again strongly suggesting that a different alloy was used in these positions versus the central flats of the blades. Calcium carbonate may be used as a flux in bloomery smelting and perhaps this might explain the difference observed.

Sulfur shows a much lesser difference.

Math could very likely bring out other relevant findings, as could the skill to interpret the actual spectra reported by an instrument calibrated for geological exploration rather than archaeology. But these are the low hanging fruits the amateur can reach.

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17th October 2025, 06:00 PM	#2
Lee EAAF Staff Join Date: Nov 2004 Location: Upstate New York, USA Posts: 980	OK, this is clearly amateur science stuff with all of the limitations that implies, but even so some conclusions may be drawn. Phosphorus is ten or more times greater in the readings from the central flats of the blade than on the bevels or edges (red arrows in the previous post.) Bands of pattern-welding are expected in a Petersen type B sword and phosphoric iron appears lighter in color and is known to have been used in the layered, twisted rods employed in pattern-welding to increase visual contrast. Calcium (blue arrows above), on the other hand, is significantly greater at the edges and bevels again strongly suggesting that a different alloy was used in these positions versus the central flats of the blades. Calcium carbonate may be used as a flux in bloomery smelting and perhaps this might explain the difference observed. Sulfur shows a much lesser difference. Math could very likely bring out other relevant findings, as could the skill to interpret the actual spectra reported by an instrument calibrated for geological exploration rather than archaeology. But these are the low hanging fruits the amateur can reach.