Saturday, March 24, 2007

Yellow Steel Box

I came across this interesting piece of information on the net thanks to sm5bsz. The interesting bit as far as I am concerned is the note about yellowish steel. I am using a box like this to mount the 4CX250B tubes in. I have other boxes that will be used in the project. It is good that I do not have to shield these boxes when used in RF gear. I think these boxes where used for microwave equipment.


Material Relative losses
Silver plating 0.96*X
Copper 1.00*X
Aluminium (pure) 1.25*X
Brass 1.87*X
Aluminium (worst case) 2.17*X
Steel 25*X or more


Steel with a yellowish surface treatment, common in electronics, has losses similar to brass. I do not know what this surface is, but it is easy to verify the dramatic reduction of losses that it gives.

2 comments:

Anonymous said...

Hi Peter,
Its zinc chromate finish:
http://en.wikipedia.org/wiki/Chromate_conversion_coating

Peter Bennett said...

Thanks Armin.