Bev,

I've had this discussion with one of the major SMT resistor manufacturers.
They consider it a glass with a "conductive phase in it"; just the same,
glass or ceramic it's exempt in electronic components.

Mike


On Mon, 26 Jun 2006 08:41:49 -0400, Bev Christian <[log in to unmask]> wrote:

>"Examples of semimetallic ceramics are lead oxide (PbO), ruthenium
>dioxide (RuO2), bismuth ruthenate (Bi2Ru2O7), and bismuth iridate
>(Bi2Ir2O7). Like metals, these materials have overlapping electron
>energy bands and are therefore excellent electronic conductors. They are
>used as "inks" for screen printing resistors into thick-film
>microcircuits. Inks are pulverized conductor and glaze particles
>dispersed in suitable organics, which impart the flow properties
>necessary for screen printing. On firing, the organics burn out as the
>glazes fuse. By varying the amount of conductor particles, it is
>possible to produce wide variations in the resistance of thick films."
>Britannica.com
>
>I would presume the use of lead in this instance is exempt.  I would
>consider fused lead oxide as a ceramic.  That is my interpretation.
>Comments?
>Bev
>RIM
>
>

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