There are a large variety of bulk TE materials that are under investigation, including singe phase and alloys of lead chalcogenides (PbX, X = S, Se, or Te) [6-11], binary skutterudites
(M[X.sub.3], M = Co, Rh or Ir; X = P, As, or Sb) [12-14], clathrates , copper chalcogenides ([Cu.sub.2-x]X, X = S, Se, or Te) , oxides (e.g., NaxCo[O.sub.2], ZnO, and Ruddlesden-Popper homologous series) [17-20], half-Heusler compounds [21, 22], [Bi.sub.2]/[Te.sub.3]/[Sb.sub.2][Te.sub.3] [23, 24], SiGe , and SnSe .
Evident Half-Heusler 500K thermoelectric Shanghai Institute Skutterudites
510K of Ceramics TEGMA Skutterudites
-- TECTEG MFR Calcium/Manganese 750K oxide TECTEG MFR cascade Calcium/Manganese 435 K modules oxides with [Bi.sub.2][Te.sub.3] TECTEG MFR hybrid BiTe-PbTe 320K modules Hotblock Onboard Silicon-based alloy 500 K Romny Scientific Magnesium silicide -- Alphabet energy P type 300 K tetrahedritesnn- type magnesium silicide OTEGOCDT Organic TEG Small temperature gradients Manufacturer Power Status Maximum weight temperature HiZ, Thermonamic, 20W 40[euro]-100[euro] 300[degrees]C Lairdtech, Marlow, 115 g Komatsu etc.
Putting atoms of another element in the skutterudite
voids makes the materials more glass-like.
In thermoelectric materials, the skutterudite
system found in Co[Sb.sub.3] is a representative material of bulk nanostructured materials [1, 2].
Bou Azzer has produced the world's finest specimens of erythrite, roselite, roselite-beta, talmessite, wendwilsonite, skutterudite
golds, silvers, a giant skutterudite
crystal, Indian zeolites, a beautiful Moroccan wulfenite.
Most outstanding were a 350-gram specimen of Schneeberg silver, a fine cabinet-size skutterudite
, fine annabergite, chloanthite, tetrahedrite, a perfect little proustite group from Chanarcillo, and a well-formed, pale copper-red nickeline group containing 3-inch pyramidal crystals from Saxony.
Other Moroccan items of interest included erythrite miniatures with crystals up to 1 cm, some skutterudite
specimens with crystals to 2 cm, roselite (or wendwilsonite?) crystal groups to 7 cm, small fine azurite roses, a few of the new golden apatites, and a scattering of cerussite and anglesite specimens.
Other minerals in the dump material are: cobaltaustinite, scorodite, bariumpharmacosiderite, olivenite, conichalcite, erythrite, arsenjosiderite, mimetite, beudantite, silver, bismuth, acanthite, galena, pyrite and skutterudite
These sheaves may be loose, or may make jumbled clusters without matrix, or may rise at all angles from a dense black matrix of ore sulfides and arsenides (recall that the world's best skutterudite
occurs at Bou Azzer, too).
Ernesto had about ten outstanding cabinet specimens, with brilliantly lustrous metallic white (think of skutterudite
at its best) 5-mm octahedrons of gersdorffite in tight spherical groups, partly etched out of white vein calcite so that the gersdorffite balls sit up well on massive gray ore (with green stains of annabergite).
There were many rarities in the "Cobalt" showcase, among them a fine sainfeldite and the largest skutterudite
crystal ever found (both from the Saint-Chretien mine).