hopeite


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Related to hopeite: parahopeite

hopeite

[′hō‚pīt]
(mineralogy)
Zn3(PO4)2·4H2O A gray, orthorhombic mineral composed of hydrous phosphate of zinc; specific gravity is 2.76-2.85; dimorphous with parahopeite.
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On the other hand, a phosphate coating that consists of a low P ratio, a major hopeite structure, coarse crystals (25-30 [micro]m), a comparatively thicker coating (3-3.5 g/m2), and higher porosity (2.6%) gives poor corrosion resistance.
The phosphate coating enriched with a phosphophyllite structure showed small globular crystals with less porosity, whereas a hopeite structure showed coarse crystals with high porosity and comparatively thicker coating.
But only hopeite is formed on galvanized steel and is measured as the ratio of hopeite (020)/hopeite (311) (151) (241) plane.
The [P] and [H] were measured at a peak intensity of 9.86 and 9.59[degrees], respectively, for a 20 value of phosphophyllite (100) and hopeite (020).
The levels of magnesium and calcium in the water will not agglomerate hopeite, so the particle size in solution is maintained thus extending the bath life.
The hopeite surface conditioner can eliminate all of the traditional concerns that accompany titanium-based conditioners while reducing both manufacturing facility operational costs and environmental concerns.
An unpublished paper by Mrose, Strunz and Ahlfeld lists hopeite as being among the species Ahlfeld found at Cerro Rico.
3[Zn.sup.2+] + 2[H.sub.2]P[O.sub.4.sup.-] + 4[H.sub.2]O [right arrow] [Zn.sub.3] [(P[O.sub.4]).sub.2].4[H.sub.2]O (Hopeite) + 4[H.sup.+] (1)
Hopeite ([Zn.sub.3][(P[O.sub.4]).sub.2].4[H.sub.2]O) has a higher alkaline solubility than phosphophyllite ([Zn.sub.2]Fe[(P[O.sub.4]).sub.2].[H.sub.2]O) [29, 32, 33].
The relatively high weight of Ni in the coating as confirmed by the EDX analysis may indicate the substitution of [Zn.sup.2+] by [Ni.sup.2+] in hopeite or the deposition of Ni in the coating.
Writer Jean Glick of Hope writes, "For the Easter sunrise service, Hopeites are awakened by a trombone band playing at street corners before the 6 a.m.