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US 5,203,915 AGranted
Passivating coating for metal oxide varistors
AssigneeHubbell Incorporated
InventorMohammed A. Alim
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AssigneeHubbell Incorporated
InventorMohammed A. Alim
Estimating the term…
It is disclosed that the properties of a ceramic mullite-kaolinite based passivating coating composition applied as a collar to metal oxide varistor valve block cylindrical surfaces are improved by including in the coating composition from 0.03 to 15% by weight of the coating composition one or more of the following additive compounds: TiO.sub.2 ; Y.sub.2 O.sub.3 ; ZrO.sub.2 ; ZnO; Boroflux (2ZnO.multidot.3B.sub.2 O.sub.3 .multidot.7H.sub.2 O; or 3ZnO.multidot.2B.sub.2 O.sub.3 .multidot.5H.sub.2 (O); or Si.sub.3 N.sub.4. The coating composition comprises by dry weight a mixture of 55-85% mullite and 15-45% kaolinite, one or a mixture of the above additive compounds, and sufficient water to form a sprayable slurry. The inclusion of the additive compound results in enhanced contact adhesion between the collar and the metal oxide varistor peripheral surface.
A passivating coating composition suitable for application as a collar to metal oxide varistor valve block cylindrical surfaces comprising a mixture by dry weight of 55-85% mullite and 15-45% kaolinite, from 0.03 to 15% by weight of the coating composition of one of the following additive compounds:
A passivating coating composition suitable for application as a collar to metal oxide varistor valve block cylindrical surfaces comprising a mixture by dry weight of 55-85% mullite and 15-45% kaolinite, from, 0.15 to 15% by weight of the coating composition including wafer of TiO.sub.2 in addition to the amount of TiO.sub.2 that may be inherently present in the kaolinite as an impurity and sufficient deionized water to form a sprayable slurry.
Dependencies are inferred from the claim text.