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Browse Prior Art Database

Determining the Surface Area of Oxidizable Powers

IP.com Disclosure Number: IPCOM000073769D
Original Publication Date: 1971-Jan-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 16K

Publishing Venue

IBM

Related People

Kenney, DM: AUTHOR

Abstract

In this method the fixed relationship between the thickness of an oxide formed on a flat surface and the weight of oxide formed on a powder of unknown surface area is used to measure the surface area of the powder.

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Determining the Surface Area of Oxidizable Powers

In this method the fixed relationship between the thickness of an oxide formed on a flat surface and the weight of oxide formed on a powder of unknown surface area is used to measure the surface area of the powder.

The weight (W) of a small sample of powder is accurately determined by weighing the powder in a quartz boat. The powder is then oxidized in a dry oxygen atmosphere along with a wafer consisting of the same material as the powder. The thickness (t) of the oxide formed on the wafer is measured, for instance by the ultra violet interference technique. The oxidized powder is then accurately weighed and the weight of the oxide formed on the powder (4W) is determined. The surface area (A) of the powder per unit weight is then determined by using the following formula: A = Delta W over WDt K. where:

D is the density of the oxide and

K is a factor to convert Delta W into weight of oxide -- i.e., K = 1.875 for SiO(2).

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