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Porcelainized Steel Substrates

IP.com Disclosure Number: IPCOM000044764D
Original Publication Date: 1984-Jul-01
Included in the Prior Art Database: 2005-Feb-06
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Burns, RW: AUTHOR [+2]

Abstract

Described is a process for improving the yield and/or dielectric strength of porcelainized steel, utilizing phosphate treatment and minimizing exposure time to sulfuric acid .

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Porcelainized Steel Substrates

Described is a process for improving the yield and/or dielectric strength of porcelainized steel, utilizing phosphate treatment and minimizing exposure time to sulfuric acid .

Many attempts have been made to provide porcelainized steel as an electronic packaging substrate. The conventional porcelainizing process includes excessive etching in a 10 to 15% sulfuric acid solution followed by nickel strike treatment. Under these conditions, hydrogen may be adsorbed by the steel. If the entrapped hydrogen does not escape completely during firing, bubbles or voids may result from nonescaped hydrogen. Voids may result as well from decomposition of frit materials at the high firing temperatures.

The new process for improving the topology of the porcelain coating on steel comprises the following steps: - Remove scale or corrosion products by treating in

a strong alkaline cleaner. -Double water rinse. -Treat in 10% sulfuric acid three to five minutes. -Water rinse. - Treat in the following solution for 3 - 5 minutes

at 120OEF:

Phosphoric acid 10 Milliters

Iron Phosphate 1 Gram

Oxalic Acid 3 Grams

Sodium Nitrate 3 Grams

Water 90 Milliters -Rinse in distilled or deionized water. -Air dry. - Apply porcelain, by spraying, dipping, or electro

deposition. -Air dry. -Bake at 250OEF for 40 minutes.

-Fire samples at 1500OEF for 4-5 minutes.

Following the above procedure results in porcelainized steel having no voids and a voltage breakdown level in exc...