REG NASA-LLIS-0434-1996 Lessons Learned Rusty Integrated Circuits (~1973).pdf

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1、Lessons Learned Entry: 0434Lesson Info:a71 Lesson Number: 0434a71 Lesson Date: 1996-07-17a71 Submitting Organization: JPLa71 Submitted by: J.A. RobertsSubject: Rusty Integrated Circuits (1973) Abstract: During the Viking program, rust spots were observed on the gold-plated Kovar lids of a number of

2、flat pack ICs. The cause was suspected to be chlorine from the lead tinning operation, and various polymeric coatings failed to prevent further corrosion.Following the use of any chlorinated product, a thorough and complete cleaning to remove all residual chlorine contamination is a necessity. Descr

3、iption of Driving Event: (Relevant Historical Lesson(s) Learned)During the Viking program, rust spots were observed on the gold-plated Kovar lids of a number of flat pack Integrated Circuits (I.C.) used in electronic equipment. Although the source was not clearly identified, chlorine apparently init

4、iated the corrosion. The chlorine is presumed to have been within activated solder flux residues from the lead tinning operation. In some cases, the corrosion penetrated through the I.C. lid and was a potential cause of I.C. failure.Although various polymeric coatings were applied over the metallic

5、coatings to interrupt the corrosion cycle, they were all permeable enough to permit water through to the Kovar surface and the corrosion continued.Reference(s): PFR 32492Lesson(s) Learned: Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-Corrosion, on

6、ce started, is extremely difficult to stop.Recommendation(s): Following the use of any chlorinated product, a thorough and complete cleaning to remove all residual chlorine contamination is a necessity.Evidence of Recurrence Control Effectiveness: N/ADocuments Related to Lesson: N/AMission Directora

7、te(s): N/AAdditional Key Phrase(s): a71 Hardwarea71 Parts Materials & ProcessesAdditional Info: Approval Info: a71 Approval Date: 1996-04-04a71 Approval Name: Carol Dumaina71 Approval Organization: 125-204a71 Approval Phone Number: 818-354-8242Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-