Functional and chemical characterization of the aging process of an igniter

✍ Scribed by Ivan Spasojevic̈; Ines Batinic̈-Haberle; Dubravka Baris̈in

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 401 KB
• Volume: 18
• Category: Article
• ISSN: 0721-3115
• DOI: 10.1002/prep.19930180208

✦ Synopsis

Abstract

The igniter consisting of 34% Mg, 60% KNO~3~, 3% KClO~4~ and 3% organic binder was subjected to accelerated aging under the conditions of 85% relative humidity at 65°C, 75°C and 85°C, and at 75°C with 92% relative humidity. Chemical aging was followed through formation of Mg(OH)~2~ and KNO~2~. Functional characterization was accomplished in a device constructed to enable simultaneous determination of the heat of combustion and pressure‐time recording of the combustion process of both fresh and aged samples.

The maximum acceptable deterioration occured at different times depending upon the conditions. The acceleration factor for every 10°C at 85% relative humidity is on average 2.8, leading to a prediction of shelf life of not more than 4 years at 25°C. At the time when burning characteristics were significantly changed, the mixture suffered only slight chemical changes, with only about 1% Mg(OH)~2~ and 0.5% KNO~2~ being formed. Thus, no chemical changes should be tolerated in such formulations.