Flow improvement of fine oxidizer using nano-additives

Ammonium perchlorate (AP) is an oxidizer and major component for any solid composite propellant. The handling and processing of AP powder plays an important role in the performance of rocket fuel. AP being hygroscopic in nature; especially particle size<50 μm is highly cohesive in nature, which results in extensive agglomeration and poor flowability. This causes inherent handling problems in the propellant processing plant. In this work, the flowability of 8 μm and 50 μm AP particles was improved through the dry coating method using nano-additives such as TiO<inf>2</inf> and Fe<inf>2</inf>O<inf>3</inf>. In addition, the influence of hydrophobic nano-silica (R972 type) coating on AP particles under high humidity was investigated. The results showed that coating of AP with nano-additive reduced the inter-particle forces hence cohesivity and improves the packing and flowability of fine AP powder. Hydrophobic coating was found to have added advantage at higher humidity. Moreover, coating with these nano-additives also improved the exothermicity of AP.