The use of passive initiation aids in self-propagating high-temperature synthesis

A modification to initiation aid-assisted ignition in bomb calorimetry that involves systemically blending boron and potassium nitrate adjacent to, and within, a bulk structural energetic elemental power blend was developed. Linear regression was used to estimate the nominal heat of reaction for the primary reaction. The technique was applied to the synthesis of TiB2 as a validation study to see if proximity to the literature values could be achieved. X-ray diffraction was used to characterize the product phases of the reactions to determine the extent and the identity of the product phases and any by-products that may have formed as a result of adding the initiation aid. The experimental data indicate the technique approximates the heat of reaction value for the synthesis of TiB2 from Ti/B powder blends and the formation of TiB2 is supported by volume fraction analysis by X-ray diffraction. Some experimental uncertainty remains as X-ray diffraction revealed that the commercially labeled amorphous boron reactant exhibited some crystalline character and may be semicrystalline, as opposed to being completely amorphous. © 2013 The Minerals, Metals & Materials Society and ASM International