Burning Rate Characterization of Guanidine Nitrate and Basic Copper Nitrate Gas Generants with Metal Oxide Additives

ABSTRACT

Automotive airbag gas generants have been studied extensively to meet design and safety requirements. Additives have historically been used to increase their burning rates, but the effects of additive size have not been thoroughly investigated. The current study evaluated the effects of nano- and micro-sized metal oxides on the combustion of guanidine nitrate (GN) and basic copper nitrate (BCN) gas generant systems. Three metal oxide additives were chosen for this study: alumina (Al₂O₃), ceria (CeO₂), and titania (TiO₂). Nano- and micro-sized particles were incorporated into gas generants at a mass loading of 4%. Cylindrical pellets with and without additive particles were manufactured, and their homogeneity was confirmed through scanning electron microscopy analyses. Pellets were burned over a range of pressures from 6.9 MPa (1,000 psi) to 27.6 MPa (4,000 psi). Micro-ceria was the only additive observed to enhance the burning rate relative to the baseline.

KEYWORDS:

• Gas Generants
• Guanidine Nitrate
• Basic Copper Nitrate
• Catalysts

Symbols and Abbreviations

Al₂O₃ Alumina

AP Ammonium Perchlorate

BCN Basic Copper Nitrate

B:KNO₃ Boron Potassium Nitrate

CeO₂ Ceria

GN Guanidine Nitrate

HTPB Hydroxyl-terminated polybutadiene

$L$ LLength of AP Pellet

MOPAC Molecular orbital package

PTFE Polytetrafluoroethylene

$r$r Burning Rate

RAM Resodyn Resonant Acoustic Mixer

RSS Root-Sum-Squares

SEM Scanning Electron Microscope

t_b Burn Time

TiO₂ Titania

Acknowledgments

This research was funded by the Texas A&M Engineering Experiment Station (TEES) Turbomachinery Laboratory.

Additional information

Funding

This work was supported by the Texas A&M Engineering Experiment Station (TEES) Turbomachinery Laboratory.