The Role of Catalysts in the Ignition and Combustion of Solid Propellants

In the present study, nano and micron‐sized barium titanate (BaTiO3) were characterized and evaluated in HTPB/AP/Al composite propellant. Different compositions were prepared by incorporating BaTiO3 from 0.5 % to 2 % in a standard composition. The BaTiO3 reduces thermal decomposition temperature of ammonium perchlorate and also of standard composition. Other propellant processing and performance parameters like viscosity, mechanical and ballistic properties were also measured. The ballistic properties results revealed that there was more than 22 % and 12 % (at 6.86 MPa) enhancement in burning rate with 2 % nano and micro‐ BaTiO3, respectively.

Section: Introductionmentioning

confidence: 93%

Barium Titanate: A Novel Perovskite Oxide Burning Rate Modifier for HTPB/AP/Al Based Composite Propellant Formulations

Jain

Khire

Kandasubramanian

2019

“…Boron particle ignited at 1630°C to 1680°C at atmospheric pressure(@ and at 1230°C at 1.5 MPa(l2). The gaseous products generated by the decomposed binder and the boron particles acted as a fuel and reacted with the decomposition products of the oxidizer AP (13)(14)(15). The energy release in the gas phase reaction, which produces the flame, dominates the combustion heat balance.…”

Section: Thermal Decompositionmentioning

confidence: 99%

Combustion Behavior of Fluorocarbon/Boron/AP Propellant at high pressure

Oyumi¹,

Nagayama²

1995

Thermal decomposition and the burning properties of fluorocarbon/boron/AP propellant granule have been investigated. The fluoro‐carbon binder (FBDR) was oxidized by the decomposition products of admixed ammonium perchlorate (AP) and its decomposition region was 150°C lowered in the slow thermolysis. The boron particles, however reacted with neither FBDR nor AP at 550°C. In the micro‐motor tests, the boron particles completely burnt at a pressure range of from 30 MPa to 80 MPa in a short period of time (one millisecond) even at a low characteristic exhaust velocity. Minimum free volume, however, was needed to complete the combustion reaction in the chamber case. The characteristic exhaust velocity significantly decreased at below the characteristic chamber length of 11 cm. The boronized propellant showed low temperature sensitivity between −30°C and 60°C.

“…The majority of work focused on catalyst additives for adjusting AP composite propellant burning rate has focused on metal oxides [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] (e.g.,F e 2 O 3 ,C uO, TiO 2 )w here metal oxides catalyze the thermal decomposition of AP and therefore increase the burning rate of AP composite propellants. Ferric oxide (Fe 2 O 3 )h as found the most use in commercial AP composite propellants due to its low cost, ease of manufacture, stability/inertness, and ability to generate high and reproducible burning rates [15].T he influence of the size of the catalyst particles has also been considered, where it is thought that smaller particles (e.g., nanoparticles) with higher surface-to-volume ratios have greater catalytic activity.H owever,n anoparticles can be dif-ficult to uniformly introduce into as olid propellant as they tend to agglomerate due to van der Walls and electrostatic forces.…”

Section: Introductionmentioning

confidence: 99%

Iron Nanoparticle Additives as Burning Rate Enhancers in AP/HTPB Composite Propellants

Styborski

Scorza

Smith

et al. 2014

a] 1I ntroductionAmmonium perchlorate (AP) composite propellants are widely used in solid rocket propulsion. Common formulations for AP composite propellants include hydroxyl-terminated polybutadiene (HTPB) as ab inder and fuel, ac urative/plasticizer to solidify the HTPB binder,s ometimes aluminum particles as fuel to increase energy density,a nd sometimes am etal oxide additive to catalyze AP thermal decomposition [1].T he burning rate of AP composite propellants has been shown to be controlled by the concentration of AP,t he size of AP particles, binder type, the type and concentration of any catalyst additives, and the concentration and particle size of any added aluminum fuel (e.g.,R efs. [1-7]);h ence, AP composite propellants can be manipulated for burning rate tailoring by simply altering the proportions of the components and using small percentages of additives which can act as catalysts for condensed and/or gas-phase reactions, ignition sources, and/or provide thermal feedback or sinks.The majority of work focused on catalyst additives for adjusting AP composite propellant burning rate has focused on metal oxides [5-20] (e.g.,F e 2 O 3 ,C uO, TiO 2 )w here metal oxides catalyze the thermal decomposition of AP and therefore increase the burning rate of AP composite propellants. Ferric oxide (Fe 2 O 3 )h as found the most use in commercial AP composite propellants due to its low cost, ease of manufacture, stability/inertness, and ability to generate high and reproducible burning rates [15].T he influence of the size of the catalyst particles has also been considered, where it is thought that smaller particles (e.g., nanoparticles) with higher surface-to-volume ratios have greater catalytic activity.H owever,n anoparticles can be dif-ficult to uniformly introduce into as olid propellant as they tend to agglomerate due to van der Walls and electrostatic forces.An abundance of literature also exists on the use of aluminum as fuel in AP composite propellants (e.g.,R efs. [21][22][23][24]), either as in nanoparticles or micro-sized particles, where aluminum increases energy density and can increase burning rate. Jayaraman et al. [24] have shown that aluminum nanoparticles can increase the burning rate of AP/ HTPB/Al propellants by up to 100 %compared to micro-aluminum. However,J ayaraman et al. also found the effect of Fe 2 O 3 additives as catalysts is mitigated for AP/HTPB/nano-Al propellants relative to AP/HTPB/micro-Al formulation (i.e.,n oa dditional burning rate increase is observed when adding Fe 2 O 3 to propellants containing Al nanoparticles).Interestingly,w ea re not aware of any literature in which iron (Fe) nanoparticles have been investigated as additives for AP compositep ropellants. Fe nanoparticles have several properties that could be advantageous as additives to AP composite propellants. Fe nanoparticles that have been exposed to air have an oxidized Fe 2 O 3 shell which can provide catalysis to AP decomposition at the propellant burning surface in the same manner as purely Fe 2 O 3 particle...