Our Expertise With Pyrotechnics

The following powders demonstrate our expertise with pyrotechnics.

For the pyrotechnics we cover here, we'll explain what they are, why we like them and what you should keep in mind when you handle them.

Pyrotechnic: Titanium Hydride/Potassium Perchlorate (THPP)

What It Is

THPP is a "booster" pyrotechnic and is a blend of a fuel (titanium hydride, TiH2), an oxidizer (potassium perchlorate, KCIO4) and binder, typically Viton. The primary use at PacSci EMC is as a pyrotechnic transfer compositions where it converts the heat energy from a bridgewire pyrotechnic (usually ZPP) to generate a flame and hot particles which ignite an output charge. THPP affords a rapid pressure rise, emits hot particles and has good thermal stability.

Why We Like It

THPP was designed to be much safer (from an ESD perspective) to use during manufacturing operations compared to TiKP which contains titanium metal (similar to ZPP) and is extremely ESD sensitive. THPP also has a lower ignition sensitivity and slower burn rate compared to TiKP and, while both materials are used in ordnance devices, they frequently have different applications. THPP is prepared at PacSci EMC from commercially available titanium hydride powder, finely ground potassium perchlorate and a small percentage of Viton binder utilizing a shock gel mixing method.

How You Should Handle It

Like ZPP, THPP requires both assembly personnel and hardware used in manufacturing processes to be efficiently grounded and have extensive PPE due to the ESD sensitivity of the composition. THPP, both bulk and pressed, has been found to be insensitive to initiation from a "typical" human body static discharge and so is considered safe relative to TiKP or TiH<2PP (titanium or titanium sub hydride). Minor compatibility issues between THPP and typical EED materials have been found. These include various amines commonly found in curatives for adhesive resins and common solvents.

Of note is that THPP is not as thermally stable as other common pyrotechnics encountered at PacSci EMC. Long term exposure at high temperatures (>250 °C) may alter the titanium/hydride ratio which changes the safety and output properties as well as the service life of components containing the composition.

Cleanup of minor spills should be done with a 50% IPA/DI water mix and a wet paper towel for blotting. Like other EM's, major spills require evacuation of the area.

Pyrotechnic: Zirconium/Potassium Perchlorate (ZPP)

What It Is

The pyrotechnic zirconium/potassium perchlorate ("ZPP") is a mixture of fuel (high purity micron range Zr powder) and an oxidizer (milled potassium perchlorate). ZPP has been widely used in electro-explosive devices for many years as a composition that converts the electrical energy applied to a bridgewire into sufficient heat and hot particles to initiate a downstream transfer charge or explosive output. ZPP is used in defense, automotive initiators and in the NASA Standard Initiator where it plays a critical role in initiating various pyrotechnic events in space applications. ZPP has the advantages of affording a rapid pressure rise, generating only minor gas, emitting hot particles, being very thermally stable (>450 C) and having a long shelf life.

Why We Like It

Due to the demanding nature of applications that utilize ZPP, it has been extensively investigated and the chemical, physical and output properties of mixtures with a variety of stoichiometrics are well known. Under the right conditions, ZPP can meet the 1 amp/ 1 watt/ 5 minute no-fire safety requirement imposed by U.S. military design specifications (e.g., MIL-I-23659). This is partially due to the high thermal conductivity of ZPP mixtures that effectively move heat away from the bridgewire and into the bulk material under no-fire conditions. In addition, ZPP has been demonstrated to function normally at both extremely high and extreme low (cryogenic) temperatures when manufactured and loaded under optimum conditions. In more extreme environments, ZPP may be utilized as a bridgewire slurry to insure consistent ignition.

ZPP is electrically conductive due to the zirconium content, which renders it particularly vulnerable to electrostatic discharge and which makes it a safety hazard during handling and loading in ordnance items. ZPP is typically produced with ~5% Viton B as a binder and may contain smaller percentages of graphite as well. Viton is incorporated to provide some level of electrostatic sensitivity protection while the purpose of the graphite is to act as a lubricant to increase packing density and as a reaction rate modifier. At PacSci EMC, ZPP is typically prepared via a wet process which afford safety benefits over other methods of production while producing a product that is extremely homogeneous and consistent.

How You Should Handle It

ZPP is not particularly sensitive to moisture but should be stored in a low humidity environment. Components containing ZPP are typically hermetically sealed and can have a long operational lifetime.

The extreme ESD sensitivity of ZPP requires both assembly personnel and hardware used in manufacturing processes to be efficiently grounded and have extensive PPE. Even with safeguards in place, inadvertent ignition of ZPP mixtures are not uncommon and may produce an audible crack along with an intensely bright flash.

Additional Comments

APD personnel at PacSci EMC are currently engaged in development of an ESD safe non-conductive replacement for ZPP called BI-820. If successful, this mixture of organic fuel and oxidizer, in optimized ratio, may provide an output similar to other pyrotechnic systems, but would have the benefit of being non-conductive both prior to and after ignition as well as being stable on very high temperatures. Detailed related to BI-820 may be found in U.S. Patent Application 2020/0223766 A1.

Talk To Us About What You Need

Contact Us today to learn more about our pyrotechnic offerings. Our team of experts will help you see how this composition can fit into your current needs and any future components you plan to develop.