What is Hydrazine?

What does hydrazine look like?

Hydrazine is a colorless, flammable liquid with a strong ammonia-like odor with a density and appearance similar to water. It is a highly reactive and unstable compound, especially in the anhydrous form used as a propellant. Represented by the chemical formula N₂H₄, hydrazine is mainly used as a powerful reducing agent and is critical in various aerospace, industrial and chemical applications.

It is important to handle hydrazine with safety as a priority. Proper training and personal protective equipment are a must, just like handling any other hazardous chemical. Engineers and operators at Calca Solutions have developed guidelines and procedures to produce, blend, store, and package hydrazine safely.

Hydrazine has the chemical formula N2H4

Different concentrations of hydrazine

Hydrazine is commonly available in various concentrations depending on its industrial use and handling safety. The main concentrations include:

Anhydrous Hydrazine (98%100%)

Pure hydrazine is highly reactive and unstable, most often used in aerospace as a rocket fuel or propulsion system. Requires careful handling due to toxicity and explosive nature. A special 70% Anhydrous Hydrazine blend is used as a propellant in F-16 and other single engine aircraft emergency power units (EPU).

Hydrazine Solutions (15.5-64%)

A more stable and safer hydrated form of hydrazine in aqueous solutions. Hydrazine Hydrate is widely used in various applications such as the deoxygenation of boiler water, preparation of chemical blowing agents, preparation of intermediates for pharmaceutical and agricultural chemicals, reducing agent for metals and halogens and chain extension of aqueous urethane formulations. There are two nomenclatures for hydrazine solutions, thus 100% hydrazine hydrate contains 64% hydrazine by weight. Hydrazine hydrate is miscible with water and lower alcohols.

Concentrations

Here is a chart that exemplifies different concentrations of hydrazine and hydrazine hydrate. Refer to the Technical Data section for a more detailed breakdown of the specifications, physical properties, and suitable materials of construction for use with hydrazine and its solutions.

Name	N2H4 Concentration	Hydrazine Hydrate %
Anhydrous Hydrazine	98-100%	N/A
Hydrazine Hydrate	64%	100%
54.4% Solution	54.4%	85%
35% Solution (Scavox)	35%	55%
15.5% Solution (Scavox)	15.5%	24%

Stability & reliability for use in space

Hydrazine's stability for use in space is a result of its unique chemical properties and controlled handling conditions. Here’s how it remains stable and useful:

Monopropellant Behavior

In spacecraft, hydrazine is typically used as a monopropellant. It remains stable under normal storage conditions but decomposes rapidly when passed over a heated catalyst, such as iridium-coated alumina in a thruster. This controlled decomposition generates significant thrust without the need for an oxidizer.

Vacuum and Low Pressure

The absence of atmospheric oxygen in space minimizes the risk of unplanned combustion or explosive reactions, enhancing hydrazine's stability during missions.

Controlled Systems

Onboard spacecraft, hydrazine is stored in pressurized tanks and fed into thrusters via precision-engineered systems. Safety measures, such as thermal insulation and non-reactive materials, prevent unintended reactions.

High Energy Density

Hydrazine’s high energy density and ability to produce thrust instantly without complex ignition systems make it ideal for satellite station-keeping, orbital adjustments, and spacecraft maneuvers.

While hydrazine is highly toxic and reactive on Earth, its stability and efficiency in controlled space conditions make it a reliable propellant for space missions.

Achieving excellence in hydrazine manufacturing through innovation, safety, and sustainability

For over 70 years, Calca Solutions has built an enduring legacy of innovation, reliability, and stewardship in hydrazine manufacturing. Our mission remains unchanged - to be the trusted industry leader, delivering essential products safely and sustainably while contributing to the wellbeing of all we serve.