What is Inert Gas Fusion (IGF) Analysis?

Some of the most important elements in an engineering material are also the easiest to overlook. Oxygen, nitrogen, and hydrogen exist in concentrations too small to see, yet they can determine whether a component performs reliably or fails prematurely. Measuring these interstitial gases demands Inert Gas Fusion (IGF) analysis, a benchmark elemental analysis technique for laboratories working with advanced materials that need to maintain tight control over quality and performance.

Defining IGF Analysis

IGF is used to determine the concentration of oxygen, nitrogen, and hydrogen trapped within inorganic materials. Laboratories routinely apply it to raw metals, specialized alloys, ceramics, refractories, and advanced composite materials where precise gas content directly affects material quality and manufacturing outcomes.

The analytical process behind IGF follows a controlled sequence:

• A carefully weighed sample is placed into a high-purity graphite crucible
• Electrical resistance heating raises the crucible temperature beyond 2,500°C
• A continuous flow of high-purity helium or argon purges the analytical chamber
• Complete fusion releases the interstitial gases into the inert carrier gas stream without interference from atmospheric oxygen or moisture.

Utilizing an inert carrier gas is fundamental to IGF. Because helium and argon remain chemically unreactive throughout the analysis, the liberated gases retain their original chemical characteristics until they reach the detection system. This controlled environment allows IGF to produce highly repeatable and reliable measurements.

How Extracted Gases Are Detected and Measured

Following complete fusion, several predictable chemical reactions occur inside the graphite crucible. Oxygen released from the molten sample immediately reacts with the surrounding graphite, producing carbon monoxide and carbon dioxide. Measuring these compounds allows the original oxygen concentration to be calculated with exceptional accuracy.

Nitrogen and hydrogen behave differently. Both gases leave the molten sample in their natural diatomic forms as nitrogen and hydrogen, remaining unchanged as they travel through the carrier gas stream.

Dedicated detectors then quantify each gas individually.

• Infrared (IR) absorption detectors determine carbon monoxide and carbon dioxide, allowing the analyzer to identify the sample’s original oxygen content
• Thermal conductivity (TC) detectors compare the thermal properties of the gas mixture against the pure carrier gas, accurately measuring nitrogen and hydrogen concentrations.

Reliable analytical performance depends on far more than sensitive instrumentation. Sample preparation must minimize contamination before analysis, calibration standards must remain traceable, and analytical consumables require exceptional purity. Atmospheric oxygen or moisture introduced during handling can influence low-level measurements, meaning disciplined laboratory procedures are essential for maintaining analytical confidence.

Combined with proper instrument calibration, IGF consistently delivers the precision demanded by research laboratories, production facilities, and quality control departments.

Industrial Sectors That Rely on IGF Analysis

Across modern manufacturing, IGF provides critical information that supports product quality and process control.

Additive manufacturing facilities routinely analyze metal powders before laser powder bed fusion and binder jetting processes take place. Their extremely high surface area enables powders to absorb oxygen and moisture during storage and handling. Confirming gas concentrations prior to production helps minimize internal porosity and supports consistent mechanical performance in finished components.

Steel producers and metallurgical laboratories need IGF for primary steelmaking and secondary refining operations. Oxygen and nitrogen concentrations influence hardness, ductility, yield strength, weldability, and grain structure. Continuous monitoring helps manufacturers retain tight process control and satisfy strict material specifications.

High-performance engineering sectors also benefit from accurate gas analysis. Oil and gas infrastructure, power generation equipment, aerospace components, and pressure vessels require strict control of hydrogen concentrations to reduce the risk of hydrogen embrittlement during demanding service conditions.

Why Dedicated Elemental Analyzers Are Necessary

Many laboratories already use X-ray fluorescence (XRF) to determine elemental composition. This analytical technique performs exceptionally well when analyzing heavier metallic elements and stable oxide chemistry, but it cannot directly measure light gaseous elements trapped between metal atoms. Oxygen, nitrogen, and hydrogen exist as interstitial elements within the material’s crystal structure. Obtaining accurate measurements requires complete melting of the sample so those gases can be physically extracted before quantification.

Extracting and measuring interstitial gases necessitates dedicated elemental analyzers with specialized hardware capable of achieving complete sample fusion and highly sensitive gas detection. An ultra-high-temperature impulse furnace generates sufficient heat to achieve complete fusion, and highly sensitive gas detection systems accurately measure the released gases. Together, these technologies allow IGF to fill an analytical gap that conventional spectroscopic techniques cannot address.

IGF Solutions for Modern Laboratories

Behind every reliable gas analysis result is an instrument built for precision. The IGF analyzers manufactured by XRF Scientific are designed to support laboratories across research, quality control, and industrial production, with solutions tailored to different analytical requirements. The G6 LEONARDO provides efficient routine oxygen, nitrogen, and hydrogen determination in production and quality control environments, while the G8 GALILEO offers high-throughput elemental analysis and advanced automation for facilities processing large sample volumes. Completing the portfolio, the G4 PHOENIX delivers specialized diffusible hydrogen analysis for laboratories investigating hydrogen embrittlement and other hydrogen-related material challenges. Explore XRF Scientific’s IGF range to locate the right IGF technology for your application.