WHAT IT IS
Spark Optical Emission Spectroscopy (Spark OES) is an elemental analysis technique used to determine the composition of metallic samples. It uses an electrical spark to excite atoms in a metal sample, causing them to emit light, which is. Spark OES is widely used in metallurgy, quality control, foundries, aerospace, automotive, and recycling industries.
HOW IT WORKS
In Spark OES, a solid metal sample is placed against an electrode in an argon-filled excitation chamber. A high-voltage electrical spark is generated between the electrode and the sample surface. This spark vaporizes a small portion of the sample, creating a plasma that excites the atoms and ions of the elements present in the material.
As these excited atoms return to their ground state, they emit light at specific wavelengths unique to each element. This light is collected by optical systems (e.g., diffraction gratings or prisms) and separated into its component wavelengths.
Photodetectors (typically photomultiplier tubes or CCDs) measure the intensity of the emitted light. The intensity at each wavelength is proportional to the concentration of the corresponding element in the sample. A calibration curve is used to convert light intensity into quantitative elemental values.
ADVANTAGES
Fast and Direct Analysis: Provides results in seconds without needing to dissolve or alter the sample, making it ideal for real-time decision-making.
Broad Elemental Range: Simultaneously detects light elements (like C, B, N, S, and P) and heavy elements (like Fe, Ni, Cr, Cu, etc.).
High Precision and Accuracy: Suitable for both major and trace elements in metal matrices, with detection limits typically in the ppm range.
Quantitative Capability: Delivers accurate compositional data, essential for confirming alloy specifications and product certification.
Versatile Sample Compatibility: Works with a wide variety of metal types, including steel, aluminum, copper, titanium, and their alloys.
Field and Lab Use: Benchtop and mobile units are available, allowing use in both laboratory and production floor settings.
CHALLENGES AND LIMITATIONS
Sample Must Be Conductive and Solid: Only works with metallic, conductive samples that have a clean, flat surface.
Surface Preparation Needed: The sample surface must be ground or polished to remove oxides or contaminants for accurate results.
Argon Gas Requirement: Requires high-purity argon gas for plasma generation and to prevent air interference.
Matrix Matching for Calibration: Calibration standards must closely match the matrix of the sample for accurate quantification.
Not Suitable for Non-Metallics: Cannot be used for ceramics, polymers, or non-conductive materials.
Surface Damage: The spark burns a small crater in the sample, which may not be acceptable for finished or critical parts.