All manufacturers strive to produce the highest quality products for their customers. As a result, materials testing services from a materials testing lab like Innovatech Labs are frequently used to ensure that product quality.
Materials testing can uncover the causes of product failures, identify contaminants or toxins, and also determine the chemical composition of samples. When it comes to analyzing the surfaces of products, Electron Spectroscopy for Chemical Analysis (ESCA) and Auger Electron Spectroscopy (AES) are two commonly used materials testing techniques. While both have similar applications, each is unique and valuable for different situations.
Below we discuss the similarities and differences between ESCA/XPS and AES, and when each technique is utilized.
ESCA and AES are both known for their ability to analyze thin films, stains and contaminants on the surfaces of products. Also, both techniques can be used to analyze passivation layers on metallic surfaces. AES can be performed on conductive and semi-conductive materials, ESCA can be performed on these types of materials in addition to polymers, glass and other insulating materials. As a result, both techniques can be useful for electronics and medical device manufacturers.
Instrumentation and Sample Extraction
ESCA analysis, which is also called X-Ray Photoelectron Spectroscopy (or XPS analysis), uses an x-ray beam to excite atoms on the surface of a solid sample, which results in the emission of photoelectrons. Then, an energy analysis of the photoelectrons is performed to identify both elemental and chemical bonding information.
On the other hand, AES uses an electron beam to excite atoms, which results in the emission of electrons known as Auger electrons. Like ESCA, an energy analysis is then conducted to uncover the analytical information.
ESCA analysis can analyze oxidation of chromium and iron. This is especially useful for electronics and medical device manufacturers that worry about oxidation leading to product malfunction or failure. For example, an electronics manufacturer discovered a haze on a polyimide film. The manufacturer believed that the haze was from the chromium film that was not completely etched away during manufacturing. ESCA scanned the area and determined that there was in fact a presence of chromium, supporting the manufacturer’s theory.
As for AES, this technique can analyze the chemistry and thickness of passivation layers of stents and small diameter wires. For example, AES was performed on a Nitinol stent to determine any impurities in the oxide layer and the thickness of the layer. Testing revealed that the passivation layer was composed mostly of titanium dioxide and its thickness was approximately 300 angstroms.
When is Each Testing Method Used?
ESCA/XPS analysis can be used to:
- Evaluate the passivation of stainless steels and the oxidation of chromium and iron
- Analyze the surface chemistry of polymers, glasses and other insulators
- Resolve issues related to metal interdiffusion, resin-to-metal adhesion or oxidation
AES can be used to:
- Determine the chemical composition of a surfaces and interfaces
- Analyze contamination and stains
- Analyze passivation layers
For more information on ESCA analysis, Auger Electron Spectroscopy or any other materials testing services from Innovatech Labs, contact us today.