 Home
|
Corrosion Analysis | ||||||||||||||||||
|
MCLinc experience dates back to the 1980’s when our investigators began corrosion study on cylinders containing depleted uranium hexafluoride. During the past 20 years MCLinc scientists have investigated corrosion mechanisms for a variety of materials. In 1998, MCLinc became a fully commercial facility. As a private, employee-owned, small business, MCLinc offers this extensive experience in the solution of corrosion problems. MCLinc’s 25,000 square-foot laboratory is equipped with instruments needed for the chemical analysis of corrosion products, corrosion films, and deposits. Four large environmental chambers are available for simulating corrosive conditions. Modern optical microscopy and scanning electron microscopy equipment is utilized to observe and characterize corrosion material and associated substrates and to define corrosive rates. Capabilities of these instruments are summarized in a following table. SEM analysis allows definitive evaluation of corrosion rates and provides significant information about the corrosion mechanism. This technique includes elemental analysis of corrosion products and visualization of the location of different constituent elements. SEM characterization of the corrosion products can be done either as cut pieces of the substrate material placed in the SEM directly or, more typically, pieces of the substrate prepared by metallographic techniques (embedding in epoxy, grinding and polishing). After polishing, the substrates still have the coating and corrosion products intact and all parts of the corroding material can be imaged, measured, and elemental components identified by energy dispersive spectroscopy (EDS). Images can be collected from all areas of the corroding part and converted to a digital image. SEM magnification range is from 20x to 1,000,000x and elemental analysis is possible for all elements of the periodic table with atomic number ≥ boron. Often SEM analysis identifies the impact on the corrosion of: coating, coating thickness, the effect of pinholes in the coating, the presence of previously unknown materials, different corrosion rates in areas of the substrate, etc.. The ESEM (environmental scanning electron microscope) is a unique SEM instrument that allows the sample to be subjected to the dry, high-vacuum conditions normally present in SEM’s as well as low-pressure gas conditions (water vapor and other gases) at pressures up to 15 torr. This allows the observation of any reaction between a substrate or its corrosion products with water vapor or other selected gases. |
|||||||||||||||||||
OM allows the observation and recording of the appearance of the corroded material at magnifications from 20x to 400x. Observations of substrates that are three to five millimeters in diameter fall into this size range. In addition to observation, digital photographic images of the observed material can be recorded. Thickness measurements can be done on the substrate also, although SEM is probably better qualified to do this determination. X-ray Photoelectron Spectrometry (XPS) can be used for identification of: compound formation, oxidation states of constituents etc. This is complementary to the elemental analysis capability of SEM instruments. Ion milling of the sample surface can be done in order to evaluate material beneath the surface as well. Materials and Chemistry Laboratory, Inc. (MCLinc) has the equipment and staff to successfully perform corrosion study. MCLinc is a fully integrated laboratory that incorporates staff experienced in both physical and chemical analysis. A list of several instruments used in previous corrosion studies and available at MCLinc follows: Instruments Applicable to Corrosion Studies
|
