Flashcards in Inhibitors Deck (42)
Scale formation over the entire surface. Most common types: Silicates Phosphates
Precipitation inducing Inhibitors
AKA volatile corrosion Inhibitors Inhibitors is vaporized into a gaseous form Inhibits corrosion by making the environment alkaline
Vapor Phase Inhibitors
Can reduce the effectiveness of inhibitors
Bicarbonates Metal cations
The corrosion Investigator's first job on-site is to:
Protect all evidence
the Corrosion Investigator's second job on-site is to:
Collect all evidence
The presence of water can be confirmed in a sample by using ....
Which gas analysis test cannot be collected with a stain tube?
A procedure that penetrates and preserves the scale, corrosion product, microbes and deposits that are present on an internally corroded pipe is:
The temperature of liquid samples is measured in the field using:
Common laboratory thermometer and with an electronic temperature probe.
The pH of aqueous samples is measured using:
pH Meter and pH Test Paper
These samples must be taken where there are differences in color, texture, density or composition of materials in the pipe
These samples are normally collected in stainless steel sample bottles or Tedlar bags. Stain tubes can sometimes be used to replace some samplings.
Collect at least 500ml in two 250 ml sample containers at the site of the cut if possible. Samples should be filled to the top to exclude air and capped.
This sample should be cut using a portable band saw or wheel-type cutter to prevent torch cutting debris from entering the sample.
Common technique used to identify crystalline phases in unknown materials. These crystalline phases are described as compounds rather than elements which is beneficial in understanding corrosion.
XRD - X-Ray Diffraction (XRD)
This method provides elemental compositional analysis of very thin (3nm) surface layers.
AES - Auger Electron Spectroscopy
These two methods are used with microscopes to examine small areas or features. Both methods usually allow mapping of the surface and are used for bulk sample analysis.
FTIR and Raman Spectoscopy
A long established technique used to identify nearly 70 diff elements in liquid and solid samples down to parts per billion.
This method is used to look for corrosion inhibitors, biocides, methanol, glycol and organic materials but the investigator must have some idea of the organic material for which they are searching.
Gas or Liquid Chromatography
These 2 methods can quantitatively identify over 70 elements in liquids, solids and particulates. They provide shorter analysis times than AAS.
DCP/ICP - Direct Current Plasma & Inductively Coupled Plasma
This procedure uses liquid chemistry data to calculate values which are simply indications as to the propensity for
This term describes laboratory analysis techniques such as gravimetry, titrimetry and numerous separation methods. It is time consuming and methods vary widely
This is a popular method for determining the concentrations of ionic species in aqueous samples. Typical results would identify sulfate, sulfite, nitrate, nitrite, phosphate, chloride, bromide and floride
Pair of tests are some of the most popular techniques used for examining and analyzing elemental surface components of corrosion-related samples.
SEM/EDS - Scanning Electron Microscopy/Energy Dispersive Spectroscopy
This technique is used more frequently in the study of microorganisms than of corrosion.
TEM - Transmission Electron Microscopy
This method is like Auger as another method that analyzes atomic surface layers for elemental composition. It is more sensitive and has better spatial resolution than EDS
SIMS - Secondary Ion Mass Spectroscopy
What is the final and most important part of instituting a corrosion mitigation program?
Monitoring the effectiveness of the treatment
Step # 1
Physically arrange the investigation results in logical progression