Page 444 - Handbook of Materials Failure Analysis

442 CHAPTER 17 Application of pyrolysis

3.1.3 Case 3: Identification of the Composition of Sludge
on the Surface of the Compressor Wall from car air
Conditioner ........................................................................... 455
3.2 Application of Py-GC/MS and SEM in Failure
Analysis in the Rubber and
Automotive Industry .........................................................................459
3.3 Application of Py-GC/MS in Failure
Analysis in the Chemical Industry ......................................................461
3.4 Application of Py-GC/MS in Failure
Analysis of a Medical Device .............................................................463
4 Conclusion ....................................................................................................... 468
Acknowledgment .................................................................................................... 468
References ............................................................................................................ 468

1 INTRODUCTION
Failure of the structure of materials or components often results in accidents and
plant shutdowns, resulting in hefty compensations. Failure analysis is the process
of collecting and analyzing data to determine the cause of a failure and to take action
to prevent it from reoccurring. It is an important discipline in many branches of
manufacturing industry, such as the automotive industry and chemical or rubber
industry.
Various analytical techniques, like microscopy imaging, scanning electron
microscopy (SEM), energy dispersive X-ray analysis, UV/Vis spectrometry, Fourier
transform infrared spectroscopy (FTIR), nuclear magnetic resonance, time-of-flight
secondary ion mass spectrometry, and others, are used for clearing of failure of raw
material, manufacturing, function, design or storage errors of various plastic or metal
components from the automotive or chemical and rubber industry. SEM is a
technique that utilizes an electron beam to produce magnified images of samples
[1]. The sample surface is scanned with a beam of energetic electrons and a number
of processes occur that can be used to generate an image of the sample surface. The
SEM allows the exact localization of damage of components from engineering and
automotive industry.
The analytical pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS)
technique has extended the range of possible tools for characterization of synthetic
polymeric materials. Under controlled conditions at elevated temperature
(500-1400 °C) in the presence of an inert gas, reproducible decomposition products
characteristic for the original polymer/copolymer sample are formed [2–5].
The pyrolysis unit (pyrolyzer) is directly connected to the injector port of a gas
chromatograph (GC) (Figures 17.1 and 17.2). Flow of an inert carrier gas, such
as helium, flushes the pyrolyzates into the fused silica capillary column, which
is installed in the thermostat of the GC (Figure 17.1). The capillary column sepa-
rates the complex mixture of the organic substances. The chromatographically