Filmic contamination

Qualitative and quantitative analysis

Do you want to identify and control filmic contamination?

Filmic contamination can involve significant potential damage. It mostly stems from manufacturing residues such as oils, greases, corrosion inhibitors or cooling lubricants. Residues of this nature often degrade downstream processes, e.g. the adhesion of adhesives or the wettability of materials.

We analyse organic compounds quantitatively and qualitatively using various inspection methods. The choice of inspection method depends on the requirements and standards, e.g. ASTM G93. Individual advice and the precise agreement of the goal of the analysis are therefore one of the basic prerequisites for success.

+49 7022 2796-681 info@qa-group.com

Analysis options at a glance

The spectrum of analytical methods ranges from simple methods such as the determination of the surface tension by means of test ink, the gravimetric determination of the contamination using spectroscopic methods for material identification, or complex methods such as gas chromatography or ion chromatography. In the video, we show you our analytical methods:

Local and integral measurement methods
for filmic contamination:

  • Determination of the surface tension by means of test ink
  • Detection of filmic contamination by means of fluorescence measurement
  • Quantification of organic compounds using gas chromatography (GC) with flame ionisation detector (FID)
  • Identification and quantification of organic compounds using gas chromatography (GC) coupled with mass spectrometer (MS)
  • Verification and material identification using RAMAN and FTIR spectroscopy
  • Identification and quantification of ionic compounds using ion chromatography (IC)
  • Gravimetric assessment (e.g. in accordance with ASTM G93)
© Plasmatreat GmbH

TEST INK

Contaminated surfaces are more difficult to wet than clean surfaces. Good wettability is the basic prerequisite for coating with paints, printing inks or adhesives. A simple method for the measurement of the surface tension on a very wide range of materials is to use test inks. For this purpose, we apply test ink to the surface. If the lines remain stable, the surface is easy to wet. The surface of the substrate then corresponds as a minimum to the surface tension of the test ink. If the ink pulls together, the wettability of the substrate is lower than that of the test ink used. The procedure is then repeated with a test ink with a lower surface tension. The higher the value is for the surface tension, the cleaner the surface. The surface tension/surface energy is stated in mN/m.

© SITA Messtechnik GmbH

FLUORESCENCE MEASUREMENT

Organic contaminating films such as greases, oils or wax fluoresce if they are excited using UV light. Materials that do not fluoresce can also be rendered visible by including fluorescing dyes as markers. In this way we can verify, quickly and without contact, the presence of organic substances on metallic surfaces. We only need an absolutely clean surface as a reference. The higher the fluorescence value measured, the thicker the filmic contamination. The measured value is stated in RFU (Relative Fluorescence Units).

Contact angle measurement

Contact angle measurement

One method for checking your component surfaces is contact angle measurement with determination of the free surface energy. It is a simple procedure that takes just seconds and can also be used on the move thanks to the handy measuring instrument.

The device dispenses drops of two liquids - one polar, e.g. water, and one disperse, e.g. diiodomethane - onto the surface to be tested. Within seconds, the device determines the contact angle, i.e. the angle that a drop of liquid on the surface of a solid forms with this surface. A contact angle < 90° indicates that the surface is well wettable, a contact angle > 90° indicates that, for example, coatings adhere poorly or not at all. The free surface energy in mN/m is also calculated from the contact angles determined for polar and disperse. The higher this is, the better the wettability by aqueous or organic liquids, the initial adhesion and also the long-term stability.

VERIFICATION AND IDENTIFICATION USING RAMAN AND FTIR SPECTROSCOPY

Chemical-filmic contamination such as oils, greases, cooling lubricants, cleaning agents, preservatives, solvents and more can be analysed directly on the surface of the component using the spectroscopic analytical methods RAMAN and FTIR. These measurement and analytical methods provide qualitative measured values. This means we can verify the presence of contamination and identify it unambiguously. Reference databases are required for these near-surface analytical methods.

VERIFICATION AND QUANTIFICATION USING GAS CHROMATOGRAPHY (GC-FID)

For this purpose, we extract the contamination from the component using a suitable solvent and analyse the organic residues released using gas chromatography coupled with a flame ionisation detector (GC-FID). As a result we obtain the sum of the soluble organic contamination in mg/component or in mg/m².

IDENTIFICATION AND QUANTIFICATION USING GAS CHROMATOGRAPHY (GC-MS)

For this purpose, we extract the contamination from the component using a suitable solvent and analyse the organic residues released using gas chromatography coupled with a mass spectrometer (GC-MS). As a result we obtain the sum of the soluble organic contamination in mg/component or in mg/m², as well as the identification of the individual components.

© KERN & SOHN GmbH

GRAVIMETRIC ASSESSMENT

Here we extract the contamination from the component using a suitable solvent and separate the solid residues using filtration. After the evaporation of the solvent, we determine the mass of the soluble residues gravimetrically using an analytical balance. The result is stated in mg/component or in mg/m².

Laboratory for technical cleanliness: Filmic contamination

Application examples and possible uses

The analysis of chemical-filmic contamination helps, for example, to characterise surface pre-treatments. In addition, we can analyse the adhesion and the stability of bonded joints and coatings. We check the wettability of plastic, ceramic, paper, glass, metal or wood. And we undertake quality control on wafers and microelectronics as well as inspect the purity of the surface of a component.

Added value at quality analysis

Speed

You receive from us precise measurement results, even at short notice. We have both the necessary personnel and the state-of-the-art analysis systems.

Analysis spectrum

We have various methods for the reliable detection of chemical-filmic contamination.

No standards

The lack of standards and limits as well as the large number of chemical analytical methods requires an individual analysis strategy.

Accreditation

The accreditation of our inspection methods and measuring rooms signifies for you certainty, dependability and objectivity.

The selection of the inspection method depends on the requirements in the related subsequent processes. Individual advice and the precise agreement of the goal of the analysis are therefore one of the basic prerequisites for success.

+49 7022 2796-681 info@qa-group.com

DAkkS accreditation according to DIN EN ISO/IEC 17025

Accredited test laboratory
for technical cleanliness verification

The identification and quantification of organic and inorganic substances, materials, residues, deposits and contamination using FTlR and energy-dispersive (EDX) spectroscopy are accredited by Deutsche Akkreditierungsstelle GmbH (DAkkS) in accordance with DIN EN ISO/IEC 17025. Furthermore, all our other specialist areas have also been accredited.

You can read more about the advantages our accreditation offers you here:

Find out more

QUALITY ANALYSIS

THE RIGHT PARTNER for

contaminating films

Do you require a sound analysis of your filmic contamination at short notice? Then you are in the right place. We would be pleased to advise you about the best, most cost-effective and efficient analytical method.


Call us, we look forward to hearing from you!

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