4 Ways to Measure Coatings

1,844 views

Published on

In this presentation, we cover how to pick the right technology to measure a coating thickness.

- An introduction to coatings
- Why coatings are used in industry
- Why to measure the thickness of a coating
- The best methods for coating thickness measurement

For more information, visit: Olympus-IMS.com.

Published in: Technology

4 Ways to Measure Coatings

  1. 1. OLYMPUS SCIENTIFIC SOLUTIONS / HAMBURG 4 Ways to Measure Coa.ngs Markus Fabich Ver.cal Market Specialist Manufacturing Scien.fic Solu.ons Division Olympus Europa SE & Co. KG
  2. 2. This session is about how to pick the right technology to measure a coating thickness
  3. 3. Agenda OLYMPUS EUROPA SE & Co. KG Page 3 Introduction to the Topic: Coatings and Layers Technology List Up Comparison Tables Summary and Q&A
  4. 4. OLYMPUS Scientific Solutions •  What is a coating? •  Why is it relevant? •  Why measure the thickness?
  5. 5. Definition OLYMPUS Scientific Solutions Object, Substrate Coating A coating is a covering that is applied to the surface of an object, usually referred to as the substrate.
  6. 6. Out of Scope: Indications and Defects OLYMPUS Scientific Solutions
  7. 7. Relevance of Coatings — Why Do Coatings Exist? OLYMPUS Scientific Solutions The purpose of applying the coating may be decorative, functional, or both. Example: an oil tank àOut of scope today: the decorative painting àIn scope today: the corrosion preventive coating
  8. 8. Why Measure the Thickness of a Coating? OLYMPUS Scientific Solutions Your reason may differ from mine, but these are just a few examples.
  9. 9. Why Measure the Thickness of a Coating? OLYMPUS Scientific Solutions time thickness Example: if over time the corrosion preventing coating thickness changes, this needs to be monitored
  10. 10. Why Measure the Thickness of a Coating? OLYMPUS Scientific Solutions function OK NG Incident: crack, delamination… Example: at the time of applying the coating you need to benchmark the thickness of a coating as it may correlate with the probability of an incident over time. Average Time until incident correlates with thickness time
  11. 11. Why Measure the Thickness of a Coating? OLYMPUS Scientific Solutions thickness Example: electrical insulation The thicker an insulation layer, the stronger the insulation effect, but at a cost function
  12. 12. Methods OLYMPUS Scientific Solutions
  13. 13. Measuring by Polished Cross Section Microscopy OLYMPUS Scientific Solutions Example: PCB plating (30 µm) Example: 3 layer car paint (with contamination) 100 µm
  14. 14. Measuring by Cross Sectioning OLYMPUS Scientific Solutions Method Polished cross section imaging Integration area None Limit of detection < 300 nm Maximum thickness Not limited Maximum number of layers Not limited Evaluation method In image; length equals thickness Measurement time Few seconds Restrictions Always destructive Strength Easy to calibrate Key usage Qualifying nondestructive methods, complex geometries
  15. 15. 1. Measuring by Conventional Ultrasound (UT Thickness Gage) OLYMPUS Scientific Solutions 1 Water-metal 2 Metal 1/metal 2 3 Metal 2-air (backwall) 21 3 2 1 3
  16. 16. Measuring by UT/PA OLYMPUS Scientific Solutions Method Measuring the time of flight of a traveling acoustic impulse Integration area Few mm Limit of detection > 80 µm Maximum thickness > 635 mm Maximum number of layers > 4 Evaluation method Time difference Measurement time Instant Restrictions Depending on material (attenuation, impedance, sound velocity), transducer, temperature, requires coupling Strengths In-line capable, portable, easy to use
  17. 17. Measuring by Confocal Microscopy OLYMPUS Scientific Solutions Example: SiO2 on SiO wafer (20 µm)
  18. 18. Measuring by Confocal Microscopy OLYMPUS Scientific Solutions Method Focus from brightness correlates with depth Integration area < 200 nm Limit of detection < 900 nm Maximum thickness > 100 µm Maximum number of layers 4 Evaluation method Travel distance between brightness peaks Measurement time 0.5 s Restrictions Knowledge of refractive index, only transparent materials Strengths Easy to calibrate, high lateral resolution
  19. 19. Measuring by the Calotest Microscopy OLYMPUS Scientific Solutions Example: hard coating on a tool
  20. 20. Measuring by the Calotest Microscopy OLYMPUS Scientific Solutions Method 2D image of a ball grinding Integration area Few mm² Limit of detection << 1 µm Maximum thickness > 100 µm Maximum number of layers 10* Evaluation method Geometric calculation Measurement time Few seconds (excluding preparation time) Restrictions Minimally destructive, limited to specified geometries Strength Easy to calibrate
  21. 21. Measuring by Direct Step Measurement and High-Resolution Microscopy OLYMPUS Scientific Solutions Ag nanowire mesh (100 nm) Ag screenprint (100 µm) Cu plating (100 µm)
  22. 22. Measuring by Direct Step Measurement OLYMPUS Scientific Solutions Method Sequence of images with different focus Integration area < 1 µm Limit of detection 5 nm Maximum thickness Few mm Maximum number of layers 4+ Evaluation method Actual z displacement Measurement time 10–100 s Restrictions The layer must be removed locally in a controlled way à “destructive” Strength High resolution, excellent if structuring a coating is part of the process anyway
  23. 23. Measuring Coatings by Eddy Current (EC) OLYMPUS Scientific Solutions •  A defined electromagnetic field interacts with the object (amplitude, frequency, distribution) •  This interaction is then monitored (phase change, amplitude change)
  24. 24. Measuring by Eddy Current (EC) OLYMPUS Scientific Solutions Method Measurement of the material interaction with an eddy current field Integration area > 1 mm²* Limit of detection < 0.001 µm* Maximum thickness 25 mm* Maximum number of layers > 2 Evaluation method Phase and amplitude change Measurement time Instant / 2 s Restrictions No penetration through ferromagnetic materials, contact/defined distance required, calibration strategy needed Strengths Portable, nondestructive, adds conductivity as information, detects surface and subsurface cracks
  25. 25. XRF with Olympus’ VantaTM Analyzer Coating Method OLYMPUS Scientific Solutions Primary X-rays Element XRF response
  26. 26. VantaTM Analyzer Coating Method OLYMPUS Scientific Solutions
  27. 27. VantaTM Analyzer Coating Method OLYMPUS Scientific Solutions
  28. 28. Measuring by XRF OLYMPUS Scientific Solutions Method Fluorescence response after X-ray excitation Integration area 3 mm Limit of detection < 50 nm Maximum thickness < 50 µm Maximum number of layers 3 Evaluation method Correlate signal strength at indicator energy level versus reference Measurement time < 30 s, typically 10 s Restrictions One unique element per layer different from substrate, radiation safety regulations apply Strengths Same instrument can perform PMI, RoHS conformity check, portable, nondestructive
  29. 29. Technology Method Integration area* LOD* D Max Layer count* Microscopy Cross section < 1 µm < 1 µm > 5 cm No limit Calotest < 1 mm² ᴓ < 0.5 µm > 200 µm 10 Step > 1 µm² < 10 nm > 1 mm 4 FTM mode > 1 µm < 1 µm > 200 µm 4 UT/PA Pulse Receiver > 3 mm ᴓ < 80 µm >> 5 mm 4 EC Phase/ Amplitude > 2 mm ᴓ < 0.05 µm > 2 mm 2 XRF Energy > 3 mm ᴓ < 50 nm < 45 µm 3 Specification Overview
  30. 30. Specification Overview Technology Method Evaluation method Time required* Accuracy* Microscopy Cross section Length in image Few seconds < 1% Calotest Derived length in Image Few seconds < 2% Step Z travel distance Few seconds < 1% FTM mode Z travel distance < 1 s < 2% UT/PA Pulse receiver Time Instant < 5% EC Phase/Amplitude Phase shift/amplitude Instant < 5%* XRF Intensity/Energy Relative quantity < 30 s < 10%
  31. 31. Specification Overview Technology Method Restrictions* Microscopy Cross section Sample preparation, object totally destroyed Calotest Sample preparation, sample geometry Step Sample preparation FTM mode Optical transmission and smooth interfaces required UT/PA Pulse receiver Coupling necessary, acoustic impedance/sound velocity/interface quality EC Phase/Amplitude Electrical/ magnetic properties, reference needed XRF Intensity/Energy Reference needed, radiation safety regulations, elements Ti-Cd (one unique per layer)
  32. 32. Specification Overview Technology Method Strength Microscopy Cross section Simple mathematics, with metallography Calotest Minimal surface damage, only 2D image required Step Ideal for structured surfaces FTM mode Nondestructive, non-contact for transparent materials UT/PA Pulse receiver Nondestructive, easy setup, in-line ready, good capability to identify interface flaws EC Phase/Amplitude Nondestructive, easy setup, in-line ready, good capability to identify surface flaws XRF Energy/Count Nondestructive, easy setup, in-line ready, good capability for PMI
  33. 33. Specification Overview Technology Method Olympus Product Name Microscopy Cross section BX53M microscope,SZX10 microscope, and OLYMPUS Stream® software Calotest BX53M microscope and OLYMPUS Stream software Step DSX510 digital microscope, OLS4100 microscope FTM mode OLS4100 microscope UT/PA Pulse receiver 38DLP and 45MG thickness gages, EPOCH® 650 flaw detector, OmniScan® MX2 flaw detector EC Phase/Amplitude NORTEC® 600 EC flaw detector, OmniScan MX2 flaw detector XRF Intensity/Energy Vanta™ analyzer, DELTA® analyzer, FOX-IQ® system
  34. 34. Disclaimer OLYMPUS Scientific Solutions There are many more technologies available to measure coatings. The above mentioned methods have one thing in common: You will get fast, accurate measurements, safe to interpret and assisted by user guidance and expert consultation from Olympus. *All shown numerical values are not necessarily exact. More effort in calibration or specific task circumstances can change these values either positively or negatively.
  35. 35. Thank you OLYMPUS Scientific Solutions Contributors: Jakob Mallmann (Microscopy) Thomas Sauer (XRF) Florin Turcu (UT) Patric Cabanis (EC)
  36. 36. Questions? OLYMPUS Scientific Solutions Learn more at www.olympus-ims.com Sign up for our newsletter for technology and application advice. Olympus, OLYMPUS Stream, EPOCH, OmniScan, NORTEC, DELTA, and FOX- IQ are registered trademarks and Vanta is a trademark of Olympus Corporation.

×