Study Examines Coating Failures in Real-Time


A new study has observed the tribological behavior of coatings in real-time, allowing researchers to better understand and design coatings for optimal results. By understanding fracturing and delamination for coatings, a team from the National Physical Laboratory in the United Kingdom hopes to improve the design of the coatings and surface treatments by the surface engineering industry.

The research has recently been published in the journal Surface and Coatings Technology.

Observing In-Situ Coating Failures

The new research reportedly focuses on the way that real time in situ measurement techniques can be used to observe the tribological behavior of coatings, revealing the mechanisms that occur and enabling the correlations of these mechanisms to the microstructure of the materials that are being tested

“The functional performance of coatings can be transformed using coatings to form an engineered surface system where resistance to wear and friction are improved relative to the uncoated substrate,” wrote the authors of the study. “Understanding the failure mechanisms of coatings in tribological contacts is difficult to achieve.”

Researchers wanted to examine the application of the world leading NPL test systems, enabling real time observation of the mechanisms of damage in tribological contact. For the experiment, the team tested two different test systems, including:

  • A microtribometer fitted inside an SEM which provides sequences of high resolution images of the deformation processes occurring in coatings; and
  • A ball on disc tribometer fitted with imaging and profilometric systems giving real-time information on the tribological response of coatings.

DLC and TiN coatings were tested on tool steel substrates, with delamination failures of the DLC coatings observed with both test systems. The highlight was reportedly the high-resolution in situ observations in the SEM, of the fracture and delamination of a DLC coating from the substrate when subjected to damage from a sharp asperity.

According to the researchers, the performance and efficiency savings that result from the improved design properties will help enable take up of these new technologies by diverse industrial sectors. This could include road and air transport, power generation and manufacturing, which will additionally driving clean growth and sustainable use of materials.

“It is a real breakthrough to be able to visualize what actually takes place in a tribological contact as it happens,” said Mark Gee, NPL Fellow. “Before now only limited information could be obtained through a laborious and time-consuming series of experiments.”

The next step of the research, according to reports, will be to improve the reliability of the test system and introduce artificial intelligence into the control system. This will potentially achieve a digitally enabled metrology for engineered surfaces.

Funding for the study was provided by the National Measurement System of the Department for Business, Energy and Industrial Strategy, U.K. Government. Samples were supplied with in the Technical Cooperation Program on Advanced Materials for Transport of the International Energy Agency.

The full video, showing the progressive failure of DLC coating in in-situ real time testing covering a width of 40 micrometers, can be viewed here.


Tagged categories: Asia Pacific; Coating chemistry; Coating failure; Coating Materials; Coatings; Coatings Technology; Coatings technology; Delamination; EMEA (Europe, Middle East and Africa); Latin America; North America; Program/Project Management; Quality Control; Research and development; Z-Continents

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