Título

CHARACTERIZATION OF SCRATCH RESISTANCE OF COATINGS USING THE NANO-TECHNOLOGY

CHARACTERIZATION OF SCRATCH RESISTANCE OF COATINGS USING THE NANO-TECHNOLOGY

Autoria

Shen, Weidian

DOI

10.5151/5463-5463-17114

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Resumo

Scratch resistance is a much desired characteristic for coatings in many applications. Characterization of scratch resistance of coatings scientifically is very important for improvement of coatings’ tribological properties and development of high-scratching resistant coatings. Traditional empirical testing, such as crock-meter test, might not characterize the scratch resistance of coatings properly. In the mid-90s, the single- probe nano techniques were developed. The tests are carried out under well- controlled conditions, thus making it possible to study different scratching mechanisms under different test conditions. The scratching damages of coatings in the real-field vary from the light damages, such as mars (shallow and narrow scratches), to the medium and severe damages, such as rough trough, cracking, delamination and chipping. A Nano-Indenter equipped with a conical-shaped diamond tip was used to scratch the surface of coatings under a constant or increasing normal load to make artificial damages similar to the real ones, and then the scanning probe microscope was used to take the high-resolution images of the scratched surface, and examine and analyze the damages. We introduced micro mar resistance (MMR) to characterize coatings’ ability against the light damage. In addition, we could identify different responses of coatings to the scratching stress, i.e., elastic response, plastic deformation and abrasive wear, quantitatively. To characterize coatings’ ability against the medium and severe damage, such as rough trough, cracking, delamination and chipping, a series of critical forces were used, at which the corresponding damage occurs. Using MMR and the critical forces, we can fully characterize scratch resistance of coatings.

 

Scratch resistance is a much desired characteristic for coatings in many applications. Characterization of scratch resistance of coatings scientifically is very important for improvement of coatings’ tribological properties and development of high-scratching resistant coatings. Traditional empirical testing, such as crock-meter test, might not characterize the scratch resistance of coatings properly. In the mid-90s, the single- probe nano techniques were developed. The tests are carried out under well- controlled conditions, thus making it possible to study different scratching mechanisms under different test conditions. The scratching damages of coatings in the real-field vary from the light damages, such as mars (shallow and narrow scratches), to the medium and severe damages, such as rough trough, cracking, delamination and chipping. A Nano-Indenter equipped with a conical-shaped diamond tip was used to scratch the surface of coatings under a constant or increasing normal load to make artificial damages similar to the real ones, and then the scanning probe microscope was used to take the high-resolution images of the scratched surface, and examine and analyze the damages. We introduced micro mar resistance (MMR) to characterize coatings’ ability against the light damage. In addition, we could identify different responses of coatings to the scratching stress, i.e., elastic response, plastic deformation and abrasive wear, quantitatively. To characterize coatings’ ability against the medium and severe damage, such as rough trough, cracking, delamination and chipping, a series of critical forces were used, at which the corresponding damage occurs. Using MMR and the critical forces, we can fully characterize scratch resistance of coatings.

Palavras-chave

Scratch resistance; Mar resistance; Wear resistance and critical force for cracking.

Scratch resistance; Mar resistance; Wear resistance and critical force for cracking.