Scratch Test Measurements on CrNx Coatings

2003 ◽  
Vol 795 ◽  
Author(s):  
R. Hoy ◽  
P. van Essen ◽  
J.-D. Kamminga ◽  
G. C. A. M. Janssen ◽  
A. P. Ehiasarian
Keyword(s):  
Critical Load ◽  
Scratch Test ◽  
Sputter Deposition ◽  
Scratch Testing ◽  
Reactive Sputter Deposition ◽  
Substrate Adhesion ◽  
Coating Failure ◽  
Coating Removal ◽  
Scratch Tests ◽  
Crn Coatings

ABSTRACTHard CrNx coatings of various composition were deposited on hot work tool steel by means of reactive sputter deposition in an industrial PVD reactor. All deposited coatings (thickness 3–4 micron) were under compressive stress. The coatings were subjected to scratch testing with a diamond stylus. Two critical loads were determined. The first critical load, Lc1, indicates the onset of chipping and/or spalling. The second critical load, Lc2, indicates complete coating removal inside the track. Micrographs showing the coating failure are presented. Stoichiomeric CrN coatings outperform understoichiometric CrN0.6 coatings in scratch tests. It was found that for all specimens the coating-to-substrate adhesion is very good, independent on composition. Although the values of Lc1 and Lc2 are distinctly different, their dependence on composition is similar.

Adhesion of Cr/CrN Multilayers to Steel Substrates

2015 ◽  
Vol 759 ◽  
pp. 27-35
Author(s):  
Marcin Kot ◽  
Kinga Chronowska-Przywara ◽  
Łukasz Major ◽  
Juergen Lackner
Keyword(s):  
Critical Load ◽  
Scratch Test ◽  
Scratch Resistance ◽  
Scratch Testing ◽  
Track Geometry ◽  
Coating Failure ◽  
Bilayer Period ◽  
Steel Substrates ◽  
Crn Coatings ◽  
Coating Hardness

Cr/CrN multilayers with a bilayer period λ = 62 ÷ 1000nm, were investigated. They were deposited by PLD technique on austenitic and ferritic stainless steel substrates. Coating hardness and adhesion to substrates were measured by nanoindentation and scratch testing. Multilayer properties were compared with single Cr and CrN coatings. The 2xCr/CrN and 4xCr/CrN multilayers exhibited hardness slightly lower than the hardness of a single CrN coating, while the critical load of the 4xCr/CrN multilayer, measured in the scratch test, was two times higher than for CrN. Furthermore, the character of coating failure also indicates the higher fracture toughness of multilayers than ceramic ones. The highest scratch resistance of the hardest multilayer with a bilayer period λ = 250nm is extremely interesting. The measured values of the critical loads LC1and LC2of all coatings were higher for harder ferritic than austenitic substrates. However, analysis of scratch track geometry indicated that coating failure occurred under the same deformation of the coating-substrate system, while the higher values of critical load for coatings on ferrite derived from the higher hardness of the substrate.

PREPARATION AND CHARACTERISTICS OF CO-DOPED HYDROXYAPATITE BIOMIMETIC COATINGS ON PRETREATED Ti6Al4V ALLOY

2020 ◽  
Vol 27 (11) ◽  
pp. 2050012
Author(s):  
TUGCE HACIOGLU ◽  
AYSEN TEZCANER ◽  
SHERIF ABBAS ◽  
ZAFER EVIS
Keyword(s):  
Critical Load ◽  
Bone Cells ◽  
Surface Characteristics ◽  
Biological Properties ◽  
Considerable Effect ◽  
Structural Investigations ◽  
Coating Failure ◽  
Scratch Tests ◽  
Co Doped

In this study, [Formula: see text] co-doped and pure hydroxyapatites (HAp) were coated on rough surfaces of Ti6Al4V plates by biomimetic method. Prepared samples were investigated with SEM, EDS, FTIR, XRD and ICP. Furthermore, mechanical scratch tests, profilometer tests and in vitro cell studies were carried out. In order to explore the antibacterial characteristics of the coating, the survival rate of a bacteria named Staphylococcus epidermidis was determined. Structural investigations showed that HAp nucleation began four days after the immersion, expectedly nucleation developed collaterally with the incubation period and co-dopants had considerable effect on surface characteristics. Besides, the pretreatment procedure and dopants had notable impact on mechanical qualifications of the coatings. The critical load values obtained for coating failure were detected above 100[Formula: see text]mN in all types of coatings (max. critical load was obtained from 0.3[Formula: see text]mM co-doped coatings). Cancerous bone cells (SaOS-2) on prepared coatings were evaluated in terms of biological properties. 0.1-C7 and 0.3-C7 exhibited highest reduction percentage among all co-doped samples. Further increase in dopants concentrations up to 0.5[Formula: see text]mM lead to increase in toxicity and decrease in cell proliferation. Antibacterial test results showed the most antibacterial samples were 0.1-C7 and 0.3-C7, the results conformed with cell culture findings.

Measurement of Adhesion at Film -Substrate Interfaces by Constant Depth Scratch Testing

1994 ◽  
Vol 338 ◽  
Author(s):  
I. Dutta ◽  
D. P. Lascurain ◽  
E. D. Secor
Keyword(s):  
Interfacial Adhesion ◽  
Interfacial Shear Strength ◽  
Scratch Test ◽  
Interface Strength ◽  
Constant Depth ◽  
Scratch Testing ◽  
Glass Substrates ◽  
Film Substrate ◽  
Scratch Tests ◽  
Theoretical Developments

ABSTRACTQuantitative tests for interfacial adhesion between films and substrates are of criticalimportance in micro-electronic applications. However, many of the available tests are applicable to a limited array of materials systems, or are experimentally complex. In thispaper, a constant depth scratch test, which has been designed to circumvent the limitations associated with currently available tests, is presented along with theoretical developments for the quantification of interfacial shear strength. Because of a fixed scratchgeometry, the test is amenable to straightforward analytical formulations unlike other versions of scratch tests. It is unique in its experimental simplicity, and allows evaluation of interface strength as function of position on the sample. Sample outputs from the test based on Cr films on glass substrates are presented.

Correlation between Adhesion Strength and Thin film/Substrate Mechanical Properties using the Nano-Scratch Technique

2011 ◽  
Vol 1297 ◽  
Author(s):  
Bo Zhou ◽  
Nicholas Randall ◽  
Barton Prorok
Keyword(s):  
Thin Film ◽  
Mechanical Properties ◽  
Adhesion Strength ◽  
Film Surface ◽  
Scratch Testing ◽  
Coating Failure ◽  
Failure Loads ◽  
Load Mode ◽  
Film Substrate ◽  
Scratch Tests

ABSTRACTScratch testing, as a mature technique for coating adhesion quantification, has been widely adopted by both industrial and academic fields in recent years. Following the urgent needs of very small materials characterization, nano-scratch testing has gradually replaced the traditional pull-off test for the study of ultra-thin film properties. In this research, the relationship between the adhesion strength and film/substrate mechanical properties was investigated to provide fundamental but crucial knowledge of the scratch mechanism. Scratch tests were performed on different film/substrate combinations using a Nano Scratch Tester with a sphero-conical diamond indenter. A progressive load mode was employed to cause coating failure during scratch on the film surface. The critical values of different failure mechanisms, such as cracking and delamination were accurately determined according to the scratch panorama image, penetration and residual depth data. In addition, the hardness (H) and modulus (E) values of the thin films and substrates were measured with an Ultra Nanoindentation Tester. The scratch critical failure loads were then plotted versus film/substrate H and E ratios. A unique relationship was found between these parameters that could help understand the true mechanism behind scratch adhesion and leverage this methodology to a new theoretical level.

Experimental and Three-Dimensional Finite Element Study of Scratch Test of Polymers at Large Deformations

2004 ◽  
Vol 126 (2) ◽  
pp. 372-379 ◽  
Author(s):  
J. L. Bucaille ◽  
E. Felder ◽  
G. Hochstetter
Keyword(s):  
Strain Hardening ◽  
Penetration Depth ◽  
Large Deformations ◽  
Numerical Study ◽  
Scratch Test ◽  
Scratch Resistance ◽  
Plastic Strains ◽  
Thermosetting Polymer ◽  
Scratch Tests ◽  
Hardening Coefficient

An experimental and numerical study of the scratch test on polymers near their surface is presented. The elastoplastic response of three polymers is compared during scratch tests at large deformations: polycarbonate, a thermosetting polymer and a sol-gel hard coating composed of a hybrid matrix (thermosetting polymer-mineral) reinforced with oxide nanoparticles. The experiments were performed using a nanoindenter with a conical diamond tip having an included angle of 30 deg and a spherical radius of 600 nm. The observations obtained revealed that thermosetting polymers have a larger elastic recovery and a higher hardness than polycarbonate. The origin of this difference in scratch resistance was investigated with numerical modelling of the scratch test in three dimensions. Starting from results obtained by Bucaille (J. Mat. Sci., 37, pp. 3999–4011, 2002) using an inverse analysis of the indentation test, the mechanical behavior of polymers is modeled with Young’s modulus for the elastic part and with the G’sell-Jonas’ law with an exponential strain hardening for the viscoplastic part. The strain hardening coefficient is the main characteristic parameter differentiating the three studied polymers. Its value is equal to 0.5, 4.5, and 35, for polycarbonate, the thermosetting polymer and the reinforced thermosetting polymer, respectively. Firstly, simulations reveals that plastic strains are higher in scratch tests than in indentation tests, and that the magnitude of the plastic strains decreases as the strain hardening increases. For scratching on polycarbonate and for a penetration depth of 0.5 μm of the indenter mentioned above, the representative strain is equal to 124%. Secondly, in agreement with experimental results, numerical modeling shows that an increase in the strain hardening coefficient reduces the penetration depth of the indenter into the material and decreases the depth of the residual groove, which means an improvement in the scratch resistance.

Sign in / Sign up

Export Citation Format

Share Document