Sliding wear behaviour of Ni–P–W composition-modulated coatings
1998; Elsevier BV; Volume: 105; Issue: 3 Linguagem: Inglês
10.1016/s0257-8972(98)00459-9
ISSN1879-3347
AutoresV.D. Papachristos, C. Panagopoulos, Peter Leisner, Max Olsen, U. Wahlström,
Tópico(s)Diamond and Carbon-based Materials Research
ResumoAbstract We studied the unlubricated sliding wear behaviour of Ni–P–W compositionally modulated coatings on mild steel pins, sliding against hardened steel discs in a pin-on-disc set-up. The multilayered coatings consisted of high and low W-content layers. The linear velocity was constant for all tests, and the normal loads used were 200, 500, 800 and 1100 g. Coatings of various layer periodicities were studied. Friction coefficients were recorded during the tests, and it was found that after a running-in period of about 30 m, friction coefficients reached a steady state. An increase in the normal load caused a decrease in friction coefficients regardless of the layer periodicity of the coating. Coatings with a smaller layer periodicity showed a better wear resistance than those with larger layer periodicities. Two major wear mechanisms were identified: brittle fracture of the individual layers accompanied by crack deflection at the interfaces between the layers and delamination of parts of the coating. The first mechanism was active for the whole range of loads, whereas the second was operative only for loads of 800 and 1100 g.
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