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Cozza R.C.,Centro Universitario da Fundacao Educacional | Cozza R.C.,Ceeteps Centro Estadual Of Educacao Tecnologica Paula Souza
Surface and Coatings Technology | Year: 2013

Several works on friction coefficient during abrasive wear tests are available in the literature, but only a few were dedicated to the friction coefficient in micro-abrasive wear tests conducted with rotating ball. This work aims to study the influence of titanium nitride (TiN) and titanium carbide (TiC) coating hardness on the friction coefficient and wear coefficient in ball-cratering micro-abrasive wear tests. A ball of AISI 52100 steel and two specimens of AISI D2 tool steel, one coated with TiN and another coated with TiC, were used in the experiments. The abrasive slurry was prepared with black silicon carbide (SiC) particles and distilled water. Two normal forces and six sliding distances were defined, and both normal and tangential forces were monitored constantly during all tests. The movement of the specimen in the direction parallel to the applied force was also constantly monitored with the help of an electronic linear ruler. This procedure allowed the calculation of crater geometry, and thus the wear coefficient for the different sliding distances without the need to stop the test. The friction coefficient was determined by the ratio between the tangential and the normal forces, and for both TiN and TiC coatings, the values remained, approximately, in the same range (from μ= 0.4 to μ= 0.9). On the other hand, the wear coefficient decreased with the increase in coating hardness. © 2012 Elsevier B.V. Source

Cozza R.C.,State University of Maringa | Cozza R.C.,Ceeteps Centro Estadual Of Educacao Tecnologica Paula Souza
Tribology International | Year: 2014

The purpose of this work is to study the influence of the normal force (N), abrasive slurry concentration (C) and abrasive wear modes on the coefficient of friction in ball-cratering wear tests. Experiments were conducted with balls of AISI 52100 steel, an AISI H10 tool-steel specimen and abrasive slurries prepared with black silicon carbide (SiC) particles+distilled water. The tangential (T) and normal loads were monitored throughout the tests and the results have shown that: (i) the coefficient of friction behavior was independent of the normal force and (ii) both the concentrations of abrasive slurries and the subsequent action of the abrasive wear modes, generally, did not affect the behavior or magnitude of the coefficient of friction. © 2013 Elsevier Ltd. Source

Camara Cozza R.,State University of Maringa | Camara Cozza R.,Ceeteps Centro Estadual Of Educacao Tecnologica Paula Souza
Tribology International | Year: 2013

The purpose of this work was to analyse the effect of the pressure (variable and constant) on the wear mode transition in ball-cratering wear tests. It was conducted using balls of 52100 steel, specimens of WC-Co P20 and abrasive slurry prepared with SiC particles and distilled water. The results showed that the conditions of variable and constant pressure had significant effects on the occurrence of the abrasive wear modes and their transitions. Under the condition of variable pressure, the transition from grooving to rolling abrasion occurred earlier than for constant pressure and the ratio A g/A p was larger for the condition of constant pressure; A p is the projected area of the crater, and A g is the projected area with grooving abrasion. © 2012 Elsevier Ltd. Source

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