Determination of the coefficient of dynamic friction between coatings of alumina and metallic materials

Abstract

Abstract:This project aims to determine the coefficient of dynamic friction between micrometric size coatings of alumina and metallic materials (Steel and aluminium); the methodology used to achieve the proposed objective consisted of 4 phases, in the first one was developed a procedure that allowed, from a Pin on Disk machine built based on the specifications given by the ASTM G99-05 standard (Standard test method for wear tests with a Pin on Disk machine), to determine the coefficient of dynamic friction between two materials in contact; subsequently the methodology was verified through tests between steel-steel and steelaluminium, due to these values are widely reported in the literature; as a third step, deposits of alumina particles of micrometric size were made on a steel substrate through thermal spraying by flame; finally, the tests were carried out between pins of steel of aluminium and alumina coating to determine the coefficients of dynamic friction between these two surfaces. The results of the project allowed to verify that the developed methodology is valid to obtain coefficients of dynamic friction between surfaces in contact since the percentages of error were of 3.5% and 2.1% for steel-steel and aluminium-steel, respectively; additionally, it was found that the coefficient of friction between steel-alumina coatings is 0.36 and aluminium-alumina coating is 0.25.

Effect of Al2TiO5 powder coating on the tribological, corrosion and mechanical properties of AISI 316L stainless steel

“…The coefficient of friction has thus increased due to the change of surface morphology on the stainless steel substrate. Also Al 2 TiO 5 coating contains aluminium that exhibits higher coefficient of friction compared to other metals [24].…”

A traveling-wave ultrasonic motor utilizing a ring-shaped alumina/PZT vibrator

“…At 250 V, larger preload can be applied to the stainless-steel/PZT vibrator as it stores higher vibration energy [4]. Meanwhile, the frictional coefficient between stainless steel and aluminum (∼0.35) is higher than that between alumina and aluminum (∼0.25) [29]. Both of them cause relatively high torque of the stainless-steel/PZT motor at 250 V. However, the maximal-torque-to-voltage (T-to-U) ratio of the alumina/PZT motor is 6.9 times the value of the stainless-steel/PZT one.…”