Tribocorrosion, the combined wear due to sliding wear and corrosion can be much worse than the arithmetic sum of the two, leading to undue materials failure. The critical importance of addressing this problem lies in the urgent needs in multiple fields like slurry transport. We performed experiments under various situations involving abrasion, corrosion and impacting with both a typical pin on disc tribometer and a modified type with hammering effect to facilitate impacting. The results show that the joint effect of corrosion and abrasion is not necessarily detrimental, but dependant on the specific surface condition of the material. We have discovered that the joint effect could benefit the wear resistance for a carbon steel consisting of ferrite and cementite. The main mechanism is that a galvanic micro coupling effect occurs on the heterogeneous surface in corrosive environment, leading to the dissolution of the soft ferrite and the protrusion of the hard cementite. The cementite is re-distributed by abrasion, resulting in a modified surface enriched with harder phase than the original surface. However, this mechanism does not prevail when introducing impacting effect to the system. The results of the hammering pin on disc show that the beneficial effect of galvanic micro coupling diminishes with the increasing extent of impacting. The microstructure of materials clearly plays a vital role when subject to tribocorrosion. These findings could eventually be translated to real life applications like slurry transport where sliding, impacting and corrosion all play a role to different extent.
|Category||Short file description||File description||File Size|
|Manuskript||Figure||This is a figure illustrating the galvanic micro-coupling effect we have discovered||3 MB||Download|
|Manuskript||Figure 2||This figure shows the effect of impacting on wear rate of samples subject to tribocorrosion||104 KB||Download|