Microstructure and Wear Properties of HVAF Sprayed Cu-Zr-Al-Ag-Co Amorphous Coatings at Different Spray Temperatures

Abstract

Wear-resistant Cu-Zr-Al-Ag-Co amorphous coatings were fabricated by high-velocity air-fuel spray technology using (Cu43Zr47Al7Ag3)99.5Co0.5 powder at different temperatures (i.e., 645, 725, and 805 K). The feedstock powders (98.6 wt.% amorphous phase) were produced by a gas atomization method. Thermal properties and microstructure of the powders and the coatings were comparably investigated by differential scanning calorimeter, scanning electron microscope, and transmission electron microscopy techniques. Wear properties were studied by a dry sliding wear tester under the linear reciprocating sliding in a ball-on-plate mode using a GCr15 ball as the counterpart at room temperature in air. A large fraction of amorphous phase (~67.5 wt.%) and crystalline phases (ZrO2, Al2.5Cu0.5Zr, and AlZr3) are found in the coating fabricated at a temperature (725 K) between the glass transition temperature (Tg) and the onset crystallization temperature (Tx). In addition, the coating also exhibits the highest Vickers hardness (554 HV0.1), bonding strength (59.3 MPa), a relatively low porosity (1.65%), and superior wear resistance. The wear mechanism of the coating is primarily abrasive wear and slight adhesive wear.

Tribological Properties of Cu-MoS2-WS2-Ag-CNT Sintered Composite Materials

“…Currently, an intense search for self-lubricating materials and surface layers that contain solid lubricants embedded in their matrix is underway [ 11 , 12 , 13 , 14 , 15 ]. They can be produced using: powder metallurgy (resulting in the formation of self-lubricating materials), laser alloying (resulting in the formation of technological superficial layers) or thermal spraying as well as PVD and CVD techniques (resulting in the formation of coatings) [ 11 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ]. The disadvantages of self-lubricating coatings are limited service life, difficulties in refilling, oxidation, aging-related degradation and poor adhesion.…”