Effect of Powder Preheating Temperature on the Properties of Cu-Based Amorphous Coating Layer by Cold Spray Deposition

Abstract

Abstract Cu54Zr22Ti18Ni6 amorphous powders were deposited onto aluminum substrates by cold spray process with different powder preheating temperature (below Tg : 623K, near Tg : 703K, and Tx : 773K). The microstructure and macroscopic properties of coating layers were investigated using OM, XRD, DSC and hardness, SUGA test, potentio-dynamic corrosion test. XRD results showed that cold sprayed Cu based amorphous coating layers of 300~350 μm thickness could be well manufactured regardless of powder preheating temperature. Porosity measurements revealed that the coating layers of 623K and 773K preheating temperature conditions had lower porosity contents (0.88%, 0.93%) than that of 623K preheating conditions (4.87%). Hardness was measured as 374.8HV (623K), 436.3HV (703K) and 455.4HV (773K) for the coating layers, respectively. Results from the wear resistance examination via SUGA test and those from the hardness testing showed the same trends. Examination of corrosion resistance of the amorphous coating layer showed that the critical anodic current density (ic) of the coating layer, for which powder preheating was provided at 623K and then cold spray deposition, was 5.6X10-3A/cm2. The ic values of the 703K and 773K coating layers were 4.8X10-4 and 1.2X10-3A/cm2, respectively. Both temperature conditions were found to offer superior corrosion characteristics to those of the 623K-prehaeted and coated specimen. This was assumed to be attributed to the relatively lower level of porosity.