Designs and preparation of advanced HVOF-PVD duplex coating by combination of HVOF and arc ion plating

Abstract

Advanced HVOF-PVD duplex coatings were produced on the medium carbon steel by combinations of High Velocity Oxygen-Fuel (HVOF) and arc ion plating. The microstructures and mechanical properties were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) in association with mechanical property measurement. The results show that the duplex coating are composed of an inner NiCr-Cr 3 C 2 -based HVOF-sprayed layer mainly consisted of γ-NiCr and Cr 3 C 2 phases, and an outmost PVD-AlCrN layer containing fcc-AlCrN phase. Duplex coatings reveal more excellent wear resistance when compared to the HVOF-sprayed coating. The improved wear resistance is mainly related to the outmost AlCrN layer with more excellent wear resistance in comparison to the

Comparative study of the fatigue performance of the micro and nanometric Cr3C2-25NiCr coating sprayed by HVOF on ASTM A516 steel substrate

“…The powder was ground up for 12 hours. Them, it was dried in an oven at 50°C for 20 minutes and finally sieved on 325 Mesh, according to a recommended protocol [15].…”

“…Therefore, it can be assumed that the nanometric powder may consist of amorphous structures and crystal dispersions. The XRD analysis ( Figure 2 ) explains the presence of Cr 3 C 2 [13,15,20,27,29], and Cr 7 C 3 in the micrometric powder. The intensity of the peaks decreases, while they expand as a function of milling time.…”

“…The HEM allows nanostructured materials to be synthesized easily in a short time [13]. Moreover, the main objectives of the HEM for the synthesis of Cr 3 C 2 -25NiCr coating powder are: i) to reduce the granulometry of the composite; ii) to ensure that the carbide particles will be surrounded by the precursor constituent of the NiCr binder phase; iii) to create new active surfaces and structural defects in the composite [15]. Reducing the particle size of the powder causes an increase in the grain boundary area of the layer splats, which increases the hardness of the layer due to the restriction of dislocations [15].…”

“…The strong mechanical bond between splat and substrate impedes the relative sliding of splat [8,11,15,23]. Thus, fatigue cracks arising from the coating surface would cause increased stresses at the interface with the substrate, favoring the crack propagation into the substrate.…”

Improvement of Wear Resistance in Toothed Harrows Coated with HVOF and PVD Methods

“…Material loss due to use or time causes a decrease in the functionality of the machine even if it does not cause serious malfunctions. Various studies have been carried out to minimize material loss by using rapidly changing and developing technology since the first tools and machines were used (Chen et al, 2016;Çiçek, 2018;Dave et al, 2016;Dizdar and Maroli, 2016;Ergül, 2015). Improvements in material quality, studies to improve material surface strength (Gupta et al, 2004…”