In this study, the tribological properties of Cr2O3–40% TiO2 coating for brake disc materials were investigated in braking performances. Plasma spraying technique was used in order to deposit coating materials onto cast iron disc with ventilation channels substrate. The braking performances of discs were tested according to SAE J2430 test standard. Microstructures of discs were characterized by means of light microscope (LM), scanning electron microscope (SEM) and energy-dispersive spectrometry (EDS). The surface hardness and roughness were measured with testers. In general, it is noted from the LM and SEM images that there was an infinite gradation between coating layer, binding material and the lamellar graphite cast iron and that bonding resistance was excellent. The coated disc exhibited less wear, approximately the same coefficient of friction and longer life than the uncoated disc. As a result, the coated disc could be a much better alternative for new-generation brake discs in the motor vehicles than the uncoated disc.

The poor abrasive wear behavior of agricultural machinery affects the farmers all over the world, rendering their activities more inefficient and negatively affecting their productivity. Therefore, innovation in the manufacture of soil cultivation machinery and the selection of wear-resistant materials has been of great importance. Recently, boron alloys, in particular, have been used in the manufacture of machinery parts that work the soil. The aim of this was to investigate the behavior of the blades of the machines widely used in soil cultivation in agricultural production following a surface treatment technique. For this purpose, the blades made of 30MnB5, a material widely used in the production of cultivator blades, were used as substrate samples in the trials as well as blades of the same substrate coated with Fe28Cr5C1Mn alloy wire via the electric arc spray technique. The morphologies and structures of the uncoated and coated samples were comprehensively analyzed by light microscopy, scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. In addition, their microhardness, porosity, and surface roughness properties were assessed separately before and after plowing. These prepared blades were tested under in the same conditions by plowing the same field at two different soil moisture. Although the weight loss was measured as 9.4 g and 5.4 g in the uncoated and in the coated sample at 9% moisture level, respectively, the weight losses were at 14% humidity level were 10.6 g and 5.9 g in the uncoated and coated samples, respectively. Although the amount of wear increased with increasing humidity levels in both groups, the mass wear loss in cultivator blades coated with Fe25Cr5C1Mn alloy wire was found to be lower in all trials. The results suggest that coating the cultivator blades using electric arc spray would increase agricultural productivity and reduce factors that cause environmental pollution.

30MnB5 boron alloyed steel surface is coated using different coating techniques, namely 60(Ni-15Cr-4.4Si-3.5Fe-3.2B 0.7C)-40(WC 12Co) metallic powder plasma spray, Fe-28Cr-5C-1Mn alloy wire arc spray, WC-10Co-4Cr (thick) powder high velocity oxy-fuel (HVOF), and WC-10Co-4Cr (fine) diamond jet HVOF. The microstructure of the crude steel sample consists of ferrite and pearlite matrices and iron carbide structures. The intermediate binders are well bonded to the substrate for all coated surfaces. The arc spray coated surface shows the formation of lamellae. The cross-section of HVOF and diamond jet HVOF coated surfaces indicates the formation of WC, W2C Cr, and W parent matrix carbide structures. The corrosion characteristic of the coated steel has been investigated in 3.5 wt.% NaCl solution using electrochemical impedance spectroscopy (EIS), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDAX) techniques. The results reveal that the steel corroded in the medium despite the coatings. However, the extent of corrosion varies. HVOF coated sample demonstrated the highest corrosion resistance while arc spray coated sample exhibited the least. EDAX mapping reveals that the elements in the coatings corroded in the order of their standard electrode potential (SEP). Higher corrosion resistance of HVOF coated sample is linked to the low SEP of tungsten.

The friction force in mechanical systems not only reduces their efficiency but also causes wear in the machine components, resulting in financial losses. As in every sector, in agricultural production, the problem of abrasion, particularly in soil tillage, is extremely important. Studies have been conducted examining the different methods for minimizing wear on tillage machinery. In this study, the cultivator blades of a boron-alloyed 30MnB5 steel substrate were coated with WC–10Co–4Cr ceramic powder by way of the Diamond Jet high-velocity oxygen-fuel (DJ-HVOF) technique. The microstructure of the sample and its wear properties under field conditions were then investigated. The microstructure, porosity, hardness, surface roughness and wear properties of the samples were revealed. The coating was observed to be well bonded, both mechanically and metallurgically, and the hardness of the coating was three times higher than that of the uncoated substrate material. In the field trials, the wear was found to be six times lower due to the hardness of the WC–10Co–4Cr coating and the hard carbide phases in its microstructure. As a result, the HVOF coating was shown to minimize wear, which is a big problem in tillage machinery. This can extend the economic life of machinery and make agricultural production more efficient.

No abstract