Times Higher Wear Resistance Research Articles

Effect of Nb Addition on the Corrosion and Wear Resistance of Laser Clad AlCr2FeCoNi High-Entropy Alloy Coatings

Laser clad AlCr2FeCoNiNbx (x = 0, 0.5, 1.0, 1.5, 2.0, with x values in molar ratio) high-entropy alloy (HEA) coatings were fabricated on Q345 carbon steel. This study delves into the impact of Nb incorporation on the reciprocating sliding wear resistance of these laser clad coatings against a Φ6 mm silicon nitride ball. The microstructure of the as-clad AlCr2FeCoNiNbx coatings transformed from a single Face-Centered Cubic (FCC) solid solution (when x = 0) to the hypoeutectic state (when x = 0.5) and progressed to the hypereutectic state (when x ≥ 1.0). This evolution was marked by an increase in the Laves phase and a decrease in FCC. Consequently, the HEA coatings exhibited a gradually increasing Vickers hardness, reaching a peak at HV 820. Despite a decline in corrosion resistance, there was a notable enhancement in wear resistance, and the friction of the HEA coating could be reduced by Nb addition. The phase evolution induced by Nb addition led to a shift in the predominant wear mechanism from delamination wear to abrasive wear. The wear rate of Nb0.5 was impressively low, at 6.2 × 10−6 mm N−1 m−1 when reciprocating sliding under 20 N in air. In comparison to Nb0, Nb0.5 showcased 3.6, 7.2, and 6.5 times higher wear resistance at 5 N, 10 N, and 20 N, respectively. Under all applied loads, Nb1.5 has the lowest wear rate among all HEA coatings. This substantiates that the subtle introduction of Laves phase-forming elements to modulate hardness and oxidation ability proves to be an effective strategy for improving the wear resistance of HEA coatings.

Features of the carbo-vibroarc surfacing in the development of multicomponent cermet wear-resistant coatings

The paper presents a simple and economical method of carbovibro-arc surfacing of metal surfaces . This method has been used to apply wear-resistant cermet coatings made of multicomponent pastes 21.17Fe–4.75C–33.48Cr–1.45Si–1.35B–2.8Mn with the addition of 25 wt% В 4 С and 10 wt% Na 3 AlF 6 on a steel substrate. The microstructure and phase composition of the cermet coating have been studied, and the distribution of microhardness from its surface to the metal substrate has been determined. It has been found that the main zone of the coating consists of the CrFe 4 and B 0.7 Fe 3 C 0.3 strengthening phases located in the matrix, which is a solid solution of C, B, Cr, and Mn in iron. Tribological tests of samples with and without the protective cermet coating have been carried out by the measuring sliding method; 2D and 3D images of the surfaces of wear grooves have been obtained. It has been found that coated samples have a 2 times lower coefficient of friction and 2.8 times higher wear resistance than uncoated samples. Protective cermet coatings have been applied to commercial parts of agricultural machinery (shins). Comparative tests of shins with protective coatings and uncoated commercial shins have been carried out in real field conditions. It has been found that the service life of parts with the developed cermet coating is 2.5–3 times higher than that of uncoated commercial parts. It is shown that this technology allows one to reduce soil contamination with metal debris and increase the performance of combines. • Wear-resistant cermet coatings on a steel substrate from multicomponent pastes • 2D and 3D images of the surfaces of wear grooves • The coated samples have a 2 times lower coefficient of friction and 2.8 times higher wear resistance.

Зносостійкі покриття на алюмінієвих сплавах

Aluminum alloys are widely used in industry. Recently, they are used as a replacement for steel for the manufacture of pulleys, gears, columns of hydraulic rotary transmissions of grabs, etc. This reduces the weight of the parts and reduces carbon emissions into the atmosphere. However, aluminum alloys have low abrasive wear resistance, so their use is possible with coatings on the surface. High-speed gas flame spraying (HVOF) was carried out on the equipment (Diamond Jet Hybrid gun). Arc coatings with a thickness of 500 µm were applied using FMI metallizer and FMI-2 powder wire (Cr6Al6B3Fe-base). PEO (oxido ceramic) coatings were synthesized on D16T aluminum alloy in an electrolyte of 3 g/l KOH + 2 g/l liquid glass (sodium silicate) with a pulsed current at a frequency of 50 Hz, with the ratio of the densities of the cathode and anode currents Jc/Ja+15/15 A /dm2. The duration of the PEO process is 60 min. The open porosity of the coatings was determined by the method of hydrostatic weighing. The phase composition of the surface layers was studied using a DRON-3.0 diffractometer. HVOF (VC) and PEO coatings have been found to have 3 to 4 times higher wear resistance than high carbon hardened steel 100Cr6 and 2 times higher than galvanic chromium coatings, but have high energy consumption. Two methods have the lowest energy consumption: electric arc spraying of coatings and hard anodizing. At the same time, the wear resistance of such coatings is significantly lower than that of coatings obtained by the PEO and HVOF (VC) methods. For the restoration of worn parts, the most appropriate methods are HVOF (VC) and electric arc spraying, as they allow applying thick coatings up to 5 mm. Conclusions: It was established that the studied HVOF (VC), PEO, EDP and hard anodized coatings significantly increase the abrasive wear resistance of aluminum alloy parts. HVOF (VC) and electric arc spraying methods can be used to protect new and worn parts from wear. PEO and hard anodizing methods can be used to protect against wear on new parts only. The use of these methods increases the wear resistance of parts made of aluminum alloys to the level of steel and allows replacing steel and cast iron with aluminum alloys with coatings, reducing the weight of parts and carbon emissions into the atmosphere.

Structural and Tribological Assessment of Biomedical 316 Stainless Steel Subjected to Pulsed-Plasma Surface Modification: Comparison of LPBF 3D Printing and Conventional Fabrication.

The structural features and nanoindentation/tribological properties of 316 stainless steel fabricated by conventional rolling and laser-based powder bed fusion (LPBF) were comparatively investigated regarding the effect of surface-pulsed plasma treatment (PPT). PPT was performed using an electrothermal axial plasma accelerator under a discharge voltage of 4.5 kV and a pulse duration of 1 ms. Optical microscopy, scanning electron microscopy, X-ray diffraction, nanoindentation measurements and tribological tests were applied to characterize the alloys. The LPBF steel presented almost the same modulus of elasticity and double the hardness of rolled steel. However, the LPBF steel manifested lower dry-sliding wear resistance compared with its wrought counterpart due to its porous structure and non-metallic inclusions. Conversely, LPBF steel showed three times higher wear resistance under sliding in simulated body fluid (SBF), as compared with wrought steel. PPT led to steel modification through surface melting to a depth of 22–26 μm, which resulted in a fine cellular structure. PPT moderately improved the dry-sliding wear resistance of LPBF steel by fusion of pores on its surface. On the other hand, PPT had almost no effect on the SBF-sliding wear response of the steel. The modification features were analyzed using a computer simulation of plasma-induced heating.

Nanoengineered Polycrystalline Diamond Composites with Advanced Wear Resistance and Thermal Stability.

Fluorinated grains of micrometer size diamonds overcoated with nanodiamond particles were used as a feedstock for high-pressure, high-temperature synthesis of new polycrystalline diamond composites (PDCs). Such a nanoengineering approach for exploring the interfacial chemistry of diamonds has been implemented in two methods: (i) infiltration of Co from the WC-Co layer into a fluorinated diamond layer with added Al and (ii) sintering of fluorinated micro- and nanosize diamond homogeneous mixtures with added Al and Co. We found that unlike commercial PDCs made with a metallic Co binder for drilling tools, the binding phase in new composites comprises only intermetallic compound AlCo or ternary carbide AlCo3C. As a result, composites made from homogeneous mixtures showed greater promise for improving the thermal stability, while the two-layer experimental composites during granite turning tests have demonstrated >2 times higher wear resistance than leached commercial PDCs.

Effect of tempering and cryogenic treatment on wear and mechanical properties of hot work tool steel (H13)

The AISI H13 is a chromium based, medium carbon content hot work tool steel which is widely used in hot working as well as cold working applications. These steels are very popular because of their key characteristics such as high hardness, high strength, high fracture toughness and high wear resistance. These steels are continuously subjected to high mechanical stresses and temperature fluctuations, fatigue and wear loss which results in limited die life. It is therefore necessary to improve the properties of these tool steels. One of the methods to improve the properties of these tool steels is with the help of conventional heat treatment. But no significant improvements in the properties were observed. From the literature survey, it is realized that implementation of cryogenic treatment can improve the properties of tool steel. In the present paper, cryogenic treatment on AISI H13 hot work tool steel is studied with the help of characterization techniques such as hardness, wear and microstructure study. One set of specimens were subjected to conventional heat treatment (HTT) viz. hardening at 1020 °C followed by double tempering at 500 °C. Another set of specimens were subjected to conventional heat treatment followed by deep cryogenic treatment at −196 °C and soft tempering at three different temperatures viz. 200 °C, 300 °C and 400 °C (HTTCT). A modified heat treatment cycle (HTCT) is also proposed with varying soft tempering temperatures viz. 200 °C, 300 °C and 400 °C and comparison is made with HTT and HTTCT. The specimens were tested for hardness, wear and microstructure study. The experimental investigation shows that cryogenically treated specimens shows significant improvement in the hardness and carbide density as compared to conventionally treated specimens. It is thus concluded that HTTCT cycle gives two times higher wear resistance than conventional heat treatment cycle (HTT) because of precipitation of fine tertiary carbides.

Structure and Wear Resistance of FeNiCrBSiC–MeB2 Electrospark Coatings

The structurization of coatings produced by electrospark deposition (ESD) from the commercial selffluxing FeNiCrBSiC alloy and FeNiCrBSiC-based composites, such as FTB20 (FeNiCrBSiC–20 wt.% TiB2) and FCB20 (FeNiCrBSiC–20 wt.% CrB2), on a steel 45 substrate was studied. The electrospark FeNiCrBSiC coating about 70 μm thick has a globular surface and the FTB20 and FCB20 coatings form a continuous layer up to 50 μm thick over the entire samples. The microhardness does not change across the deposited coating thickness and is 10–14 GPa. The chemical compositions of the ESD coatings and the electrodes are the same, which indicates that the electrode material does not mix with the steel substrate. The structure of the FeNiCrBSiC, FTB20, and FCB20 electrodes and coatings differs significantly because chromium boride and/or titanium boride inclusions refine from 20–25 μm to 1 μm in the ESD process. The heterophase structure of the ESD coatings represents a nickel–iron-base matrix reinforced with fine boride and carboboride particles. The effect of speeds and loads on the wear rate of ESD coatings in dry friction conditions was examined. Electrospark coatings produced from the WC–6% Co hardmetal were tested as wear resistance reference. The wear rate of the FeNiCrBSiC, FTB20, and FCB20 coatings decreases and that of the WC–6% Co coating increases when the speed rises from 4 to 12 m/sec. The wear rate of the ESD coatings becomes one order of magnitude higher when the load increases from 0.1 to 0.4 MPa. Analysis of the friction surfaces showed that wear of the FeNiCrBSiC coating was caused by failure of the globules and that of the FCB20 coating by brittle fracture of the deposited layer. The ESD FTB20 coating has two to three times higher wear resistance than the FeNiCrBSiС coating because of the oxidative wear mechanism whereby protective oxide films develop on the friction surfaces and act as a solid lubricant.

The cathodic electrolytic plasma hardening of the 20Cr2Ni4A chromium-nickel steel

In order to obtain the modified surface structure of the 20Cr2Ni4A steel plasma electrolytic hardening (PEH) method was used. The surface hardening process was conducted in the aqueous electrolyte solution of 20% sodium carbonate and 20% urea. The sample consists of a ferritic-pearlitic structure, i.e. the part retains its viscous core, and the surface layer contains carbide particles. Hardening process induces martensite transformation and creation of carbide particles in the surface layer. The presence of carbide particles in the surface layers has a positive effect on the tribo-mechanical performance. Hardened structure 600μm long was obtained with hardness increase up to 520 HV and 2.5 times higher wear resistance. Tribological test results showed the difference of the coefficient of friction as a function of surface roughness determined by plasma-electrolytic hardening process.

Structure and Properties of Electro-Explosive TiC–Ni–Mo Coatings of Die Steel after Electron-Beam Treatment

In this paper, we studied the phase and elemental composition of the surface layer of die steel 5KhNM subjected to electro-explosive sputtering deposited composite TiC–Ni–Mo coating and subsequent pulsed irradiation with a high-intensity submillisecond electron beam. The modes of electron-beam processing providing the formation of a dense, with a mirror gloss, surface layer with a submicrocrystalline structure based on titanium carbide and intermetallic compounds based on Mo, Ni, and Ti are determined. The electron-beam processing of an electro-explosive coating in the melting mode is shown to lead to the formation of a structurally uniform and concentration-uniform surface layer. TiC–Ni–Mo coatings have a 1.26 times higher wear resistance compared to die steel 5KhNM used as a substrate. The microhardness of the formed coatings is 450–2400 HV, the nanohardness is 25.5 GPa, and the modulus of elasticity is E = 398 GPa.

STUDY OF WEAR RESISTANCE OF REINFORCED POLYAMIDE COMPOSITES FOR METAL-POLYMER GEAR DRIVES

An experimental study of the wear resistance of two dispersion-filled composite materials based on polyamide used in metal-polymer gear drives with a 30% volume content of short glass or carbon fibres was performed according to the technique proposed by the authors. As a result of tribotests in the “pin-disk” scheme, the mass wear of these composites was determined under dry friction conditions for steel 45 at room temperature in the range of contact pressures of 10–40 MPa, as well as the kinetics of the coefficient of sliding friction and the contact temperature of the tribosystem elements. It was established that polyamide strengthened by carbon fibres has almost four times higher wear resistance in comparison with a polyamide filled with glass fibres. The wear resistance characteristics that are the basic parameters of the tribokinetic wear model are calculated, using the durability of the straight spur metal-polymer gear drive on the basis of the original calculation method. It was established that gear drive durability with a pinion or a wheel reinforced with carbon fibres is more than eight times the durability of gear drive with gear wheels from polyamide filled with glass fibres. The gear drive durability with the steel pinion and the composite gear wheel increases in proportion to the gear ratio as compared to the gear drive with the composite pinion and the steel wheel. The change in the maximum contact pressures in the mesh interval was calculated.

In-situ TiC-TiB2 coating on Ti-6Al-4V alloy by tungsten inert gas (TIG) cladding method: Part-II. Mechanical performance

TiC-TiB2 composite coating was produced on Ti-6Al-4V alloy by TIG cladding method (an economical alternative of laser cladding process) through in-situ reactions between Ti and B4C pre-deposited powder mixture. The experimental results revealed significant variation in the hardness value along the depth of the coatings for the alteration of processing conditions, which mainly occurred due to discrepancy in the dilution of substrate material and consequent change in the percentage of hard TiC and TiB2 phases. The fracture toughness of the coatings measured by indentation method are found (5.65–6.97 MPa·m1/2), much higher than that of individual TiB2 or TiC. The sliding abrasive wear test performed against alumina abrasive wheel revealed that abrasion wear is predominant for removal of the coating. However, adhesive wear due to plastic deformation and brittle fracture resulted from the stress induced due to cyclic loading by the abrasive particles are also effective to remove the coating material subjected to the concentration of hard TiC and TiB2 phase in the coating. The produced coating exhibited up to four times higher hardness and three times higher wear resistance as compared to Ti-6Al-4V alloy substrate, which makes the coating a suitable candidate for application in wear resistance components.

Wear Resistance of Sintered Composite Hardfacings under Different Abrasive Wear Conditions

The article focuses on vacuum liquid phase sintered (PM) composite hardfacings and their behaviour under different abrasive wear conditions. Hardfacings studied contained 30 – 50 vol % fine, coarse or multimodal (fine and coarse) hardmetal reinforcement. For wear resistance studies, we used the Abrasive Rubber Wheel Wear (ARWW) test as a three-body abrasive wear test, the Abrasive Wheel Wear (AWW) test as a two-body abrasive wear test and the Abrasive-Impact Erosion wear (AIEW) test as an abrasive-erosive wear test. Tested materials were compared to Hardox 400 steel and CDP112 wear plate (Castolin Eutectic® Ltd.). It was found that under three-body abrasion conditions (ARWW test) hardfacings with high content of spehrical coarse reinforcement are suitable; their wear resistance is about two times higher than that of unreinforced hardfacings. Under two-body abrasive wear (AWW test), hardfacings with a high content of coarse reinforcement are recommended; their wear resistance is up to eight times higher than that of unreinforced hardfacings from the figures and graphs mentioned in the text. Under abrasive-erosive wear (AIEW test), unreinforced ductile materials are recommended; they have two to three times higher wear resistance than composite hardfacings reinforced with fine or multimodal reinforcement. DOI: http://dx.doi.org/10.5755/j01.ms.23.3.16323

Effect of Multilayer Nanocomposite TiAlSiN/TiSiN/TiAlN Coating on Wear Behavior of Carbide Tools in the Milling of Hardened AISI D2 Steel

Thin hard coatings are widely used in the protection of cutting tools, dies and molds to prolong their wear resistance and lifetime. Superior properties of different coatings can be combined with multilayer design, and especially a higher microhardness can be obtained by nanocomposite structures. In this study, a multilayer design composing of TiAlSiN, TiSiN and TiAlN layers was applied on carbide cutting tools. The top TiAlSiN layer has a nanocomposite structure of crystalline fcc-TiAlN and amorphous Si3N4 phases. The multilayer nanocomposite TiAlSiN/TiSiN/TiAlN coating was deposited on the carbide cutting tool using an industrial magnetron sputtering system. Wear behavior of the coated tools was investigated in the milling of hardened AISI D2 steel (~55 HRc). The changes in tool wear and surface roughness as a function of cutting distance were recorded. Wear mechanisms and types were investigated using optical and scanning electron microscopy in combination with energy dispersive spectroscopy. It was found that the multilayer nanocomposite TiAlSiN/TiSiN/TiAlN coating provides at least 1.2 times higher wear resistance and a longer lifetime than single layer TiN and TiAlN coatings. Main wear mechanisms are abrasion and adhesion of the workpiece material on the cutting edge. As a result, wear types are notch wear and build-up-edge formation.

Wear behavior and corrosion properties of Fe-based thin film metallic glasses

Fe48Mo14Cr15Y2C15B6 (at%) thin film metallic glasses (TFMGs) with various thickness (125–745 nm) were deposited on glass and 304 stainless steel (SS) by using single-alloy target magnetron sputtering. X-ray diffraction and transmission electron microscopy verified the fully amorphous structure of the as-deposited films. Results of dry friction and wear tests against Si3N4 demonstrated that Fe-based TFMGs had lower friction coefficient and nearly three times higher wear resistance with respective to 304SS. The corrosion properties of the Fe-based TFMGs were evaluated in an artificial sweat solution by various electrochemical analytical techniques, including potentiodynamic, potentiostatic polarization and Mott–Schottky analysis. It was shown that the Fe-based TFMGs exhibited highly stable passivity and pitting resistance, which was significantly higher than that of uncoated 304SS. The good corrosion resistance of Fe-based TFMGs results from the lower defect density and higher thickness of the as-formed passive film as compared to 304SS. The pitting of the Fe-based TFMGs follows three distinct stages, i.e., pitting initiation, metastable pitting and stable pitting, as well as substrate dissolution-induced film rupture due to the adsorption and penetration of chloride ions in the artificial sweat solution. These findings are expected to broaden the application of Fe-based TFMGs as a highly protective film for electronic device applications.

Influence of particle size and temperature on the wear properties of rutile-reinforced aluminium metal matrix composite

In the present investigations, LM13 aluminium alloy reinforced with 15 and 20wt.% rutile mineral of fine (50–75 µm) and coarse (106–125 µm) size range was prepared through stir casting technique. The microhardness on different phase of the composite was measured to check the interfacial bonding of particles with the base material. The wear properties of the samples were studied using pin-on-disc tribometer at high load (49 N) with variation in temperatures from 50℃ to 300℃. Wear results indicated that the composites containing fine size reinforced particles showed around two times higher wear resistance over a wide range of temperature than the composite-containing coarse particles. A transition in wear mode from mild to severe was observed above 200℃. Wear track and wear debris were analysed to understand the nature of wear.

Studies on Electroless Coatings at IIT Roorkee - A Brief Review

Since the introduction of Electroless (EL) coating in 1946 by Brenner and Riddle, the process has been the subject of steady growth. It is one of the most elegant methods available for the production of alloy coatings on surface. The technique involves the autocatalytic reduction, at the substrate/solution interface, of cations by EL bath released from suitable chemical reducing agents. EL coating technique is simple one, as can be manifested just by controlling pH and temperature of the coating bath. Such coatings are reported to provide excellent physical and mechanical properties. The electroless coatings are being studied at Indian Institute of Technology Roorkee since 1985. The structural and morphological behavior of Ni-P coatings for different phosphorous contents has been extensively studied. Sub-micron size coating islands and their transformations have been deduced. The metallography studies using hot stage within TEM to follow the phase transformations occurring at various temperatures have been studied for Ni-B EL coatings. The realization of mechanical bonding along with chemical bonding between EL coating and the substrate has been explained by coated copper on ceramic powder. As a forward step towards composite coatings, Ni-P-C, Ni-P-Al2O3, Ni-P-ZrO2has been developed by EL co-deposition technique. Ag-graphite coatings produced by EL technique exhibits nearly five times higher wear resistance and nearly two times better corrosion resistance apart from a good electrical conductor. The tribological behavior of electroless Ni-P-X and Ni-P coatings on steel and aluminium substrates in different conditions i.e., as coated, heat treated at various temperatures at different extents of time with different normal loads, have been studied in terms of dry sliding friction and wear against counter face of case hardened steel. In Ni-P-X nanocoating (X= ZrO2-Al2O3-Al3Zr), X has been producedin-situand are of nanosize particles. Such coating could be done on carbon fibre of 7µ diameter uniformly. Ni-P-ferrite nanocoatings with thickness less than nearly 1mm thick, is exhibiting good absorption of microwave in the range of 12-18 GHz which can be exploited for radar applications. Micro-thickness coatings are paying ways to nanocoatings. Nanocoatings are the coatings in which either the thickness of the coating is in nanolevel or second phase that dispersed in the coat matrix is of nanosize. To further explore the field of EL nanocomposite coatings, now days, a work on EL Ni-P-ZnO, TiO2, Al2O3, ZrO2and Ni-B-ZrO2for its mechanical properties has been carried out.

Microstructure and Wear Resistance of Laser Cladding of Ni-Based Alloy on Copper Substrate

In order to improve the service life of copper crystallizer, a layer of Ni-based alloy on thick copperplate surface was performed by plasma spray process, and then YAG pulsed laser was used to remelt spray coating. Microstructure analysis, hardness test, and the wear resistance comparison experiments were taken to the specimen. The result shown that the Ni-based alloy cladding, metallurgy bonding with the copperplate, can be performed by taking the method of the YAG laser remelt technology; the structure of the cladding is compact, without defects such as pores and cracks. The micro hardness of cladding zone is between 450-490HV, which is much higher than that of the copper substrate (about 90 HV). The wear tests showed the laser cladding layer performed 14 times higher wear resistance compared to copper substrate.

Micro-Slurry-jet Erosion (MSE) testing of CVD TiC/TiN and TiC coatings

Several different experimental techniques are normally used to evaluate tribological properties of thin hard coatings. However, most of the tests cannot assess properties of coating, substrate and interface independently. In this study, the potential of a Micro-Slurry-jet Erosion (MSE) test to swiftly evaluate the intrinsic wear properties of thin single layered and multilayered coatings is demonstrated. A slurry containing 1.2 μm alumina particles was impacted at high velocity perpendicular to CVD TiC/TiN (TiN on top of TiC) and TiC coatings deposited on cemented carbide. In addition, nano-indentation and XRD, GDOES, AFM analyses were done for the original and worn surfaces. For the TiC/TiN coating, the wear depth of the TiN layer increased linearly until the TiC layer was reached. There after the wear occurred at a lower rate but tended to increase towards the TiC/substrate interlayer. The single layered TiC coating showed the same wear behaviour as the TiC layer of the TiC/TiN coating. The wear rate was constant within the individual TiN and TiC layers, but changed near the interfaces. The micro-topographies of the worn surfaces observed by AFM correlated to the difference in the wear rate of the individual layers and the change in wear rate at the interface to the substrate. The TiC layer proved to have about two times higher wear resistance than the TiN layer. Consequently, the MSE test can distinguish between small differences in the properties of the coatings and of the interlayer zones, and can be used as a screening test when evaluating multilayered as well as single layered coatings.

S1105-2-2 CVD TiC/TiN膜とTiC膜のマイクロスラリージェットエロージョン(MSE)試験(表面改質とトライボロジー2)

A slurry containing 1.2μm alumina particles was impacted at high velocity perpendicular to CVD TiC/TiN (TiN on top of TiC) and TiC coatings deposited on cemented carbide using a Micro Slurry-jet Erosion (MSE) tester. In addition, nano-indentation and XRD, GDOES, AFM analyses were done for the original and worn surfaces. For the TiC/TiN coating, the wear depth of the TiN layer increased linearly until the TiC layer was reached. There after the wear occurred at a lower rate but tended to increase gradually towards the TiC/substrate interlayer. The single layered TiC coating showed the same wear behaviour as the TiC layer of the TiC/TiN coating. The micro topographies of the worn surfaces observed by AFM correlated to the difference in the wear rate of the individual layers and the change in wear rate at the interface to the substrate. The TiC layer proved to have about two times higher wear resistance than the TiN layer.

Effect of Oxidation on the Wear Behavior of a ZrN Coating

In the present study tribological performance of ZrN coatings deposited on hardened AISI D2 quality cold work tool steel by arc-Physical Vapor Deposition technique has been examined in as-deposited and oxidized conditions. ZrN coatings were oxidized at 400 oC for various times up to 12 h. Reciprocating wear tests carried out by rubbing Al2O3 balls on the coatings, revealed significant improvement in wear resistance of ZrN coating upon oxidation. Oxidation treatment at 400 oC for 12 h yielded seven times higher wear resistance than as-deposited ZrN coating, beside significant reduction in the wear of counterface (Al2O3 ball).