Tribo-mechanical Properties Research Articles

Electrodeposited Co-P alloy and composite coatings: A review of progress towards replacement of conventional hard chromium deposits

Hard chromium coatings have attracted much attention due to their strong tribological and corrosion performance. There is a global need to replace such coatings in industrial applications owing to technical problems, environmental concerns and legislation. Co-P electrodeposits are a promising alternative to hard chromium in a variety of engineering applications due to their appreciable microhardness and high corrosion resistance . Attractive magnetic, tribomechanical and electrical properties are evident together with excellent thermal stability. Environmentally acceptable process conditions may be used which allow controlled deposition on diverse workpieces across a wide scale. This review provides an overview of the influence of operational parameters, including type of current control, electrolyte composition, pH, current density and electrolyte agitation on the physicochemical and mechanical characteristics of the deposits. The incorporation of ceramic particles into Co-P electrodeposits to produce tailored composite coatings is also considered. An insight is given into the development of next generation alloy and composite deposits to replace hard chromium deposits from acidic Cr(VI) baths. Diverse applications for Co-P electrodeposits are considered and topics deserving further R & D are highlighted. • A concise overview of Co-P alloy electrodeposits is provided. • The most common types of bath used for Co-P electrodeposition are considered. • The influence of operating conditions on properties of deposits is addressed. • Effects of included particles on deposit characteristics are comprehensively discussed. • Potential applications of Co-P films are highlighted.

Investigation of mechanical and tribological properties of electroless Ni-P-B ternary coatings on steel

The Ni–P-B ternary coating was prepared on steel specimens through electroless deposition and their microstructural and tribo-mechanical properties were investigated. Heat treatment of the as plated coating was carried out at 390 °C to realize its effect on microstructural, mechanical, tribological properties of the coating. Microstructural analysis was carried out to study phase structure, morphology, topography, and coating compositions by using XRD, FESEM, AFM, and EDS. Contact angle measurement was also performed to evaluate the wetting behavior of the coatings. The as-plated coating exhibited hydrophobic character with a contact angle of ∼ 96.7°, whereas the heat-treated coating resulted in hydrophilic character with a contact angle of ∼ 79.5°. Mechanical and tribological properties were evaluated by using Vickers microhardness, nanoindentation, and dry sliding friction test. It is observed that the heat treatment process has an excellent impact on mechanical and tribological properties. Heat-treated ternary coating resulted in higher hardness (6 GPa) than as-plated coating (5 GPa). Similarly, higher young’s modulus was also achieved in the heat-treated coating (232 GPa) during nanoindentation experiments. Profound improvement in tribological performance is executed in both coatings over steel specimens. Maximum up to ∼ 33% and ∼ 45% decrement in COF is observed for as-plated and heat-treated Ni-P-B ternary coatings respectively. Due to greater hardness in heat-treated samples, the formation of the protective bilayer is observed along wear tracks as harder third particles created a strong adhesive bond by plastic deformation. The non-uniformity of the protective layer in the as-plated coating leads to higher COF and wear depth compared to heat-treated coating. Residual third particles behaved as micro cutters for as-plated coating while rolling effect is observed in case of heat-treated ternary coating.

Optimization of tribo-mechanical properties of boron carbide reinforced magnesium metal matrix composite

In this study, magnesium–boron carbide composites are developed through the powder metallurgy technique and investigated for their tribological properties using a pin-on-disc tribometer. The process parameters such as load, sliding distance, sliding velocity, and concentration (wt%) of boron carbide are optimized using Taguchi's L16 array. A lower wear rate of magnesium–boron carbide composite is obtained at optimized process parameters. Further, the analysis of variance result shows that the most dominating factor that affects the wear loss is load followed by concentration of boron carbide reinforcement. Moreover, the optimum parameters for the low wear rate of magnesium–boron carbide composites are obtained as 5 N, 6 wt% of boron carbide, 1200 m, and 3 m/s through signal-to-noise ratio analysis. Further, the mechanical properties of magnesium–boron carbide composites such as hardness and compressive strength are also analyzed. The result shows that the hardness and compressive strength of magnesium–boron carbide composites are improved with the inclusion of boron carbide reinforcement.

Mechanical and Tribological Properties of Co-Electrodeposited Particulate-Reinforced Metal Matrix Composites: A Critical Review with Interfacial Aspects.

Particulate-reinforced metal matrix composites (PRMMCs) with excellent tribo-mechanical properties are important engineering materials and have attracted constant scientific interest over the years. Among the various fabrication methods used, co-electrodeposition (CED) is valued due to its efficiency, accuracy, and affordability. However, the way this easy-to-perform process is carried out is inconsistent, with researchers using different methods for volume fraction measurement and tribo-mechanical testing, as well as failing to carry out proper interface characterization. The main contribution of this work lies in its determination of the gaps in the tribo-mechanical research of CED PRMMCs. For mechanical properties, hardness is described with respect to measurement methods, models, and experiments concerning CED PRMMCs. The tribology of such composites is described, taking into account the reinforcement volume fraction, size, and composite fabrication route (direct/pulsed current). Interfacial aspects are discussed using experimental direct strength measurements. Each part includes a critical overview, and future prospects are anticipated. This review paper provides an overview of the tribo-mechanical parameters of Ni-based co-electrodeposited particulate-reinforced metal matrix composite coatings with an interfacial viewpoint and a focus on hardness, wear, and friction behavior.

Tribo-mechanical properties and biocompatibility of Ag-containing amorphous carbon films deposited onto Ti6Al4V

The addition of Ag to amorphous carbon (a-C) films is highly effective in tailoring the tribo-mechanical properties and biocompatibility. For biomedical applications, Ag-containing a-C (a-C:Ag) represents a promising film material for improving the biofunctional surface properties of Ti-based alloys. In a sputtering process, a-C:Ag films, with Ag contents up to 7.5 at.%, were deposited with a chemically graded TixCy interlayer onto Ti6Al4V. The tribo-mechanical and biocompatible properties of a-C:Ag were evaluated. The influence of the Ag content on these properties was analyzed and compared to those of uncoated Ti6Al4V.Raman spectroscopy reveals that the amount of incorporated Ag does not induce significant structural changes in the disordered network, only a reduced number of vacancies and sp3-coordinated C bonds within the sp2-dominant a-C network is assigned to the films with high Ag concentration. With increasing Ag content, stresses, hardness, and elastic modulus decrease from (2.02 ± 0.07) to (1.15 ± 0.03) GPa, from (17.4 ± 1.5) to (13.4 ± 0.9) GPa, and from (171.8 ± 8.1) to (138.5 ± 5.8) GPa, respectively. In tribometer tests, the friction behavior against Al2O3 in lubricated condition with a simulated-body-fluid-based lubricant is not affected by the Ag concentration, but the Al2O3 counterpart wear is reduced for all a-C:Ag films compared to a-C. The friction against ultra-high-molecular-weight polyethylene (UHMWPE) decreases continuously with increasing Ag concentration and the counterpart wear is lower at higher Ag contents. Compared to a-C:Ag, Ti6Al4V demonstrates lower friction against UHMWPE and higher friction against Al2O3. The a-C:Ag films are not exposed to abrasion by Al2O3 or pronounced material transfer of UHMWPE. The hardness difference and chemical affinity between the friction partners are decisive for the tribological behavior of a-C:Ag. Compared to Ti6Al4V, the a-C:Ag films show antibacterial activity against Staphylococcus aureus, while the proliferation of osteoblast-like cells is reduced by Ag.

Structure and tribo-mechanical properties of Si- and W-containing amorphous carbon based multilayers

Designing the film architecture of amorphous carbon based systems is effective in tailoring the tribo-mechanical properties. For this purpose, alternating a-C and a-C:X layers, with X = Si or W, were grown with a layer ratio of 1, a bilayer period of ~200 nm, and a bilayers number of 5 in a magnetron sputtering process. By comparing with a-C(:X) monolayers, the structure and tribo-mechanical properties of alternating a-C/a-C:X films were evaluated.Although the bonding state of the a-C network of a-C:X in a-C/a-C:X is comparable to monolayered a-C:X, the multilayer design significantly affects the tribo-mechanical properties. The a-C/a-C:X multilayers exhibit a higher hardness compared to a-C:X. With a coefficient of friction of 0.12 ± 0.01, a-C/a-C:Si shows a low friction as a-C:Si with 0.09 ± 0.01, but the wear rate is significantly lower for a-C/a-C:Si with (3.4 ± 0.7) × 10-7 mm³/Nm than a-C:Si with (8.3 ± 1.0) × 10-7 mm³/Nm. Contrarily, a-C/a-C:W and a-C:W provide similar wear rates of 1.2 to 1.4 × 10-7 mm³/Nm, but the coefficient of friction is lower for a-C/a-C:W with 0.29 ± 0.02 than a-C:W with 0.36 ± 0.01. Hence, the multilayer design is efficient in improving the tribo-mechanical properties of a-C:X based films.

Enhancing the Surface Quality and Tribomechanical Properties of AA 6061-T6 Friction Stir Welded Joints Reinforced with Varying SiC Contents

Obtaining high-quality AA6061-T6 weldment is difficult because of the dissolution of its strengthening precipitates at temperatures beyond 250°C. In this work, the surface quality, mechanical and wear properties of AA6061-T6 friction stir welded joints at varying SiC addition (0.56-1.72 g) and number of weld passes (1-6) were investigated and discussed. SiC content was varied by changing the center groove width (CGW). Also, microstructure analysis of the entire welded joints was performed. For the first time, a process map predicting the surface characteristics of SiC reinforced AA6061-T6 friction stir welded joint at varying combinations of CGW and number of weld passes was developed. Increasing the number of passes resulted in better matrix refinement, particles fragmentation and improved particles distribution while increase in SiC content produced particles clustering and lower particles fragmentation. All the reinforced joints showed higher hardness but lower ductility than the unreinforced joint. Only joints reinforced with 0.56 g SiC showed improved tensile strength than the unreinforced joint (156 MPa) with the highest value of ~196 MPa (67% of the base metal) obtained at 4 weld passes. Increased hardness and tensile strength obtained as the weld passes increased from 2 to 4 was traced to better grain refinement, improved particles distribution and fragmentation. However, slight reduction in these properties at 6 passes was observed. Ductile fracture mode was found in all the joints except for joints reinforced with 1.01-1.72 g of SiC that showed evidence of brittle fracture. The specific wear rates of the entire reinforced joints are lower than that of the unreinforced joint. The weldment formed with 0.56 g SiC addition at 4 weld passes exhibited the best combination of properties among the entire weldments.

Drilling of High Volume Fraction Al2O3 Metal Matrix Composites

Abstract Composites of high volume fraction are suitable in many applications because of their high strength-to-weight ratio, high hardness, and wear resistance. In this study, the influence of drilling parameters and volume fraction of aluminum oxide (Al2O3) on the material removal rate (MRR), surface finish, and overcut was investigated. Al-Al2O3 metal matrix composites were stirred cast with 10 %, 20 %, and 30 % of Al2O3 concentration and subsequently machined using computer numerical controlled drilling. Experiments based on Taguchi’s methodology were carried out with L9 orthogonal array. Analysis of variance and signal-to-noise ratio analysis revealed the ranking of the most influencing process parameters. High volume fraction reinforcement of Al2O3 shows an adverse effect on MRR, surface roughness, and overcut. The drilling of high volume fraction ceramic-reinforced composite shows a brittle fracture of hard particles leading to the generation of overcut on the top surface. An empirical relationship between the process parameters under consideration and response variables were established by using regression analysis. The mathematical equations obtained through this work can be extended to find out the optimum volume fraction of Al2O3 to have better MRR and accuracies. This work will be useful to the metalworking industry towards the development of products having excellent tribo-mechanical properties.

Co-deposited Zn-Cu/Gr nanocomposite: Corrosion behaviour and in-vitro cytotoxicity assessment

ABSTRACT Zn-Cu alloys have been considered as potential candidates for bioimplant applications due to their moderate corrosion rate and admirable mechanical properties with non-toxic nature to the human body. However, with the incorporation of advanced reinforcements, such as carbon allotropes, the properties and applicability of a Zn-Cu alloy matrix can be further enhanced. In this research, graphene (Gr) nanoplatelets reinforced Zn-Cu/Gr nanocomposites were synthesised through a modified electro-codeposition method with different concentrations of Gr (25, 50 and 100 mg L−1) in the electrolyte bath. The prepared powder samples were compacted and sintered to form pellets. The pellets were tested for mechanical and in-vitro corrosion. The obtained micro-hardness, compressive yield strength (CYS) and ultimate compressive strength (UCS) of Zn-Cu/Gr (100 mg L−1) nanocomposite are 151 HV, 340 MPs and 362 MPa with increments of 84.1%, 118% and 70.7% compared to pure Zn-Cu alloy, respectively. The reduced wear rates and friction coefficients of Zn-Cu/Gr nanocomposites are attributed to crystallite size refinement and Gr content. The electrochemical corrosion rate is reduced by 66.6% from 33 × 10−3 mm year−1 for pure Zn-Cu alloy to 11 × 10−3 mm year−1 for Zn-Cu/Gr (100 mg L−1) nanocomposites, owing to Gr barrier protection. The in-vitro cytotoxicity assessment reveals that the prepared Zn-Cu/Gr nanocomposite is non-toxic for Gr concentration up to 50 mg L−1 in the electrolyte bath. The results show that a non-toxic Zn-Cu/Gr nanocomposite with outstanding tribo-mechanical and anti-corrosion properties can be synthesised by the proposed method.

A review on tribo-mechanical properties of micro- and nanoparticulate-filled nylon composites

Abstract Nylon composites are of evolving interest due to their good strength, toughness, and low coefficient of friction. Various fillers like micro- and nanoparticulates of metals and metal compounds were used to enhance the mechanical and tribological properties of nylons for many years by researchers. In this paper, an overall understanding of composites, filler materials, especially particulate filler materials, application areas of polymer composites, wear of polymers, and the effect of various fillers on tribo-mechanical properties of nylons have been discussed. The detailed review is limited to micro- and nanoparticulate fillers and their influence on the mechanical and tribological properties of various nylon matrices.

Novel approach in experimental and statistical investigations on titanium matrix composite

Titanium matrix composite (TMC) is comprehensively used in aerospace, turbo-machinery, automobiles and bio-medical industries for its improved strength properties and wear, corrosion and fatigue resistance. The major aim of this paper is to focus on the development of the current state-of-art of improving the tribo-mechanical properties by developing the TMC through laser engineering net shaping (LENS) process. A novel approach has been proposed in the multi-objective optimization (MOO) technique by combining grey relational analysis with desirability, named as desirable grey relational analysis (DGRA). The main advantage of incorporating such, is to include the predicted responses obtained by response surface methodology (RSM) with the actual experimental performances. Advanced non-traditional machining like wire electro-discharge machining (WEDM) has been used for the experimental runs on the developed TMC by varying power (P), time off (Toff) and peak current (IP) as chief input process parameters. Box–Behnken design (BBD) model has been projected to obtain MOO on key performance measures, like material removal rate (MRR), surface roughness (SR), kerf width (KW) and over cut (OC). The optimized solution is improved by 1.022% when compared with desirability approach to novel DGRA technique. MRR is enhanced by 1.463%, SR by 13.221%, KW by 1.594% and OC by 6.025% when compared with DGRA method.

A molecular dynamics study of the oxidation mechanism, nanostructure evolution, and friction characteristics of ultrathin amorphous carbon films in vacuum and oxygen atmosphere

Amorphous carbon (a-C) films are characterized by extraordinary chemical inertness and unique thermophysical properties that are critical to applications requiring oxidation-resistant, low-friction, and durable overcoats. However, the increasing demands for ultrathin (a few nanometers thick) a-C films in various emerging technologies, such as computer storage devices, microelectronics, microdynamic systems, and photonics, make experimental evaluation of the structural stability and tribomechanical properties at the atomic level cumbersome and expensive. Consequently, the central objective of this study was to develop comprehensive MD models that can provide insight into the oxidation behavior and friction characteristics of ultrathin a-C films exhibiting layered through-thickness structure. MD simulations were performed for a-C films characterized by relatively low and high sp3 contents subjected to energetic oxygen atom bombardment or undergoing normal and sliding contact against each other in vacuum and oxygen atmosphere. The effect of energetic oxygen atoms on the oxidation behavior of a-C films, the dependence of contact deformation and surface attractive forces (adhesion) on surface interference, and the evolution of friction and structural changes (rehybridization) in the former a-C films during sliding are interpreted in the context of simulations performed in vacuum and oxidizing environments. The present study provides insight into the oxidation mechanism and friction behavior of ultrathin a-C films and introduces a computational framework for performing oxidation/tribo-oxidation MD simulations that can guide experimental investigations.

Switching (bio-) adhesion and friction in liquid by stimulus responsive polymer coatings

Controlling (bio-) adhesion and friction is essential in many bio-medical and industrial applications. Such control can be achieved using stimulus responsive polymers. Coatings composed of these polymers are able to adapt their physicochemical properties to changes in the surrounding environment, such as temperature, light, pH, electronic and magnetic fields. This responsive behavior can be employed in the development of advanced technologies as for example underwater adhesives, self-adhering wound dressings, soft robotics and targeted drug delivery. In this review, we present an overview of the current status of research on controlling adhesion and friction in liquid environments using surface-bound stimulus responsive polymers. We focus in particular on polymer brushes and the role of specific interactions between the surfaces in the contact. These interactions can give rise to complex relations between swelling of the polymer film and its tribomechanical properties. A careful characterization of the change in specific interactions upon varying the environment is, therefore, critical for the design of effective smart coatings. We will finish this review with an overview of the open questions in the field and a discussion of the potential impact that the polymer-based smart adhesives and lubricants can have on industry and society.

Tribological and mechanical investigation of coir-silk reinforced polypropylene based matrix composites.

Silane treated natural fibers such as silk, coconut coir is reinforced into the polypropylene (PP) with a varying weight fraction of fibers and matrixes are developed in twin screw extruder at a constant temperature followed by the hot compression molding. Totally three different weight percentage of the polymer composites are developed. Such as silk fiber reinforced composites (S-PP), coir fiber reinforced composites (C-PP) and silk along with coir fiber reinforced composites (S-C-PP). The developed composites are then subjected to various tests. The water absorption capabilities of the all three composites are investigated. The composites are tending to abrasive wear test as per the ASTM standards. Design of experiments L-9 orthogonal array was introduced to identify the optimal wear condition of the composites developed. From the results it is observed that the tricholo vinyl silane chemical treatment to the coir and silk fibers enhances the tribo-mechanical properties of the fiber reinforced polymer composites. Also, the wear life of the composites was increased by 35% and water absorption capability increased by 42%. The scanning electron microscopy helped in identifying the impact of wear test over the surface of the composites at higher magnifications. The detailed surface morphology was executed in order to identify the behavior of the composites upon application of load.

Tribo-mechanical properties evaluation of HA/TiO2/CNT nanocomposite

In this study, a combination of reverse microemulsion and hydrothermal techniques were used to synthesize HA. A hydrothermal method was used to synthesize HA/TiO2/CNT nanocomposite powders. Cold and hot isostatic pressing techniques were used to fabricate tablet-shaped samples. To investigate the biocompatibility and tribo-mechanical properties of HA/TiO2 and HA/TiO2/CNTs, four samples were prepared with different percentages of CNTs, namely, HA/TiO2 (S0), HA/TiO2/CNT (S1.0), HA/TiO2/CNT (S2.0), and HA/TiO2/CNT (S3.0). The microstructure and morphology of the HA/TiO2/CNTs were characterized by transmission electron microscopy, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Hardness test results show that S3.0 displayed the highest surface hardness (285 HV) compared to other samples. The wear rate of HA/TiO2/CNT with the highest CNT content showed a decrease compared with those of the other samples. The results from nanoindentation tests showed that Young’s modulus of the S3.0 sample was 58.1% greater than that of the S0 sample. Furthermore, the human MDA-MB-231 cell line demonstrated good binding to the surface of the samples in the in-vitro biocompatibility evaluation of the HA/TiO2/CNT composites.

A brief manifestation of anti-bacterial nanofiller reinforced coatings against the microbial growth based novel engineering problems

An anti-bacterial material coating can help to break the spread of bacteria and viruses via metallic surfaces of biomedical devices, communication devices, food packages, research laboratories and public infrastructures like shopping malls, transports, toilets, etc. In addition, anti-bacterial material coatings owing to adequate tribomechanical and anti-corrosion properties can also help to resolve a major engineering problem of biofouling on marine installations and watercrafts’ surfaces. In recent times, the use of anti-bacterial nanocomposites coatings is emerging rapidly for various engineering applications. Here, metal matrix nanocomposites (MMNCs) are acquiring a significant role in the upcoming field of anti-bacterial material applications owing to high tribo-mechanical and anti-corrosion properties. The bio-responsive mechanism of MMNC coatings to perform anti-bacterial activities can protect the surfaces in biological environments. The nanofillers in the metal matrix plays a key role during anti-bacterial activities to kill the microbials. The composition of nanofillers can be inorganic, organic and hybrid, including advance nano tropes (i.e., allotropes of carbon and BNNT), which can be reinforced in metal matrix. This review study is addressing a problem of bacterial colonization on the surfaces that causing microbial growth based novel engineering problems and suggesting a facile and low-cost solution through an anti-bacterial MMNC coating.

Влияние фазового состава аустенитно-мартенситной трип-стали ВНС9-Ш на характеристики сухого трения скольжения в трибоконтакте со сталью ШХ15

The influence of content of the martensite phase that is from 0 to 50% (vol.) on hardness and tribomechanical properties of trip-steel VNS9-Sh (ВНС9-Ш) under conditions of dry sliding friction on steel ShKh15 (ШХ15) (counterbody) has been investigated. It was found out that the best combination of hardness and wear resistance was possessed by steel with martensite phase content ≈32% (vol.). It is shown that with comparable hardness and tribomechanical properties, VNS9-Sh steel is more than twice as strong as 110G13L steel (110Г13Л).

Tribomechanical Properties of the Modified Surface of Alloys of the WC-Co System

The research results of tribological characteristics of the surface hardened by electric explosion alloying of tungsten-cobalt hard alloys with carbon, titanium and aluminum are presented. The correlation of tribomechanical properties of the modified surface of alloys with changes in the structure and phase composition of the surface layer of the material is established. It is shown that the best wear characteristics are achieved during hardening of alloys by electric explosion of titanium. In this case, the coefficient of friction decreases by almost 3 times, the wear resistance estimated by the depth of the wear track increases by more than 10.0 times, and by the area of the wear track – by 53.2 times.

Comparative Study of Tribomechanical Properties of HiPIMS with Positive Pulses DLC Coatings on Different Tools Steels

Diamond-like carbon (DLC) coatings are very interesting due to their extraordinary properties; their excellent wear resistance, very low friction coefficient, great hardness, high elastic modulus or biocompatibility can be highlighted, as can their multifunctionality. Because of this, over recent decades they have been widely used in tribological applications, improving the performance and the useful life of machining tools in an effective way. However, these coatings have a disadvantage compared to other coatings deposited by commercially available techniques—their resultant adhesion is worse than that of other techniques and limits their industrial applications. In this work, tribological results of a scratch test, wear resistance and nanoindentation of tetrahedral amorphous carbon (ta-C) and tungsten carbide:carbon (WC:C) DLC coatings deposited by means of novel high-power impulse magnetron sputtering (HiPIMS) technology with positive pulses are reported. The coatings were deposited in three different tools steels: K360, vanadis 4 and vancron. These tools’ steels are very interesting because of their great and wide industrial applicability. Experimental results showed excellent tribological properties, such as resistance to wear or adhesion, in the two types of DLC coatings.

EFFECT OF DEPOSITION PARAMETERS ON MICROSTRUCTURE AND TRIBOLOGICAL PROPERTIES OF HARD CA-PVD MULTICOMPONENT TiAlCrN AND TiAlCrCN COATINGS

Multicomponent TiAlCrN and TiAlCrCN coatings were deposited using vacuum arc evaporation technique on AISI 430 stainless steel. The influence of working gas pressure, C/N ratio, bias voltage on the structure and tribomechanical properties of the obtained coatings has been studied. The surface morphology, chemical compound of the coatings obtained under the various conditions has been analyzed by SEM with EDX, XRD, and XRF analysis. The dry wear pad-on-disc tests against 100Cr6 counterbody at 20 N load have been carried out. It was established that Vickers micro-hardness was varied from 26 to 41 GPa depending on deposition parameters.