Si3N4 Ball Research Articles

Investigation on Tribological Behavior of Ti2AlN/TiAl Composite at Room and Elevated Temperature

In current investigation, tribological properties of TiAl matrix composite reinforced with 15 vol%Ti2AlN and TiAl alloy prepared through in situ reactive method of powder metallurgy were evaluated against Si3N4 balls at room and elevated temperature. The wear mechanism along with the variation of temperature was also systematically analyzed. The results reveal that Ti2AlN/TiAl presents lower friction coefficients and wear rates in comparison with TiAl alloy at all test conditions. Along with the increment of temperature, the primary wear mechanisms of two materials both transform from abrasion wear to adhesion wear. Particularly, more efficient formation of tribo-oxidation films with protective feature on the worn surface of Ti2AlN/TiAl plays a dominant role in the improvement in wear resistance at elevated temperature. Additionally, the excellent tribological properties of the composite attribute to the other advantages of additive Ti2AlN phase, such as the load-carrying role, inhibition on the slipping of wear debris, as well as the refined microstructure of TiAl matrix phase.

Effect of different lubricants on microstructural and tribological properties of TC21 titanium alloy against Si3N4 under fretting–reciprocating sliding

The tribological properties of a Si3N4 ball sliding against a TC21 disc lubricated by pentaerythritol ester (5750), bis (2-ethylhexyl) sebacate (1088), 1-butyl-3-methylimidazolium tetrafluoroborate (L-B104) and an as-synthesized ionic liquid L-C8F17SO3P4444(L-4P) have been studied by an Optimol SRV-V oscillating reciprocating friction and wear with load, temperature and frequency. Scanning electron microscopy and X-ray photoelectron spectroscopy results showed that L-4P has an excellent extreme pressure wear resistant effect (750N) and the lowest friction coefficient (<0.08), in addition to possess excellent tribological behavior due to the formation of chemical reaction (SnF2 and a friction oxidation product lubrication film) and deposition films on the rubbing surface. The wear mechanisms were mainly adhesive wear, abrasive wear and microcosmic fatigue wear, with less cracks on the worn surface. Under the 5750, 1088 and L-B104 lubrications conditions, the friction coefficients were markedly increased with the load increasing and the values were larger, friction surface was a clear plowing effect. The wear mechanisms were mainly surface plowing and abrasive wear. In this investigation, the results demonstrated that L-4P could react with the TC21 titanium alloy to produce lubrication film to improve the tribological properties.

Microstructural characterization and tribological behavior of surface plasma Zr-Er alloying on TC11 alloy

The Zr coating and Zr-Er coating are grown on TC11 substrate by double-glow plasma surface metallurgy technique, followed by the wear tests at ambient temperature and 500 °C. The data of nanohardness and elastic modulus of the samples are collected by the nano-indentation test. The adhesion strength of coatings is investigated by means of the scratch test. The study of wear resistance is performed using a ball-on-disc wear test system by running against the Si3N4 ball and measured by scanning electron microscope (SEM) and X-ray diffraction (XRD). Experimental results indicate that the nanohardness of the Zr coating and Zr-Er coating are 5.94 GPa and 7.98 GPa, respectively, which are 1.79 times and 2.41 times greater than that of TC11 substrate. Zr coating and Zr-Er coating realize the metallurgical bonding with TC11 substrate with continuous and compact structure. Compared with the Zr coating and TC11, the Zr-Er coating presents the lowest specific wear rates, which are 1.689 × 10−6 mm3 Nm−1 and 1.851 × 10−6 mm3 Nm−1 at ambient temperature and 500 °C respectively, indicating the excellent and improved wear resistance of TC11.

A comparative study of tribological characteristics of hydrogenated DLC film sliding against ceramic mating materials for helium applications

The tribological behaviors of hydrogenated DLC film sliding against Al2O3, ZrO2, Si3N4 and WC mating balls have been comparatively investigated by a ball-on-disk tribometer at 150 °C under helium and air (RH = 6%) conditions. The results showed that the mating material influenced the friction and wear behavior remarkably in helium atmosphere, where the wear rates were in inversely proportional to the friction coefficients (COF) of those tribo-pairs. Compared to the tests in helium, the tribological performance of DLC film significantly improved in air. Scanning electron microscope (SEM) and Raman spectroscopy were performed to study the friction behavior and wear mechanism of the film under different conditions. It suggested that the severe abrasion was caused by the strong interaction between the tribo-pairs in helium atmosphere at 150 °C, whereas the sufficient passivation of the dangling bonds of carbon atoms at sliding interface by chemically active molecules, such as water and oxygen, dominated the ultralow friction under air condition. Meanwhile, Hertz analysis was used to further elucidate the frictional mechanism of DLC film under helium and air conditions. It showed that the coefficient of friction was consistent with the varied tendency of the contact radius, namely, higher friction coefficient corresponded to the larger contact radius, which was the same with the relationship between the wear rate and the contact pressure. All of the results made better understanding of the essential mechanism of hydrogenated DLC film sliding against different pairs, which were able to guide the further application of DLC film in the industrial fields of helium atmosphere.

The Sliding Wear and Friction Behavior of M50-Graphene Self-Lubricating Composites Prepared by Laser Additive Manufacturing at Elevated Temperature

M50 steel is widely applied to manufacture aircraft bearings where service lives are mainly determined by the friction and wear behaviors. The main purpose of this study is to investigate the tribological behaviors and wear mechanisms of M50-1.5 wt.% graphene composites (MGC) prepared by laser additive manufacturing (LAM) (MGC-LAM) sliding against Si3N4 ball from 25 to 550 °C at 18 N–0.2 m/s. XRD, EPMA, FESEM, and EDS mapping were conducted to understand the major mechanisms leading to the improvement in the sliding behavior of MGC-LAM. The results indicated that MGC-LAM showed the excellent friction and wear performance at 25-550 °C for the lower friction coefficient of 0.16-0.52 and less wear rate of 6.1-9.5 × 10−7 mm3 N−1 m−1. Especially at 350 °C, MGC-LAM obtained the best tribological performance (0.16, 6.1 × 10−7mm3 N−1 m−1). It was attributed to the dense coral-like microstructure, as well as the formed surface lubricating structure which is composed of the upper uniform lubricating film with massive graphene and the underneath compacted layer.

Influence of composition and microstructure on the tribological property of SPS sintered MCrAlY alloys at elevated temperatures

In order to explore the mechanical and tribological properties of high-temperature alloy materials, the present study aims to investigate the synthesis, microstructure, composition, mechanical and tribological properties of high-temperature monolithic MCrAlY (M = Ni or NiCo) alloys. The alloys were prepared by spark plasma sintering technique. The microstructure and composition were studied by Scanning Electron Microscopy and X-ray diffractometry. The tribological properties of Ni-based alloys were tested by friction tester against Si3N4 balls at elevated temperatures. The results showed that the NiCrAlY alloy was composed of γ-Ni(Cr) solid solution, β-NiAl, and γ′-Ni3Al with little CrAl. The NiCoCrAlY alloy was consisted of γ-Ni(Cr/Co) solid solution, β-NiAl and γ′-Ni3Al. The hardness of NiCrAlY alloy was higher than that of NiCoCrAlY alloy. However, its flexural strength was lower than the NiCoCrAlY alloy. The more uniform microstructure of NiCoCrAlY alloy along with the evenly dispersed fine reinforced phases and the less pores defects contributed to the higher flexural strength. The μs and WRs of NiCrAlY and NiCoCrAlY alloys increased firstly to reach the highest value at 200 and 400 °C, and then declined with the temperature increasing to 800 °C. The WRs of NiCrAlY were lower than that of NiCoCrAlY for all the temperatures. Adhesive wear dominated the wear mechanism of NiCrAlY/Si3N4 tribo-pair, while abrasive wear was the main wear mechanism for NiCoCrAlY/Si3N4 tribo-pair. At high temperature, oxidation of worn surfaces to a certain extent decreased the wear for both the tribo-pairs. The higher hardness of NiCrAlY may contributed to the lower wear than NiCoCrAlY.

Tribological Performance of Ni3Al Matrix Self-Lubricating Composites Containing Multilayer Graphene Prepared by Additive Manufacturing

In order to improve tribological performance of Ni3Al-based alloy, Ni3Al matrix composites containing 1.5 wt.% multilayer graphene (MLG) are prepared through additive manufacturing (AM) and spark plasma sintering (SPS), which are denoted as NMAM and NMSPS, respectively. Tribological behaviors of NMAM and NMSPS against Si3N4 balls are researched under constant speed (0.2 m/s) and varied loads (from 4 to 16 N) for evaluating the tribological properties of NMAM and NMSPS. The results present that NMAM exhibits the excellent tribological properties [low friction coefficients (0.26-0.40) and considerable wear resistance (2.8-4.6 × 10−5 mm3 N−1 m−1)] as compared to NMSPS, which attributes to the uniform enrichment of MLG with properties of high tensile strength and being easily sheared off on the worn surfaces. Owing to the use of spherical prealloyed powder containing multilayer graphene and the characteristics of layer by layer depositing in the AM process, NMAM has a more compact and uniform substrate, which persistently provides a source of the formation of continuous and stable frictional layer. Due to the characteristics of AM rapid solidification, NMAM has the small grain size and well-compacted microstructure, which can effectively reduce the probability of spalling wear and lead to the increase in wear resistance of materials. The research can offer the reference for self-lubricating materials prepared by AM technology.

Tribological properties of self-lubricating Ta-Cu films

In this paper, Ta and TaCu films were deposited by using magnetron sputtering, and the tribological properties of the films against Si3N4 balls were investigated under the loads of 2 N and 5 N. The average grain sizes of both films are below 25 nm. Ta and TaCu films have approximate hardness. While the wear rate of TaCu film is much smaller than that of Ta film. Post-wear testing XRD, Raman and XPS revealed the formation of tantalum oxide on the worn surface of both Ta and TaCu films. Tantalum oxidation is effectively lubricating to reduce friction coefficient. So the friction coefficient of both Ta and TaCu film is about 0.45 under different applied loads. Meanwhile, the addition of Cu could increase the toughness of the film, and avoid the generation of wear debris, resulting in a significant increase in wear resistance.

Evaluation of Wear Rate of Nanocrystalline Diamond Films Using Abbott Curve

The nanocrystalline diamond films were deposited by microwave plasma enhanced chemical vapour deposition (PE-CVD) on Si (100) substrate. Reciprocating sliding tests were conducted using Si3N4 balls as a counter body. A method based on the construction of the Abbott curve representing the areas of pristine and worn surface in the wear scars was applied for estimation of the wear rate. The calculated wear rates were compared with the results obtained by profilometric measurements and direct measurement of the wear scars cross sections by scanning electron microscopy (SEM).

Anti-Irradiation and Wear Resistance of Polyimide Composites

Space exploitation and development need high-performance polymer based tribo-materials in order to reduce the weight and improve the reliability of mechanical moving components. However, the wear resistance of polymer composites will decrease after space irradiation. In order to improve the anti-irradiation and wear resistance, the high performance polyimide (PI) composites reinforced with aramid fibers (AF), filled with polytetrafluoroethylene (PTFE) and Al2O3were designed and prepared using hot press sintering. The effect of the individual atomic oxygen or proton irradiation as well as both on the tribological properties of the PI composites were systematically investigated against Si3N4 ball on a ball-on-disk test rig under simulating space environment system, and coefficient of friction and wear rate were considered as responses. The worn surfaces of the composites were observed by scanning electrical microscopy to reveal wear mechanisms of the materials’ damage. Experimental results indicated that the wear rate of the PTFE/AF/PI greatly increased after atomic oxygen and proton irradiation due to oxidation degradation effect on the polymer matrix. However, filling Al2O3 nano-particles into polyimide matrix can improve the wear resistance because of oxidation layer, gradually formulated during the process of atomic oxygen irradiation, which can protect the polymer composites and avoid further oxidation. This study will expect to provide the helpful guidance for designing high performance polymer based frictional materials in the application of space science.

Wear resistance and solid lubricity of molybdenum-containing nitride coatings deposited by cathodic arc evaporation

Molybdenum-containing MoTiN, MoAlTiN, MoCrN and MoZrN coatings were deposited on the 17-4 PH stainless steel substrate by the cathodic arc evaporation technique. Pin-on-disc dry sliding tests were performed to investigate their wear resistance and the solid lubricity of the coatings. All of these coatings, with MoTiN and MoAlTiN in particular, demonstrated superior wear resistance and a significantly lower coefficient of friction against WC-6Co ball material when compared to their corresponding Mo-free TiN, AlTiN, CrN and ZrN monolithic coatings. For example, the specific wear rate of the MoAlTiN coating is only 0.14% of the wear rate of the AlTiN coating, and its coefficient of friction is only 0.28 compared to 0.60 of AlTiN. The excellent tribological performance of the Mo-containing coatings is attributed to the formation of a MoO3 surface layer on the wear tracks through the tribo-oxidation process. Further wear tests of the MoTiN and MoAlTiN coatings against Al2O3 ball material revealed less improvement in wear resistance and reduction of the coefficient of friction. When tested against Si3N4 ball material, both coatings, though still showing noticeably better wear resistance than their corresponding Mo-free coatings, did not demonstrate any beneficial effect of Mo on lowing the coefficient of friction. The scanning electron microscopy and energy dispersive X-ray spectroscopy analyses of the wear track surfaces illustrated the importance of retaining a stable and sufficiently thick MoO3 surface layer in order to maintain the beneficial effect of Mo on the tribological performance of the coatings.

A comparative study on the wear behavior of a polymer infiltrated ceramic network (PICN) material and tooth enamel

ObjectiveTo investigate the wear mechanisms of a polymer infiltrated ceramic network (PICN) material, to compare its wear behavior with that of tooth enamel, and to provide evidence relevant to its clinical use. MethodsThe Vickers hardness (HV) and elastic modulus (E) of a commercial PICN material (ENAMIC) and enamel were measured. Reciprocating wear tests were performed under a ball-on-flat configuration. Three wear pairs were explored including ENAMIC and enamel subjected to Si3N4 ball antagonists and ENAMIC subjected to enamel cusp antagonists. The coefficients of Friction (CoFs) were monitored continuously to 5×104 cycles. The wear depth of ENAMIC, enamel specimens and enamel cusps were quantified using white light interferometry, and the wear morphologies were examined using scanning electron microscopy (SEM) to distinguish the wear mechanisms. ResultsThe HV of ENAMIC is similar to tooth enamel but the E is much lower. For both materials, the CoFs increased sharply in the early stage and then reached plateaus in the later phase. Throughout the cyclic loading history, ENAMIC exhibited larger wear depths than enamel. However, the damage evolution in ENAMIC was similar to that of enamel as the polymer phase was worn preferentially similar to inter-rod enamel, and then the ceramic phase exfoliated from the wear surface akin to enamel rods. The SEM images showed evidence of few cracks within wear tracks of ENAMIC, in comparison to numerous cracks in tooth enamel. SignificanceENAMIC has lower wear resistance than tooth enamel, but it exhibits a wear damage mode similar to tooth enamel.

Low friction of graphene nanocrystallite embedded carbon nitride coatings prepared with MCECR plasma sputtering

Graphene nanocrystallite embedded carbon nitride (GNECN) coatings were fabricated with the mirror confinement electron cyclotron resonance (MCECR) plasma sputtering system under low energy electron irradiation at various N2/Ar ratios. N2/Ar ratio was clarified to be an effective deposition parameter for tailoring the composition and structure of the GNECN coatings. It was observed that the deposition rate, N/C atomic ratio, internal stress, surface roughness, and scratch depth of the prepared GNECN coatings change greatly with the increasing N2/Ar ratio from 1/11 to 1/3. Graphene nanocrystallite was clearly identified in the amorphous carbon nitride structure from the analyses of TEM, XPS, and Raman spectroscopy. Moreover, the friction behavior of the GNECN coatings sliding against Si3N4 balls in both ambient air and N2 gas stream showed less dependency on the N2/Ar ratio. Specifically, high friction coefficients ranging from 0.10 to 0.15 were obtained in ambient air, whereas, stable and low friction coefficients of <0.05 were achieved in N2 gas stream. Optical images and Raman spectra of the worn surfaces on the Si3N4 balls and GNECN coatings suggested that a homogeneous tribofilm on the mating ball surface together with the generation and evolution of the nano-size graphene structure in the GNECN coating are the key points in achieving stable and low friction coefficients of <0.05 of the GNECN coatings in N2 gas stream. Finally, it was argued that the combination of low energy electron irradiation and nitrogen atom incorporation in the MCECR plasma sputtering system results in the embedding of soft graphene nanocrystallites into hard carbon nitride matrix, providing a beneficial architecture for achieving stable and low friction coefficients of GNECN coatings in N2 gas stream.

Effect of Waveform and Heat Treatment Processes on the Performance of Electrodeposited Co-P Coating

Cobalt-phosphorus (Co-P) alloy is a promising material for the replacement of traditional hard chromium alloy of high hardness. In this paper, the cobalt-phosphorus alloy layer with high phosphorus content was formed by electrodeposition in a cobalt sulfate solution system under direct current (DC), single pulse (SP) current and double pulse (DP) current, separately. Surface morphology, structure and properties of the deposited layer were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), Vickers microhardness and a neutral salt spray test, respectively. The results showed that the dense Co-P coatings could be obtained by DC, SP and DP with P content of 9.6, 8.9 and 9.1 wt %, respectively. After 30 min heat treatment at 400 °C, coatings deposited under DC, SP and DP currents transformed from an amorphous to a nanocrystalline state, while the grain size was 12–13 nm, 10–12 nm and 8–10 nm, respectively. Among all these conditions, the microhardness of coatings deposited under DP current was the highest, which was 1211 HV, while the microhardness of coatings deposited under DC current was the lowest but higher than that of hard chromium. The wear rate of Co-P coatings was 4 × 10−6–5 × 10−6 mm3/N m with Si3N4 ball as bearing material, which was lower than that of hard chromium. In coatings deposited under different currents with a thickness of ca. 40 μm, no visible corrosion area appeared after 1000 h of a neutral salt spray test. Coatings heated at 300 and 400 °C reached the corrosion grade 7 and grade 4–5, respectively after 1000 h of a neutral salt spray test, so the wear resistance of Co-P coatings was better than that of hard chromium.

Tribological Performance of Ni3Al Matrix Self-Lubricating Composites Containing Multilayer Graphene and Ti3SiC2 at Elevated Temperatures

The application of Ni3Al-based alloy (NA) in the field of aerospace was limited by its poor tribological properties. For improving the tribological performance of NA, multilayer graphene (MLG) and Ti3SiC2 were added in Ni3Al matrix composites. Tribological behavior of Ni3Al matrix composites containing 1.5 wt.% MLG and 10 wt.% Ti3SiC2 (NMT) against Si3N4 ball at 12 N-0.2 m/s from 25 to 750 °C was investigated. The results showed that NMT exhibited the excellent tribological behavior [lower friction coefficients (0.26-0.57) and less wear resistance (3.1-6.5 × 10−6 mm3 N−1 m−1)] due to synergetic effect of MLG and Ti3SiC2 over a wide temperature range from 25 to 750 °C. At 25-350 °C, part of MLG enriched on worn surface could play a role in reducing friction and improving wear resistance. At 350-550 °C, although MLG gradually lost the lubricating properties, the partial decomposition of Ti3SiC2 could continually improve the tribological properties of NMT. At 550-750 °C, Ti3SiC2 on worn surface was oxidized to form lubricating film, while Ti3SiC2 in the subsurface played an important role in supporting the film, resulting in the excellent high-temperature tribological performance. The research had good guiding significance for the preparation of wide temperature range self-lubricating material and the study of synergetic effect of complex solid lubricants.

Tribological performances of CrAlN coating coupled with different ceramics in seawater

This paper attempts to present a comparative study of tribological performances of chromium aluminum nitride (CrAlN) coating coupled with Si3N4, SiC, WC, Al2O3 and ZrO2 balls in air and seawater. The comparison results show that the tribological performance of different tribopairs is determined by the property of ceramics. Seawater plays an important role in reducing the coefficient of friction (COF) by forming tribochemical films and developing a hydrodynamic lubrication regime. The wear rates of CrAlN/SiC in air and seawater are much lower than that of the combination of CAIN and other tribopairs because of the integrated effect of tribochemical film and micro-dimples on SiC ball. It is therefore apparent that CrAlN/SiC has the smallest COF and lowest wear rate in both air and seawater.

Influence of Coating Deposition Parameters on the Mechanical and Tribological Properties of TiCN Coatings

This paper is a continuation of our previous work. The article presents an investigation of the influence of coating deposition parameters, in particular a variation with 50% of both cathodic arc current and bias voltage, on the mechanical and tribological properties of TiCN coatings deposited by the cathodic arc evaporation of metals at a constant gas ratio. The thicknesses of the coatings are measured by the Calotest method using a 30-mm hard steel ball. The determined values are in the range of 734 – 1534 nm. Surface morphology and chemical composition are estimated by a Scanning Electron Microscope (SEM) and an Energy Dispersive Spectrometer (EDS) of SEM. The determined values of nanohardness are in the range of 10 - 23 GPa and adhesion values are in the range of 28 - 70 N. Tribology of the TiCN coatings is investigated with three different load forces (3N, 5N and 8N) by the CETR UMI Multi-Specimen Test System from Bruker with an Si3N4 ball counter-body. The friction coefficient is measured in the range of 0.19 - 0.23. Coating wear and wear of the counter-body are calculated, according to the standard EN1071-13:2010, wherein the values of the latter are in the range of (2.5 - 30) x 10-6 mm3.

Dry Sliding Wear of TiAl-Graphene-Silver Composite at Elevated Temperatures

The dry sliding friction and wear behaviors of TiAl matrix self-lubricating composite (TMSC) containing multilayer graphene (MLG), silver (Ag) and MLG-Ag sliding against Si3N4 balls from 25 to 750 °C were comparatively studied in this paper. The results suggested that TMSC containing MLG-Ag (TMA) showed better tribological properties over the wide temperature range, if compared to TMSC only containing MLG or Ag. Moreover, TMA exhibited the lower fiction coefficient and the less wear rate at 450 °C, which was attributed to the formation of intact lubricating films containing MLG and Ag on the worn surface. Furthermore, in the formed lubricating films, Ag worked as the solid lubricant to provide good lubricating effect, while MLG with high strength played the active role in enhancing the anti-rupture ability of lubricating films. The study indicated that TMA obtained the excellent tribological performance at 450 °C due to the remarkable synergistic effect of MLG and Ag.

A study of the friction layer of TiAl-10 wt.% Ag composite and the prediction model of friction and wear behaviors

It was significant to study the longevity of mechanical component by analyzing the effect of friction layer on the predicting models of wear rates and friction coefficients. In this study, based on the changes in applied load F and testing temperature T, the friction and wear behaviors of TiAl-10 wt.% Ag were carried out sliding against Si3N4 ball (6 mm in diameter). At 0–80 min, the prediction models of friction coefficients and wear rates were constructed by the method of bivariate rational interpolation. The predicting accuracies of Pcomp-f: 94–98.7% (friction coefficient) and Pcomp-w: 87.7–98.5% (wear rate) indicated that the constructed prediction model was able to evaluate the friction coefficients and wear rates of TiAl-10 wt.% Ag. The high predicting accuracies were mainly attributed to the excellent plastic fluidity of silver, the smooth morphology of wear scar, and the friction layer of low grain strain.

Boundary Tribological Behaviors of Untreated and Surface-Modified M50 Steel Lubricated by Fuel JP-10

ABSTRACTTo explore the possibility of using advanced surface engineering techniques (ASETs) to solve the wear problems caused by the poor lubricity of pure, low-viscosity aviation fuel JP-10, polished M50 bearing steel sample surfaces were treated with nitrogen ion implantation, TiAlN coating deposition, and Ta coating deposition followed by high current pulsed electron beam (HCPEB) irradiation, respectively. Boundary tribological behaviors of these ASET-treated and untreated steel samples sliding in pure JP-10 against a Si3N4 ball (ball-on-disc model) were investigated under 2.0 GPa in the atmosphere and the friction tests indicated that significant, reductions, although to different extents, in friction and wear were achieved by these modified surfaces. Simultaneously considering the tribological performance and potential pollution caused by wear debris to JP-10, HCPEB-treated Ta coating with a lowest average friction coefficient of 0.11 and a specific wear rate of around zero was the fittest to offset the inadequate lubricity of JP-10 itself under the laboratory condition.