ZrO2 Ceramic Ball Research Articles

Insight into the tribological performances of coconut shells as a potential natural water lubrication material

To better understand the tribological performance of coconut shell and to demonstrate its potential as a wear-resistant material for use in a water-lubricated environment, the microstructure of coconut shell was hereby characterized, and its hardness and water absorption properties were correspondingly measured. The tribological characteristics of coconut shells rubbing against a ZrO2 ceramic ball in dry and wet environments were studied, and the wear mechanism was revealed. The measurement characterization and experimental results indicate that the long axis of coconut shell ellipsoid cells grows along the direction of the long axis pointing towards the coconut shell ellipsoid, but this directionality has a relatively small impact on the tribological properties. The average sliding friction coefficient of coconut shell rubbing against ZrO2 ceramic balls is about 0.52 and 0.095, respectively under dry and wet friction conditions. Under dry friction conditions, the wear of coconut shells is mainly because of cell tearing, detachment and abrasive wear caused by alternating friction forces. Mainly considering the combined effects of the high hardness, high strength and good water absorption of coconut shells, as well as the water film at the friction interface, the friction force significantly reduces and makes it difficult to damage the cell structure, leading to a wear rate decrease by more than 100 times under wet friction conditions, much lower than that of lignum vitae. Overall, this study indicates the potential of coconut shell as a water lubricated friction pair material featuring excellent performance.

Preparation and acoustic properties of high-temperature acoustic emission sensor based on La3Ga5SiO14 crystal

With the rapid development of modern industries, the high-temperature piezoelectric sensors that can work in extreme environments are in great demand. In this work, langasite (La3Ga5SiO[Formula: see text], LGS), as a high-temperature piezoelectric crystal with stable electro-elastic performance, is used as core element, and air and porous Al2O3 are selected as backing layers respectively to prepare two kinds of high-temperature acoustic emission (AE) sensors. The detection sensitivities at 25-500[Formula: see text]C are analyzed by the ball falling test and Hsu–Nielsen experiment. Under the condition of 25–500[Formula: see text]C, the received amplitude signals by both sensors are maintained above 90 dB stimulated by the ZrO2 ceramic ball dropping. In the Hsu–Nielsen experiment, as the temperature rising from 25[Formula: see text]C to 500[Formula: see text]C, the signal amplitude of sensor with air backing layer decays from 447 mV to 365 mV, while the signal amplitude varies from 270 mV to 203 mV for the sensor with porous Al2O3 backing layer. Significantly, compared with the bandwidth of the air-backing sensor (37–183 kHz), the sensor with porous Al2O3 backing layer broadens bandwidth to 28–273 kHz. These results show that both these AE sensors have strong and stable response ability to AE signals at high-temperature of 500[Formula: see text]C. Therefore, piezoelectric AE sensor based on LGS has great potential application in the field of high-temperature structural health monitoring.

INFLUENCE OF FEMTOSECOND-LASER-INDUCED PERIODIC SURFACE STRUCTURES ON THE TRIBOLOGICAL PERFORMANCE OF CVD NANO-CRYSTALLINE DIAMOND FILMS

Laser-induced periodic surface structures (LIPSS, ripples) are generated on CVD nano-crystalline diamond (NCD) films by femtosecond laser irradiation in air (pulse duration 200 fs and central wavelength 1040 nm). The experimental conditions (laser fluence and spatial spot overlap) are optimized to obtain a 3 × 3 mm2 area covered with homogenous LIPSS. Then, the influence of LIPSS on the frictional performance of NCD films is investigated by dry reciprocating ball-on-disc tests, where ZrO2 ceramic balls are used as counterparts. The results show that the friction behavior is very sensitive to the orientation of nano-structured ripples in LIPSS. The frictional coefficient can be greatly reduced when the sliding direction is parallel to the orientation of the nano-structured ripples, indicating potential benefit of LIPSS on NCD films for frictional applications.

Study on the Penetration Performance of a 5.8 mm Ceramic Composite Projectile.

The penetration ability of a 5.8 mm standard projectile can be improved by inserting a ZrO2 ceramic ball with high hardness, high temperature, and pressure resistance at its head. Thereby, a ceramic composite projectile can be formed. A depth of penetration (DOP) experiment and numerical simulation were conducted under the same condition to study the armor-piercing effectiveness of a standard projectile and ceramic composite projectile on 10 mm Rolled Homogeneous Armor (RHA) and ceramic/Kevlar composite armor, respectively. The results show that both the ceramic composite and standard projectiles penetrated the armor steel target at the same velocity (850 m/s). The perforated areas of the former (φ5 mm & φ2 mm) were 2.32 and 2.16 times larger, respectively, than those of the latter. The residual core masses of these two projectiles (φ5 mm & φ2 mm) were enhanced by 30.45% and 22.23%. Both projectiles penetrated the ceramic/Kevlar composite armor at the same velocity (750 m/s). Compared with the standard projectile, the residual core masses of the ceramic composite one (Ø5 mm & Ø2 mm) were enhanced by 12.4% and 3.6%, respectively. This paper also analyzes the penetration mechanism of the ceramic composite projectile on target plates by calculating its impact pressure. The results show that the ceramic composite projectile outperformed the standard projectile in penetration tests. The research results are instructive in promoting the application of the ZrO2 ceramic composite in an armor-piercing projectile design.

Tribological Study of Borocarburizing/Sulfurizing Composite Coatings on 2Cr13 Stainless Steel

The aim of this work was to investigate the mechanical properties and wear characteristics of 2Cr13 stainless steel coated with borocarburized and sulfurized layers using pack cementation. The microstructure and phase composition of the composite coatings were analyzed using scanning electron microscopy, energy-dispersive x-ray spectroscopy, and x-ray diffraction. The tribological properties under dry sliding against a ZrO2 ceramic ball were evaluated using a ball-on-disk friction tester at different loads, and the wear mechanism was proposed. The sulfurized layer mainly consisted of FeS and Fe2S, with the FeS phase acting as a solid lubricant for the coating. The borocarburized layer was mainly composed of FeB, Fe3C, and Fe2B, with a maximum hardness of approximately 1200 HV. The borocarburizing/sulfurizing treatment significantly decreased the friction coefficient and improved the wear resistance of the 2Cr13 steel. In addition, the composite coating exhibited excellent antifriction and wear resistance under slight adhesive and oxidation wear in high-load conditions.

Dry Sliding Friction of Tool Steels and Their Comparison of Wear in Contact with ZrO2 and X46Cr13.

Tool steels are used in stamping, shearing processes, and as cutting tools due to their good mechanical properties. During their working cycle, steels are subject to aggressive conditions such as heat stress, fatigue, and wear. In this paper, three tool steels, namely X153CrMoV12, X37CrMoV5-1, and X45NiCrMo4 were selected against two types of bearing balls, ZrO2 and X46Cr1. All measurements were performed on a UMT TriboLab universal tribometric instrument under dry conditions. The main objective of the experiment was to analyze and compare tool steel wear in contact with two kinds of bearing balls with a diameter of 4.76 mm. This evaluation is focused on the hardness, surface roughness, and microstructure of all samples and on the impact of the input parameters on the resulting wear. All three types of tool steels were measured in the basic annealed state and, subsequently, in the state after hardening and tempering. Experimental results show that tool steels, belonging to high strength steels, can successfully represent wear resistant steels. The content of carbide elements, their size, and shape in the microstructure play an important role in the friction process and subsequent wear. Three types of loads were used and compared in the experiments 30, 60, and 90 N. Increasing the load results in significant degradation of the material on the sample surface. Lastly, the impact of hardness and roughness of materials on wear has also been proven. If abrasive wear occurs in the friction process, there is a greater degree of wear than that of adhesive wear. This is due to less abrasive particles, which behave like a cutting wedge and are subject to subsequent deformation strengthening due to the load increase, which adversely affects the further friction process. Analysis of the results showed that the ZrO2 ceramic ball showed significantly better wear values when compared to the X46Cr13 stainless steel ball. It also improves the values of the coefficient of friction with respect to the type of wear that occurs when the experimental materials and counterparts are in contact.

Influence of temperature on tribological properties of microarc oxidation coating on 7075 aluminium alloy at 25 °C –300 °C

Abstract The high-temperature tribological properties of bare 7075 Al – Zn – Mg – Cu alloy substrate and microarc oxidation (MAO) coating against ZrO2 ceramic ball were evaluated at 25 °C −300 °C. Coefficients of friction were recorded, and wear rates were determined. Surface morphology and wear scars on the ZrO2 ball were observed. Furthermore, wear mechanisms at three different temperatures were discussed. It was found that the MAO coating could maintain a low wear rate and a stable wear performance in an elevated temperature environment. At 300 °C, the wear rate of MAO coating was merely 1/11 of 7075 aluminium alloy substrate. MAO coating suffered mainly adhesive wear at ambient temperature, and both adhesive wear and abrasive wear at elevated temperatures.

The effect of ceramic tribo-elements on friction and wear of smooth steel surfaces

The pin-on-disc dry sliding friction and wear experiments have been made on 42CrMo4 steel in contact with Si3N4, SiC, WC, Al2O3, and ZrO2 ceramic balls. The tests were carried out at sliding speeds of 0.16 m/s, 0.24 m/s, and 0.32 m/s. During the tests, the friction force was monitored as a function of time. Discs and balls wear was measured after the tests using a white light interferometer Talysurf CCI Lite and Altisurf 520 optical profilometer with a CL1 confocal probe. To decrease variations in the experimental results, during the tests, wear debris was continuously removed from the disc surfaces. It was found out that with Al2O3 counterpart the wear volume of the steel discs was the largest. However, the largest wear volume of the balls was observed for Si3N4 ceramic balls.

High temperature tribological behavior of microarc oxidation film on Ti-39Nb-6Zr alloy

The TiO2-Nb2O5-ZrO2 composite film on Ti-39Nb-6Zr alloy was in-situ synthesized by microarc oxidation (MAO) process in potassium hydroxide electrolyte. Morphology, composition and hardness of MAO film were characterized. The tribological behavior of bare and coated Ti-39Nb-6Zr alloy under dry sliding against ZrO2 ceramic ball were studied by a ball-on-disk friction tester at the ambient temperature, 200 °C and 400 °C. Their friction coefficient and wear rate were obtained and wear mechanism analyzed. The MAO surface treatment significantly decreased friction coefficient and wear rate of Ti-39Nb-6Zr alloy at the ambient temperature and 200 °C, but the friction coefficient showed a periodical fluctuation at 400 °C while the wear rate clearly decreased. The MAO film has excellent wear resistance at different temperatures due to the formation of TiO2, Nb2O5, and ZrO2 ceramic phases. The wear mechanism of Ti-39Nb-6Zr alloy was mainly the abrasive wear at ambient temperature, but was transformed to abrasive, adhesive and oxidation wear at high temperature. The MAO treated alloy mainly displayed the adhesive wear at ambient temperature, 200 °C and 400 °C. Furthermore, the polished treatment for MAO film could obviously reduce its low friction coefficient and wear rate at the ambient temperature and 200 °C.

Preparation and tribological behaviors of DLC/spinel composite film on 304 stainless steel formed by cathodic plasma electrolytic oxidation

In this paper, the diamond-like carbon (DLC)/spinel composite film on 304 stainless steel was fabricated by cathodic plasma electrolytic oxidation (CPEO) in glycerin solution, and its microstructure, composition and phase constituents were characterized. The friction performance of the film under dry sliding against ZrO2 ceramic ball at ambient and high temperature up to 500 °C was evaluated. The thickness of the two-layer structure composite film reaches 18 μm under 260 V for 5 min discharge. The DLC/spinel composite film could significantly reduce the friction coefficient and improve the wear resistance of the 304 stainless steel especially at ambient temperature. The friction coefficients and wear rates of both the 304 stainless steel substrate and the composite film increase with increase of the environment temperature, but the wear process of the composite film was more stable than that of the stainless steel substrate even at high temperature. The wear mechanism of the composite film is adhesive wear at ambient temperature, but the slight plastic deformation along with adhesive could be found at high temperature.

The effect of temperature and sliding speed on friction and wear of Si3N4, Al2O3, and ZrO2 balls tested against AlCrN PVD coating

Abstract Advanced modern materials are required to operate at challenging conditions including mutual interactions under pressure and at elevated temperatures. In the present work, unidirectional sliding tests were performed to evaluate the wear behaviour of tribo-couple of AlCrN PVD coating deposited onto a stainless steel substrate and Si3N4, Al2O3, and ZrO2 ceramic balls counterbodies at different speeds ranged from as low as 0.002 up to as high as 1.458 m s−1 and temperatures from 20 up to 800 °C. The wear scars were studied with the help of 3D optical surface profilometry, scanning electron microscopy, energy-dispersive and Raman spectroscopy. Bulk and flash temperatures conditioned by sliding were analytically calculated. The wear mechanisms responsible for surface degradation are detailed.

Effect of the counterpart material on wear characteristics of silicon carbide ceramics

The pin-on-disc dry sliding friction and wear experiments have been made on SiC ceramics in contact with Si3N4, Al2O3, and ZrO2 ceramic balls and WC-Co ball at 5N load in an ambient environment. Coefficient of friction and specific wear rate were measured, and wear damage mechanisms were identified. The friction coefficient of SiC varied in the range of 0.5–0.65 against Al2O3 ball, between 0.62 and 0.67 against Si3N4, in the range of 0.45–0.54 against ZrO2, and between 0.46–0.59 against WC-Co ball. The SiC materials with fine globular microstructure had lower COF and wear rate than SiC materials with coarser rod-like microstructure. The results showed that with the ZrO2 and WC-Co counterpart the wear rate of SiC decreased while with the Si3N4 ceramic counterpart the wear rate of SiC was about one order of magnitude higher. The main wear mechanism was similar for all studied materials in the form of mechanical wear (micro-fracture) and tribochemical reaction (creation of coherent layers composed mainly of a large amount of oxygen).

Role of Al additions in wear control of nanocrystalline Mo(Si1−xAlx)2 coatings prepared by double cathode glow discharge technique

Four kinds of nanocrystalline Mo(Si1−xAlx)2 coatings with differing Al contents are prepared onto a Ti–6Al–4V substrates by a double cathode glow discharge apparatus. The microstructural features of the deposited coatings were characterised by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. These coatings are composed of the equiaxed C40–MoSi2 grains with the average grain size of ∼5 nm. Nano-indentation measurements indicated that the hardness H, elastic modulus E and the H/E or H3/E2 ratio of the nanocrystalline Mo(Si1−xAlx)2 coatings slightly increase with the increase in Al content. The tribological behaviour of the nanocrystalline Mo(Si1−xAlx)2 coating sliding against a ZrO2 ceramic ball at room temperature has been compared using a ball-on-disc type tribometer under unlubricated conditions. Experimental results showed that the specific wear rates of the nanocrystalline Mo(Si1−xAlx)2 coatings decrease with increasing Al content and are dramatically reduced by more than 1–2 orders of magnitude over the uncoated Ti–6A1–4V. The enhancement of wear resistance of the nanocrystalline Mo(Si1−xAlx)2 coatings by Al additions is correlated with the increased mechanical properties and the forming oxide layer by tribochemical reactions.

High temperature tribological behaviors of plasma electrolytic borocarburized Q235 low-carbon steel

Plasma electrolytic boronizing is a novel technique to fabricate rapidly a hardening layer on steel. In this study, a boride layer on Q235 low-carbon steel was prepared by plasma electrolytic borocarburizing process (PEB/C) in the 30% borax electrolyte with carbon-containing organic additive at 330V. The microstructure and phase constituent of the PEB/C steel were analyzed by SEM and XRD. Microhardness profile of the PEB/C steel was determined, and its tribological properties under dry sliding against ZrO2 ceramic ball were evaluated using a ball-on-disk friction tester at ambient temperature and high-temperature (up to 500°C) environments. Friction coefficient and wear rate before and after PEB/C treatment were measured, and the wear mechanism was also discussed. The results show that the boride layer mainly consists of the Fe2B phase, the hardness of which is close to 1800HV. The PEB/C treatment could significantly decrease the friction coefficient and improve wear resistance of the low-carbon steel. Meanwhile, the friction coefficient and wear rate of the untreated and PEB/C treated steel samples also increase with increasing the environment temperature, but the wear rate of PEB/C treated steel is always much lower than that of the untreated steel at different environment temperatures. Plasma electrolytic borocarburized low-carbon steel can maintain higher wear resistance at high temperature environment, which ascribes to the formation of Fe2B phase with good thermal stability in the hardening layer. The wear mechanism of untreated low-carbon steel is mainly the fatigue wear at ambient temperature and the fatigue wear and adhesive wear at 200°C. The PEB/C treated steel displays the adhesive wear at 200°C. However both the untreated and PEB/C treated samples are transferred to the oxidation wear and adhesive wear at 500°C.

Novel high damage-tolerant, wear resistant MoSi2-based nanocomposite coatings

In this study, novel MoSi2-based nanocomposite coatings were deposited on Ti-6Al-4V substrates by a two-step process involving firstly, deposition of MoSi2-based coatings, using a double cathode glow discharge process and, secondly, plasma nitridation of the as-deposited coatings. The aim of this latter step is to introduce nitrogen into the coating and promote the formation of amorphous silicon nitride. The resulting coatings were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). It was found that the nanocomposite coatings were composed of nanocrystallite Mo5Si3 and MoSi2 grains embedded in an amorphous Si3N4 matrix. The mechanical properties and damage resistance of the coatings were evaluated by both Vickers indentation and nanoindentation techniques. Dry sliding wear tests were performed using a ball-on-disc type tribometer, in which the coated samples were tested against a ZrO2 ceramic ball at normal loads of 2.8 and 4.3N under ambient conditions. Compared with the monolithic MoSi2 nanocrystalline coating, the specific wear rates of the nanocomposite coatings decreased by an order of magnitude. The specific wear rate was further improved by about 20% through the addition of Al, which was attributed to an optimum combination of mechanical properties.

Nanocomposite bilayer film for resisting wear and corrosion damage of a Ti–6Al–4V alloy

A nanocomposite NiSi2/Ti5Si3 bilayer film was engineered onto Ti–6Al–4V alloy by double cathode glow discharge. The outer layer of the resulting film comprised of NiSi2, having dense and fine-grained (35nm in size) columnar structure with a fraction of nanoscale twin bundles, and the inner layer consisted of equiaxed Ti5Si3with a grain size of 50nm. Nanoindentation was carried out on polished cross-sections to measure the elastic modulus and hardness of each layer of the as-deposited film. Scratch tests were undertaken to evaluate the resistance of the as-deposited film to both abrasive and adhesive damage. The dry sliding wear experiments were conducted against ZrO2 ceramic balls under the applied load ranging from 3.3N to 4.8N at room temperature and 500°C using a ball-on-disc tribometer. Compared with the Ti–6Al–4V alloy, the specific wear rates of the alloy coated with the bilayer film decreased by one order of magnitude at room temperature and were further reduced by one order of magnitude at 500°C. The electrochemical behavior of the coated alloy was characterized by potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in 5wt.% HCl solution. The results revealed that nanocomposite NiSi2/Ti5Si3 bilayer film exhibited a higher corrosion resistance than the Ti–6Al–4V alloy.

Study on Wear Behaviour of Ceramics/1Cr18Ni9Ti Wear Components in H<sub>2</sub>O<sub>2</sub> Solution

The wear performances of three types of ceramics (ZrO2, Al2O3, Si3N4)/1Cr18Ni9Ti stainless steel rubbing pairs were analyzed under 0% (pure water), 10%, 30%, 50%, 70% and 90% hydrogen peroxide (H2O2) solution. The results showed that, under different concentrations of H2O2 solution, the worn surface roughness of the 1Cr18Ni9Ti stainless steel was bigger than that under pure water when the counterpart was ZrO2 ceramic ball, while the worn surface roughness of the 1Cr18Ni9Ti stainless steel was smaller than that under pure water when the counterpart was Al2O3 ceramic ball. For the ZrO2, Al2O3, Si3N4 ceramics ball, the average worn surface roughness of Al2O3 ceramic ball was the smallest, and the average worn surface roughness of Si3N4 ceramic ball was the biggest. When the concentration of H2O2 solution was 10%, the metal particles from the ZrO2/1Cr18Ni9Ti and Al2O3/1Cr18Ni9Ti stainless steel rubbing pairs had the features with large size and bright surface. The surfaces of the metal particles were oxidized clearly when the concentrations of H2O2 solution were 70% and 90%.

Defects in ZrO<sub>2</sub>-Reinforced Aluminum Foam Prepared by Infiltration Process

The aluminium foam is reinforced by compositing ZrO2ceramic balls with high hardness. The production process includes preparing precursor using NaCl particles and ZrO2ceramic balls, infiltrating molten aluminium into precursor and cleaning NaCl particles. The defects presented during the process make the structure inhomogeneous and influence the performance of aluminium foam composite. The defects consist of inner and surface shrinkage caused by insufficient infiltration and inhomogeneous distribution of ZrO2ceramic balls in the composite. By analyzing the forming mechanism, offering right control of process and choosing correct parameters, the sound aluminium foam composite was prepared. The optimum value of pouring temperature, preheating temperature of die and particles and the suction was determined as 740°C-760°C, 480°C-500°C and -0.04Mpa, respectively. The composite has the structure with 0.8-1.2mm pore size, 60-70% porosity and ZrO2ceramic balls of 40 percent by volume. The research makes a basis for the application of the new aluminium foam composite.

Study on Bio-Tribological Properties of Nitrogen Ion Implanted UHMWPE

As the aseptic loosening induced by polyethylene wear debris is the main cause of long-term failure of total joint replacements, increasing the wear resistance of ultrahigh molecular weight polyethylene (UHMWPE) will be very important to obtain long-life artificial joint. In this paper the UHMWPE was implanted with 450 keV N+ ions to three doses of 5×1014/cm2, 2.5×1015/cm2 and 1.25×1016/cm2. The friction and wear behaviors of UHMWPE were studied under lubrication of distilled water and blood plasma using a ball-on-disk tribometer with a ZrO2 ceramic ball as a counterface. Experimental results showed that the friction coefficient of ions implanted UHMWPE are higher than un-implanted UHMWPE. Under blood plasma lubrication condition, the wear rate of implanted UHMWPE was lower than un-implanted UHMWPE, and the wear rate decreased with increasing implantation dose. The plow, plastic deformation and fatigue were wearing mechanism for un-implanted UHMWPE and the abrasive wear for implanted UHMWPE.