Removal Of Surface Layer Research Articles

Breakthrough 4π helium ion energy spatial distribution in plasma focus space applying novel mega-size panorama cylindrical ion image detector

Recently Sohrabi theorized and discovered that ions in plasma focus devices (PFD) are emitted in 4π ion space instead of within small solid angle above anode, as commonly believed. Ion energies are commonly determined by others at single points above or around anode top. In this study, He ion energy distributions were in 4π PFD space applying a novel mega-size panorama cylindrical polycarbonate ion image detectors pre-etched by surface layer removal (SLR) process before electrochemical etching. The SLR is pre-etching process which remove certain thickness of detector surface. Results show that track density versus layer thickness removed has saturation plateau corresponding to countable track density which is equal to penetration range of “minimum detected energy” in the detector. Also, thickness in which track density approaches zero is equal to penetration range of “maximum detected energy” in detector. At different cylindrical detector heights studied, corresponding minimum ion energies (7.0 to 328 keV) and maximum ion energies (70 to 640 keV) and for top cylinder base at different angles minimum energies (57 to 535 keV) and maximum energies (135 to 640 keV) were determined. The novel methods applied proved quite efficient for determination of He ion energies in 4π PFD ion space.

Proposal of an alternative method for residual stress measurements in clad nickel alloy after shot peening

Cladding of Ni-based superalloy 625 is often used to enhance mechanical resistance and corrosion performance of the high strength low alloy pipeline, for use in CO2 injection units in oil wells. It is well known that the use of the shot peening can improve its properties by creating a thin surface layer with compressive residual stresses. In this regard, the aim of this work is to propose an alternative method to evaluate the residual stresses of clad Ni-based superalloy 625 based on the deflection measurements of a thin strip separated from the shot peened samples by EDM cutting. The stress distribution in shot peened layer was measured by XRD sin2ψ method with electrolytic removal of surface layers. Measurements by the alternative and XRD method showed that the difference between the average stress values determined by these methods is 4%.

Efficient and Sustainable Cleaning: A Comparative Analysis of Cryogenic Technology

Dry ice blasting is a technology that has been widely studied and applied in different industrial sectors as an alternative to the use of solvent, water, or abrasive spraying methods. It is a CO2 spraying system capable of balancing efficiency and sustainability with a wide variety of equipment available on the market. This study analyses and compares cryo-cleaning equipment manufactured by pioneering companies in the cryogenic industry. Based on data sheets, safety data sheets, and contact with manufacturers, a quantitative comparative study has been carried out. The aim of this study is to identify those with the best performance, efficiency, and adaptability to operational and environmental requirements. The results reflect the strengths and weaknesses of the equipment in terms of occupational safety and operability. These have been discussed and evaluated, recognising improvements of this technology, which is capable of removing surface layers of different natures without altering the underlying substrate.

β-Phase Crystallinity, Printability, and Piezoelectric Characteristics of Polyvinylidene Fluoride (PVDF)/Poly(methyl methacrylate) (PMMA)/Cyclopentyl-Polyhedral Oligomeric Silsesquioxane (Cp-POSS) Melt-Compounded Blends.

Poly(vinylidene fluoride) (PVDF) is a semicrystalline polymer that exhibits unique piezoelectric characteristics along with good chemical resistance and high thermal stability. Layer-based material extrusion (MEX) 3D printing of PVDF is desired to create complex structures with piezoelectric properties; however, the melt processing of PVDF typically directs the formation of the α crystalline allomorph, which does not contribute to the piezoelectric response. In this work, PVDF was compounded with poly(methyl methacrylate) (PMMA) and cyclopentyl-polyhedral oligomeric silsesquioxane (Cp-POSS) nanostructured additives in binary and ternary blends to improve MEX printability while maintaining piezoelectric performance. Overall crystallinity and β phase content were evaluated and quantified using a combination of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and differential scanning calorimetry (DSC). Enhancement of MEX printability was measured by quantifying the interlayer adhesion and warpage of printed parts. All blends studied contained a significant percentage of β allomorph, but it could be detected by ATR-FTIR only after the removal of a thin surface layer. Inclusion of 1% Cp-POSS and up to 10% PMMA in blends with PVDF improved interlayer adhesion (2.3-3.6x) and lowered warpage of MEX printed parts compared to neat PVDF. The blend of 1% Cp-POSS/1% PMMA/PVDF was demonstrated to significantly improve the quality of MEX printed parts while showing similar piezoelectric performance to that of neat PVDF (average piezoelectric coefficient 24 pC/N). MEX printing of PVDF blends directly into usable parts with significant piezoelectric performance while reducing the challenges of printing the semicrystalline polymer opens the potential for application in a number of high value sectors.

АТОМНО-ДИСЛОКАЦИОННАЯ МОДЕЛЬ УДАЛЕНИЯ ПОВЕРХНОСТНЫХ СЛОЕВ СТРУЙНЫМ ЭЛЕКТРОЛИТНО-ПЛАЗМЕННЫМ ПОЛИРОВАНИЕМ

This work is devoted to the development of a model for the removal of surface layers of anode material due to a jet electrolyte-plasma discharge formed by a hollow cathode. The results of studies of the main types of discharges that occur during the formation of jet electrolyte-plasma processing are presented. The influence of each type of discharge on the morphology of the surface layer of the anode-product was studied. The power, lifetime and energy of single discharges are estimated, and their influence on the surface is assessed. A theory has been proposed for the removal of surface layers by single discharges at the atomic dislocation level. Theoretical calculations are confirmed by the results of experimental studies and multiphysics simulations carried out in the COMSOL Multiphysics program. Practical research results confirm the possibility of reducing the roughness parameter Ra during jet electrolyte plasma by more than 20 times, while obtaining an extremely low parameter Ra of 0.019 μm. The area of application of the results of these studies may be the development of technological processes for dimensional and finishing processing of curved surfaces, such as blisks, turbine blades, and various products for household and medical purposes.

A flexible z-layers approach for the accurate representation of free surface flows in a coastal ocean model (SHYFEM v. 7_5_71)

Abstract. We propose a discrete multilayer shallow water model based on z-layers, which, thanks to the insertion and removal of surface layers, can deal with an arbitrarily large tidal oscillation independently of the vertical resolution. The algorithm is based on a classical two-step procedure used in numerical simulations with moving boundaries (grid movement followed by a grid topology change, that is, the insertion/removal of surface layers), which avoids the appearance of surface layers with very small or negative thickness. With ad hoc treatment of advection terms at nonconformal edges that may appear owing to insertion/removal operations, mass conservation and the compatibility of the tracer equation with the continuity equation are preserved at a discrete level. This algorithm called z-surface-adaptive, can be reduced, as a particular case when all layers are moving, to the z-star coordinate. With idealized and realistic numerical experiments, we compare the z-surface-adaptive against z-star and we show that it can be used to simulate coastal flows effectively.

Technological principles for removal of defective surface layer on grinded ceramic products by etching with accelerated argon

The article describes the technological principles and equipment for “dry” ion-plasma etching of the surface layer of SiAlON dielectric ceramics and subsequent deposition of (TiAl)N coatings. The proposed approach made it possible to ensure the high-performance removal of a defective layer formed during diamond grinding from the ceramic samples’ surface. Accelerated argon atoms with an energy of 5 keV are used as a source of energy impact on ceramic samples, which bombard the surface layer and ensure its sputtering at a rate of 9 μm/h. It is shown that the (TiAl)N coating deposition on ceramic samples after the preliminary removal of the defective layer reduces the volumetric wear under abrasive action by a factor of 2.6 compared to the initial samples subjected to diamond grinding.

Optimization for the HP-CORD UV chemical decontamination process for AISI 304 stainless steel

The decontamination of stainless-steel surfaces in Light Water Reactors components, that may suffer from nuclear activation and contamination, is still a topic that deserves research and development studies. In this paper, the HP-CORD-UV chemical method for the removal of thin surface layers from AISI 304 stainless steel samples is addressed, considering multiple cycles of oxidation and cleaning. A procedure for the optimization of the oxidation phase considering in particular the pH of the solution, the ([KMnO4]/[H+] ratio), and the immersion time (oxidation time), was developed and is here presented. The experimental results show that 10 oxidation cycles at pH 3, [MnO4-] = [H+], for 2 h, followed by 30 min of cleaning in oxalic acid, allowed to reach a thickness of dissolved metal of about 3–4 μm. Despite the intrinsic localised morphology of the corrosion attack on AISI 304 sample surface, scanning electron microscopy showed good reproducibility of the process.

Erosion resistant coating to stabilize the surface strength of the casting mold.

To obtain high-quality castings, molding and core mixtures, from which one-time molds are made, must have certain mechanical, technological and physical properties. The surface strength of molding mixtures is the most important factor in obtaining high-quality casting. This property of the mixture is defined as the resistance of the surface layer of the mold to abrasion, and is characterized by crumbling (GOST 23409.9‒78). The lack of surface strength is manifested by the ability of surface sand grains to easily separate with little friction (melt flow during pouring). Insuffi-cient surface strength of the mold causes defects in the castings, forming sand shells and blockages, i. e. particles of the molding material get into the casting, and the mismatch of the casting geometry, i. e., the removal of surface layers from the casting mixture. This phenomenon is caused by the occurrence of convective processes, which leads to the loss of process water in the surface layers of the mold, as well as to increased filtration flows of water in the thickness of the molding mixture. All these processes are carried out to a reduced concentration of water on the surface of the mold. Drying (required by technology) and storage (before using wet molds) are not always the cause of reduced surface strength. In production it is possible that abnormal conditions may occur, leading to crumbling. The situation occurs when the surface and deep layers of the form will be in different conditions. Such situations appear when the chemical composition of the melt does not match, when the melt is not ready for pouring, or when open half-forms accumulate on the conveyor. These factors lead to an increase in the standing time of the open surface of the half-forms, and as a consequence of the appearance of reduced surface strength, which leads to increased crumbling. The purpose of the work is to develop of an erosion resistant coating that prevents the crumbling of the surface layers of the molding mixture

Removal of the endothelial surface layer via hyaluronidase does not modulate monocyte and neutrophil interactions with the glomerular endothelium.

The endothelial surface layer (ESL), a layer of macromolecules on the surface of endothelial cells, can both impede and facilitate leukocyte recruitment. However, its role in monocyte and neutrophil recruitment in glomerular capillaries is unknown. We used multiphoton intravital microscopy to examine monocyte and neutrophil behavior in the glomerulus following ESL disruption with hyaluronidase. Constitutive retention and migration of monocytes and neutrophils within the glomerular microvasculature was unaltered by hyaluronidase. Consistent with this, inhibition of the hyaluronan-binding molecule CD44 also failed to modulate glomerular trafficking of these immune cells. To investigate the contribution of the ESL during acute inflammation, we induced glomerulonephritis via in situ immune complex deposition. This resulted in increases in glomerular retention of monocytes and neutrophils but did not induce marked reduction in the glomerular ESL. Furthermore, hyaluronidase treatment did not modify the prolonged retention of monocytes and neutrophils in the acutely inflamed glomerular microvasculature. These observations indicate that, despite evidence that the ESL has the capacity to inhibit leukocyte-endothelial cell interactions while also containing adhesive ligands for immune cells, neither of these functions modulate trafficking of monocytes and neutrophils in steady-state or acutely-inflamed glomeruli.

Traps inhomogeneity induced conversion of Shockley–Read–Hall recombination in NiO/β-Ga2O3 p+–n heterojunction diodes

In this Letter, the trap inhomogeneity within β-Ga2O3 is correlated with the conversion of Shockley–Read–Hall (SRH) recombination in NiO/β-Ga2O3 p+–n heterojunction diodes. For the virgin epi-wafer, both near-surface traps E2 (EC-0.82 eV) and E3 (EC-1.11 eV) and bulk E2* traps (EC-0.76 eV) are identified by a transient capacitance analysis, and the corresponding forward current–voltage characteristics of diodes are well fitted in the framework of field-dependent SRH recombination. The SRH recombination rates for E2, E3, and E2* traps are determined to be 1.3 × 107, 8.6 × 108, and 2.4 × 108 s−1, respectively. In this circumstance, carrier transport under forward bias is governed by trap-assisted tunneling through E3 traps with high recombination rates, and the hysteresis is pronounced. With the removal of the defective surface layer, E2 and E3 traps are almost completely eliminated, together with the reduced density of E2* traps to 5.6 × 1014 cm−3. The resultant diode performs an improved rectification ratio of >1011 at ±3 V and an enhanced reverse breakdown voltage of 1692 V. The elimination of near-surface traps leads to the conversion of carrier transport into the conventional SRH recombination, accompanied by the negligible forward hysteresis characteristics. The established fundamental correlation of carrier transport and traps within Ga2O3 is beneficial to develop a high-performance power rectifier toward practical applications.

The Influence of Polishing on the Mechanical Properties of Zirconia—A Systematic Review

Purpose: To systematically review studies that investigated the consequences of various polishing protocols on the mechanical properties of zirconia. The effects on the roughness and crystalline phase transformation were also evaluated. Materials and methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) was followed. The electronic searches were conducted via OVID MEDLINE (R) and Scopus for publications between 1996 and August 2022. The search strategy was limited to full texts in the English language and in vitro studies. The influences on flexural strength, hardness, fracture strength, fracture toughness, wear resistance, roughness and phase transformation were collected. Various methodologies to measure these properties were also outlined and compared. The risk of bias for included studies was evaluated according to a modified Consolidated Standards of Reporting Trials (CONSORT) checklist. Results: After removing duplicates, the systematic search identified a total of 419 studies. Nineteen studies satisfied the inclusion criteria and were selected for final analysis. Fifteen of the included studies observed the changes in surface roughness along with the mechanical properties and ten studies detected the tetragonal (T) to monoclinic (M) phase transformation. Eight studies also investigated the change in properties after polishing the ground surface. Testing parameters were not consistent among studies due to the varying methods. Conclusions: To a certain extent, polishing influences the strength, hardness, toughness and wear resistance. The damage in some mechanical properties, as well as the roughened surface, from grinding can be restored via an appropriate polishing treatment. The polishing process itself barely induces the transition from the tetragonal to monoclinic phase of zirconia, while this commonly occurs after grinding. If the subsequent polishing is adequate, the transformed monoclinic phase can be eliminated with the removal of the outermost surface layer. In dentistry, polishing is an imperative step to maintain the superior functions and service life of zirconia for patients.

Complex Study of a Painted Gypsum XVIII Century Bas-Relief by Optoelectronic Methods to Develop a Combined Cleaning Technique

In this work, a painted gypsum bas-relief from the facades of the inner courtyard of the St. Petersburg Academy of Arts building was examined using UV and visible light photography and optical and electron scanning microscopy, which showed the heterogeneous layers of white painting on the surface of the bas-relief that covered the historical ones. These undesirable layers should be removed during the restoration work, but it was found that the traditional method of removing surface layers of painting with the help of chemical solvents and mechanical cleaning does not solve the problem to the full extent. A cross-section of all the painting layers was prepared to investigate the stratigraphy of the paint layers. These studies were conducted using optical and electron scanning microscopy in order to determine the structure of the paint layers more properly and study the chemical composition of every layer. After this study, a complex cleaning technique was developed. This technique combines chemical and laser cleaning, making it possible to effectively remove the upper dense layers of paint without damaging the historical paint layers.

Influences of surface state on thermal stability and magnetic properties of Fe-Si-B-C amorphous alloy

Influences of surface state on thermal stability and magnetic properties for Fe82Si1B12C5 completely amorphous alloys and Fe83Si1B12C4 amorphous alloys with partial crystallization at their surface have been investigated by layer polished-removal method. The crystallization enthalpy of α-Fe phase for the two amorphous alloys decreases obviously with polishing removal of surface layer with the thickness of removal, due to the alteration of internal stress state. An increase of only 1.2% in Fe content causes an increase of 8.4% in crystallization enthalpy of α-Fe phase for the alloy system with an initial casting thickness, indicating that the thermal stability is stress-sensitive for Fe-based amorphous alloys with high Fe content close to amorphous forming boundary are easier to crystallize. It was found that in the as-quenched state the coercivity for both of them increases linearly with the thickness of removal, which is caused by an increase in internal stress. And it was confirmed by experiment that adequate annealing can greatly improve the soft magnetic properties and alter thermal stability.

Application of a New Alloy and Post Processing Procedures for Laser Cladding Repairs on Hypereutectoid Rail Components.

The development of a laser cladding repair strategy is critical for the continued growth of heavy-haul railway networks. Premium hypereutectoid rails have undergone laser cladding using a new martensitic stainless-steel alloy, 415SS, developed for high carbon rails after standard cladding metals were found to be incompatible. Non-destructive neutron diffraction techniques were used to measure the residual stress in different layers generated across a dissimilar metal joint during laser cladding. The internal stress distribution across the cladding, heat-affected zone (HAZ), and substrate was measured in the untempered rail, after 350 °C and 540 °C heat treatment procedures and two surface grinding operations. The martensitic 415SS depositions produce compressive stress in the cladding, regardless of tempering procedures, which may inhibit fatigue crack propagation whilst grinding operations locally relive surface stress. Balancing tensile stresses were recorded below the fusion boundary in the HAZ due to thermal gradients altering the microstructure. The combination of 540 °C tempering and 0.5 mm surface layer removal produced a desirable combination of compression in the cladding deposition with significantly reduced tensile stresses in the HAZ. A comparison with the current literature shows that this alloy achieves a unique combination of desirable hardness, low tensile stress, and compression in the cladding layer. Data obtained during strain scanning has been used to determine the location of microstructural changes at the fusion boundary and HAZ through correlation of the stress, strain, full width at half maximum (FWHM), and intensity profiles. Therefore, neutron diffraction can be used for both the accurate measurement of internal residual stress and to obtain microstructural information of a metallurgical join non-destructively.

Plasma-Beam Processing of Tools Made of SiAlON Dielectric Ceramics to Increase Wear Resistance When Cutting Nickel–Chromium Alloys

This research aimed at an increase in wear resistance of round cutting plates manufactured with SiAlON dielectric ceramics through deposition of wear-resistant coatings. To increase effectiveness of the coatings, their adhesion was improved by the removal of defective surface layers from the cutting plates before the deposition. As the depth of caverns and grooves appearing on the cutting plates due to manufacturing by diamond grinding reached 5 µm, a concentrated beam of fast argon atoms was used for the removal of defective layers with a thickness exceeding the depth of caverns and grooves. At the equal angles of incidence to the front and back surfaces of the cutting wedge amounting to 45 degrees, two-hour-long etching of rotating cutting plates provided removal of defective layers with thickness of ~10 µm from the surfaces. After the removal, the cutting edge radius of the plates diminished from 20 to 10 µm, which indicates the cutting plates’ sharpening. Wear-resistant TiAlN coatings deposited after the etching significantly improve the processing stability and increase wear resistance of the cutting plates by not less than 1.7 times.

Exfoliation methods for compositional and electronic characterization of interfacial Mo(Sex,Sy) in Cu(In,Ga)(Se,S)2 solar cells by X‐ray and UV photoelectron spectroscopy

Mo(SexSy) is a transition metal dichalcogenide typically applied as a back contact interlayer in Cu(In,Ga)(Se,S)2 (CIGSSe) solar cells. Band alignment at the buried Mo/CIGSSe junction mediated by Mo(SexSy) is important for current transport and enables quasi‐ohmic behavior between the CIGSSe absorber and the Mo back electrode. Furthermore, the S/(Se + S) ratio is a crucial parameter that determines the height of the valence band offset at the CIGSSe/Mo(SexSy) interface. Because the interlayer is formed during rapid thermal processing, an MoSe2 or MoS2 thin film grown on free substrate surfaces will not be representative for a realistic solar cell device. Thus, for fundamental thin‐film material analysis, as well as functional characterization and modeling, appropriate preparation and analytical techniques are required in order to prevent artifacts. In principal, the weak van der Waals forces between two‐dimensional stacked Mo(SexSy) sheets allow the implementation of exfoliation procedures to generate free Mo(SexSy) surfaces out of CIGSSe solar cell layer stacks. In this article, two different exfoliation‐based Mo(Sex,Sy) preparation methods are investigated and evaluated with respect to subsequent surface analytical characterization by X‐ray and ultraviolet photoelectron spectroscopy. A special focus is laid on an artifact‐free characterization of chemical and electronical properties of the exposed layers for a number of samples. In a first instance, the compositional Se/S and (Se + S)/Mo ratios at the surface are quantitatively analyzed on the basis of dedicated peak‐fitting routines. Artifacts from carbonaceous contamination due to different exfoliation glues can be prevented through a detailed comparative analysis of carbon 1s and KLL Auger peaks. Furthermore, a significant surface band bending is observed that can be reduced by low‐energy Ar ion in situ sputtering. A simple model for the sputter removal of a charged surface layer is presented, which allows to approximately calculate the absolute valence band maximum (VBM) positions required for band alignment and numerical device simulations. The presented exfoliation surface analysis methodology is important for the whole CIGS(Se) solar cell community and may be of general interest for emerging applications of further 2D transition metal dichalcogenides as well.

Usefulness of conventional glass ionomer cements in an environment of insufficient moisture exclusion.

Moisture exclusion while treating dental caries can be challenging, and the glass ionomer cements (GICs) used for these procedures are susceptible to water. Few studies have examined the effects of the powder/liquid ratio (PLR) on the physical properties of GICs exposed to water. In this study, the hardness and thickness of the water-susceptible surface layer of three GICs were evaluated. Three conventional GICs were mixed in increasing PLRs, and hardness over time was measured under conditions of no water exposure, distilled water exposure, and saliva exposure. Furthermore, the thickness of the water-susceptible layer for each GIC was determined. A water-susceptible layer of approximately 250 μm was evident for all GICs, and the thickness decreased with increasing PLR. GIC hardness increased with increasing PLR in conditions without water for all GIC types. Furthermore, the removal of the water-susceptible layer restored the physical properties of each GIC. Overall, the results indicate that conventional GIC restoration with the removal of the water-susceptible surface layer is a feasible strategy for treating dental caries in individuals for whom exclusion of moisture can be difficult.

Residual stress determination by the layer removal and X-ray diffraction measurement – correction method

Very often a manufacturing process is followed by some surface treatment. Such a process induces residual stress into the manufactured component. Compressive residual stress is desirable for enhancing the fatigue properties of the component. The residual stress is often measured only at the surface, if at all. However, residual stress is equilibrating in the whole component. Therefore, compressive residual stress at the surface induces undesirable tensile stress inside in the component. Knowledge of the residual stress distribution in a body can be very useful in engineering applications. The authors found this knowledge necessary for a proper description of fatigue crack propagation in railway axles described in the original paper [1]. With the onset of modern surface treating technologies, e.g. induction hardening, which can affect the entire cross-section of the component, the residual stress determination is even more critical.The presented paper aims to describe a procedure developed for proper residual stress determination. The procedure can be easily used e.g. in R&D centers, where X-ray diffraction residual stress measurement is already in use. The procedure is suitable for the residual stress determination in sizable cylindrical bodies or components, e.g. railway axles. It uses X-ray diffraction residual stress surface measurement and layer removal by machining. Results experimentally obtained are corrected by a general procedure developed in MATLAB software in order to obtain the original residual stress state in the cylindrical body.•More accurate procedure for a residual stress determination in cylindrical bodies.

Assessment of the tribolological behavior of a metallic tribopair: LM25 alloy-Si3N4 composites against EN 31 steel

In the present research work, tribological behavior of hard ceramic silicon nitride (Si3N4) reinforced aluminium alloy LM 25 based composites against EN 31 steel in ambient conditions at various loads (19.60–58.86 N) and sliding distances (1200–2400 m) on pin-on-disk test rig was investigated for commercial purpose of machine components. Three sets of composites were fabricated with 4–12 % of silicon nitride by stir casting technique. SEM Micrographs revealed formation of a homogeneous α-aluminum dendrites network structure developed due to the super-cooling of casting during solidification. EDS showed increased content of hard silicon and nitrogen from 29.04 to 73.96 % and 6.68–14.54 % respectively with 4–12 % reinforcement addition which led to high hardness. Increase in hardness from 58.02 to 63.70 BHN is observed with increase in reinforcement which led to reduction in wear by reducing the actual contact area during sliding whereas strength is reduced on addition of Si3N4. The wear resistance of composite is found greater with 12 % Si3N4 reinforced composite with reduced wear at low sliding distance. Due to continuous sliding, wear debris embedded with the surface forming a layer which resulted in variation in coefficient of friction (COF). COF increased at a high rate up to 1800 m followed at a slow rate up to 2400 m sliding distance with increase of normal load. SEM analysis of worn surfaces revealed removal of surface layer with generation of micro cracks with subsequent sliding in composites reinforced with 4 % and 8 % silicon nitride whereas ploughing mechanism is observed in composite with addition of 12 % Si3N4. The linear increasing trend was observed in wear loss against the dissipated energy for the investigated composites.