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At least 1,495 records · Page 83
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Ameliorated mechanical and thermal properties of SiC reinforced Al matrix composites through hybridizing carbon nanotubes

Highlights: • The carbon nanotubes were hybridized into SiC reinforced Al based composites. • Hybridization of CNTs leads to the uniform dispersion of SiC in the Al matrix. • Hybridization of CNTs enhances the strength and ductility of the composites. • CNTs can help to decrease the coefficient of thermal expansion of the composites. - Abstract: By hybridizing carbon nanotubes (CNTs) into SiC reinforced Al matrix composites, a novel composite was fabricated to achieve excellent mechanical properties and low coefficient of thermal expansion simultaneously. The study demonstrated that the CNTs can help to acquire the uniform dispersion of SiC particles in the Al matrix, because of their interaction during ball milling and hot rolling processes. In addition, the results revealed that such design optimizes both the mechanical and thermal properties, due to homogeneous microstructure as well as tight and uniform interfaces induced by the addition of CNTs. Strengthening mechanism and Sideridis's model were used to discuss the effects of the CNTs on the mechanical and thermal properties. This study opens up an unexplored avenue for simultaneous improvement of the mechanical and thermal properties of metal matrix composites.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Effects of the rolling temperature on microstructure and mechanical properties of 2Cr13/316L laminated composites prepared by accumulative roll-bonding (ARB)

Highlights: • The rolling temperature affects the grain size and microstructural phases of the composite plates. • The rolling temperature affects tensile strength and bending strength of 2Cr13/316L properties of the composite plates. • The temperature gradient and thermal deformation of center and outside regions are different during rolling process. • Composite plate with higher strength and elongation can be obtained by rolling processes. - Abstract: The microstructure and mechanical properties of 2Cr13/316L composite plates by hot-rolling at different rolling temperatures of 1130 °C, 1180 °C, 1250 °C, 1300 °C are investigated in details. With the increase of the rolling temperature, the tensile strength and bending strength of 2Cr13/316Lwere reduced first and then increased slightly due to the coarsening of grains and the increasing of ferrite content in 2Cr13 layers. The highest tensile elongation is obtained at the composite plate with rolling temperature of 1180 °C. 2Cr13/316L composite plates obtained by hot rolling processes were able to withstand larger bending deformation, and no cracks or interfacial delamination can be found in the bending process because of a strong combined interface.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Synthesis of ZnO/Ag/graphene composite and its enhanced photocatalytic efficiency

Highlights: ► ZnO/Ag/graphene composite was synthesized via a facile aqueous reaction. ► ZnO/Ag composite nanoparticles are anchored on a two-dimensional graphene sheet. ► Enhanced photocatalytic efficiency was obtained compared to ZnO/Ag composite. ► The composite shows excellent stability after four photodegradation cycling runs. - Abstract: ZnO/Ag/graphene composite was synthesized via a facile low-temperature aqueous solution reaction. The morphology and crystal phase of the obtained samples were well characterized by SEM, TEM, and XRD. The results indicated that ZnO/Ag nanoparticles (NPs) are anchored on the two-dimensional graphene sheet. The photocatalytic trials confirmed that the ZnO/Ag/graphene composite exhibited improved photocatalytic efficiency compared with the ZnO/Ag NPs and pristine ZnO NPs. The increased photocatalytic activity of ZnO/Ag/graphene was attributed to the effective charge separation and the suppressed recombination of photogenerated electron–hole pairs. Moreover, the ZnO/Ag/graphene sample showed excellent stability after four photodegradation cycling runs.

36 MATERIALS SCIENCE↗
DOE OSTI2013

Dielectric, ferromagnetic and maganetoelectric properties of BaTiO{sub 3}–Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} composite ceramics

Graphical abstract: - Highlights: • The lead-free ME ceramic composites BaTiO{sub 3}–Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} were successfully synthesized. • The composites showed high dielectric constant and low dielectric loss. • The composite with 30% NiZn ferrite presented good soft magnetic properties and ME performance. - Abstract: Lead-free magnetoelectric composite ceramics (1 − x)BaTiO{sub 3}–xNi{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} (x = 0.15, 0.3, 0.45) were successfully prepared by conventional oxide ceramic process. The tetragonal perovskite BaTiO{sub 3} and cubic spinel Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} were confirmed by X-ray diffraction. The dielectric behaviors of all composite samples show a normal response to the increasing measurement frequency and Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} ferrite content. Well defined ferromagnetic hysteresis loops and obvious magnetoelectric coupling effect are observed in the composite ceramics. The influence of applied dc bias magnetic field and Ni{sub 0.7}Zn{sub 0.3}Fe{sub 2}O{sub 4} ferrite content on the magnetoelectric coupling responding voltage is investigated. The strongest peak magnetoelectric coupling voltage coefficient is 124 μV/cm Oe when x = 0.3, which corresponds to the maximum magnetoelectric coupling responding voltage of 200 μV.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Synthesis and photocatalytic property of BiOBr/palygorskite composites

Graphical abstract: - Highlights: • BiOBr/palygorskite composite photocatalysts were prepared for the first time. • The synchronous role of adsorbability and photocatalytic oxidation was studied. • BiOBr/palygorskite composite exhibit enhanced photocatalytic activities. • The optimal ratio of [Bi]/palygorskite was identified. - Abstract: BiOBr/palygorskite composite photocatalysts were prepared by a hydrothermal method for the first time, which were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transformed infrared spectroscopy (FTIR), N{sub 2}-sorption and UV–vis diffuse reflectance spectroscopy. The photocatalytic activity of the as-prepared samples was evaluated by decomposition of methyl orange (MO) under visible light irradiation. The results revealed that BiOBr/palygorskite composites had strong photoabsorption in the visible light region. All BiOBr/palygorskite composites possessed higher photocatalytic activity than pure BiOBr. The highest activity was obtained by S5.0 sample. The enhanced photocatalytic performance was attributed to strong photoabsorption, the synchronous role of adsorbability and photocatalytic oxidation on BiOBr/palygorskite composites and the efficient separation of photogenerated electron–hole pairs.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Visible light-driven photocatalytic H{sub 2}-generation activity of CuS/ZnS composite particles

Highlights: • Preparation of CuS/ZnS composite photocatalyst by cation-exchange reaction. • Visible light photocatalytic activity for H{sub 2} evolution without cocatalyst. • The H{sub 2}-evolution rate from water splitting depends on the CuS content. • The highest rate of H{sub 2} evolution is obtained with CuS (0.5 mol%)/ZnS composite. - Abstract: CuS/ZnS composite particles with diameter of 200–400 nm were successfully prepared by a simple cation-exchange reaction using ZnS spheres as a precursor. CuS nanoparticles with a few nanometers in diameter were observed on the surface of composite particles. The synthesized CuS/ZnS composite particles showed photocatalytic property effective for H{sub 2} evolution from an aqueous Na{sub 2}S and Na{sub 2}SO{sub 3} solution under visible light irradiation without any cocatalysts. The rate of H{sub 2} generation was found to be strongly dependent on the CuS content. The highest rate of H{sub 2} evolution reached 695.7 μmol h{sup −1} g{sup −1}, which was almost 7 times as high as that of the mechanical mixture of CuS and ZnS. The enhancement in the photocatalytic activity of CuS/ZnS composite particles is supposed to be due to the direct interfacial charge transfer of the CuS/ZnS heterojunction.

36 MATERIALS SCIENCE↗
DOE OSTI2018

Fabrication of CeO2/PANI composites for high energy density supercapacitors

Highlights: • Fabrication of CeO{sub 2}/PANI composite was successfully prepared using easy solution mixing method. • Combinational approaches of rare earth oxides with conducting polymer composites posses’ excellent pseudocapacitive nature. • Superior specific capacitance, rate capacitance and cyclic stability. • Outstanding performance of asymmetric and symmetric devices. - Abstract: Combinational approaches of rare earth oxides with conducting polymer composites have gained vast attention in supercapacitor field due to the outstanding pseudocapacitive property. Here we detail the redox reaction based on CeO{sub 2}/polyaniline nanostructure to grasp the superior electrochemical nature of the composite. The CeO{sub 2}/polymer nanostructure showed the improved specific capacitance of 1452 F g{sup −1} at 2 A g{sup −1} when compared to pristine CeO{sub 2} (927 F g{sup −1} at 2 A g{sup −1}). The composite also maintains excellent rate capacitance (875 F g{sup −1} at 10 A g{sup −1}) and good cyclic stability upto 1500 cycles at high current density of 20 A g{sup −1}. Symmetric and asymmetric supercapacitor devices were fabricated using CeO{sub 2}/ PANI as an electrode. Moreover, the asymmetric supercapacitor possesses excellent specific capacity (256 F g{sup −1} at 2 mV s{sup −1}) with high energy density (75 Whkg{sup −1}) and high power density (566 Wkg{sup −1}). These results suggest a potential usefulness of CeO{sub 2}/ PANI composite exploit as an efficient electrode for supercapacitor applications.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Additive manufacturing of multi-directional preforms for composites: opportunities and challenges

Current additive manufacturing methods present the potential to construct net-shape structures with complicated architectures, thus eliminating the need for multi-step processing and fasteners/joints. Combined with these features is the ability to ascribe material properties at the sub-millimeter scale, inspiring multi-material, functionally graded designs. These features make additive manufacturing an attractive option for composite materials development. In an effort to extend this family of technologies beyond nano- and micro-composites, we explore the additive manufacture of multi-directional composite preforms. This exercise has served to highlight the aspects of additive manufacturing critical to composite and general materials processing, as well as to demonstrate the high fidelity between modeled and additively manufactured structures. Within the scope of composites development, we review the state-of-the-art and discuss challenges facing the broad adoption of additive manufacturing for directionally reinforced composites processing.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Quasi-static and dynamic response of a Cu/Nb composite following equal channel angular extrusion

The article presents a study of the plastic properties of a Cu–18%Nb composite following equal channel angular extrusion under both low- and high-strain rate loadings. The microstructures are characterized by optical and scanning electron microscopy as well as electron backscatter diffraction. Comparisons are also made with a Cu–50%Nb laminate made by accumulative roll bonding. Textures obtained within the respective phases in the extruded composite closely mimic those previously reported for the pure components alone (Cu, Nb). Grain sizes of the major phase (Cu) exhibit broad distributions, due largely to partial recrystallization during the extrusion process. Further re-crystallization is obtained within localized deformation bands produced at high strain rates (3 × 10 3 s –1 ). While the degree of anisotropy and the strain rate sensitivity of the composite response are similar to those of pure Cu after extrusion, the strength levels of the composite are somewhat greater, falling broadly between those obtained in the pure components after extrusion to comparable plastic strains. Furthermore, the implications for selection of composite composition and processing for achieving higher strengths are briefly discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Thermal mechanical assessment of a SiC-SiC-composite clad fuel pin concept in a light water reactor environment

Accident Tolerant Fuels (ATFs) are designed to increase coping time following an accident scenario while preserving or improving current steady state reactor operational performance. A potential ATF concept is SiC-SiC composite claddings. Fuel performance simulations were conducted on a SiC-SiC based cladding concept utilizing a multilayered approach for improved performance. This cladding concept referred to as the Duplex concept is a duplex structure composed of a monolithic SiC layer placed on the outside of a SiC-SiC composite. A liquid metal is added to fuel-cladding gap for improved heat dissipation from the fuel. The monolithic SiC layer is used to improve the coolant corrosion characteristics and protect the SiC-SiC composite layer from exposure to the coolant. The fuel performance code BISON was used to conduct fuel performance simulations on the cladding concepts. Comparisons are made with a current prototypic fuel rod design (UO 2 fuel enclosed in Zircaloy-4 cladding). Representative steady-state cases were considered for normal power and two cycle power histories. Additionally, a PCI ramp case was simulated to analyze potential anticipated operational occurrences. Transient response during a Loss of Coolant Accident and a Reactivity Initiated Accident were also simulated. This computational study demonstrated that for normal operating conditions, the SiC concept cladding performed as well as the baseline for the standard power cases evaluated. The ramping evaluations indicate potential fracturing of the SiC-SiC composite of the composite cladding compared to the Zircaloy-4 cladding due to the temperature gradient and the subsequent differential thermal conductivity degradation and swelling across the composite thickness. In conclusion, the rod fails early at low enthalpy for RIA but survives a LOCA with minimal material loss due to high temperature steam corrosion.

11 - NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2021

Improving ChemCam LIBS long-distance elemental compositions using empirical abundance trends

The ChemCam instrument on the Curiosity rover provides chemical compositions of Martian rocks and soils using remote laser-induced breakdown spectroscopy (LIBS). The elemental calibration is stable as a function of distance for Ti, Fe, Mg, and Ca. The calibration shows small, systematically increasing abundance trends as a function of distance for Al, Na, K, and to some extent, Si. The distance effect is known to be due to a dependence with distance on the relative strengths of atomic transition lines. Emission lines representing transitions from relatively low energy levels remain intense at longer distances while emission lines representing transitions from higher energy levels decrease in intensity more rapidly as a function of distance. The multivariate algorithms used to determine elemental compositions rely on a large number of emission lines in many cases, so rather than trying to correct all emission lines, a study was made of the predicted compositions as a function of distance, in order to determine an empirical correction. Abundance trends can be well approximated by a linear trend with distance within the ranges of abundances and distances observed up to ~6 m. Data from 11 distinct geological members and data groups of the Murray formation in Gale crater, Mars, were used to form the model, selecting the members and data groups yielding the best statistics. The model was tested using data from several targets observed from two different distances, and using data from the Kimberley formation, the composition of which is significantly different from the Murray formation, showing that the model works on other compositions beyond those used to build the model. For long-distance observations up to ~6 m, corrections can be made back to an equivalent composition at the median distance of ChemCam observations (2.6 m). Finally, the model has been validated up to 6.2 m, although ChemCam is able to observe bedrock targets to >7 m, and iron meteorites to distances of >9 m.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Mineral-hydrogel composites for mitigating harmful algal bloom and supplying phosphorous for photo-biorefineries

Harmful algal blooms (HAB) are a major environmental concern in eutrophic aquatic systems. To mitigate HABs and recover the phosphorus that drives algal growth, this study developed hydrogel composites seeded with calcium phosphate and wollastonite particles, which first adsorb phosphate (P) and then precipitate it as calcium phosphate. Using a fast-growing cyanobacterium, Synechococcus elongatus 2973, as a model microalga, we found that the mineral-hydrogel composites reduced dissolved P in BG11 media from 5.1 mg/L to 0.31 mg/L, initially reducing the biomass growth rate by up to 73 % and ultimately reducing the total biomass concentration by 75 %. When applied to municipal wastewater and agricultural run-off, the composites removed 96 % and 91 % of the dissolved P, respectively. Moreover, when the recovered P-enriched composites were reused as a slow-release bio-compatible fertilizer in a photobioreactor, they effectively supported algal growth without blocking light and interfering with photosynthesis. The P-enriched composites could tune the P concentration in the culture medium and significantly promote algal lipid accumulation. Finally, this study demonstrates the mineral-hydrogel composites' potential to treat point sources of P pollution and subsequently facilitate photoautotrophic biofuel production as a nutrient, effectively recycling the captured P.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Hydrogen sensing in different hydrogen-carrying gases using composites of PdSnO 2 and halloysite nanotubes

Here, in this work, we developed composites of palladium-decorated tin dioxide (PdSnO 2 ) and halloysite nanotubes (HNTs) by adding different amounts of HNTs as additives into PdSnO 2 , and investigated how the different amounts of HNTs in the composites and the different hydrogen (H 2 ) carrying gases (air and helium (He)) could affect the H 2 sensing performance of such composites (PdSnO 2 -HNT). Through the sensing-performance characterization using H 2 carried by air, it was found that PdSnO 2 with an appropriate small amount of HNTs (i.e., 2 % of PdSnO 2 mass) can improve the sensing performance with respect to limit of detection (LOD) and response/recovery time. Further, the optimal PdSnO2-HNT composite as a sensor was tested to detect H 2 in He. The testing results indicated that the composite can detect H 2 in He, but its performance parameters (i.e., the profile of calibration curve, LOD, and response time) are different from those of such a sensor in detecting H 2 in air. Moreover, the composite still presented better sensing performance than PdSnO 2 without HNTs in detecting H 2 in He. Possible reasons for the effects of HNT and H 2 -carrying gas on the sensing performance of PdSnO 2 -HNT-based sensors were discussed. We believe that this study provides valuable insights into the functionality and the adaptability of PdSnO 2 -HNT-based H 2 sensors in diverse operational conditions.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Municipal solid waste composition: Sampling methodology, statistical analyses, and case study evaluation

Highlights: • Tiered approach to waste sorting ensures flexibility and facilitates comparison of solid waste composition data. • Food and miscellaneous wastes are the main fractions contributing to the residual household waste. • Separation of food packaging from food leftovers during sorting is not critical for determination of the solid waste composition. - Abstract: Sound waste management and optimisation of resource recovery require reliable data on solid waste generation and composition. In the absence of standardised and commonly accepted waste characterisation methodologies, various approaches have been reported in literature. This limits both comparability and applicability of the results. In this study, a waste sampling and sorting methodology for efficient and statistically robust characterisation of solid waste was introduced. The methodology was applied to residual waste collected from 1442 households distributed among 10 individual sub-areas in three Danish municipalities (both single and multi-family house areas). In total 17 tonnes of waste were sorted into 10–50 waste fractions, organised according to a three-level (tiered approach) facilitating comparison of the waste data between individual sub-areas with different fractionation (waste from one municipality was sorted at “Level III”, e.g. detailed, while the two others were sorted only at “Level I”). The results showed that residual household waste mainly contained food waste (42 ± 5%, mass per wet basis) and miscellaneous combustibles (18 ± 3%, mass per wet basis). The residual household waste generation rate in the study areas was 3–4 kg per person per week. Statistical analyses revealed that the waste composition was independent of variations in the waste generation rate. Both, waste composition and waste generation rates were statistically similar for each of the three municipalities. While the waste generation rates were similar for each of the two housing types (single-family and multi-family house areas), the individual percentage composition of food waste, paper, and glass was significantly different between the housing types. This indicates that housing type is a critical stratification parameter. Separating food leftovers from food packaging during manual sorting of the sampled waste did not have significant influence on the proportions of food waste and packaging materials, indicating that this step may not be required.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2015

Development of a sintering process for recycling oil shale fly ash and municipal solid waste incineration bottom ash into glass ceramic composite

Highlights: • Glass ceramic composite is prepared from oil shale fly ash and MSWI bottom ash. • A novel method for the production of glass ceramic composite is presented. • It provides simple route and lower energy consumption in terms of recycling waste. • The vitrified slag can promote the sintering densification process of glass ceramic. • The performances of products decrease with the increase of oil shale fly ash content. - Abstract: Oil shale fly ash and municipal solid waste incineration bottom ash are industrial and municipal by-products that require further treatment before disposal to avoid polluting the environment. In the study, they were mixed and vitrified into the slag by the melt-quench process. The obtained vitrified slag was then mixed with various percentages of oil shale fly ash and converted into glass ceramic composites by the subsequent sintering process. Differential thermal analysis was used to study the thermal characteristics and determine the sintering temperatures. X-ray diffraction analysis was used to analyze the crystalline phase compositions. Sintering shrinkage, weight loss on ignition, density and compressive strength were tested to determine the optimum preparation condition and study the co-sintering mechanism of vitrified amorphous slag and oil shale fly ash. The results showed the product performances increased with the increase of sintering temperatures and the proportion of vitrified slag to oil shale fly ash. Glass ceramic composite (vitrified slag content of 80%, oil shale fly ash content of 20%, sintering temperature of 1000 °C and sintering time of 2 h) showed the properties of density of 1.92 ± 0.05 g/cm{sup 3}, weight loss on ignition of 6.14 ± 0.18%, sintering shrinkage of 22.06 ± 0.6% and compressive strength of 67 ± 14 MPa. The results indicated that it was a comparable waste-based material compared to previous researches. In particular, the energy consumption in the production process was reduced compared to conventional vitrification and sintering method. Chemical resistance and heavy metals leaching results of glass ceramic composites further confirmed the possibility of its engineering applications.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2018

Characterisation of sludge for pyrolysis conversion process based on biomass composition analysis and simulation of pyrolytic properties

Highlights: • Characterisation of different types sewage sludge for pyrolytic properties. • Developed analytical procedure to categorise and quantify composition of sludge. • Observed qualitative similarity and quantitative variation on properties of sludge. • Correlated organic components with thermochemical properties of sludge. • Coupled model compounds selection and composition analysis for simulation study. - Abstract: Pyrolytic behaviour of sludge is highly complex and obscure because of its heterogeneous and diverse composition. Therefore, an analytical procedure is proposed to categorise and quantify the main constituents in sludge. In addition, a simulation study of sludge characteristics is carried out to complement the composition analysis and to improve our understanding on the relationship between composition of sludge and its corresponding properties. Different types of sludge samples were collected at different treatment stages from four Water Reclamation Plants in Singapore in two separate batches. Model compounds are selected to represent components identified and are used in simulation of pyrolytic properties of sludge. Constituents of sludge are adequately categorised, quantified and characterised in this study. Qualitative similarities and quantitative variations on characteristics of different sludge samples were identified. Comparison among the samples collected with the simulation provided insights on how differences in organic composition of sludge affected its properties.

09 BIOMASS FUELS↗
DOE OSTI2018

Spatial-temporal variations of dissolved organic nitrogen molecular composition in agricultural runoff water

Leaching of dissolved organic nitrogen (DON) has been reported as a pathway of N loss from agriculture, but the molecular composition of DON in agricultural water is poorly understood. Runoff water samples were collected from citrus grove furrows (CGF), ditches (CGD) and pasture ditches (PD) in four seasons. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) was used to investigate molecular composition of DON. Chemodiversity index of DON had spatiotemporal variations, while the molecular composition of total DON showed minimal variations, except for PD in November. Lignin derivatives constituted 61% of the total DON compounds. Relative abundance of aliphatic compounds, char and condensed aromatics of unique DON compounds varied spatiotemporally and had a significant correlation with DON concentration. Aromaticity index decreased from CGF to connected CGD, implying that photodegradation is possibly the dominant process that alters molecular composition of aquatic DON during the transport. Significant differences in unique DON composition between CGD and PD indicates that fertilization and land use affect DON composition. The information on molecular characterization of DON should be useful for tracking DON source and developing technologies to remove DON in the agricultural runoff water.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Tribological behavior of hybrid Aluminum-TiB 2 metal matrix composites for brake rotor applications

Here, this research investigates the feasibility of hybrid aluminum metal matrix composites (MMC) incorporating TiB 2 particles for brake rotor applications. The composites were produced by incorporating both in-situ, submicron-sized TiB 2 particles and regular micron-sized TiB 2 powders via stir and squeeze casting techniques into A206 aluminum alloy matrix. Systematic adjustments in the fractions of in-situ and ex-situ TiB 2 particles were conducted to evaluate their impact on wear behavior and mechanisms. Combination of both particle types allowed composites with up to 10 vol% of reinforcements. Composites with higher proportions of ex-situ particles demonstrated increased wear resistance compared to those solely composed of in-situ particles, control specimens without TiB 2 , and conventional cast iron counterparts. The lowest wear rate for the hybrid composites sliding against phenolic brake pads was 1.1 × 10 -5 mm 3 /Nm, signifying a 3-fold reduction relative to cast iron sliding against the same pads. Wear analysis elucidated distinctive mechanisms within the hybrid composites, characterized by mild fragmented abrasive wear, adhesive wear, and plastic deformation, accompanied by the formation of an intermixed tribo-oxide layer.

42 ENGINEERING↗