Reinforcing the novolac matrix with glass fiber (GF) and graphite (Gr) was a promising method for producing high‐performance friction composites. In this context, the morphology of the matrix and ...additive particles used in the production of friction composites, microstructures, wear surfaces, and wear debris of friction composites were examined by scanning electron microscopy‐energy dispersive spectroscopy, while the crystal phases of the materials were scanned by X‐ray diffraction. Density measurements (Archimed's method), hardness, tensile behaviors, and thermal analyses (thermogravimetric analysis and differential scanning calorimetry) of friction composites were performed. The variations in coefficient of friction (COF) and temperature with the change in sliding time were observed in detail at different additive ratios. The tribological behaviors of these composites were tested using a computer supported block‐on ring machine at sliding speeds of 200, 250, 300, and 350 rpm, applied loads of 50, 100, 150, and 200 N and constant time of 1800 s under dry conditions. Results indicated that with increase in the GF and Gr content, the stability of the (COF) became more stable and effectively reduced the specific wear rate. In addition, the wear resistance increased in parallel with the increase in normal loads and sliding speeds for all conditions.
Fabrication of novolac/graphite (Gr)/glass‐fiber (GF) friction composites. Investigate the effect of glass fiber and graphite contents on wear behavior. Obtaining advanced tribological properties with the reinforcement of Gr and GF.
In this study, the effects of ball milling (BM) technique and carbon nanotube (CNT) content on the thermal and mechanical properties of hybrid reinforced composites were investigated. The composites ...were prepared using glass fiber (GF), novolac resin (No), and CNTs with different wt% (1, 2, and, 4). Various milling times were used to optimize the entanglement/agglomeration of CNTs in the polymer matrix and subsequently enhance the final thermal and mechanical properties. Through precise investigations, it was found that the nanocomposite with 2 wt% CNT reinforcement, subjected to 2 h of BM, exhibited remarkable enhancements in key properties. The tensile strength was significantly improved to 45.6 MPa, while the elastic modulus reached 3.419 GPa. Hardness was measured at 96 HRM, and thermal conductivity was enhanced to 0.463 W/mK. Moreover, this sample demonstrated a weight loss that was 43.65% lower compared to the sample reinforced with 1 wt% CNT and subjected to 1 h of BM. Overall, this study highlights the importance of optimizing the milling time and CNT content in the preparation of polymer nanocomposites, and it provides valuable insights for the development of advanced materials with superior performance in various applications.
The production route of nanocomposites.
This study aims to examine the physical and mechanical properties of novolac matrix glass fibers (GFs) and graphite particles (GPs) reinforced hybrid composites as the function of the GFs and GPs ...content. In accordance with this purpose, the GFs content was kept constant at 20 %wt., while the GPs ratio was changed at 20 %wt., 30 %wt., and 40 %wt. On the other hand, the GPs ratio remained constant at 40 %wt., and the GFs ratio was changed between 20 %wt., 30 %wt., and 40 %wt. To obtain homogeneous hybrid composite powders, the GFs/GPs/Novolac resin powders was blended by a mechanical mixer. Then, the hybrid composite powders were placed in a steel mold and kept in the oven followed by the pressing at 20 MPa. The morphology of the matrix and additive particles used in the production of hybrid composites, the microstructures and fracture surfaces of hybrid composites were examined by scanning electron microscopy (SEM) while the crystalline phases of the materials were investigated by X-ray difftaction (XRD). The density measurements were made by the Archimed’s method. The mechanical properties of hybrid composites (hardness and tensile strength) were investigated. Thermal and flammability analyses were performed using thermogravimetric analysis (TGA) and by limited oxygen index (LOI) tests. According to the results, an increase in hardness, maximum tensile strength was determined with the increase in GFs and GPs content in hybrid composites. The hardness and maximum tensile strength obtained in pure novolac were determined as 32 HRM and 12 MPa, respectively, while those determined in hybrid composites were 98 HRM and 33.8 MPa (30 %wt. GFs and 40 %wt. GPs). When the limited oxygen index (LOI) test results were examined, 40 %wt. GPs and 40 %wt. GFs-added composites were determined to be the material with the highest non-flammability. This value shows that the flammability was improved when the required amount of oxygen increased from 37 % to >50 % compared to that of pure novolac.
In this study, effect of recycled zinc powder reinforcement ratios and ball milling time on novolac matrix hybrid composites were investigated. The ball milling time of 2 h showed a positive effect ...on the hardness of the composites up to 100 HRM. Thermal analysis results showed that the increasing zinc reinforcement ratio was increased thermal stability of the composite powders. The assessment of wear resistance was conducted using a block-on-ring tribometer, and the results demonstrated that the incorporation of zinc particles significantly decreased wear rates. Additionally, 2 h ball milling times showed superior wear resistance. Specimens with 20 wt% Zn reinforcement and subjected to 2 h ball milling time exhibited approximately 93% less wear loss than Zn-free specimens.
•Zinc powder recycled from waste Zinc anode.•Novolac matrix Zinc reinforced hybrid composites synthesized.•Thermal stability was increased with increasing Zinc reinforcement ratio.•The highest hardness value was obtained as 100 HRM.•The minimum wear rate in this study was obtained as 0.39 × 10−5 mm3/N.m.
Novolac matrix composites are crucial due to their exceptional resistance to heat, chemicals, and mechanical stress. These advanced materials find applications in aerospace, electronics, and ...automotive industries, providing high-performance solutions for components requiring superior durability and reliability. In this context, the microstructure, thermal, phase, and mechanical properties of the composites obtained as a result of the recycling-oriented reinforcement of the waste candle-soot (CS) reinforcement at the rate of 1 wt% to the pure novolac (PN) and shaping with the hot press method were examined in detail at first time in the literature. While microstructural properties and fracture mechanisms were investigated by scanning electron microscopy (SEM), thermal properties were investigated by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The results obtained provided critical findings as the composite hardness, tensile strength, and flexural strength values were 3.28, 2.47, and 3.21 times higher than PN, respectively. CS-reinforced novolac composites made a significant contribution to the literature by introducing a novel and eco-friendly approach to enhance material properties. Their use as a filler material provided insights into sustainable novolac composites, offering potential applications in various industries, such as electronics and aerospace, with improved mechanical and thermal properties.
This study extensively investigates the effects of 10 wt% graphite reinforcement and varying B4C content (1 wt%, 2 wt%, 4 wt%) on the properties of Novolac matrix polymer composites prepared by ...mechanical milling-assisted hot pressing. The microstructures, wear surfaces, wear debris, and fracture surfaces of the produced polymer composites were examined using SEM and EDS. The density measurements were conducted according to the Archimed’s principle. Their tribological behavior was evaluated with a reciprocating ball-on-flat sliding wear test at 50 N, 75 N, and 100 N loads. After the wear tests, surface topography was analyzed in 3D with an optical profilometer. The results indicated that composites with 2 wt% B4C had the lowest specific wear rate and the highest wear resistance.
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In this study, Ag coated ABS granules were fabricated by using different plating bath composition and diameter of ABS granules and the effect of the Ag coated ABS granule content and hot-pressing ...temperature on the properties of microstructure evolution and novel Ag/ABS composites were also investigated. As a result of the study, it was found that there is a direct relationship between the composition of the coating bath and the coating. It was also observed that the diameter of the substrate directly affects the coating quality as it directly affects the total amount of granules surface area in the coating bath. The relative amount of silver deposited on the substrate decreased with increasing granule diameter. For the smallest granule diameter, 93 wt.% silver content was determined, while for the highest granule diameter this value was 87.4 wt.%. The increase in formability properties with increasing temperature led to an increase in the hardness properties of the bulk samples up to a certain temperature value. The highest hardness values were obtained at the temperature of 210 ℃ in the hot pressing.
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In this comprehensive study, we investigated the mechanical and wear characteristics of AISI 4140 steel specimens subjected to quench hardening and coated with Titanium Carbo Nitride (TiCN) using the ...Physical Vapor Deposition (PVD) technique. Our analysis encompassed microstructure characterization, cross-sectional examination of the coating layer, phase analysis, microhardness evaluation, and wear behavior assessment, aiming to discern the combined impact of TiCN coating and pre-hardening treatment. The surface imaging and characterization of the coating layer were conducted employing Energy Dispersive Spectroscopy (EDS) assisted Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD) techniques. Hardness measurements were performed utilizing a microhardness testing apparatus. Furthermore, wear assessments were executed employing a ball-on-disc tribometer, employing two distinct loads of 20 and 40 N. Results revealed that the pre-hardening process led to a remarkable coating surface hardness of 2473 HV, surpassing the 2230 HV recorded in AISI 4140 steel without pre-hardening. Pre-hardening notably improved coating thickness and hardness, and substantially reduced wear rates, especially when combined with TiCN coating. In conclusion, the combined approach of pre-hardening and TiCN coating emerges as a highly effective strategy for enhancing the mechanical and wear properties of this steel alloy.
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•Researching the influence of TiCN coatings by PVD method on the properties of 4140 steel•Pre-coating heat treatment for microstructure refinement and creating a more suitable substrate surface for the coating•Strong adhesion on the interface of the TiCN coating layer due to water quenching of substrate.•Pre-hardening water quenching's effect on wear resistance before TiCN coating applications•Pre-coating water quenching as a pre-treatment significantly enhances wear characteristics.
