Search Results (269)

This study reports poly(acrylic acid) (PAA)-containing ceria slurries for shallow trench isolation (STI) chemical mechanical polishing (CMP). HNU15 ceria nanoparticles were prepared by precipitation at room temperature. PAA was synthesized by aqueous free-radical polymerization, characterized by gel permeation chromatography and Fourier-transform infrared spectroscopy, and used as the polymeric dispersant in both HNU15 and commercial HC10 slurries. The primary-particle sizes determined by TEM were 12.2 ± 1.5 nm for HNU15 and 14.6 ± 1.4 nm for HC10, whereas the crystallite sizes calculated from XRD were 10.2 nm and 8.7 nm, respectively. HNU15 showed a higher BET surface area and Ce³⁺ fraction than HC10, indicating measurable differences in textural properties and surface chemical states. After 5 h of milling, the HNU15 and HC10 slurries exhibited DLS d₅₀ values of 111 nm and 122 nm and zeta potentials of −53.60 mV and −49.40 mV, respectively. Both slurries maintained generally stable colloidal properties during four weeks of storage at 25 °C and 60 °C. Under the laboratory CMP conditions, HNU15 slurry exhibited an HDP-SiO₂ removal rate of 114.4 Å min⁻¹, an HDP-SiO₂-to-Si₃N₄ selectivity of 8.0, and lower post-polishing roughness than HC10. These results support the use of the PAA-containing HNU15 slurry for STI CMP applications. Full article

This study addresses the need for dark-current control and stable current response in planar high-purity germanium (HPGe) detectors for low-energy X-ray detection. A device fabrication strategy based on the coupled optimization of near-surface treatment, N/P junction formation, and guard-ring electrode design is proposed. Unlike previous studies that mainly focused on contact-layer fabrication, segmented electrode structures, low-noise readout, or response simulation, this work investigates low-damage near-surface construction, N-type and P-type contact-layer formation, and edge-related leakage-current regulation as an interconnected processing route. The relationship among the near-surface state, junction quality, electrode configuration, and edge-related leakage current is emphasized. Chemical mechanical polishing (CMP) reduced the surface roughness Sa of the HPGe crystal to 6.68 nm, providing a low-damage near-surface foundation for subsequent junction fabrication. On this basis, the optimized Li thermal diffusion process, namely 0.5 Å s⁻¹, 325 °C, and 5 min, formed an N-type contact layer with preserved lattice ordering and favorable electrical properties. B ion implantation combined with rapid thermal processing (RTP) achieved acceptor activation and implantation-damage recovery, and the condition with Rp = 198.1 nm showed relatively better structural recovery and electrical characteristics. After introducing the guard-ring electrode, the dark current of the device at −20 V decreased from 6.5 × 10⁻⁹ A to 2.03 × 10⁻⁹ A, and a stable switching current response was obtained under 12 keV monochromatic synchrotron X-ray irradiation. Geant4 simulations were further used as an auxiliary analysis to evaluate the effect of the guard-ring structure on the simulated response spectra and full-energy peak efficiency (FEPE) for low-energy X-rays. Overall, this study provides experimental evidence for process optimization of planar HPGe detectors with low dark current and stable low-energy current response. Full article

Single-crystal diamond (SCD) has the characteristics of a hard surface and stable chemical properties, making it difficult to achieve ultra-smooth and ultra-low-damage surface polishing using conventional polishing slurries. In this study, a novel green chemical mechanical polishing (CMP) slurry containing only hydrogen peroxide, nicotinic acid, silica (SiO₂) abrasive particles and deionized water was developed to achieve ultra-smooth, ultra-low-damage (0.5 nm) and atomic-scale surface roughness (Ra 0.473 ± 0.035 nm) polishing of SCD. Additionally, the influence of diamond, silicon carbide and SiO₂ abrasive particles on the surface quality of SCD after CMP was investigated by single-factor experiments. Based on XPS characterization, the mechanism of SCD CMP was revealed: the SCD surface was first oxidized to form C-O and C=O groups, and then these groups were removed under the mechanical action of SiO₂ abrasives, ultimately achieving atomic-scale removal of the material. Full article

Brewery wastewater is a high-strength industrial effluent containing substantial organic, suspended, and colloidal fractions and therefore requires multistage treatment. This study evaluated sedimentation, prefiltration, coagulation, ceramic membrane filtration, and reverse osmosis (RO) polishing for improving the quality of actual brewery wastewater under short-term laboratory conditions. The acidic wastewater had chemical oxygen demand (COD), biochemical oxygen demand (BOD₅), and dissolved organic carbon (DOC) values of 48,230 mg O₂/L, 34,160 mg O₂/L, and 6492 mg C/L, respectively. Three configurations were investigated: mechanical treatment; PIX 113 coagulation followed by ceramic microfiltration (MF), ultrafiltration (UF), or fine UF; and an integrated UF-RO system. Performance was assessed using contaminant removal, relative permeate flux (J/J₀), particle size analysis, dynamic light scattering, and zeta potential. Sedimentation and prefiltration provided limited treatment, whereas coagulation effectively destabilized colloids; a PIX 113 dosage of 2 mL/L was selected as a favorable compromise among the tested dosages. Among the ceramic membrane-based trains, the train ending with the 1 kDa membrane produced the highest-quality permeate, with overall COD, BOD₅, and DOC removals of 78.2%, 88.7%, and 49.8%, respectively. The tested sedimentation–prefiltration–coagulation-50 kDa UF-RO train achieved the highest overall removals: 97.9% COD, 98.6% BOD₅, and 94.0% DOC. The overall removals of chloride and nitrate ions in this train were 92.5% and 68.5%, respectively. The results indicate that coagulation-assisted ceramic membrane filtration followed by RO can substantially improve permeate quality. The novelty of the work lies in linking coagulation-assisted ceramic membrane filtration and RO polishing with particle-size and electrokinetic characterization, thereby clarifying the role of each treatment barrier and identifying an effective laboratory-scale train for upgrading high-strength brewery wastewater. Full article

Additive Manufacturing (AM) for jewelry applications is increasingly adopting Binder Jetting (BJ) to overcome the fusion-related limitations associated with precious metals, including unstable melt pools, excessive reflectivity, and high thermal conductivity. In this context, the present review establishes a thermophysical and manufacturability-oriented framework that redefines thermal management beyond localized melt-pool stabilization toward the furnace-scale control of densification kinetics, shrinkage evolution, atmosphere-assisted sintering, and viscoplastic deformation. Particular emphasis is placed on gold-, silver-, and platinum-based jewelry alloys, with a specific focus on the thermal, mechanical, and chemical phenomena governing Binder Jetting sintering. During consolidation, low-density green bodies (~40–65% relative density) must transform into highly dense components through extensive volumetric shrinkage and gravity-driven deformation, creating major challenges in dimensional fidelity and surface quality. The review further examines predictive viscoplastic constitutive models (SOVS/ROH), reversed-deformation compensation strategies, and atmosphere-engineering approaches for oxide reduction, pore-pressure regulation, and residual-porosity control. By linking thermophysical consolidation, dimensional fidelity, polishability, and jewelry-grade manufacturability within a hierarchical framework, this review provides a structured basis for the development of high-precision and low-waste precious-metal additive manufacturing. Full article

Monocrystalline silicon, with its high refractive index, high infrared transmittance, and excellent dimensional stability, serves as a key optical component in high-energy laser systems, infrared imaging, and guidance fields. Its processing quality directly affects the performance indicators of related systems. To address the challenges of nanoscale precision shape and property control during processing, methods such as ultra-precision cutting, magnetorheological polishing, laser micromachining, ion beam processing, plasma etching, and chemical–mechanical polishing have been adopted to improve the surface shape accuracy and repair defects of monocrystalline silicon components. This paper reviews the research progress of key technologies, including nanoscale precision surface shape control manufacturing technology, nanoscale precision property control generation methods, and combined processes for its nanoscale shape and property control, providing technical support for achieving nanoscale precision shape and property control manufacturing of monocrystalline silicon components. Full article

This study investigates the effects of post-processing on the surface roughness, wettability, and frictional behavior of selective laser-melted (SLM) cobalt–chromium–tungsten (CoCrW) alloys for orthodontic use. The SLM-CoCrW specimens were tested in as-manufactured, mechanically polished, and electropolished states. Surface characterization via stylus profilometry and atomic force microscopy (AFM) showed that both polishing methods reduced macro- and micro-scale roughness, with electropolishing producing the smoothest, most uniform topography. Static water contact angle (WCA) measurements revealed that mechanical polishing provided an optimal balance of roughness and hydrophilicity, resulting in the lowest friction, while ultrasmooth electropolished surfaces exhibited slightly higher friction due to increased hydrophobicity and a uniform Cr-rich oxide layer confirmed by X-ray photoelectron spectroscopy (XPS). XPS also indicated that electropolishing generated a homogenous chromium oxide passive film, whereas mechanical polishing left a chemically heterogeneous surface with exposed metallic sites. Importantly, performance is not governed solely by surface roughness; surface chemistry is equally critical, and both must be considered together—along with wettability and tribological behavior—to achieve optimal functional outcomes. From a clinical perspective, optimization of surface roughness and surface chemistry may result in decreased frictional resistance, improved sliding mechanics, and enhanced long-term performance of additively manufactured orthodontic components; however, the present study was restricted to in vitro characterization under simplified laboratory conditions, and further investigations involving artificial saliva, long-term aging, wear and clinical simulations are necessary to validate the translational relevance of these findings. Full article

To address surface quality defects caused by traditional mechanical polishing of gears, such as machining scratches and large surface waviness, this study proposes a novel immersed chemical-mechanical polishing (CMP) process for gear finishing. Numerical simulations were conducted in FLUENT to analyze the gear surface stress distribution and polishing fluid flow trajectories under different process conditions. The Euler–Euler method and RNG k–ε turbulence model were used to optimize process parameters and clarify the formation mechanism of ultra-smooth tooth surfaces. Experimental results for spiral bevel gears show that the proposed immersed CMP process effectively improves surface quality. The tooth profile roughness was reduced from Ra 1.531 μm to 0.509 μm, and surface scratches were significantly alleviated. These results confirm the feasibility and effectiveness of the proposed process. This study provides a reliable approach for efficient and precision polishing of complex-structured gears and extends the application of CMP technology to non-planar mechanical components. Full article

Single-crystal diamond (SCD) is an ideal substrate material for semiconductor devices due to its extremely wide bandgap and exceptionally high thermal conductivity. However, diamond’s extreme hardness and chemical inertness pose challenges for the fabrication of ultra-smooth surfaces. Traditional polishing processes are not only inefficient but also prone to introducing subsurface defects, which severely degrade device performance. To address the above issues, this study proposes a hybrid polishing process combining reactive ion etching (RIE) surface modification with chemical mechanical polishing (CMP), which enables low-loss atomic-level processing of SCD. The study found that RIE treatment induces lattice disorder on the diamond surface, forming a sp²-hybridized amorphous carbon-modified layer. Compared to the sp³ structure of native diamond, this modified layer has lower hardness and is easier to remove. We conducted the verification of the optimized process using high-quality single-crystalline diamond (SCD) samples with an initial surface roughness Ra of 0.68 nm. Under the optimized RIE parameters (substrate bias power: 200 W, etching time: 600 s, gas flow ratio of Ar:O₂:CF₄ = 40:50:10), the surface roughness Ra was reduced to as low as 0.35 nm after 2 h of CMP treatment. Furthermore, systematic characterization of the SCD’s as-received surface, RIE-modified surface, and CMP-treated surface was performed using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS), elucidating the “etching modification–mechanical removal” polishing mechanism. Full article

Polyetheretherketone (PEEK) is a high-performance thermoplastic polymer with low surface energy, chemical inertness, and a highly crystalline structure, which limit durable adhesion to resin-based materials and require improved bonding strategies. This in vitro study evaluated the effect of incorporating multifunctional methacrylate (TMPTMA) and acrylate monomers (A-TMPT and A-DPH) into an experimental primer on the 24 h shear bond strength (SBS) of resin cement to PEEK (n = 6 per group). Experimental primers were prepared by adding varying amounts (100–500 µL) of each multifunctional monomer to a UDMA/MMA-based primer, and SBS was measured after cementation with a dual-cure resin cement. TMPTMA-containing primers produced median SBS values of approximately 10–12 MPa, while acrylate-based primers showed slightly higher values, particularly at higher concentrations, reaching up to ~15.8 MPa; however, no statistically significant improvement over the control group was observed (p > 0.05). Failure modes were predominantly mixed across all conditions. These findings indicate that multifunctional monomers, despite their potential to enhance cross-link density and wetting, do not substantially overcome the intrinsic adhesion-resistant nature of polished PEEK. The results underscore that monomer modification alone is insufficient and that effective adhesion to PEEK likely requires integrated strategies combining chemical activation with mechanical surface conditioning. Full article

Achieving efficient and high-quality surface processing of single-crystal diamond (SCD) remains challenging due to its extreme hardness and chemical inertness. Traditional Fenton-based slurries using H₂O₂ suffer from poor stability, safety risks, and strict acidic pH requirements. In this study, peroxymonosulfate (PMS) is introduced as an alternative oxidant to develop a novel chemical mechanical polishing (CMP) slurry for SCD. Compared with H₂O₂, PMS exhibits higher stability and generates sulfate radicals (SO₄⁻·) with stronger oxidation capability when activated by Fe²⁺. The proposed slurry achieves efficient material removal over a wider pH range (2–6). Under optimal conditions (pH = 3), a maximum material removal rate (MRR) of 676 nm/h is obtained, along with an ultra-smooth surface (Sa = 0.177 nm in the measuring area of 868 × 868 μm²). Notably, the slurry maintains high MRR (>400 nm/h) even under weakly acidic conditions (pH 5–6). XPS and radical quenching experiments confirm that continuous generation of reactive radicals promotes surface oxidation and stable material removal. This work provides a stable and efficient CMP slurry for SCD with enhanced pH adaptability. Full article

The pulping and paper-making (P&P) industry is one of the world’s largest manufacturing sectors, yet it is plagued by high water/energy consumption and massive discharge of highly polluted wastewater. The effluents from pulping, bleaching and papermaking processes are characterized by high chemical oxygen demand (COD), intense color, toxic adsorbable organohalides (AOX) and abundant refractory lignin, which pose significant threats to aquatic ecology and human health. Although conventional physical, chemical and biological treatments have been widely applied, they are constrained by insufficient degradation efficiency toward recalcitrant organics, high cost and potential secondary pollution. In recent years, electrocatalytic technologies including electrocatalytic oxidation, electroreduction and their integrated processes, have demonstrated superior efficacy in specific scenarios of P&P wastewater treatment, such as lignin degradation, toxic side-streams treatment, pretreatment for enhancing biodegradability, and polishing steps in integrated treatment systems, which are not universally applicable solutions for P&P wastewater remediation. Meanwhile, biomass fuel cells typified by direct biomass fuel cells (DBFC) and microbial fuel cells (MFC) provide promising pathways for synchronous pollutant removal, energy production and resource recovery. Representative studies have reported COD removal efficiencies of 60–100% for electrochemical and advanced oxidation processes, while integrated electro-Fenton–biological treatment increased the BOD/COD ratio from 0.34 to 0.52 and achieved an overall COD removal of 94%. It should be noted that these advanced electrochemical technologies are still confronted with challenges in industrial scale-up, high energy and electrode material costs, and stable continuous operation. This review systematically elaborates on the physicochemical properties, generation mechanisms and environmental impacts of P&P wastewater, comprehensively summarizes the mainstream treatment technologies including physicochemical, biological, electrochemical and integrated processes, and analyzes their reaction mechanisms, efficiencies and applicable conditions. Particular emphasis is placed on electrocatalytic treatment and bio-electrochemical valorization strategies. This review is anticipated to provide a valuable reference for the efficient and targeted treatment as well as sustainable utilization of P&P wastewater, thereby supporting the green and low-carbon development of the P&P industry. Full article

Water pollution due to insufficient wastewater treatment is a global concern. In this paper, coagulation and flocculation as a tertiary polishing unit process were investigated to find a solution for a non-compliant wastewater treatment facility. The Palapye Pond Enhanced Treatment and Operation (PETRO) system has not been compliant for a long time with effluent characterised by high turbidity, Biological Oxygen Demand/Chemical Oxygen Demand (BOD/COD), Total Suspended Solids (TSS), Nitrates (NO₃⁻), and Phosphates (PO₄³⁻) The effluent from the plant is released into the stream that drains into the nearby Lotsane dam, posing significant danger to the water quality of the dam. The main objective of the study was to investigate the effect of coagulation and flocculation processes at the tertiary stage of the wastewater treatment process. Response Surface Methodology (RSM), Central Composite Design (CCD) and Multi Response Surface (MRS) were used to optimise the coagulation process and generate regression models to predict the coagulation and flocculation. The performance was evaluated using turbidity, Colour, COD and TSS as response variables. Response surface analysis indicated that the experimental data could be adequately fitted to quadratic polynomial models. Under optimum conditions the removal efficiency for Al₂(SO₄)₃·18H₂O: 91.1% (turbidity), 88.2% (colour), 58.9% (COD), 83.0% (TSS); for FeCl₃·6H₂O: 93.2%, 88.7%, 63.8%, 91.3%; for Moringa: 91.8%, 85.4%, 56.6%, 83.7%. The optimal removals based on MRS for Al₂(SO₄)₃.18H₂O, FeCl₃.6H₂O and Moringa oleifera were 90.7%, 89.7%, 59.9% and 88.5%; 94.7%, 90.8%, 58.1% and 93.8%; 94.0%, 87.2%, 60.1% and 82.1% for turbidity, colour, COD and TSS respectively. This research has demonstrated that the coagulation/flocculation process, operating synergistically with pH-induced precipitation softening, can be incorporated as an enhancement to the secondary treatment stage of the wastewater treatment facility. At the optimal alkaline conditions (pH 12–12.6), the dominant mechanism is the precipitation of native hardness ions (Mg²⁺, Ca²⁺) as Mg(OH)₂ and CaCO₃, which enmesh colloidal particles, while the added coagulants play a refining role by enhancing floc structure and settling. The study introduces a comparative evaluation of three coagulants within a single RSM-CCD optimisation framework, employing desirability functions for multi-response optimisation. Full article

This study investigates the effect of chemical modification of xylite—a fraction derived from Polish lignite—using succinic anhydride (SA) on the morphology and mechanical performance of isotactic polypropylene (iPP) composites. Xylite was incorporated at loadings of 1, 10, and 25 wt% and in two particle size ranges (40–63 µm and 63–125 µm), with and without SA (0.5 and 2 wt%). The composites were characterized by wide-angle X-ray scattering (WAXS), Fourier-transform infrared spectroscopy (FTIR), and tensile testing to evaluate crystallinity (X_c), β-phase content (k_β), and mechanical properties. Unmodified xylite reduced crystallinity (X_c down to ~37%) and significantly decreased ductility, with elongation at break strongly negatively correlated with filler content (r ≈ −0.68), indicating poor dispersion and weak interfacial adhesion. In contrast, SA addition (0.5–2 wt%) partially restored crystallinity (up to ~48%) and increased stiffness (Young’s modulus up to 2120 MPa), while altering β-phase content. FTIR analysis indicated reduced intermolecular hydrogen bonding between xylite surface hydroxyl groups in the presence of SA, consistent with interfacial chemical interactions, likely via esterification. The β-phase content showed a moderate positive correlation with xylite loading (r = +0.43) and a negative correlation with elongation at break (r = −0.46), suggesting that excessive β-phase formation may reduce toughness. Larger particles (63–125 µm) provided slightly improved elongation at break and stiffness. Overall, SA acts as both a compatibilizer and a morphology-directing agent, enabling precise control of the stiffness–ductility balance and crystalline structure in iPP/xylite composites. These results establish chemically modified lignite-derived fillers as a viable strategy for engineering cost-efficient polyolefin materials with tunable structure–property relationships, offering strong potential for scalable industrial implementation. Full article

The effects of mass fractions of ferric chloride (FeCl₃) and oxalic acid (H₂C₂O₄) in polishing slurry on the polishing of 304 stainless steel were studied. The stainless steel polishing experiments with different compositions of polishing liquids were designed, the material removal rate was calculated, the surface roughness value was measured, and the Fe²⁺ content in the polishing waste liquid was determined by spectrophotometry. The mechanism of FeCl₃ on stainless steel polishing was investigated. The results indicated the existence of the reaction 2Fe³⁺ + Fe → 3Fe²⁺ during the polishing process; Fe³⁺ in the polishing slurry promoted the reaction and significantly increased the material removal rate; and the composition ratio of the FeCl₃-H₂C₂O₄ slurry for polishing 304 stainless steel was optimized. After optimization, the material removal rate achieved more than 200 nm/min, and the surface roughness after polishing was reduced to less than 10 nm. Qualitative analysis of the surface material of the polished 304 stainless steel with FeCl₃ polishing slurry by XRD proved that the phase of the matter was basically unchanged. This experiment provides reference value for the preparation of polishing slurry for 304 stainless steel. Full article