Chemical Polishing Process Research Articles

SAL5087 bright welding wire two acid polishing process and its effect on surface roughness

Abstract In order to obtain bright aluminum alloy wires and eliminate the environmental and human hazards of traditional chemical polishing, the H3PO4-H2SO4 system chemical polishing process was developed for SAL5087, and the surface roughness was measured by laser confocal microscopy and the surface morphology was observed by sweeping electron microscopy as the evaluation index of the polishing quality. The process optimization was carried out by orthogonal experiments and the role of each component was analyzed. The experiments showed that phosphoric acid dominates the polishing process, which can effectively enhance the polishing effect under the synergistic effect with various additives. The surface roughness of the polished wire was reduced to 0.257 μm in the optimum process, and the surface was free of defects such as burrs and scratches.

Novel hybrid chemical magnetorheological fluid for polishing Ti–6Al–4V alloy

ABSTRACT This study presents a highly efficient chemical and magnetorheological fluid (C-MRF) hybrid polishing process established by using an eco-friendly slurry of malic acid, Fe3O4–SiO2 abrasive particles, and hydrogen peroxide (H2O2) as an oxidant, all mixed with purified water, highlighting its efficacy in a wide range of polishing applications. Herein, the polishing processes of Ti–6Al–4V alloy utilizing C-MRF with on Fe3O4–SiO2 abrasives are detailed, and the polishing performance is assessed by investigating the influence of oxidizing agent H2O2 and acid malic to the surface finish of the Ti–6Al–4V alloy. The linear variable magnetic field by improved Halbach array was proposed to improve the material removal rate and surface quality and create a polishing process with a highly efficient magnetic field source. Single-factor and orthogonal experimental analysis methods are applied to provide the technological parameters factors with varying influences on surface quality and material removal ability.

A Surface Composition Study of Niobium after BCP for SRF Cavity in Particle Accelerator

Nitrogen contamination from post-processing significantly affects the performance of niobium superconducting radiofrequency (SRF) cavities. Therefore, several performance-boosting strategies, including nitrogen doping, infusion and chemical acid reactions, have been explored in various studies. Among these studies, some secondary ion mass spectrometry (SIMS) results showed that nitrogen contamination exists on the niobium surface after the buffered chemical polishing (BCP) process. However, the compositions of these nitrogen byproducts were hard to detect. In this work, we calculated the chemical reaction process by the density function theory (DFT), predicted the reaction product, and then analyzed the Nb sample surface after BCP with X-ray Photoelectron Spectroscopy (XPS) to determine the composition of these contaminations.

A Systematic Study of the Factors Affecting the Surface Quality of Chemically Vapor-Deposited Diamond during Chemical and Mechanical Polishing.

Diamond surfaces must be of high quality for potential use in semiconductors, optical windows, and heat conductivity applications. However, due to the material's exceptional hardness and chemical stability, it can be difficult to obtain a smooth surface on diamond. This study examines the parameters that can potentially influence the surface quality of chemically vapor-deposited (CVD) diamonds during the chemical and mechanical polishing (CMP) process. Analysis and experimental findings show that the surface quality of polished CVD diamonds is significantly influenced by the crystal structure and the growth quality of the diamond. In particular, when the surface roughness is below Ra 20 nm, the pores and grain boundaries on CVD diamond obstruct surface roughness reduction during mechanical polishing. To obtain a smooth polished surface, careful consideration of the size of diamond abrasives and polishing methods is also a prerequisite. Chemical mechanical polishing is a novel method to achieve a surface quality with roughness below Ra 3 nm, as in this method, the anisotropy of the CVD diamond allows the uneven steps to be efficiently erased. However, the chemical actions of polishing slurry should be controlled to prevent the formation of chemical etching pits.

Passivation-free high performance self-powered photodetector based on Si nanostructure-PEDOT:PSS hybrid heterojunction

Hybrid heterojunction between organic PEDOT:PSS and inorganic Silicon (Si) nanostructures is promising for high-performance self-powered photodetectors due to their favourable band energetics and ease of processing. Traditionally, Si nanostructures require additional passivation layers to reduce surface defect states, which adds complexity and involves the use of harmful organic solvents. Here in, we demonstrate a simple chemical polishing process to reduce defects and fabricate a conformable heterojunction between Si nanostructures and PEDOT:PSS. Si nanostructures fabricated by metal-assisted chemical etching (MACE) technique and subsequently treated by the chemical polishing process are spin-coated with PEDOT:PSS to form heterojunction and employed as self-powered broadband photodetector. The optimized device shows superior performance, such as high responsivity of 555.34 mA/W, quick rise/fall times of 79 ms/81 ms, high External Quantum Efficiency (EQE) of 0.8 at zero bias (0 V) and high photostability up to 500 illumination cycles. Dark I-V characteristics and carrier lifetime measurements reveal that the enhanced performance of chemically polished devices is attributed to the formation of a conformable heterojunction and reduction in defects in the Si nanostructures. Given the scalability and simplicity of the demonstrated passivation-free approach, this work may aid the fabrication of high-performance hybrid Si nanostructured photodetectors.

Evaluation of Treatment Effect and Mechanism Analysis of Ti6AL4V Porous Scaffolds Prepared by Selective Laser Melting with Different Chemical Polishing Processes

Evaluation of Treatment Effect and Mechanism Analysis of Ti6AL4V Porous Scaffolds Prepared by Selective Laser Melting with Different Chemical Polishing Processes

Laser‐Activated Selective Electroless Plating on 3D Structures via Additive Manufacturing for Customized Electronics

AbstractThis work proposes a facile and economical hybrid additive manufacturing (HAM)technology combining fused deposition modeling (FDM) 3D printing and laser‐activated selective electroless plating (ELP) for fabricating full functional end‐use 3D customized electronics. A functional acrylonitrile butadiene styrene (ABS) filament doped with dicopper hydroxide phosphate (Cu2(OH)PO4) catalysts is developed for FDM 3D printing. The 3D printed structure is selectively laser‐activated to generate CuI plating seeds on the ABS surface and then electrolessly plated. The poor surface finish, especially the layer lines, is an intrinsic defect of extrusion 3D printing, which not only affected the fabrication quality of the 3D substrates but also the electrical performance of the attached circuitry. Herein, a chemical polishing process based on acetone vapor is explored and characterized to significantly improve the surface quality and thereby the electrical performance of the attached copper layer. In this way, highly conductive metallic circuitry can be freeformly deposited and patterned on the 3D structure which is extremely attractive for customized 3D electronics. To show the application potential of this technology, a 3D conformal 555 timer astable oscillator circuit board and a hot‐wire flowmeter are developed as demonstrators.

Study on new magnetorheological chemical polishing process for GaN crystals: polishing solution composition, process parameters, and roughness prediction model

High-quality and high-efficiency processing of gallium nitride (GaN) crystals is urgently required for optoelectronic communications and other major industries. This study proposes a novel high-efficiency non-damage magnetorheological chemical polishing (MCP) process to overcome the existing problems of low efficiency and lattice distortion during processing. The effects of the MCP fluid composition and key processing parameters on the surface roughness and material removal rate (MRR) of GaN crystals were studied experimentally. The results showed that a compounded abrasive containing silica fluid exhibited better polishing effects than a single abrasive. The polishing efficiency could be improved by adding NaOH solid particles, and the MRR reached 13.19 nm min−1 when the pH of the MCP fluid was 10. The MRR increased gradually with an increase in the pole rotation speed and worktable speed and a decrease in the polishing gap. The surface roughness of the GaN crystals was improved from Ra 115 nm to Ra 0.375 nm after polishing for 4 h. The surface and sub-surface damage of the polished GaN crystals was analyzed using scanning electron microscope and transmission electron microscope. The results confirmed that the MCP process can realize the non-damage polishing of GaN crystals. Moreover, a prediction model for the surface roughness of GaN crystals in the MCP process was constructed. The overall difference between the actual and predicted surface roughness values for the model was 11.6%.

A novel dry processing technique to construct a high-performance superfine diamond grinding wheel with thermal and material characterizations

A novel dry process that prepared in mixing with a pore-forming agent employs a single batch process in production of grinding wheels with the advantage without using resin liquid as an additive binder. The agglomeration of a pore-forming agent can be avoided due to no dressing agent mixing with the superfine diamond abrasives and binders. Bulk mass production can still ensure to fulfill the excellent homogeneity in mixing cross the entire grinding wheel. Therefore, an uneven mixing caused by mixing errors and human factors can be minimized. The grinding wheel can reach an ultrahigh porosity (~82 %) at a lower sintering temperature of 620 °C. Low-temperature sintering can effectively reduce the carbon footprint. A thermogravimetric-differential scanning calorimeter (TG-DSC) was used to determine the thermal properties of superfine frits. Further characterization of ultrafine binders by an optical non-contact dilatometry is utilized to set-up a protocol sintering plan of grinding wheels. Microstructure from scanning electron microscope (SEM) measurement on grinding wheel presents a uniform large pore structure which offers a benefit to wafer surface removal and less scorching during grinding. Atomic force microscopy (AFM), laser scanning digital microscope (LSCM) and SEM results revealed that the ground silicon (Si) wafer had a low surface roughness (~6 nm), without deep scratches, and with a low damaged layer (~0.7 μm) respectively. The wear test on grinding wheels demonstrates it is very cost effective to use a dry processing wheel. This work provides a new method for grinding Si wafers with a new type of wheel being developed by a novel dry superfine diamond grinding technique in a manufacturing process. It is realized that the use of a dry grinding process can save part of chemical polishing process (CMP) and effectively reduces the polishing time.

Mechanical chemical polishing of large-size single-crystal diamond substrates with a sol-gel polishing tool

To process large-size single-crystal diamond (SCD) substrates efficiently, we proposed a method that utilises mechanical action to induce a chemical reaction for SCD polishing. In this study, a novel semi-fixed abrasive polishing tool suitable for high-speed polishing was fabricated using the sol-gel technique. A single-diamond abrasive and a mixed abrasive of diamond and CuO were selected for the SCD (100) plane polishing. After polishing for 2.5 h, the surface roughness of the SCD was reduced from approximately Ra 80 nm to approximately Ra 9 nm. The material removal rate (MRR) was measured quantitatively, and it was found that the mixed abrasive polishing performance was superior. In addition, the amorphous carbon content on SCD surface/subsurface after mixed abrasive polishing was significantly lower than single-diamond abrasive diamond abrasive. These results indicate that the scratching of the SCD surface by diamond abrasives induced the transformation of the carbon into amorphous carbon, which could then react with CuO powder. The wear debris morphology indicates that the surface material of the SCD was peeled off with a slice shape during single-diamond abrasive polishing, while it was removed with a slag-shape by the chemical reaction and slightly crushed during the mixed abrasive polishing. The material removal process for the mixed abrasive polishing was CDia→MechanicalCAmo→CuOCu+CO, which is a mechanical chemical polishing process. Experiments confirmed that the synergistic effects of the mechanical action and chemical reaction could increase the MRR and produce a smoother surface and less damage to the subsurface of the SCD, which provides inspiration for the processing of large-size SCD substrates.

A template-free, more environmentally friendly approach for glass micro-texturing

Micron and nanometer size textured silicate glass surfaces are of interest in consumer electronics, photovoltaics, and biosensing applications. Typically, texturing glass surfaces requires applying a patterned mask or a pre-etching treatment (e.g. sandblasting) on the glass substrate, followed by a mask transferring or etching process using a fluoride-containing compound. The major challenges of such a process are the complexity and cost of masking, and the safety and environmental concerns around the usage and disposal of hydrofluoric acid. Here, we describe a template-free method to construct micron-sized and submicron-sized texture on isotropic glass surfaces in one step. The new texturing mechanisms are well supported by experimental data and peridynamic simulations. With this novel strategy, the etchant uses fluoride-free chemicals such as citric acid to texture silicate glass. Etchant concentration, etch temperature, time, and additives are the primary parameters that dictate the texturing process. Surface feature size and depth can be independently controlled by tuning the leaching and chemical polishing process. We hope this study can trigger more research on novel and more environmentally friendly texturing of isotropic materials.

Role of micro-nano fabrication process on the temperature coefficient of resistance of platinum thin films resistance temperature detector

In this work, we studied the effect of micro-nano fabrication process on the temperature coefficient of resistance (TCR) of platinum thin films temperature detector (Pt RTD) prepared on alumina ceramics (Al2O3) substrate, focusing on substrate chemical polishing process (CMP) and platinum films annealing process. It is found that CMP process can effectively improve the TCR of Pt RTD, and the smaller polish particle size is, the larger TCR will be. Annealing process can also significantly improve the TCR of the Pt RTD. After annealing treatment, the TCR increased from 2800 ppm/°C at 500 °C to 3439 ppm/°C at 1100 °C.

Ground fused silica processed by combined chemical etching and CO2 laser polishing with super-smooth surface and high damage resistance.

Laser damage in fused silica, particularly ultraviolet laser damage, is still a key problem limiting the development of high-power laser systems. In this Letter, a combined process of chemical etching and CO2 laser polishing was applied to ground fused silica. A super-smooth surface with a root-mean-square roughness of 0.25 nm was achieved through this combined process. Furthermore, the combined process can reduce the introduction of photoactive metal impurity elements, destructive defects, and chemical-structure defects, resulting in a 0% probability damage threshold nearly 33% higher than a conventional chemical mechanical polished sample for a 7.6 ns pulse at a wavelength of 355 nm.

A Flexible Piezoelectric Strain Sensor Array With Laser-Patterned Serpentine Interconnects

In consideration of its high electromechanical coupling coefficient, thinned piezoelectric thick film from the bulk materials by chemical and mechanical polishing (CMP) process is used for high-performance piezoelectric harvesters and flexible sensors. Here, the flexible strain sensor 3 × 3 array based on CMP fabrication method is presented for the first time, and the laser-patterned flexible stainless steel serpentine wires as interconnects signal. The testing results show that the output voltages of the strain sensor array exhibit good linearity towards the corresponding strains, and also increase with the applied frequency. The maximum sensitivity of strain sensor array is 1.88 mV/μe. Moreover, this sensor array is demonstrated to monitor the surface strain of a complex structure such as the contraction and expansion of irregular balloon, which indicates its great promising in monitoring vital signs for heart healthcare.

Enhancing the Removal of Sb (III) from Water: A Fe3O4@HCO Composite Adsorbent Caged in Sodium Alginate Microbeads

To remove antimony (Sb) ions from water, a novel composite adsorbent was fabricated from ferriferous oxide and waste sludge from a chemical polishing process (Fe3O4@HCO) and encapsulated in sodium alginate (SAB). The SAB adsorbent performed well with 80%–96% removal of Sb (III) ions within a concentration range of 5–60 mg/L. The adsorption mechanism of Sb (III) was revealed to be the synergy of chemisorption (ion exchange) and physisorption (diffusion reaction). The adsorption isotherms and kinetics conformed to the Langmuir isotherm and the pesudo-second-order kinetic model. Both initial pH and temperature influenced the adsorption performance with no collapse of microbeads within solution pH range 3–7. Most importantly for practical applications, these microspheres can be separated and recovered from aqueous solution by a magnetic separation technology to facilitate large-scale treatment of antimony-containing wastewater.

Highly Sensitive Surface Acoustic Wave Flexible Strain Sensor

This letter presents a highly sensitive flexible strain sensor based on surface acoustic wave (SAW) working principle. The SAW strain sensor employs the piezoelectric single crystal PMN-PT thick film, which significantly improves the sensitivity of the strain sensor to 1243.49 Hz/ $\mu \varepsilon $ . Meanwhile, the flexible strain sensor fabricated by the chemical and mechanical polishing process can realize a wide strain measurement range from −1000 to $+ 1000\,\,\mu \varepsilon $ . The repeatability of the device is also evaluated under the strain of 0 and $900~\mu \varepsilon $ . The testing results demonstrate that this developed sensor is an excellent candidate for small stain measurement.

Adaptive neuro fuzzy determination of impactful factors on non-uniformity of polished surface

In this study, the neuro fuzzy logic selection of the most influential parameters for non-uniformity of polished surface was performed. The influence of three parameters was analyzed: carrier load, thickness and the pads elastic modulus. Adaptive neuro fuzzy logic or ANFIS was used for establishing the nonlinear relationships between the three parameters and the non-uniformity polished surface. Dataset for training and testing procedure was extracted by finite element model. According to the regression models, thickness of pad has the greatest influence on the non-uniformity. Moreover, elastic modulus and pad thickness are the optimal combination of non-uniformity. Results could be useful in the improvement of chemical polishing process.

The Optimal Crane Scheduling for Chemical Polishing Process Based on Expert System

The Optimal Crane Scheduling for Chemical Polishing Process Based on Expert System

On-wafer fabrication of cavity mirrors for InGaN-based laser diode grown on Si

Direct bandgap III-V semiconductor lasers grown on silicon (Si) are highly desired for monolithic integration with Si photonics. Fabrication of semiconductor lasers with a Fabry–Pérot cavity usually includes facet cleavage, however, that is not compatible with on-chip photonic integration. Etching as an alternative approach holds a great advantage in preparing cavity mirrors with no need of breaking wafer into bars. However, gallium nitride (GaN) sidewalls prepared by dry etching often have a large roughness and etching damages, which would cause mirror loss due to optical scattering and carrier injection loss because of surface non-radiative recombination. A wet chemical polishing process of GaN sidewall facets formed by dry etching was studied in detail to remove the etching damages and smooth the vertical sidewalls. The wet chemical polishing technique combined with dry etching was successfully applied to the on-wafer fabrication of cavity mirrors, which enabled the realization of room temperature electrically injected InGaN-based laser diodes grown on Si.

Determination of micro sized texturing and nano sized etching procedure to enhance optical properties of n-type single crystalline silicon wafer

Crystalline silicon (c–Si) wafer was manufactured by applying micro texture and nano etching process without lapping and polishing for solar cell applications. Before micro texture and nano etching, wafers were exposed to chemical polishing process in high concentrated alkaline solution to remove saw damages and obtain a surface with low surface roughness (Ra). Uniform pyramidal structures were formed in alkaline solution. On pyramidal structures, nano sized porous shapes were formed by using Ag nano particles via wet chemical etching method. Micro textured and nano etched surface formed without any chemical mechanical (CM) lapping and polishing step, examined by Scanning Electron Microscope (SEM) for surface structure and UV–visible spectrometer for reflectance and absorbance measurements. Considerably good uniform porous surface with low reflectance was formed and compared with usual solar wafers produced with CM lapping and polishing. Furthermore, present process for preparing solar cell provides low cost, short time and less material consumption by removing lapping and polishing steps from overall process. Reflectance values were measured between 7 and 10% for best micro textured and nano etched c-Si wafers, respectively. Absorbance values were measured 0.4 and 1.2% for best micro textured and nano etched c–Si wafers, respectively. Curves of \({\text{h}}{\upnu }\) versus \({\left({\upalpha }{\text{h}}{\upnu }\right)}^{2}\) indicated the optical band gaps almost 1.12 e.V. for all wafers cut from same n-type single c-Si ingot.