Showing papers on "Hydrofluoric acid published in 2016"
TL;DR: In this paper, a metal-organic framework MIL-101(Cr) was synthesized by solid-phase reaction without the addition of solvent and hydrofluoric acid at 220 °C in 4 h.
Abstract: Metal–organic frameworks MIL-101(Cr) have been rapidly synthesized by solid-phase reaction without the addition of solvent and hydrofluoric acid at 220 °C in 4 h. The obtained MIL-101(Cr) material exhibited superior catalytic activity in the oxidation of cyclohexene.
117 citations
TL;DR: In this paper, a comparison of conventional and HF free-synthesized MIL-101(Cr) for hydrogen adsorption capacity determined at 77 k up to 4500 kPa was conducted.
Abstract: The present study focused on the hydrofluoric acid (HF) free synthesis of chromium based metal organic framework, MIL-101(Cr) and its application for hydrogen storage. MIL-101(Cr) has been synthesized hydrothermally using HF, acetic acid, perfluorobenzoic acid, and without acid. The characterization of the synthesized materials were carried out using powder X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, and surface area (BET) by nitrogen adsorption isotherm at 77 K. The results demonstrated that acetic acid mediated synthesized MIL-101(Cr) exhibited higher surface area and pore volume than those synthesized with other organic acids. This may be due to the enhanced dissolution of terephthalic acid in the presence of acetic acid which facilitates the formation of MIL-101(Cr) nuclei during the synthesis. A comparison of conventional and HF free-synthesized MIL-101(Cr) for hydrogen adsorption capacity determined at 77 K up to 4500 kPa revealed that MIL-101(Cr) synthesized using acetic acid exhibited higher hydrogen adsorption capacity (5.6 wt %) than the MIL-101(Cr) synthesized with perfluorobenzoic acid (3.7 wt %) and without acid (4.8%). However, it is slightly less than the H2 adsorption capacity of MIL-101(Cr) synthesized using HF (6.1 wt %). The higher H2 adsorption capacity of MIL-101(Cr) synthesized using acetic acid can be attributed to the better terephthalate–chromium interaction which facilitates the formation of more crystalline product thereby creating more unsaturated metal centers in MIL-101(Cr). The present study suggested that acetic acid may be a suitable alternative for highly corrosive and hazardous HF which led to easier preparation of MIL-101(Cr) for the large-scale production and applications. © 2015 American Institute of Chemical Engineers Environ Prog, 35: 461–468, 2016
54 citations
TL;DR: In this article, the effect of hydrogen peroxide as a novel oxidizing agent on purifying metallurgical grade silicon (MG-Si) by leaching with hydrofluoric acid was investigated as a function of temperature, leaching duration, stirring and hydrofluororic acid concentration.
38 citations
TL;DR: In this article, the fixed carbon content of microcrystalline graphite (MG) was investigated by using a combination of hydrochloric acid and sodium fluoride to increase the carbon content.
28 citations
TL;DR: In this article, the main reaction forms of hydrofluoric acid and sandstone mineral in sandstone acidizing were revealed based on theoretical analysis and laboratory experiments, and an acid-rock reaction rate mechanism model was developed using Freundlich adsorption theory.
27 citations
TL;DR: In this paper, the influence of several parameters, such as stirring speed, temperature, and reaction time, were studied in order to deduce the kinetics of the dissolution reaction of β-spodumene.
Abstract: Parameters affecting the kinetics of the dissolution of β-spodumene with hydrofluoric acid have been investigated. The experimental tests were carried out in a closed vessel. The influence of several parameters, such as stirring speed, temperature, and reaction time were studied in order to deduce the kinetics of the dissolution reaction. The other parameters, particle size −45 μm; HF concentration 4% v/v, and the solid–liquid ratio 0.95% w/v were kept constant. The results indicate that the stirring speed does not have an important effect on the dissolution of the mineral above 330 rpm. The extent of the leaching of β-spodumene increases with temperature and reaction time augmentations. Scanning electron microscope (SEM) analyses of some residues in which the conversion was lower than 30% indicated a selective attack on certain zones of the particle. The treatment of the experimental data was carried out using the Modelado software. The model that best represents the dissolution of the mineral is the following: ln(1 − X) = −b1 [ln(1 + b2t) − b2t/(1 + b2t)]. This model is based on “nucleation and growth of nuclei” theory, and describes the style of attack physically observed by SEM on the residues.
25 citations
TL;DR: A sonochemical and reductive approach is investigated for PuO2 dissolution under relatively mild conditions and the rapid and complete dissolution of PuO 2 under selected conditions is accompanied by Pu(iii) accumulation in solution.
Abstract: PuO2 is considered an important material for current and future nuclear fuel; however it is a very refractive compound towards dissolution. Among other techniques, its reprocessing can be performed via complexing dissolution in concentrated and boiling nitric acid containing hydrofluoric acid, or via oxidant dissolution in the presence of reagents with redox couples having high potentials such as Ce(IV)/Ce(III), or Ag(II)/Ag(I). Reductive dissolution can be performed under softer conditions and is considered an alternative to these methods which may suffer from several drawbacks (corrosion, effluent management, compatibility with nuclear waste disposal, etc.). In this study, a sonochemical and reductive approach is investigated for PuO2 dissolution under relatively mild conditions. At the first stage, the experiments are performed with CeO2 as an inactive surrogate for PuO2. The quantitative dissolution of both oxides can be achieved under ultrasound (20 kHz, 0.35–0.70 W mL−1) in 0.5 M HNO3/0.1 M [N2H5NO3]/2 M HCOOH sparged with Ar at 33–35 °C in the presence of Ti particles as a generating source of reductive species. Ultrasound enables the depassivation of the Ti surface (usually strongly passivated in nitric solutions) through acoustic cavitation which then allows further generation of the intermediate Ti(III) reductive species. Dissolution rates and yields can be further increased with the injection of dilute fluoride aliquots (NH4F or HF) in the sonicated solution to favor Ti chemical depassivation. The rapid and complete dissolution of PuO2 under selected conditions is accompanied by Pu(III) accumulation in solution.
21 citations
TL;DR: In this article, an innovative approach is proposed to texture a pyramid structure on a silicon surface via Cu-catalyzed chemical etching in the HF/FeCl3 system, and the surface and cross-section morphologies of the formed pyramid structure were examined by scanning electron microscopy and atomic force microscopy.
19 citations
Patent•
17 Aug 2016
TL;DR: In this article, cost effective methods of preparing MXene carbide compositions having a formula M n+1 C n (T s ), especially those comprising titanium and carbon, are presented.
Abstract: The present invention(s) relates to cost effective methods of preparing MXene carbide compositions having a formula M n+1 C n (T s ), especially those comprising titanium and carbon, the methods comprising reacting an oxide of M, elemental A, and carbon at elevated temperatures (eg, greater than 800°C) under an inert or non-oxidizing atmosphere to form an intermediate product; optionally reducing the particle size of the intermediate product, and reacting the intermediate product directly with a source of aqueous hydrofluoric acid
18 citations
Patent•
27 Jul 2016TL;DR: In this paper, a texturing method of polycrystalline silicon wafer cut by a diamond wire is described, which consists of the following steps: first, immersing the polycrystaline silicon wire cut by the diamond wire into a mixed water solution of an alkaline solution and an alkaline reaction control agent, removing a surface damage layer of the silicon wire, and then placing it into a hydrofluoric acid solution containing inorganic ions and organic molecules.
Abstract: The invention discloses a texturing method of a polycrystalline silicon wafer cut by a diamond wire. The method comprises the following steps: firstly, immersing the polycrystalline silicon wafer cut by the diamond wire into a mixed water solution of an alkaline solution and an alkaline reaction control agent, removing a surface damage layer of the silicon wafer and immersing the polycrystalline silicon wafer into a hydrofluoric acid solution containing inorganic ions and organic molecules for reaction; secondly, carrying out pretreatment on the polycrystalline silicon surface by a mixed solution of a hydrofluoric acid and hydrogen peroxide and simultaneously adding a pore-forming regulator; and finally texturing the silicon wafer surface by a mixed acid solution of the hydrofluoric acid and a nitric acid. The texturing method has the advantages that the prepared polycrystalline textured wafer is uniform in suede, small in color difference and consistent in etching depth, and has low surface reflectivity and relatively high conversion efficiency; the preparation method is simple and feasible; the reagent cost is relatively low; the reaction conditions are easy to implement; and the texturing method is relatively good in compatibility with an existing industrial production procedure and is suitable for popularization and application.
18 citations
TL;DR: Treatment of N-heterocyclic carbene (1,3-Bis(2,6-diisopropylphenyl)-1, 3-dihydro-2H-imidazol-2-ylidene; (LDipp)) with different sources of hydrofluoric acid (Et3N∙3HF, anhydrous hydrofluric acid and KHF2) in 1:1, 1:2, 1 :3 ratios affords [(LDipp)H]+[F]− (1), [(
TL;DR: In this paper, the latent track formation in silicon dioxide (SiO 2 ) and silicon nitride (Si 3 N 4 ) irradiated with swift heavy ions (SHI) has been studied using computer simulation in the frame of the thermal spike model.
TL;DR: This work reports on the development of plasma-enhanced atomic layer deposition (PEALD) composites of SiN and AlN to minimize WER and leakage current density and the role of aluminum and the optimum amount of Al contained in the composite structures have been explored.
Abstract: The continued scaling in transistors and memory elements has necessitated the development of atomic layer deposited (ALD) of hydrofluoric acid (HF) etch resistant and electrically insulating films for sidewall spacer processing. Silicon nitride (SiN) has been the prototypical material for this need and extensive work has been conducted into realizing sufficiently lower wet etch rates (WERs) as well as leakage currents to meet industry needs. In this work, we report on the development of plasma-enhanced atomic layer deposition (PEALD) composites of SiN and AlN to minimize WER and leakage current density. In particular, the role of aluminum and the optimum amount of Al contained in the composite structures have been explored. Films with near zero WER in dilute HF and leakage currents density similar to pure PEALD SiN films could be simultaneously realized through composites which incorporate ≥13 at. % Al, with a maximum thermal budget of 350 °C.
TL;DR: In this article, a graphite sample was obtained at high current densities in 47% HF aqueous solution and cyclic voltammetry indicated that covalent C F bonding formed above 2.4 V vs Pb/PbF2.
01 Jan 2016
TL;DR: In this article, the ammonium hydrogen difluoride (NH4HF2) was used as a versatile fluorinating agent for the decomposition of natural materials and the mechanism of the latter process was proposed.
Abstract: Recently, interest in ammonium hydrogen difluoride (NH4HF2) as a versatile fluorinating agent for the decomposition of natural materials resumed. It is considered to be a new and more efficient than hydrofluoric acid (HF) reagent in analytical chemistry. Thermodynamically possible fluorination reactions with NH4HF2 are exothermic and proceed even at room temperature with the entropy reserve. The fluorination products are of high symmetry phases (tetragonal or cubic) with partial substitution of fluoride ion for oxide (or hydroxide). The fluorination of refractory silicate zircon (ZrSiO4) is kinetically hindered, and its complete decomposition requires the use of a Teflon autoclave at 200oC. The fluorination products are cubic (NH4)3Zr(OH)xF7-x (x ≤ 0.3) and tetragonal double salt (NH4)3SiF7, which can be separated due to incongruent sublimation of (NH4)2SiF6. The mechanism of the latter process is proposed.
TL;DR: In this paper, a mesostructured tin phosphate (SnPi) material has been prepared in the presence of an amphiphilic block copolymer (F127), tin chloride (SnCl4), and phosphoric acid (H3PO4) in an ethanol-water mixed solvent medium.
Abstract: A mesostructured tin phosphate (SnPi) material has been prepared in the presence of an amphiphilic block copolymer (F127), tin chloride (SnCl4), and phosphoric acid (H3PO4) in an ethanol–water mixed solvent medium. The mesoporous SnPi material, with a large pore diameter (7.4 nm), nanocrystalline walls, a high surface area (310 m2 g−1), and a unique flake-like particle shape, is successfully synthesized by a two-step heat treatment of the parent mesostructured SnPi under flowing N2 gas followed by flowing air. Under moderate conditions (293 K and 60% relative humidity), our mesoporous SnPi shows 6.5 times more proton (H+) conductivity compared to its non-porous/bulk analogue (SnPi-B), due to its higher surface area and unique nanocrystalline porous structure enriched with free O–H groups. The preliminary electrochemical properties of our crystalline mesoporous SnPi as an anode for lithium-ion batteries (LIBs) have been studied as well, which exhibits good reversible specific capacity with good cycling stability and excellent capacity retention of 92%.
TL;DR: In this paper, the dissolution of thorium oxide (ThO 2 ) was investigated in nitric acid/hydrofluoric acid (HNO 3 /HF) system as a function of several parameters such as reaction fluoride ion content, HNO 3 concentration and reaction temperature using an experimental reactor.
Patent•
17 Aug 2016
TL;DR: In this paper, a preparation method of the textured structure of a crystalline silicon solar cell is described. And the method includes the following steps that: (1) a porous medium layer structure is formed on the surface of a silicon wafer; (2) cleaning is performed with an alkaline chemical solution; (3) residual metal particles are removed through using a cleaning solution; and (4) surface etching is performed using a first chemical etching solution, and then, the texture structure of the crystalline solar cell can be obtained.
Abstract: The invention discloses a preparation method of the textured structure of a crystalline silicon solar cell. The method includes the following steps that: (1) a porous medium layer structure is formed on the surface of a silicon wafer; (2) cleaning is performed with an alkaline chemical solution; (3) residual metal particles are removed through using a cleaning solution; and (4) surface etching is performed with a first chemical etching solution, and then, the textured structure of the crystalline silicon solar cell can be obtained. With the preparation method of the invention adopted, the service life of a hydrofluoric acid and nitric acid mixed liquid can be greatly prolonged, and the stability and uniformity of the textured structure can be ensured.
TL;DR: In this paper, Colloidal MEL zeolite was successfully synthesized using raw powder glass as a new silica source at 114 and 150°C and the results concluded that the samples have plate-like morphologies in both synthesis conditions.
TL;DR: In this article, the use of hydrofluoric acid before and during chemical functionalization of silicon nanocrystals with hydrocarbon chains is found to be very efficient for removing original surface defects of the nanostructures as well as for preserving them from oxidation induced defects appearing on their surface during photoinitiated hydrosilylation procedure.
Abstract: Introduction of hydrofluoric acid before and during chemical functionalization of silicon nanocrystals with hydrocarbon chains is found to be very efficient for removing original surface defects of the nanocrystals as well as for preserving them from oxidation induced defects appearing on their surface during photoinitiated hydrosilylation procedure. In consequence, stable sols of highly luminescent silicon quantum dots in organic solvents with photoluminescence quantum yield up to 20% are shown to be easily obtained. Moreover, our approach allows considerable improvement of electric transport through meso-porous silicon nanostructures which is still a serious challenge for their applications in photovoltaics and thermoelectrics. Finally, the use of hydrofluoric acid appears as a cheap and efficient alternative to development of painstaking procedures and set-ups preventing oxidation induced deterioration of physico-chemical properties of the individual and interconnected silicon nanocrystals during their chemical functionalization.
Patent•
12 Oct 2016
TL;DR: In this paper, the authors provided a one-step wet black silicon preparation and surface treatment method, which comprises the steps of enabling a silicon wafer with a surface damage layer being removed to be immerged into a corrosive liquid so as to prepare black silicon through reaction, wherein the corrosive mixture is a mixed aqueous solution of a metal ion containing concentrated hydrofluoric acid, an oxidizing agent and a high-molecular polymer.
Abstract: The invention provides a one-step wet black silicon preparation and surface treatment method, which comprises the steps of enabling a silicon wafer with a surface damage layer being removed to be immerged into a corrosive liquid so as to prepare black silicon through reaction, wherein the corrosive liquid is a mixed aqueous solution of a metal ion containing concentrated hydrofluoric acid, an oxidizing agent and a high-molecular polymer; and enabling the black silicon to be immerged into a surface treatment corrosive liquid so as to carry out surface optimization treatment, and acquiring a silicon wafer with a sub-micrometer structure and uniform texturing, wherein the surface treatment corrosive liquid is an additive containing mixed acid aqueous solution The wet black silicon preparation method provided by the invention is simple in process and low in cost, the texturing surface of the black silicon after corrosion treatment is uniform and has no sharp boundary, and the reflectivity is 7-15% The one-step wet black silicon preparation and surface treatment method greatly improves the absorption efficiency of a silicon cell for light, a solar cell prepared by using the black silicon prepared according to the method has low cell electric leakage rate, stable open-circuit voltage and high conversion efficiency
TL;DR: In this article, a mechanism leading to the formation of porous structures was proposed, discussed, and illustrated along with schematized energy band structures at the semiconductor/electrolytic solution interface, where a comparison in terms of strain analysis via high resolution X-ray diffraction, surface morphology via field emission scanning electron microscopy and surface topography via atomic force microscopy, band gap calculation via UV-visible absorption and photoluminescence measurements, Urbach energy determination, as well as in-plane biaxial stress relaxation and optical phonon mode determination
Patent•
07 Dec 2016
TL;DR: In this article, a technology for purifying scandium, titanium, and vanadium from an acid solution step by step was proposed, where the acid solution obtained by leaching red mud through sulfuric acid is subjected to three-time extraction work, and an extraction organic phase is composed of a P507 extraction agent, a TBP synergist and sulfonated kerosene.
Abstract: The invention relates to a technology for purifying scandium, titanium and vanadium from an acid solution step by step. According to the technology, the acid solution obtained by leaching red mud through sulfuric acid is subjected to three-time extraction work, and an extraction organic phase is composed of a P507 extraction agent, a TBP synergist and sulfonated kerosene; in the first-time extraction process, the acid solution is directly subjected to scandium extraction and enrichment without pH value adjustment, after two-phase separation, a scandium-enriched organic phase and a titanium and vanadium containing solution are obtained, the scandium-enriched organic phase is subjected to sulfuric acid scrubbing and reverse extraction of sodium hydroxide, and scandium-enriched liquid is obtained; after the titanium and vanadium containing solution is subjected to pH value adjustment, the second-time extraction work is conducted for enrichment and separation of titanium, after two-phase separation, a titanium-enriched organic phase and a vanadium-containing solution are obtained, and after the titanium-enriched organic phase is subjected to sulfuric acid scrubbing and reverse extraction of hydrofluoric acid, titanium-enriched liquid and the vanadium-containing solution are obtained; and after the vanadium-containing solution is subjected to pH value adjustment and reducing treatment, the third-time extraction is conducted, and after two-phase separation, a vanadium-enriched organic phase and raffinate are obtained. The technology has the beneficial effects that the separation efficiency is high, the enrichment multiple is large, the technology is simple, and the number of the kinds of extraction agents is small.
Patent•
11 May 2016
TL;DR: In this paper, a fluorine-doped fluorescent carbon quantum dot preparation method is described. But the method is not suitable for the use of high-dimensional laser rangefinders.
Abstract: The invention relates to a fluorine-doped fluorescent carbon quantum dot preparing method. The method comprises the steps of adding 7-250 mmol/L glucose dispersion liquid into a polytetrafluoroethylene hydrothermal reaction still, and then adding hydrofluoric acid solution, wherein the volume ratio of the hydrofluoric acid solution to the glucose dispersion liquid is 2.5-12.5%; placing the reaction still in a muffle furnace for reaction lasting 6-24 h at 160-210 DEG C; making the obtained solution pass through a filter membrane with bore diameter of 0.22 micron to remove large particles, and adding obtained filtrate into a dialysis bag for dialysis, wherein deionized water serves as dialyzate and dialysis time is 2-7 days; transferring the product in the dialysis bag into a flask, and removing solvent through reduced pressure distillation; placing the solid in a vacuum drying oven to be dried for 48 h, so that a fluorine-doped fluorescent carbon quantum dot product is obtained. According to the method, operation is easy, sources of raw materials are wide, cost is low, yield is high, and chemical stability is high. The method can be applied to fields including photocatalysis, bioimaging and biochemical analysis.
Patent•
30 Mar 2016
TL;DR: In this paper, a recovery method of high-purity silicon in waste solar cells is proposed, which consists of aluminum removal by hydrochloric acid, silver removal by nitric acid, aluminium-silicon alloy layer removal by sodium hydroxide, silicon nitride antireflection layer removal and surface metal impurity removal by either the mixed acid of hydrofluoric acid and Nitric acid.
Abstract: The invention discloses a recovery method of high-purity silicon in waste solar cells. The method comprises the following steps: the waste solar cells are sequentially subjected to aluminum removal by hydrochloric acid, silver removal by nitric acid, aluminium-silicon alloy layer removal by sodium hydroxide, silicon nitride antireflection layer removal by hydrofluoric acid, phosphorus diffused layer removal by sodium hydroxide and surface metal impurity removal by hydrochloric acid or hydrofluoric acid or the mixed acid of hydrofluoric acid and nitric acid to obtain the high-purity silicon. Through the method, all parts in the solar cells are removed except a high-purity silicon layer, silicon with the purity of 99.9,999% can be obtained finally and can be directly used as a silicon source in the cell manufacturing process.
TL;DR: In this article, an alternative new eco-friendly and easily implemented process for the production of hydrofluoric acid and sodium hydroxide from sodium fluoride was carried out by bipolar membranes electrodialysis.
Abstract: The purpose of this study was to offer an alternative new eco-friendly and easily implemented process for the production of hydrofluoric acid and sodium hydroxide. The production of hydrofluoric acid and sodium hydroxide from sodium fluoride was carried out by bipolar membranes electrodialysis. The process feasibility was tested using a laboratory electrodialysis cell. The behavior of the process was investigated for 0.05, 0.025 M concentration and 5, 7.5, 10 V potential. In conclusion, the current efficiencies were obtained up to a value of 98.51 at the applied potential of 10 V and 0.05 M, and the purities were found to be 99.7% and as 99.1% for hydrofluoric acid and sodium hydroxide, respectively. These high purities of acid and base were obtained without any harmful waste material or side product. When in terms of both production technique and environmental impact were compared to hydrofluoric acid production by the reaction of acid-grade fluorspar (CaF2) with sulfuric acid (H2SO4) and sodium ...
Patent•
30 Mar 2016
TL;DR: In this article, a method and device for synchronously recycling sulfuric acid and fluorine and chlorine from polluted acid was proposed, which includes the following steps: filtering out the suspended solids, treating the polluted acid wastewater through an electrodialysis device to increase the concentration of acid in the concentrated liquid, and treating the liquid in an improved falling film evaporation device; collecting 70-80% of concentrated sulfuric acids by mass from the bottom, and completely absorbing the generated secondary steam by a falling film to obtain fluorine-chlorine mixed acid.
Abstract: The invention relates to a method and device for synchronously recycling sulfuric acid and fluorine and chlorine from polluted acid The method comprises the following steps: (1) filtering out the suspended solids; (2) treating the polluted acid wastewater through an electrodialysis device to increase the concentration of acid in the concentrated liquid; and (3) treating the concentrated liquid in an improved falling film evaporation device; collecting 70-80% of concentrated sulfuric acid by mass from the bottom, and completely absorbing the generated secondary steam by a falling film to obtain fluorine-chlorine mixed acid Through the method provided by the invention, open loop of fluorine and chlorine in the polluted acid wastewater can be realized while the concentrated sulfuric acid is recycled Moreover, the invention also provides a device matching the method The method and device provided by the invention have the advantages of fast and synchronous treatment and recycling of sulfuric acid, hydrochloric acid and hydrofluoric acid in the polluted acid and the like
Patent•
06 Jan 2016
TL;DR: In this article, a surface treatment process for carbon steel is described, which consists of the following steps: chemical degreasing, warm water rinsing, mechanical cleaning, alkali cleaning, ultrasonic washing, acid cleaning for removing the oxidation film on the surface, deionized water washing, heat treatment, activation, nickel preplating, chemical nickel-plating; chemical nickel plating; passivation; heat treatment and heat preservation; drying by a heating furnace.
Abstract: The invention discloses a surface treatment process for carbon steel. After the surface of carbon steel is pre-treated and an oxidation film on the surface of carbon steel is removed, nickel is chemically plated on the surface layer of carbon steel. The process comprises the following steps: chemical degreasing; warm water rinsing; mechanical cleaning; alkali cleaning; ultrasonic washing; acid cleaning for removing the oxidation film on the surface; deionized water washing; heat treatment; activation; nickel preplating; chemical nickel-plating; passivation; heat treatment and heat preservation; drying by a heating furnace. During clean water rinsing, the water temperature is 70-90 DEG C, and the water pressure is 1.5MPa. Acid cleaning comprises hydrofluoric acid corrosion or mixed acid corrosion with sulfuric acid and nitric acid and aims to remove the oxidation film on the surface. A chemical nickel-plating solution is prepared from 30-40g/L of nickel sulfate, 3-4ml/L of a stabilizer, 15-20g/L of sodium acetate, 10-15ml/L of hydrofluoric acid and 10-15ml/L of sodium carbonate, wherein the stabilizer is a citric acid and lactic acid mixed solution, the PH of the chemical nickel-plating solution is 4.0-4.5, the temperature is 70-80 DEG C, and the time is 60-90min. The chemical nickel-plating layer is stable, the corrosion resistance and the abrasion resistance of carbon steel can be effectively improved, and the mechanical property of the carbon steel surface is improved.
Patent•
26 Oct 2016
TL;DR: In this paper, a preparation method of a crystalline silicon solar cell textured structure is presented, which comprises of forming a porous medium layer structure on the surface of a silicon wafer, and then carrying out surface etching by using a first chemical corrosive liquid so that the crystalline solar cell texture can be obtained.
Abstract: The invention discloses a preparation method of a crystalline silicon solar cell textured structure. The preparation method comprises the following steps: (1) forming a porous medium layer structure on the surface of a silicon wafer; (2) and then carrying out surface etching by using a first chemical corrosive liquid so that the crystalline silicon solar cell textured structure can be obtained. The first chemical corrosive liquid is a mixed solution of hydrofluoric acid and an oxidizing agent, wherein the molar ratio of the hydrofluoric acid to the oxidizing agent is 1: (1 to 5). According to the preparation method, the proportion of HF to HNO3 is adjusted, the generation is beneficial for diffusing a gettering loosened porous silicon layer besides hole enlarging and metal particle removal; the loosened porous silicon layer has extremely excellent gettering performance, and the recombination of PN junctions can be greatly reduced through subsequent high-temperature diffusion and gettering, so that the open-circuit voltage and battery conversion efficiency are improved.
TL;DR: It is anticipated that a sensitive RT surface passivation technique will be imperative for examining bulk silicon defects when their concentration is low (<10(12) cm(-3)).
Abstract: A procedure to measure the bulk lifetime (>100 µsec) of silicon wafers by temporarily attaining a very high level of surface passivation when immersing the wafers in hydrofluoric acid (HF) is presented. By this procedure three critical steps are required to attain the bulk lifetime. Firstly, prior to immersing silicon wafers into HF, they are chemically cleaned and subsequently etched in 25% tetramethylammonium hydroxide. Secondly, the chemically treated wafers are then placed into a large plastic container filled with a mixture of HF and hydrochloric acid, and then centered over an inductive coil for photoconductance (PC) measurements. Thirdly, to inhibit surface recombination and measure the bulk lifetime, the wafers are illuminated at 0.2 suns for 1 min using a halogen lamp, the illumination is switched off, and a PC measurement is immediately taken. By this procedure, the characteristics of bulk silicon defects can be accurately determined. Furthermore, it is anticipated that a sensitive RT surface passivation technique will be imperative for examining bulk silicon defects when their concentration is low (<1012 cm-3).