Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/02—Making metallic powder or suspensions thereof using physical processes
  • B22F9/04—Making metallic powder or suspensions thereof using physical processes starting from solid material, e.g. by crushing, grinding or milling
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
  • B22F1/05—Metallic powder characterised by the size or surface area of the particles
  • B22F1/054—Nanosized particles
  • B22F1/0545—Dispersions or suspensions of nanosized particles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
  • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F9/00—Making metallic powder or suspensions thereof
  • B22F9/16—Making metallic powder or suspensions thereof using chemical processes
  • B22F9/18—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds
  • B22F9/24—Making metallic powder or suspensions thereof using chemical processes with reduction of metal compounds starting from liquid metal compounds, e.g. solutions
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B82—NANOTECHNOLOGY
  • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
  • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/30—Inkjet printing inks
  • C09D11/32—Inkjet printing inks characterised by colouring agents
  • C09D11/322—Pigment inks
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D11/00—Inks
  • C09D11/52—Electrically conductive inks
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C1/00—Making non-ferrous alloys
  • C22C1/04—Making non-ferrous alloys by powder metallurgy
  • C22C1/0466—Alloys based on noble metals
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C5/00—Alloys based on noble metals
  • C22C5/02—Alloys based on gold
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C5/00—Alloys based on noble metals
  • C22C5/04—Alloys based on a platinum group metal
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C5/00—Alloys based on noble metals
  • C22C5/06—Alloys based on silver
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2999/00—Aspects linked to processes or compositions used in powder metallurgy

Definitions

• the invention relates to a method for the production of nanoparticles from a noble metal and the use of nanoparticles produced by the method for the production of printable suspensions, inks or pastes for printing or for forming functional layers (eg electrically conductive layers) or decorative (eg optically reflective Layers) surfaces.
• the process is intended to produce nanoparticles of silver, gold or platinum. It can also be exploited the catalytic effect of these precious metals.
• Precious metal nanoparticles in particular silver are used for the production of inks which are applied to substrates by a wide variety of application methods. can be used. Since the sintering behavior of such inks, and in particular the temperature required for adequate sintering, is influenced by the particle size and also the particle size distribution, it is of great interest to use such nanoparticles of noble metal with a predefinable particle size and possibly also
• this object is achieved by a method using the features of claim 1.
• a chemical compound of the respective noble metal in an aqueous solution or the coarse-grained noble metal should be dissolved in an acid mixture.
• at least one surfactant or an aqueous or alcoholic solution containing at least one surfactant and, in the case of silver and platinum, a reducing agent should additionally be added.
• the influencing of the particle size of the nanoparticles produced by the process takes place with the parameters Pa: concentration of the chemical compound or of the noble metal, temperature and the proportion of surfactant.
• An influence may also be the pH or the setting of certain pH values in individual process steps in the synthesis.
• the precious metal particles precipitated from the respective solution are centrifuged out.
• the particle size can be reduced with a smaller concentration of the chemical compound used or of the noble metal in the respective solution and / or elevated temperature and / or an increased proportion of surfactant.
• these precious metals can be dissolved in a mixture of hydrochloric acid and nitric acid.
• the mixing ratio should be 75 mass% hydrochloric acid 25 mass% nitric acid.
• This acid mixture is also known as aqua regia.
• tetrachloride-gulic acid or hexachloride-platinic acid forms.
• nitric acid may be used which is at least 50%.
• the nitric acid should be heated, and a temperature in the range 100 ° C to 150 ° C preferably having 120 '° C.
• AgNO 3 forms and again a surfactant and additionally hydroxylamine, preferably in aqueous solution, can be added as a reducing agent.
• surfactants which are selected from
• Alkoxylates alkylolamides, esters, amine oxides, alkylpolyglucosides, alkylphenols, arylalkylphenols, water-soluble homopolymers, water-soluble random copolymers, water-soluble
• Block copolymers water-soluble graft polymers, polyvinyl alcohols, copolymers of polyvinyl alcohols and polyvinyl acetates, polyvinylpyrrolidones, cellulose, starch, gelatin, gelatin derivatives, amino acid polymers, polylysine, polyaspartic acid,
• Polyacrylates polyethylene sulfonates, polystyrenesulfonates, polymethacrylates, condensation products of aromatic sulfonic acids with formaldehyde,
• polyvinylpyrrolidones block copolyethers and block copolyethers with polystyrene blocks, hydroxy-functional carboxylic acid esters having pigment-affinic groups, copolymers having pigment-affinic, preferably acidic groups, alkylolammonium salts of a block copolymer having pigment-affinic, preferably acidic groups and / or mixtures or solutions thereof.
• block copolymers having pigment affinic groups for example polystyrene blocks (eg Disperbyk 190 from BYK-Chemie, Wesel), alkylolammonium salts of a copolymer having acidic groups (eg Disperbyk 180 from BYK-Chemie, Wesel) or polyvinylpyrrolidones (eg PVP the company Fluka) or mixtures thereof are used as a surfactant.
• Dysperbyk 180 is an alkylolammonium salt of a copolymer having acidic groups.
• Dysperbyk 190 is an aqueous solution of a high molecular block copolymer with pigment affinic groups.
• Hydrazine hydrate or sodium borohydride can be used as a reducing agent.
• the pH in each solution can be adjusted during synthesis with added NaOH or NH 3 added.
• An adjustment of the pH value is also possible with piperidine and thus free of sodium.
• the coarse particles can be burned out of the adhering organic dispersant and returned to AgNO 3 by subsequent conversion with boiling HNO 3 .
• FIG. 1 shows SEM images of nanoparticles according to Examples 1.1 and 1.2 from Table 1.
• the particles prepared from the synthesis according to Example 1 are further processed to a silver particle ink.
• Centrifuge bottom sediment is centrifuged at 4600 g for 2 h, mixed with as little water as possible and provided in a ball mill with 10% by mass PEG (polyethylene glycols) and 0.05% by mass Disperbyk 348 (information on the mass of the sediment) and over a period of 0.5 hours.
• PEG polyethylene glycols
• Disperbyk 348 information on the mass of the sediment
• the resulting ink was freed from any coarse agglomerates with the aid of a 5 ⁇ m steel filter.
• the viscosity of the ink is 21 mPas at a shear rate of 100 / s and at 25 ° C.
• This ink was made using a Dimatix SQ128
• Printhead deposited on silicon.
• the layer thickness in single-pressure was 2.5 ⁇ m, with a line width of 37 ⁇ m-40 ⁇ m.
• layer thicknesses between 18 ⁇ and 20 pm, at line widths of 60 ⁇ - reached 65 ⁇ .
• the printed structures were baked in a tube furnace at a heating rate of 10 K / min up to a temperature of 380 ° C. Simultaneously, the electrical resistance of the printed structure is determined by 4-point measurement.
• the printed layer was previously dried at 180 ° C for 0.5 hours. This makes them already electrically conductive.
• a commercial gold powder (Heraeus 200-03) were completely dissolved in at least 20 ml of 75% by mass of HCl with 25% by mass of HNO 3 at 50 ° C. Since impurities should be avoided, metallic equipment should not be used.
• the solution was passed through a hard paper filter.
• a glass beaker 800 ml of deionized water were mixed with the surfactants DisperbyklBO and Disperbykl90 with a magnetic stirrer. The amount of surfactant added corresponded to 60% by weight of the previously reacted gold mass.
• the acid solution was then added to the water-surfactant mixture and titrated to a neutral pH via the addition of NaOH (3..5 molar).
• a pH electrode was used for this purpose.
• the pH was first stabilized at pH 7 and then gradually increased to a pH of 10 after a further 5 to 7 minutes.
• gold nanoparticles precipitated in the solution.
• a centrifuge with 2000 rpm (800-fold gravitational acceleration g) for 10 min coarser particle sizes were separated and can be recycled.
• a separation of finer particles with an average particle size d 50 of ⁇ 80 nm should be centrifuged again. It should be centrifuged at a speed of 4700 U / min (4600 times the gravitational acceleration g) over a period of 2 hours.
• the residual gold particulate slurry was washed with water to reduce the sodium content in the solution. Apart from gold, residues of sodium chloride from the synthesis were present, which can be reduced by further washing of the particle-containing solution. As a result, it was possible to obtain particles of a size which were suitable for the production of printable inkjet inks.
• the gold sludge was first filled with water after the centrifugal treatment, so that a gold solid content of 25% by mass was achieved in the solution.
• the density of the ink was then 1.3 g / cm 3 .
• Byk 348 By adding 0.05 mass% of Byk 348, the surface tension was lowered to 30 mNm.
• the produced gold nanoparticle ink was coated with a commercial ink jet device with Dimatiax SE128 printhead on silicon wafer and alumina sub- Straten printed in 21 mm long meander test structures.
• the line width achieved was 120 ⁇ ⁇ and the layer thickness in single pressure 1.5 ⁇
• a significant sintering occurred with a drop in electrical resistance to 4.7 ohms.
• the 50-fold mass of deionized water was added in relation to the gold mass used and the whole was mixed in a magnetic stirrer.
• the surface tension ratios were influenced by the addition of Byk 180 and Byk 190 as surfactant into the water. Both surfactants were added with 60% by weight of the gold used in the water.
• a pH sensor was used.
• This mixture was then warmed to 60 ° C and then added with 3-5 molar NaOH. After reaching a pH of 7, this then dropped to a pH between 1.5 and 2.
• the pH reached is influenced by the proportion of surfactant.
• the finer nanoparticles could then be separated by centrifugation analogously to Example 2.
• the sediment can be separated by centrifuging and then washed several times to remove Na and NaCl as completely as possible.
• the unused coarse fraction of the sediment can be recycled. This avoids larger gold losses.
• Example 4 In a first step, 10 g of a commercial platinum powder in at least 16 ml of a mixture of 75 mass HCL with 25 mass% HNÜ 3 , at a temperature at the boiling point of nitric acid in the amount of about 86 ° C completely dissolved. Since other metals would also dissolve in the acid mixture and cause contamination of the platinum, no metallic devices should be used. After cooling, the solution was replaced by a hard one
• This solution was also filtered through a hard paper filter.
• Nanoparticles in the desired particle size range could be separated from the sediment by centrifuging, as explained in Example 3.
• Disperser Disperbyk 180 and 4.8 g Disperbyk 190 (both Byk-Chemie) added.
• the solution is heated to 35 ° C and adjusted to a pH of 9 using NH 3 .
• 20 ml of aqueous 50% hydroxylamine solution (type Merck, for synthesis) are added. Due to the strong gas evolution In the reaction, a volume of at least 5 liters should be provided for the reaction described. After about 30 seconds, the reaction comes to a standstill. The temperature rises in this time in the solution to about 40 ° C.
• the reaction vessel is cooled with constant stirring to room temperature and then centrifuged.
• a separation of coarse particles greater than 300 nm at an acceleration of 800 g for 10 min is suitable.
• the mixture is then centrifuged at maximum acceleration of the centrifuge, for example at 4600 g for 2 hours.
• maximum acceleration of the centrifuge for example at 4600 g for 2 hours.
• the coarse particles which are too coarse for use can be freed of the adhering organic dispersant by burning out and subsequently returned to the process as pure silver.
• the particles prepared from the synthesis described above are further processed to a silver particle ink.
• the centrifuge bottom set after centrifuging at 4600 g for 2 hours, is added to as little water and dispersed in a ball mill for 0.5 hours.
• Additives such as 10 mass PEG (polyethylene glycol) and 0.05% by weight of Disperbyk 348 (information related to. The mass of the Bodensat ⁇ ZES) can be added to improve the printability.
• the ink thus obtained was freed from any coarse agglomerates with the aid of a 5 ⁇ m steel filter.
• the viscosity of the ink is 18 mPas at a shear rate of 100 / s and at 25 ° C in the cylinder cup system (TA Instruments, DA100).
• the solid content of the ink was calculated by a density measurement and was 75% by mass at a density of 3.30 g / cm 3 .
• a FESEM recording of the Ag particles of this ink on polished Al is in
• the ink was deposited on silicon using a Dimatix SQ128 printhead.
• the layer thickness in single pressure was 3.2 ⁇ , with a line width of 50 ⁇ .
• layer thicknesses of 16 ⁇ be achieved at line widths of 60 ⁇ .
• a FESEM image of these printed layers is shown in FIG.
• the printed structures were in a tube furnace with a
• the electrical resistance of the printed structure was determined by a 4-point measurement. The course as a function of the temperature is shown in FIG. The printed layer becomes conductive even at temperatures above 275 ° C.
• a specific electrical resistance of the Ag track of 0.05 Qmm 2 / m was determined - this corresponds to approximately three times the bulk Ag resistance 0.016 Qmm 2 / m. This corresponds to about three times that of pure silver (0.016 0.05 Qmm 2 / m) and thus represents a very good value for a printed layer. Above 949 ° C, the Ag track begins to melt, with the electrical track Resistance rises sharply.
• Example 2 In contrast to Example 1 can be prepared with the obtained according to Example 6 silver nanoparticles a "coarser” ink with an extremely high solids content.
• This achievable solids content for printable inks of up to 75% by mass goes far beyond that of conventional printable inks with silver nanoparticles. With them, a maximum solids content of 40% by mass is known.
• Dispergator freed and then, as pure silver recycled to the process.
• the particles prepared from the previously described synthesis are further processed to a silver particle ink.
• the centrifuge bottom set after centrifuging at 4600 g for 2 hours, is mixed with as little water as possible and dispersed in a ball mill for 0.5 hours.
• Additives such as 10% by mass PEG (polyethylene glycol) and 0.05% by mass Disperbyk
• the resulting ink was freed of any coarse agglomerates with the aid of a 5 ⁇ m steel filter.
• the viscosity of the ink is 20 mPas at a shear rate of 100 / s and at 25 ° C in the cylinder cup system (TA Instruments, DA100).
• the solids content of the ink is calculated by means of a density measurement and was 74% by mass, at one

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• 2010
  • 2010-08-03 DE DE102010033924A patent/DE102010033924A1/de not_active Ceased
• 2011
  • 2011-07-29 EP EP11776686.5A patent/EP2600997A2/de not_active Withdrawn
  • 2011-07-29 KR KR1020137002755A patent/KR20140026318A/ko not_active Application Discontinuation
  • 2011-07-29 US US13/813,566 patent/US20130205950A1/en not_active Abandoned
  • 2011-07-29 WO PCT/DE2011/001551 patent/WO2012016565A2/de active Application Filing
  • 2011-07-29 JP JP2013522101A patent/JP2013540888A/ja not_active Withdrawn

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