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Nano tin bismuth(Sn-Bi) alloy —fusible alloy/low melting point alloy/environmentally friendly alloy

Nano tin bismuth alloy is a low-melting-point and environment-friendly alloy. Low-melting-point alloy refers to a fusible alloy with a melting point lower than 232°C (the melting point of Sn), usually composed of low-melting-point metal elements such as Bi, Sn, Pb, and Cd.

 

Fusible alloys have good fluidity after heating and melting, so this type of low melting point metal is also widely used in casting methods. The superiority is obvious. In addition, low melting point metals are also widely used in medicine to make blocks for radiotherapy. Blocks made of fusible alloys can effectively block normal human tissue during radiotherapy. The method of making blocks with low melting point metal nanoparticles alloys effectively improves the accuracy and safety of radiation therapy.

 

Low melting point alloys are often widely used as solders, as well as heat-sensitive components such as fusible cutouts and fuses in electrical appliances, steam, fire protection, fire alarms and other devices.

Specific application areas of low melting point alloys:

1) In medical treatment, it is mainly used to make special-shaped radiation protection blocks.

2) It can be conveniently used for casting molds, producing special products for molds and casting.

3) For electronic and electrical automatic control, as thermal element, insurance material, fire alarm device, etc.

4) As a filler when bending metal pipes.

5) When making metallographic samples, it is used as a mosaic agent.

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What is the catalytic activity of gold nanoparticles as catalysts?

Regarding the catalytic properties of gold, the first ionization ability of gold is very large, and it is difficult to lose electrons, so the interaction force between gold and surface molecules is usually very weak. At temperatures below 200 °C, even highly reactive molecules, such as hydrogen and oxygen, are not easily adsorbed on the surface of single crystal gold. Since the adsorption of molecules on the catalyst surface is a prerequisite for the catalytic reaction, it can be considered that elemental gold does not have good activity for hydrogenation and oxidation reactions. Gold does not have very good catalytic activity. In fact, the prerequisite for the catalytic activity of gold catalysts is to prepare highly dispersed nano scale gold particles.

The characteristics of nano-gold catalysts: low temperature activity, good selectivity, and environmental friendliness.

An obvious feature of gold nanoparticles as catalysts is low temperature activity.

When the nano-gold catalyst catalyzes some reactions, it can be at room temperature or even below 0 °C, and the real good catalytic activity, such as catalytic CO oxidation and O3 decomposition, can be carried out at room temperature. In fact, the activity of gold catalysts for most reactions occurs below 230 °C. However, the activity of gold catalysts above 230 °C is significantly lower than that of other precious metal catalysts.

Nano gold particle catalysts have good selectivity when catalyzing certain reactions, and their catalytic properties are usually different from other noble metal catalysts.

For example, in the hydrogenation of CO2 catalyzed by Au/Zno catalyst, although its catalytic activity to methanol is slightly lower than that of commercial Cu/ZnO-Al2O3 catalyst, its selectivity is higher.

The nanogold powdercatalyst is environmentally friendly. Nano-gold catalysts can purify some polluted gases in the environment under normal temperature and humidity conditions without consuming too much thermal energy.

In terms of hydrogen energy generation, the catalyst can provide some new green synthesis methods and processing processes.

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High-fidelity 3D Color Printing Achieved by Photochromic Properties of Nano-tungsten Trioxide WO3

A few days ago, the Barcelona Institute of Technology (ICFO) published a discovery in Nano Letters: mixing nano-tungsten oxide particles with polyamide as a photosensitizer for color 3D printing can avoid the problem of discoloration in printing caused by traditional carbon-based photosensitizers , which contributes to the realization of high-fidelity 3D color printing.

 

In order to reduce cost and increase printing speed, selective sintering 3D printing usually incorporates photothermal sensitizers, which can accelerate the rate at which incident light is converted into heat. However, when printing white and color products, commonly used carbon-based photothermal sensitizers are used. Agents can cause discoloration of the work.

 

Previous ICFO related research has used gold-coated nanosilica microspheres to overcome the above problems (ie strong absorption in the near-infrared with minimal interaction with visible light). It turns out that while it works well in color printing, it has limitations when it comes to large gradation colorful high fidelity and pure white printing.

 

This time ICFO uses nano-tungsten oxide (WO3) as a photothermal sensitizer, which greatly reduces the production difficulty and material cost. It is colorless at high concentrations and has strong absorption in the near-infrared region, proving that they can convert light into heat at a very fast rate, making them a fast flux; UV light is effectively activated or deactivated; more importantly, they are stable at very high temperatures and have shown superior heating to color change rates compared to other sensitizers available. Finally, when mixed with other color inks, these nanoparticles were able to reproduce the same color as the original powder, maintaining the color purity of the original sample. This also opens up a new avenue for high-fidelity 3D color printing.

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Hongwu Nano is supplying high-tap density silver powder for solar photovoltaic cells in bulk

The basic structure of a crystalline silicon solar cell consists of a P-type silicon substrate, an n-type layer, an anti-reflection film (TiO2, SiO2 or Si3N4), a front silver electrode, a back aluminum electrode and a back silver electrode. The back-side silver electrode is an electrode formed by using silver conductive paste through screen printing and then sintering.

In the case of the same solid content, the different particle size, morphology, and ratio of silver powder would affect the viscosity performance. Tests show that the silver powder used in the back silver paste plays a key role in ensuring electrical performance, improving adhesion and welding power. In the case of low solid content, using a slurry prepared from micro-flaky silver powder, the resulting electrode film is dense and smooth, has excellent electrical properties, and good adhesion and welding properties.

The silver electrode paste on the light-receiving surface of solar cells uses high-performance metal conductive spherical silver powder.

The silver electronic paste used for the front electrode of silicon solar cell is mainly composed of three parts:
1. Superfine metallic silver powder with conductive effect. 70-80wt%. Ag powder has high photoelectric conversion efficiency.
2. Inorganic phase that plays a role of solidifying flux after heat treatment. 5-10wt%
3. The organic phase that acts as a binding agent at low temperatures. 15-20wt%

Ultra-fine silver powder is the main component of silver electronic paste, which ultimately forms the electrode of the conductive layer. Therefore, the particle size, shape, surface modification, specific surface area and tap density of silver powder have a greater impact on the performance of the slurry. The particle size of the silver powder used in the silver electronic paste is generally controlled within 0.2-3um, and the shape is spherical or quasi-spherical. If the particle size is too large, the viscosity and stability of the silver electronic paste will be significantly reduced, and because the gap between the particles is relatively large, the sintered electrode is not close enough, the contact resistance is significantly increased, and the mechanical properties of the electrode are also not ideal. If the particle size is too small, it is difficult to mix uniformly with other ingredients during the preparation of silver paste.

The silver coated copper powder materials prepared by Hongwu Nano’s technical engineers have relatively good sphericity, good dispersibility, uniform particle size, adjustable high tap density and superior electrical conductivity. The solar photovoltaic cell front electrode paste prepared by high-tap density silver powder has the characteristics of non-sticky rolls, easy printing, very small shrinkage, and dense sintered film, which fills the gap in the production of high-tap-density spherical silver powder in China.

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Application prospect of platinum group metal nanoparticles in automobile exhaust gas purification catalyst

Vehicle exhaust pollution control is mainly achieved by improving oil quality, engine performance, combustion efficiency, and installing exhaust purifiers. Platinum group metals are mainly platinum, palladium and rhodium, the three kinds of noble metal nanoparticles can be used in automobile exhaust purification catalysts. Rhodium prices are currently very high, so there is more demand for platinum and palladium nanoparticles. We are also seeing widespread automotive and industrial use of catalytic converters using platinum and palladium.

Due to their high melting point and strong corrosion resistance, pt platinum nanoparticles are important materials for catalysts in the automotive industry. In addition, driven by the heavy vehicle market in China, platinum demand in the automotive industry is expected to continue to increase by the end of this year.

In industrial use, platinum is currently gaining share in the auto-catalyst market as it continues to replace outperforming palladium on a one-to-one basis in gasoline-engine vehicles. The bulk of nano platinum consumption this year will come from the automotive industry and other industrial uses.

In addition to industrial demand, the development of the hydrogen energy industry also drives the demand for nano platinum. As a large part of renewable energy, hydrogen energy is the key to the deep decarbonization of the global industrial sector, so the entire hydrogen fuel industry has also been boosted. Among them, platinum is an indispensable material in the current hydrogen energy stack technology, and the long-term demand is expected to increase significantly.

Platinum group metals are used as catalysts for automobile exhaust gas purifiers and catalysts for fuel cells. Therefore, on the demand side, with the recovery of the production and sales levels of the automobile industry in the third quarter, the tightening of China 6 emission regulations, and the promotion of the hydrogen economy, the price and demand for platinum group metals will be well supported. This makes it possible to catalyze many difficult-to-achieve reaction processes by platinum catalysts, and enables many industrial production processes such as petroleum and chemical industry to be improved and optimized due to the use of newly developed platinum catalysts, simplifying the process and increasing economic benefits. Platinum catalysts still have great prospects for development.

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The choice of the particle size of silver powder for conductive adhesive

With the rapid development of electronic technology, conductive adhesive, as a kind of electronic interconnection material, is increasingly used in surface packaging and chip interconnection. As a substitute for traditional Sn/Pb solder, conductive adhesive has the advantages of low curing temperature, simple process, and environmental protection.

 

Conductive adhesive is an adhesive formed by dispersing conductive particles in a resin matrix. After curing and drying, it has conductive properties similar to metals. It has a certain bonding performance. By bonding different conductive materials together, a conductive path is formed between these materials to conduct electricity. Before curing, the conductive adhesive is a paste-like glue that can flow, and can be cured by heating and ultraviolet light, and the cured product meets certain properties, such as stable electrical conductivity and certain shear strength.

 

According to the conductive mechanism of conductive adhesive, the general selection principle is: more contact area can be formed between particles. There are many shapes of silver powder, such as flake, spherical, dendritic, irregular shape, etc. Different silver powders can be selected according to different uses. Generally, flake silver powders are mostly used in conductive adhesives, and the diameter is usually between 1-10um. Hongwu Nano can customize different specifications, such as the particle size, SSA, apparent density, of flake conductive silver powder for customers. For example, the flake silver used for LED dispensing and touch screen circuits has key differences in parameters and performance.

 

HONGWU is the first domestic manufacturer of large-scale and specialized production of silver powders. This series of products include: nano antibacterial silver powder, conductive flake silver powder, bright silver powder, conductive spherical silver powder, ultrafine silver powder, flake silver-coated copper powder, spherical silver-coated copper powder, dendritic silver-coated copper powder. Hongwu Nano has many years of professional and technical personnel engaged in the research and development and production of nano powders to provide technical support for the enterprises. At the same time, the company has established close cooperative relations with many domestic and foreign universities and research institutions to ensure the sustainable development of the company. Hongwu currently has an annual production capacity of 3 tons of nano silver powder and 5 tons of conductive silver powder. https://www.hwnanomaterial.com/

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Thermally Conductive Plastic with nanomaterials is An Important Porter for Heat Dissipation in The LED Industry

Some people say that HEAT is the number one enemy of LEDs. Theoretically, the electro-optical conversion efficiency of the LED is about 54% (the estimated result under ideal conditions), but any omissions in the manufacturing process and any defects in the material will cause its energy conversion efficiency to drop. Based on the current level of LED technology development, the electro-optical conversion efficiency is basically less than half of the theoretical value, and in practical applications, most of them are even less than 1/4 of the theoretical value, and the remaining electric energy will be released in the form of heat energy. , This is the reason why the LED generates heat.

Among all the solutions, the heat-conducting plastics with the characteristics of uniform heat dissipation and light weight are prepared into the heat-dissipating parts of the LED: such as lamp holders, cooling and heat-dissipating lamp cups and shells, which are currently one of the most respected methods. Compared with metal materials, thermally conductive plastics consume less energy and produce less pollution in production, are more environmentally friendly, and have the characteristics of high safety factor and flexible design. With the improvement of LED light efficiency and the reduction of heat generation, the requirements for LED heat dissipation will gradually decrease, and thermally conductive plastic heat sinks will be able to meet the heat dissipation requirements of most conventional LED lamps.

Most polymer materials themselves are thermally insulating materials. To obtain materials with excellent thermal conductivity, one is to make polymer materials with high thermal conductivity; the other is to fill and modify the polymer through blending methods to form composite materials to improve Thermal conductivity of polymers.

For plastic manufacturers, the former is more technically difficult and costly, while the latter is easier to implement. According to statistics, the thermal conductivity of general plastics is only about 0.2 W/(m·K). If the plastic is filled with thermally conductive fillers, the thermal conductivity can be 1W/(m·K)～20 W/(m·K) About 5-100 times the thermal conductivity of traditional plastics.

The matrix of thermally conductive plastic is PA6/PA66, PPS, TPE, PC, PE, PP, etc.; thermally conductive fillers can be divided into two categories: thermally conductive inorganic insulating fillers and thermally conductive non-insulating fillers. Thermally conductive inorganic insulating fillers include Al2O3, BN, AlN, MgO, etc. These fillers can ensure the thermal conductivity of the composite material and maintain the electrical insulation of the resulting products, so they have been widely used. Non-insulating thermally conductive plastic fillers include metal powder, graphite, carbon black, carbon fiber, etc., which have high electrical and thermal conductivity. The former is mixed with the plastic matrix to make a thermally conductive insulating plastic, and the latter is a thermally conductive non-insulating plastic.

For filled thermally conductive polymer materials, if the filler has high thermal conductivity and good electrical insulation, the thermal conductivity of the composite material depends on the molecular chain vibration of the polymer matrix and the interaction of lattice phonons and filler lattice phonons. ; If the filler has electrical conductivity, the heat conduction in the composite material depends on the result of the interaction between the heat transfer of electrons and the lattice vibration of the polymer and the filler.

As mentioned above, the importance of thermally conductive plastics for LED lamps is self-evident. With the increasing demand for plastics in LED lights, light radiators, electric vehicles, medical equipment and light vehicles, the prospects are very optimistic.

Hongwu is supplying a variety of thermal conductive materials, such as nano diamond powder, boron nitride powder, aluminum nitride powder, alumina powder, silicon carbide powder, zinc oxide powder, etc., welcome to consult for more information on nanomaterials. https://www.hwnanomaterial.com.

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Conductive fillers (carbon nanotubes, silver powder, copper powder) and conductive inks

Conductive ink is a special conductive coating that has been developed rapidly with the emergence of modern printed electronic technology. Compared with electronic products manufactured by traditional conductive coatings, printed electronic products based on conductive inks are flexible, large-area, lot sizing, lightweight, low cost, and environmentally friendly, and the market prospects are broad. Carbon nanotubes have high conductivity and large aspect ratio. As a conductive filler, it is very easy to build a conductive path and an ideal conductive ink filler.

Conductive ink is a composite material composed of conductive fillers, resin binders, solvents, dispersion stabilizers and additives. Among them, conductive fillers are the key functional phase. According to the properties of conductive fillers, it can be divided into three categories: silver, copper, and carbon (carbon nanotubes, graphene).

The latest application of nano conductive ink:

1.Flexible transparent conductive film

Using nano silver conductive ink as the conductive raw material, latest manufacturing technology-nano imprinting technology to produce the flexible transparent conductive film to replace the traditional conductive film. The flexible transparent conductive film produced by this process has the following characteristics: the surface resistance and light transmittance of the film are adjustable, which is better than the ITO transparent conductive film; the patterned electrode can be realized at one time, the flexible substrate is used, and the roll-to-roll large area and batch can be realized. It can be manufactured at a low cost and achieve extremely high surface conductivity.

2.RFID antennas

As early as many years ago, some people began to study using nano conductive ink to print RFID antennas. Its biggest advantages are simple process, environmental protection, and low drying temperature (applicable to a variety of substrates). Commonly used RFID antennas are divided into high frequency and ultra high frequency. The high frequency antenna manufacturing process is relatively cumbersome, and the circuit needs to be bridged between the front and back; the UHF antenna only needs to be printed on the substrate once, and the chip can be obtained after drying, RFID tags. Therefore, the nano conductive ink printing UHF RFID antenna has more efficiency advantages.

3.Transistors

The benchmark for measuring the chip manufacturing process is the width of the connecting wires of the transistors in the chip, that is, the line width. The line width of a semiconductor chip is limited by the atomic size and has its physical limit. The chip volume cannot be infinitely small, and the frequency of power-on and power-off cannot be increased any more. Breaking through this bottleneck requires a thorough innovation in materials and technology. CNTs transistors can be used to replace silicon transistors. The performance of transistors made of CNTs is 3 to 5 times higher than that of traditional silicon transistors, and the production cost is low.

At present, some R&D institutions have begun to use carbon nanotubes conductive ink to print transistors. Use printing technology to make CNTs transistors on flexible substrates reach a practical level, and are used for RFID tags.

4.Paper battery

Paper batteries refer to ultra-thin batteries printed with conductive inks (mainly as electrodes) using paper or film substrates as carriers. The terminal products of paper batteries include active or semi-active RFID tags, tag sensors, smart cards, smart packaging, medical electronic drug stickers, etc..

Nano silver(Ag) conductive ink can also be applied to paper battery electrodes. Domestic manufacturers have also done this test, using nano silver conductive ink through inkjet printing to obtain electrodes on the PET film. After charging and discharging tests, it is found that it has better battery capacity and stable performance.

 

Conductive ink is an indispensable material for printed electronic devices, and is the key and core technology in the upstream of the printed electronics industry chain. It is believed that in the near future, large-scale flexible displays, environmentally friendly ultra-thin batteries, RFID tags, etc. will bring great convenience to people’s lives.

 

Hwnanomaterial is supplying conductive fillers for conductive inks in bulk, including silver, copper, silver-coated copper powder, carbon nanotubes, graphene, and so on. Welcome to contact us if you have any requirements!

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Nanomaterials for textiles

With the development of science and technology and the improvement of human living standards, people have imcreasing requirements on comfortable and novel health care for clothing. Now people apply nano materials to textiles, and various functional textiles have emerged. Here are a few nano materials for textiles.

1.Nano zinc oxide

The photocatalytic antibacterial mechanism of Zinc Oxide Nanopowder and the antibacterial mechanism of metal ion dissolution have an antibacterial and deodorizing function; the nano zinc oxide has a strong absorption effect on ultraviolet rays in the range of 200-400 nm, and can be used as an ultraviolet shielding agent.

Nano zinc oxide itself is non-toxic and environmentally friendly; compared with antibacterial nano silver, the price is much lower.

Because of these functions and advantages, nano zinc oxide can be used to make functional textiles with antibacterial deodorizing function and UV protection.

2.Nano titanium oxide

Nano TiO2 has the basic properties of nano functional materials, and is used in textiles to have functions such as UV resistance, self-cleaning, air purification, anti-static, anti-infrared, anti-aging, etc.

Nano titanium dioxide is used in the textile slurry. Through the perfect combination with starch, the comprehensive weaving performance of the yarn is improved, the amount of PVA is reduced, the cooking time is short, the slurry cost is reduced, the sizing efficiency is improved, and the PVA pulp is also solved. It is not easy to desizing, environmental pollution and many other problems. Nano-titanium dioxide nano-titanium dioxide is mainly used to replace PVA in the yarn, which acts as a smooth hair, fills the gap and lubricates.

3.Nano silica

Nano-silica powder used in textiles can enhance the adhesion of the slurry to the fiber. The active hydroxyl groups on the surface and the hydrogen bonds on the starch and the hydroxyl groups on the cotton fibers have strong or weak hydrogen bonding, which can effectively improve the pure cotton and polyester. The sizing performance of cotton yarn; nano-silica is more beneficial to the sizing of cellulose fibers; it has the effect of enhancing and grinding and reducing hairiness.

Hydrophobic nano silica can be used to make hydrophobic textiles.

 

4.Nano antimony trioxide

Nano Antimony trioxide is a commonly used inorganic flame retardant and does not have good flame retardancy. However, when it is used together with a halogen flame retardant, it will have a great synergistic effect. Commonly used cerium oxides are antimony trioxide and antimony pentoxide, mainly antimony trioxide, and its flame retardant performance is 3-5 times that of antimony pentoxide. Therefore, it is generally believed that the flame retardant of antimony is antimony trioxide, which can be used for preparing flame retardant textile coatings, non-woven coating coating flame retardant, carpet flame retardant and other fireproof coatings, fire retardant coating flame retardant and the like.

In practical applications, it is often the case that several nano materials are mixed with other auxiliaries in textiles for new and functional textiles.

Nano-textiles are favored by researchers and companies for their superior performance, and the variety is growing. It is believed that these nano materials market for textiles will be increasing. https://www.hwnanomaterial.com/

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The Application Of Nano Silver Antibacterial In Clinical Treatment

Nano silver powder is a new type of antibacterial product developed based on nanotechnology. Due to the quantum effect, small size effect and large specific surface area, it has an antibacterial effect that traditional inorganic antibacterial agents can’t match. It has high safety and long-lasting effectiveness. , Is an antibacterial agent with long-lasting and weather resistance.

Regarding the principle of the bactericidal effect of nano-silver, most scholars believe that the specific surface area of ultra-fine silver is very large and presents AG+ in water. Therefore, the bactericidal effect of nano-silver is mainly related to silver ions, which can be related to the -SH in the enzyme protein in the bacteria. It binds quickly to inactivate key metabolic enzymes, making pathogenic bacteria unable to metabolize and die; secondly, nano-silver can bind to DNA bases of pathogenic bacteria and form cross-links to replace hydrogen bonds between adjacent nitrogens in purines and pyrimidines. Which denatures DNA without being able to replicate, leading to inactivation of pathogenic bacteria. The atomic arrangement of nano-silver shows that it is a “medium state” between solid and molecule. This extremely active nano-silver particle has super antibacterial ability and can kill bacteria, fungi, mycoplasma, chlamydia and other pathogenic microorganisms. In addition, nano-silver is a non-antibiotic bactericide, and no bacteria are resistant to nano-silver.

1. Application in burns, scalds, burn skin grafts
The results of skin grafting for dozens of burn patients showed that nano-silver increased the epithelialization rate of reticuloepithelial grafts by 40%, and had a better effect on promoting repair of residual burn wounds. The healing time of the experimental group was significantly shorter than that of the control group. Researchers believe through clinical observations and animal experiments that nano-silver antibacterial medical dressings are a kind of clinical external medicine for burns with strong anti-infective effect, low absorption, small toxic and side effects, and convenient use.

2. Application in dermatology
Nano silver is effective in treating acne vulgaris. The nano-ulcer patch is used to treat I-II bedsores. In comparison with the control, it is found that the active ingredient of the nano-ulcer patch is nano-silver particles, which has super permeability, produces a biothermal effect, improves the microcirculation of the damaged tissue, and eliminates the local area. Edema is conducive to tissue regeneration and wound healing.

3. Application in dentistry
Nano silver antibacterial agent can be used to prevent oral caries and mucosal diseases, and can also solve the problem of easy pollution during the production and use of dental materials.

In summary, due to its quantum effect, small size effect and large specific surface area, nano-silver materials are easily in close contact with pathogenic microorganisms, thereby exerting greater biological effects, so they have high safety, wide antibacterial range, and continuous Advantages such as long sterilization time. However, nano-silver materials are prone to particle aggregation and lose their nano-characteristics under conventional conditions without protective agents, which will affect the antibacterial effect of nano-materials. Therefore, the packaging and storage of nano-silver are also extremely important. For details, please consult Hongwu Nano staff online our website:https://www.hwnanomaterial.com/.