Preparation Method of Superfine Silver Powder and Nano Silver Powder
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Update time : 2020-10-07 10:43:02
Properties of superfine silver powder and nano silver powder:
The particle morphology of ultrafine silver powder includes spherical, dendritic, flake, cubic and microcrystalline. After the silver nitrate is complexed with ammonia water, it is obtained by adding dispersant, adding hydrazine for reduction, washing with water, filtering and drying. The average particle size is <0.5μm. The specific surface area is 0.1～5m2/g. There is also the silver oxide reduction method with formaldehyde. And convert silver nitrate into silver carbonate, add triethanolamine to reduce to obtain molecular silver method.
Ultrafine silver powder is an essential material in the electrical and electronic industries, and it is a kind of precious metal powder widely used in the electronics industry. Nanosilver particles have small size effects, quantum size effects, surface effects and macro-quantum tunnelling effects due to their unique structure, and thus have physical and chemical properties that traditional materials do not have. Nanosilver particles occupy a significant position in the fields of surface-enhanced Raman spectroscopy, surface-enhanced resonance scattering spectroscopy, molecular biology, supramolecular systems, etc., and are one of the essential materials for basic theoretical research.
Nanosilver powder has high surface activity and catalytic performance and is widely used in catalysts and ultra-low temperature refrigerator diluents. At the same time, due to its unique physical and chemical properties, it has also been commonly used in immunoassays, sensor development, and molecular electronics. Besides, adding a small amount of nanosilver to chemical fibre can improve specific properties of chemical fibre products and make it have strong sterilization ability. According to the shape of the ultrafine silver powder, there are roughly spherical, flocculent, dendritic and flake-like types; according to the particle size, it can be divided into fine silver powder with an average particle size of 10-40μm; ultrafine silver powder with an average particle size of 0.5-10μm; Fine silver powder, average particle size <0.5μm; nano silver powder, particle size <0.1μm.
Preparation method of superfine silver powder and nano silver powder:
The preparation methods of ultrafine silver powder mainly include gas phase method, liquid phase method and reliable phase method. The gas-phase process has large investment, high energy consumption and low yield; the ultrafine silver powder prepared by the reliable phase method has a large particle size and a broad particle size distribution; the liquid phase chemical reduction method is currently a standard method for low-cost and small-batch preparation of ultrafine silver powder.
The principle of the liquid phase chemical reduction method for preparing ultrafine silver powder is to use a reducing agent to deposit silver from its salt or complex aqueous solution or organic system in powder form. Commonly used reducing agents include formaldehyde, ascorbic acid, glycerin, organic amines, unsaturated alcohols, sodium citrate, hydrazine and hydrazine compounds, etc. Generally, hydrazine hydrate is used. In the silver ammonia aqueous solution, a certain amount of additive nitrate is added. Under the action of the reducing agent hydrazine hydrate, the amount of the additive is adjusted to obtain a silver powder with different particle sizes. The nitrate additives used can be one or two, and the addition amount is determined according to requirements. The silver powder prepared by this method has a small particle size, a short particle size distribution range and good reproducibility.
TRUNNANO (aka. Luoyang Tongrun Nano Technology Co. Ltd.) is a trusted global chemical material supplier & manufacturer with over 12 years’ experience in providing super high-quality chemicals and Nanomaterials. The superfine silver powder produced by our company has high purity, adequate particle size and impurity content. Lower, please contact us if necessary.
