Activated carbon desiccant, powder, granular, irregular granular, cylindrical, spherical and fibrous, etc.
Activated carbon desiccant is based on the unique adsorption principle of activated carbon, choosing good coconut shell, fruit shell and wood chips as raw materials, after high temperature activation and special pore size adjustment process, so that it has a vast incomparable specific surface area and rich medium and micro pore structure, which can effectively dispel the odor, stench and water in various packaging products. For packaging, storage, transportation and other processes moisture deodorization effect is obvious.
The silver powder has a dark gray appearance, has good thermal and electrical conductivity, and the electrical conductivity decreases with the increase of temperature. This is determined by the structure of silver itself. On the silver lattice nodes, metal positive ions are arranged. There are free electrons between these positive ions. The free electrons move continuously to form a metal bond, which connects the positive metal ions to form a metal crystal. The free electrons can flow in a certain direction under the influence of a small potential difference. Electric current is formed, which is the reason why silver and all metals can conduct electricity.
When the temperature rises, the vibration of the metal positive ions on the lattice node is strengthened, and it is more difficult for free electrons to move between them. Therefore, the conductivity of silver and metals decreases with the increase of temperature.
Silver not only has excellent electrical conductivity (pv=1.159×10-0·cm), but also has strong oxidation resistance and stable performance. The disadvantage is that silver ions are prone to migration under humid and hot conditions, leading to an increase in coating resistance and a decrease in performance, and the price of silver is expensive.
The shape of silver powder is different depending on the preparation method. According to ptfe powder rate the shape of silver powder, it is divided into spherical silver powder, flake silver powder, flat silver powder, dendritic silver powder and sponge silver powder. The flake-shaped contact surface is much larger than the spherical-shaped contact surface, so it has better conductivity. In the case of the same ratio, the resistivity of the spherical silver powder is in the order of 10-2, while the scaly silver powder is 10 “. The conductivity is related to the particle size of the silver powder. The smaller the particle size, the higher the conductivity. Conductive paint made of extremely fine ultrafine silver particles (particle size ranging from 1jm to several microns) has a resistance value of only 10-Q, but attention should be paid to the thickness of the flake silver powder. According to reports, the flaky silver powder directly prepared by chemical methods is too thin, with a thickness of only a few nanometers to tens of nanometers. When used with resin, it is easy to deform, form particles and become thick during heat curing. The flake silver powder used recently is machined.
Silver powder is only suitable for certain special occasions due to its relatively high price and shortage of resources, which limits its promotion and application.
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