Quick review of conductive functional powder materials

Conductive material is a new kind of functional material, which has been widely used in electronics, aerospace, communication, printing, packaging and other fields.  At present, conductive powder is mainly used as filler, so that the matrix material has conductivity, antistatic, shielding electromagnetic waves and other functions.

Conductive powder characteristics  

The characteristics of conductive powder are shown in the following table

Classification and application of conductive materials  

According to the different chemical composition of conductive materials can be divided into carbon series, metal series, metal oxide series, structural polymer series and compound series.  

Different according to conductive material function, can be divided into anti - static material, conductive material, electrode material, heating material, electromagnetic wave shielding material.  

1. Carbon conductive materials  

Carbon conductive materials include conductive carbon black, graphite, carbon fiber, etc., with good electrical conductivity, strong coloring power, high chemical stability, low density, low price and other characteristics, to prepare conductive ink, conductive adhesive is widely used in electronics, chemical and other fields.  

The shortcomings of carbon conductive materials are mainly poor dispersion stability and dark color, so they are limited in practical application.  At present, carbon nanotube materials, graphene and other new materials have been explored as new carbon conductive materials.

2. Metal conductive materials  

Metal conductive materials mainly include silver, copper, nickel and other conductive materials, with good conductivity and ductility, relatively light color, therefore, more widely used.  

Among them, silver conductive materials have the best conductivity and the strongest oxidation resistance, but the price is high, and silver ion migration is easy to cause short circuit in the process of use.  

Nickel and copper prices are much cheaper than metallic silver, but these two kinds of material preparation into powder, prone to oxidation reaction, causing a sharp rise, resistance of affect conductivity, with organophosphorus compounds, coupling agent, heterocyclic compounds or carbonylation technique treatment can improve its antioxidant capacity, but the use of the relatively high cost, and limit its application fields.

3. Metal oxide system conductive material  

Metal oxide conductive materials are favored by downstream application enterprises because of their high melting point, strong oxidation resistance and moderate price.  

At present, the more common conductive metal oxides are antimony doped tin dioxide (ATO), aluminum doped zinc oxide (ZAO), indium doped tin oxide (ITO).  

a. Antimony doped tin dioxide (ATO)  

The stannic oxide doped with antimony (ATO) has obvious improvement in conductivity, light color, good stability and other excellent characteristics.  In a certain amount of antimony doping range, the more antimony, the better the conductivity, but the color of the powder is darker.  At present, the existing technology is to use a small amount of antimony evenly doped in the powder of tin dioxide, can overcome the problem of dark powder color, while ensuring the conductivity.

b. Aluminum doped zinc oxide (ZAO)  

Aluminum - doped zinc oxide (ZAO) is a replacement solid solution formed by zinc oxide and alumina.  Aluminum doped zinc oxide (ZAO) not only has good uv absorption, high chemical stability, but also has light color, high visible light transmittance, good electrical conductivity and other excellent characteristics, which can be widely used in antistatic coatings, rubber and plastics, and has a tendency to replace ITO material with good electrical conductivity but high price.

c. Indium-doped tin oxide (ITO)  

Indium-doped tin oxide (ITO) has the advantages of low resistivity and high visible light transmittance.  Doped indium tin oxide can cut off harmful electronic radiation, ultraviolet and far infrared ray, is widely used in a variety of flat panel displays, sensors, gas sensitive elements.

4. Structural conductive polymer material  

Structural conductive polymer material is also called intrinsic conductive polymer material. Compared with traditional composite conductive polymer material, it has the characteristics of light weight, good environmental stability, design structure, adjustable conductivity, and can make up for the defects of metal fillers.  At the same time, it also has the characteristics of antistatic, electromagnetic shielding or absorbing electromagnetic wave, electroluminescence, photochromism and nonlinear optical effect.  

It has potential application value in many fields, such as electric conductivity, anticorrosion, electromagnetic interference shielding, chip manufacturing, microelectronics, liquid crystal display and other fields.

5. Composite conductive material  

With the development of information industry, the demand for conductive composite materials is becoming more and more urgent.  Composite conductive material is a new kind of conductive material which is filled with conductive material and forming material.