"Six aspects" explain why LED power is afraid of sulfur

LED light source is afraid of sulfur, this is because the sulfur containing gas through its porous structure of silica gel or bracket gap, and the light source silver coating sulfide reaction. After curing reaction of LED light source, the functional area of the product will darken, the luminous flux will gradually decline, and the color temperature will drift obviously. The conductivity of silver sulfide increases with the increase of temperature. A more serious condition is that the silver layer is completely corroded and the copper layer is exposed. As the gold wire ii solder joint is attached to the surface of the silver layer, when the silver layer in the functional area of the support is completely vulcanized, the gold ball falls off, resulting in dead light.

LED lamps contain more than 50 raw materials, which may also contain sulfur, chlorine and bromine. In a closed, hot environment, these sulfur, chlorine and bromine elements may evaporate into gas and corrode LED light sources. Therefore, the lighting factory has the responsibility and obligation to provide sulfur free environment to LED light source.

LED lamps may contain materials containing sulfur/chlorine/bromine:

1.Power supply: there are 20 or 30 kinds of raw materials in the built-in power supply of LED, including PCB board, power cord containing sulfur rubber, insulating and packaging plastics of rubber, plastics containing halogen flame retardant and electronic components, which may contain sulfur, chlorine and bromine. When the power supply is hot, these materials will volatilize sulfur-chlorobromine gas. When the sulfur-chlorobromine gas combines with nitrogen-containing water vapor, it will generate corrosive and harmful gas, causing corrosion to LED.

2. PCB board: PCB produced in the market has a certain content of sulfur element residue, although PCB manufacturers will clean the board in the process process, eliminate the residue containing sulfuric solvent, but the common production process is difficult to clean completely.

3. Sulfur rubber power cord and rubber insulation packaging: plastic rubber can be in 65 ~ 250 ℃ temperature range keep elasticity for a long time, and it has excellent electrical performance and chemical stability, can waterproof, resistance to ozone, climate ageing, combined with the usage simple, the craft is applicability, therefore widely used in electronic industry, as the electronic components of coating, sealing and packaging materials.

4. Halogen-containing flame retardants: printed circuit board, shell, plastic, aluminum substrate insulation layer: PBB, PBDE, tbbp-a, PCB, hexabromododecane, tribromophenol, short-chain chlorinated paraffin and other halogen compounds are often used as flame retardants for printed circuit board, shell, plastic and other materials. When heated to a certain temperature, these materials will volatilize halogen gas. When the halogen gas combines with nitrogen-containing water vapor, corrosive harmful gas will be generated, causing corrosion to LED. In addition, according to many scientific studies, halogen flame retardants have become the ubiquitous pollutants in the daily environment, releasing harmful substances in the process of combustion and heating, threatening human health, the environment and future generations. Halogen flame retardants are used against the environmental performance of LED. Therefore, it is suggested that LED material suppliers should choose halogen-free flame retardant materials as far as possible.

Solder paste flux: flux in the activator composition usually contains a few halogen or organic acid components, it can quickly eliminate the oxidation film on the surface of the metal being welded, reduce the surface tension of the solder, make the solder quickly spread on the surface of the metal being welded. The halogens, which usually use bromine/chlorine, turn the silver into black silver bromide/silver chloride.

6. Ink: green oil on PCB, white oil on aluminum substrate, characters, paint on lamps and radiators may contain sulfur. This is because the oil in the paint has sulfide, its composition is very complex, there are element sulfur, hydrogen sulfide, mercaptan class, sulfur ether class, disulfide and so on. Active sulfide, such as hydrogen sulfide, mercaptan and elemental sulfur, can react directly with silver. Oil paint contains oilfield water, which contains salts such as sodium chloride, magnesium chloride and calcium chloride. In crude oil processing, magnesium chloride and calcium chloride are easily hydrolyzed by heat to form highly corrosive hydrogen chloride. Therefore, it is recommended that LED material suppliers choose sulfur free or low sulfur crude oil as paint materials.