The corrosion resistance of high-pressure die-cast LED light housings is a key factor affecting their lifespan and stability, especially in outdoor or high-humidity environments. Corrosion can lead to structural damage and seal failure, ultimately impacting LED light source performance. Improving corrosion resistance requires a comprehensive approach encompassing material selection, surface treatment, structural design, process optimization, and environmental control.
Material selection is fundamental to enhancing corrosion resistance. High-pressure die-cast LED light housings typically use aluminum alloys due to their lightweight, high strength, and good thermal conductivity. However, ordinary aluminum alloys are prone to electrochemical corrosion in humid or corrosive environments, necessitating the selection of alloy systems with superior corrosion resistance. For example, ADC12 aluminum alloys with added magnesium and silicon can enhance corrosion resistance by forming a dense oxide film; alternatively, special aluminum alloys containing zinc and copper can be used, enhancing corrosion resistance through solid solution strengthening and second-phase precipitation. Furthermore, avoiding the use of recycled aluminum with high iron and other impurities can reduce localized corrosion caused by the galvanic effect.
Surface treatment is the core element in enhancing corrosion resistance. Anodizing is the most common process for high-pressure die-cast LED light housings. It involves electrolysis to create an aluminum oxide film approximately 10-25 micrometers thick on the aluminum alloy surface. This film possesses high hardness and insulation, effectively blocking the penetration of water, oxygen, and corrosive ions. Further sealing treatment can fill the pores of the oxide film, improving its resistance to salt spray and damp heat. For high-corrosion environments, an epoxy or polyester powder coating can be applied after anodizing to form a composite protective layer 60-80 micrometers thick, enhancing weather resistance and resistance to chemical corrosion. Additionally, electroplating with nickel, chromium, or other metals, or depositing ceramic films such as titanium nitride using PVD (physical vapor deposition) technology, can significantly improve the corrosion resistance and surface hardness of the lamp housing.
Structural design optimization can reduce corrosion risk. Gaps, sharp corners, and threads in high-pressure die-cast LED light housings are prone to retaining moisture or corrosive media, leading to accelerated localized corrosion. Therefore, structural gaps should be minimized during design, with rounded corners to avoid sharp edges; O-rings or waterproof joints should be added to threaded connections to prevent moisture infiltration; for outdoor lighting fixtures, drainage holes or ventilation structures should be designed to prevent condensation buildup. Furthermore, the contact surface between the lamp housing and the LED light source must be insulated to prevent galvanic corrosion caused by potential differences.
Process control is crucial for corrosion resistance. During high-pressure die casting, parameters such as mold temperature, injection speed, and pressure directly affect the density and surface quality of the lamp housing. Defects such as porosity and shrinkage within the casting can become the starting point for corrosion. Therefore, the die casting process must be optimized to ensure a uniform and dense casting structure; simultaneously, the cleanliness of the mold must be strictly controlled to avoid residual release agents or impurities causing surface contamination. In addition, the lamp housing must be thoroughly cleaned before surface treatment to remove oil, scale, etc., ensuring the adhesion between the coating and the substrate.
Environmental control is an auxiliary means to extend the life of the lamp housing. During storage and transportation, contact between the lamp housing and corrosive substances (such as sulfides and chlorides) should be avoided to prevent damage to the surface passivation film. For lamps exposed to the outdoors for extended periods, surface dust and dirt should be cleaned regularly to reduce the adhesion of corrosive media. In coastal areas or areas with severe industrial pollution, lamp housings with higher protection ratings (such as IP66 or higher) can be selected, and the thickness of the anti-corrosion coating should be increased.
Through material upgrades, surface treatment enhancements, structural design optimization, precise process control, and improvements in environmental adaptability, the corrosion resistance of high-pressure die-cast LED light housings can be significantly improved. These measures not only extend the lifespan of the lamp housing but also reduce maintenance costs, ensuring the long-term stable operation of LED lamps in harsh environments.
