Nickel-Free Sealing Agent

The formulation of nickel-free sealing agents contains no nickel, hence the name. They are primarily composed of surfactants, dispersants, ash inhibitors, penetrants, buffers, chelating agents, and other raw materials. Main variants include room-temperature, high-temperature, color-retaining, and wide-temperature types. The mechanism of nickel-free sealing agents involves a series of reactions that generate oxide precipitates to block the micro-pores in the aluminum anodized oxide film. This reduces the film's adsorption properties, enhancing the aluminum material's corrosion resistance, stain resistance, and wear resistance. Performance is comparable to nickel-containing sealing agents. Key characteristics include fast sealing speed, minimal weight loss, high hardness, and short aging time.

Product Features

1. Nickel-Free, Eco-Friendly

Compared to nickel-containing sealers, this product contains no nickel or chromium, preventing environmental pollution from wastewater during use and reducing wastewater treatment costs.

2. Versatile Applicability

Multiple formulations are available, including standard temperature, high temperature, color-specific, and fluorine-free types, accommodating diverse sealing conditions and processes. Corresponding formulations exist for various aluminum alloys and anodizing processes, ensuring excellent compatibility with oxide films.

3. Superior Appearance

Post-sealing results exhibit no powder residue, frosting, or color unevenness, and withstand 72-hour salt spray testing.

Process Parameters (Example: Model LX-C6619H)

Nickel-free sealer: 4-6 g/L (recommended bath concentration: 5 g/L)

Deionized water: Balance

Temperature: 60-90°C

pH: 5.2-5.8

Time: 1-1.5 μm/min (adjust based on oxide film thickness)

Note: Process parameters vary by nickel-free sealer model. Contact our engineers for specifics.

Bath Maintenance

1. Determine sealer dosage based on bath analysis results.

2. Strictly maintain bath pH between 5.2–5.8 during production. Adjust elevated pH with dilute acetic acid; lower pH with sodium acetate or dilute ammonia solution.

Precautions

1. The nickel-free sealer is a weakly acidic agent. Avoid contact with alkaline chemicals. It is hygroscopic; store in a moisture-proof environment.

2. In regions with low winter temperatures, thoroughly shake the product before use to prevent flocculation caused by low temperatures. This does not affect performance.

Mechanism of Action

The formulation of the nickel-free sealing agent contains rare earth metal salts. Under electrical current, metal ions penetrate the micro-pores of the columnar aluminum anodic oxide film. In an alkaline environment, these metal ions undergo hydrolysis to produce metal hydroxide precipitates. As these precipitates accumulate, they gradually block the micro-pores of the aluminum anodic oxide film, forming a dense sealing layer. This layer acts as a barrier against corrosive chlorine, oxygen, sulfur, and moisture, thereby achieving corrosion protection. It also enhances the hardness of the aluminum anodized film.

Packaging, Storage, and Transportation

This product is packaged in 25kg plastic drums. Protect from heat and moisture during storage and transportation.

The solution of nickel-free sealing agent reacts with aluminum oxide in the anodized film to form denser aluminum hydroxide precipitates. These precipitates fill the remaining microporous spaces, combining with metal precipitates to create a composite dense layer that enhances the surface sealing properties of aluminum. The nickel-free sealer does not rely on nickel-formed nickel hydroxide precipitation for sealing. The resulting rare earth metal precipitation is more stable and exhibits greater adaptability to temperature and pH variations.