Cobalt Blue powder is a deep blue inorganic pigment with excellent properties, which has a wide range of applications in industry, art, and scientific research. Here is a detailed introduction about it:

1. Chemical composition

Chemical name: Cobalt Aluminate.
Chemical formula: CoAl2O4

Crystal structure: It has a stable spinel structure, which allows it to maintain extremely high stability under extreme physical and chemical conditions.

2. Core Features

Excellent heat resistance: It is one of the most heat-resistant pigments known, capable of withstanding high temperatures of up to 1200 ° C without color change or decomposition. Therefore, it is the preferred coloring agent for the ceramic and glass industries.
Excellent weather resistance: It has strong resistance to ultraviolet rays, acids, alkalis, solvents, and atmospheric corrosion, and will not fade or become brittle due to long-term sun exposure.
Environmentally friendly: Unlike some pigments containing cadmium or lead, cobalt blue has very stable properties after curing and is considered a relatively environmentally friendly inorganic pigment.
Excellent covering and coloring power: Its color tone is deep, pure, and has a unique luster.

3. Synthesis process: How is it manufactured?

The performance of cobalt blue powder greatly depends on its synthesis method, especially for nanoscale products like SAT NANO:

Traditional Solid state method: Cobalt oxide and aluminum oxide are calcined for a long time at 1100 ° C-1300 ° C. The powder crystals produced by this method are intact, but the particle size is relatively large (usually in the micrometer range) and the transparency is low.
Sol gel method: the precursor solution is mixed at the molecular level and formed at a lower temperature (600 ° C -800 ° C). This process can produce cobalt blue at the nanometer level (<100nm), with extremely high specific surface area and transparency, commonly used in high-end automotive paints and inkjet inks.
Hydrothermal synthesis method: generated in a closed high-pressure reactor. This method can precisely control the morphology of the powder (such as spherical or rod-shaped), giving it special activity in certain catalytic applications.

Regarding nanoscale cobalt blue (powder), the following sets of core experimental data are usually focused on in industrial research and academic studies. These data not only demonstrate its material properties, but also directly guide its application in coatings and ceramics.

The following is a summary of experimental data based on SAT NANO nanoscale cobalt blue products:

1. Basic Physicochemical Properties

These parameters define the quality and dispersibility of the nanopowder.

Parameter	Typical Value (Nano-grade)	Test Method
Average Particle Size (D50)	30 - 50 nm	DLS / TEM
BET Specific Surface Area	45 - 65 m2/gm2/g	N2 Adsorption
Crystal Structure	Spinel Phase	XRD (X-Ray Diffraction
Density	4.3 - 4.5 g/cm3g/cm3	Pycnometer
pH Value	6.5 - 7.5	10% Aqueous Suspension
Oil Absorption	20 - 30 g/100g	ASTM D281

2. Thermal Stability Data (For Ceramics)

This test simulates the high-temperature firing process in ceramic glazes.

• TGA (Thermogravimetric Analysis): Mass loss is < 0.5% up to 1000°C, indicating extreme structural stability and no volatile components.
• Color Stability (ΔEΔE Color Difference):
  • At 800°C vs. 25°C: ΔE<0.8ΔE<0.8
  • At 1200°C vs. 25°C: ΔE<1.5ΔE<1.5
• Conclusion: The color remains consistent and vibrant even at extreme temperatures, making it the industry standard for "underglaze blue" and high-fire ceramics.
  

3. Weathering and Lightfastness (For Coatings)

This evaluates the coating's resistance to long-term outdoor exposure.

• QUV Accelerated Weathering Test:
  • Condition: 1000 hours of UV-B irradiation (simulating 5-10 years of outdoor exposure).
  • Gloss Retention: > 95%
  • Color Change (ΔEΔE): 0.2 - 0.5 (In comparison, organic blue pigments typically show a ΔEΔE of 3.0 or higher).
• Chemical Resistance:
  • 5% HCl immersion (48h): Grade 5 (No change)
  • 5% NaOH immersion (48h): Grade 5 (No change)
• Conclusion: Cobalt Blue is virtually impervious to acid rain, alkaline detergents, and intense UV radiation.

4. Optical and Colorimetric Performance

Comparing Nano Cobalt Blue with traditional micron-sized powders.

• Reflectance Spectrum: Exhibits a strong reflectance peak at 450nm - 480nm (Blue region) with reflectance > 85%.
• Tinting Strength: Nano-grade powder provides 30% - 50% higher tinting strength than micron-sized alternatives. This allows for lower pigment loading while achieving the same color intensity.
• Haze & Transparency: In a 1% loading clear coat, nano cobalt blue maintains high transparency and low haze, ideal for "Deep-Sea Blue" metallic car paints.

SAT NANO is a best supplier of cobalt blue powder in China, we can supply 50nm, 100nm, 300-500nm particle size, if you have any enquiry, please feel free to contact us at admin@satnano.com