The same material sometimes has different crystal forms. What is the difference between them? Some information about Hongwu nanomaterials has been found as follows for your reference:

1. TiO2-Titanium Dioxide Nano Powder (Anatase and Rutile Crystal)

      Anatase titanium dioxide has good whiteness, while rutile titanium dioxide has better tinting strength and weather resistance;

      Due to the smaller specific surface area of rutile titanium dioxide, the ability to adsorb O2 is lower. A large number of articles reported that the photo-catalytic activity of anatase TiO2 is higher than that of rutile.

      As the rutile -type product crystals tend to be hexahedron, the anatase is more easily dispersed and uniform, and the formed agglomerates are more uniform and the particle size distribution is narrower.

      Application: The rutile titanium dioxide can be used for outdoor paints such as automotive ships, durable plastic products, etc.; Anatase titanium dioxide is used for colorants and fillers in white and light-colored interior paints, paper-making, plastics, and rubber products.

2. Al2O3-alumina nano powder (Alpha and gamma crystals)

      Alpha alumina has stable crystal form, simple purity control, narrow range of particle size distribution, and lower ratio than the surface; gamma alumina particle size is difficult to make large, and its specific surface area is large. When it is heated to 1200 degrees, it will be converted into alpha alumina.

Application: Alpha alumina is used in refractories, flame retardants, grinding machines, fillers, large scale integrated circuit boards, etc.; gamma alumina can be used as an adsorbent, catalyst, catalyst carrier, desiccant, etc.

3. BN-boron nitride nanopowder (hexagonal boron nitride and cubic boron nitride)

      Boron nitride has these types of crystals: hexagonal boron nitride (HBN), rhombohedral boron nitride (RBN), cubic boron nitride (CBN), and Wurlitzer boron nitride (WBN). The more widely used is hexagonal boron nitride, by cubic boron nitride, and the other two crystal types are not widely used.

      The core difference between cubic boron nitride and hexagonal boron nitride is that the physical structure is different. The cubic boron nitride crystal is more resistant to pressure and wear; the hexagonal boron nitride, this crystalline boron nitride has super-lubrication function, high temperature resistance, And metal does not moisten.

      Application: Cubic Boron Nitride is used for molds and tools. It can be processed hard and tough or highly viscous metal materials, especially iron-based materials; Hexagonal boron nitride is used as a lubricant, die-retardant agent, and prepared in accordance with ceramics and electricity. Insulation and so on.

4. Si3N4-Silicon Nitride Nanopowder (Alpha-Nitride and Beta-Nitride)

      Silicon nitride (Si3N4) has three kinds of crystal structures, namely, three phases of α, β, and γ. The alpha and beta phases are the most common forms of Si3N4.

      α-Si3N4, needle-like crystals, white or gray, the other is β-Si3N4, darker, dense granular polyhedron or short prism. Both are hexagonal crystal systems. The longer stacking sequence results in the alpha phase having a higher hardness than the beta phase. However, the alpha phase is chemically unstable compared to the beta phase. So at high temperatures in the liquid phase, the alpha phase is always converted to beta phase.

      Application: Silicon nitride is an important structural ceramic material, but also can be used for refractory materials, cutting tools, molds, etc., β-Si3N4 is the main form used in silicon nitride ceramics.

5. SiC- Silicon Carbide Nanopowders (Alpha-Nitride and Beta-Silicon Carbide)

      β-SiC is a cubic system, and the equiaxed structure of the crystal determines that the powder has better natural sphericity and self-sharpening than α-SiC.

      The temperature of β-SiC is much lower than that of α-SiC during its manufacture, so its particles can be more easily refined and homogenized.

      β-SiC has better electrical properties than α-SiC and higher purity in preparation

      The β-SiC powder has high purity, narrow particle size distribution, small pores, high sintering activity, and regular crystal structure; β-SiC whisker has a large aspect ratio, a high surface finish and a high diameter ratio.

Above 2100°C, β-SiC is converted into the form of α-SiC.

      Application: It can greatly improve the mechanical properties, thermal properties and corrosion resistance of polymer materials, various coating materials, and military materials. Can also be used for semiconductors, molds, structural materials and so on.

      Beta-type silicon carbide has better grinding and polishing effects in precision grinding, and has better sealing properties in the production of materials, sealing products and military products; beta-silicon carbide powder is superior to alpha silicon carbide powder Sintering activity.

6. Fe2O3 - Iron Oxide Nanopowder (Alpha Iron Oxide and Gamma Iron Oxide)

      γ is magnetic, α is the most stable, the other two phases γ, σ are very unstable and generally do not appear as the final product.

      Application: Nano-iron oxide has unique optical, magnetic, thermal and catalytic properties. It is widely used in the preparation of magnetic materials, pigments, fine ceramics and plastic products, and in the catalyst industry. At the same time, it is also a new type of sensor material.

by rachale