Apparent Density of Violet Tungsten Oxide

Violet tungsten oxide with low apparent density has high application value in the field of powder metallurgy. It is an extremely important material for the preparation of ultrafine tungsten powder and tungsten carbide. Low apparent density of violet tungsten oxide is determined by its unique needle structure.

Apparent density refers to the mass of powder per unit volume when the powder is naturally filled into the specified container. It is not only an important index of powder property, but the comprehensive embodiment of various properties of powder. Apparent density has a great effect on powder quality.

Generally, apparent density is affected by many factors. Here are the factors as following as:

1. Density of raw material.

2. Shape of powder particle.

The more irregular the powder is, the lower the apparent density is, and vice versa.

3. The size of powder particle.

The smaller the powder particle is, the larger the specific surface area is, which leads to the lower apparent density, and vice versa.

4. Size distribution of powder particle.

The effect of size distribution on apparent density is often determined by two functions of powder particle: filling and bridging. If the latter is dominant, apparent density of powder will be reduced; if the former is dominant, apparent of powder will be increased.

5. Roughness of powder surface.

The coarser the powder surface is, the lower the apparent density is, and vice versa.

Violet tungsten oxide has irregular structure of needle. The cracks inside violet tungsten oxide particle are usually rich, which leads to the rough particle surface. Unlike the spherical particles, the needle-like particles can’t be close to each other. Therefore, the internal space of violet tungsten oxide is usually large, which accounts for the low apparent density of the material. With low apparent density, violet tungsten oxide is widely used in the preparation of tungsten powder and tungsten carbide. And during the preparation process of these metal powder, hydrogen penetrates the powder better. Rate of hydrogen reduction is fast with violet tungsten oxide.

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