What are the physical properties of rutile titanium dioxide?

Rutile titanium dioxide as one of the two most important types of titanium dioxide rutile titanium dioxide is an excellent white pigment, with high dispersion, high weather resistance, high hiding power, excellent stability. Widely used in interior and exterior wall latex paint, industrial coating, composite ink, flexo ink, laminated paper, plastic masterbatch, powder coating, etc.

So, what are the physical properties of rutile titanium dioxide?

Relative density

The relative density of titanium dioxide is related to its crystalline form, particle size, chemical composition, and especially the amount of surface treatment. In the manufacturing process, it increases with the increase of calcination temperature and the extension of calcination time.

Among the commonly used white pigments, the relative density of titanium dioxide is the smallest, and the surface area of titanium dioxide is the largest and the pigment volume is the highest for white pigments of the same quality. The relative density of anatase type titanium dioxide is 3.8 ~ 3.9g/cm3, and that of rutile type titanium dioxide is 4.2 ~ 4.3g/cm3.

Melting and boiling points 

Since both anatase and plate titanium dioxide change to rutile at high temperatures, their melting and boiling points are virtually nonexistent. The melting point value of rutile titanium dioxide is not consistent with the data. It is generally believed that at 1800~1875℃, the melting point in air is 1830±15℃, and the melting point in oxygen-rich is 1879±15℃. The melting point is related to the purity of titanium dioxide. The boiling point of rutile titanium dioxide is (3200±300) K.

Constant of permittivity

Titanium dioxide has excellent electrical properties due to its high dielectric constant. Under the action of external electric field, the ions interact with each other and form a very strong local internal electric field. Under the action of this internal electric field, the outer electron orbitals of the ion are strongly deformed, and the ion itself is greatly displaced.

Titanium dioxide crystal containing trace impurities and so on have a great impact on the dielectric constant. The permittivity of rutile type varies with the orientation of Tio 2 crystal. When it is parallel to the C axis, the permittivity of rutile type is 180. 90 at a right Angle; The average value of the powder was 114. The dielectric constant of anatase titanium dioxide is only 48.

Electrical conductivity

Titanium dioxide has the properties of a semiconductor, its conductivity increases rapidly with temperature, and it is also very sensitive to hypoxia. For example, rutile titanium dioxide is an insulator at 20℃, but when heated to 420℃, the conductivity increases by 107 times; According to the stoichiometric composition of titanium dioxide (TiO2) conductivity < 10-10s/m, and when titanium dioxide loses a small amount of oxygen, such as TiO1.9995 conductivity is 10-1s/m. The dielectric constant and semiconductor properties of rutile titanium dioxide are often used in the electronics industry to produce electronic components such as ceramic capacitors.

Hardness

The hardness of ANATase titanium dioxide is 5.5 to 6.0 and rutile titanium dioxide is 6 to 7 if the hardness of Mohs hardness is measured on a 10-point scale (its value only indicates the hardness level of each crystal and does not indicate its true ratio). The hardness is related to the crystal structure of titanium dioxide, and is related to the purity of the product and the calcination temperature in the production. The high temperature is easy to sintering, and the hardness is also increased.

It is because of the rutile type of titanium dioxide hardness is high, difficult to crush so the spinneret hole wear rate is high, the wear of the roller is also large, so it is not suitable for chemical fiber matting and photographic concave plate printing.

Moisture absorption

Although titanium dioxide is hydrophilic, its hygroscopic property is not very strong. The hygroscopic property of anatase type is larger than that of rutile type. The moisture absorption of titanium dioxide is related to the properties of the treatment agent when it is treated on the surface, and also has a certain relationship with the size of its specific surface area. The moisture absorption of large specific surface area is also slightly higher.

Thermal stability

Titanium dioxide is a thermostable compound. When it is heated under vacuum, there will be a slight loss of oxygen, accompanied by a dark blue color. The reaction is reversible and will return to the original white color after cooling.