Introduction

Tungsten dioxide is a brown monoclinic crystal powder, also known as brown tungsten oxide, is mainly used in preparing tungsten powder and tungsten trioxide. Tungsten dioxide is easily being oxidized which shows it’s unstable, and usually can not be sold directly.

Tungsten dioxide is a brown monoclinic crystal powder, also known as brown tungsten oxide, is mainly used in preparing tungsten powder and tungsten trioxide. Tungsten dioxide is easily being oxidized which shows it’s unstable, and usually can not be sold directly.

Physical properties of tungsten diooxide：

Chemical Property

1.Tungsten is insoluble in water, alkali solution, hydrochloric acid and sulfuric acid, but it will dissolve in H2SO4 to generate the red salt; and easily oxidized and convert to high valence of tungsten trioxide by nitric;

2.Easy disproportionate in an inert gas to produce metal tungsten and tungsten trioxide; and decompose when heating to melt in the N2 gas stream under 1500~1600℃; it can be reduced to metallic tungsten at high temperature in the hydrogen; it is stable in 45% to 60% of water vapor at 900℃ and 40% to 55% of hydrogen;

3.It will quickly oxidized to tungsten trioxide in the air, and transformed to blue tungsten oxide when heated to 500 ℃ in a nitric oxide gas; tungsten trioxide will be reduced by hydrogen into metallic tungsten at high temperature of 1020℃.

Production Process

1.Mix tungsten powder and WO3 at the molar ratio of 1:2 and heated to 950℃ in the vacuum atmosphere, or restore the WO3 at the condition of 900℃ in the H2 airflow with saturated steam;

2.Generated from tungsten trioxide by the reduction of hydrogen under 575~600℃, or the reduction of metal tungsten and tungsten trioxide.