Tungsten Dioxide

Tungsten trioxide is used for many purposes in everyday life. It is frequently used in industry to manufacture tungstates for x-ray screen phosphors, for fireproofing fabrics and in gas sensors. Due to its rich yellow color, WO3 is also used as a pigment in ceramics and paints.In recent years, tungsten trioxide has been employed in the production of electrochromic windows, or smart windows. These windows are electrically switchable glass that change light transmission properties with an applied voltage.This allows the user to tint their windows, changing the amount of heat or light passing through.

Tungsten dioxide prepare process is ammonium paratungstate at about500℃ air calcined as tungsten trioxide, or a slight reduction to blue tungsten oxide at about 450℃ in hydrogen. Making tungsten filament  incandescent lamp is incorporated in a small amount of potassium hydroxide, silicon oxide and aluminum oxide in the tungsten trioxide or blue tungsten oxide, the amount does not exceed the sum of 1%, which is Baz invention in 1922 tungsten silk doping process. After doped  tungsten oxide reduction process of the metal tungsten powder with hydrogen. Reduction process is generally carried out in two steps: the first step to restore about 630℃ to tungsten oxide (brown tungsten oxide), the second step is reduced to tungsten metal powder at about 820 ℃. The purpose is to make the two-step reduction of potassium incorporated into full play the role and control of particle size. Such doped tungsten powder and then get in a special mold pressed into thin side bar. The side bar in hydrogen powered by self resistance heating (temperature of about 3000 ℃) method sintered tungsten sintered density can reach more than 85% of the theoretical value. This tungsten by swaging method can be processed into about 3mm in diameter tungsten rod, and then further processed by drawing mold into a variety of different ways thickness of the tungsten filament. For example 220V,15W incandescent tungsten filament with a diameter of about 15μm, and 10000W bromine tungsten lamp with a tungsten filament diameter of about 1.25mm. Finer tungsten as 220V, 10W incandescent tungsten filament diameter of about 12μm, will have to use the method to produce electrolytic corrosion.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn

• < Prev
• Next >