Several preparation techniques have been used to deposit tungsten oxide thin films, including sol-gel, hydrothermal technologies, chemical vapor deposition, thermal evaporation, pulsed laser deposition, and magnetron sputtering. In fact, reactive magnetron sputtering is one of the most versatile techniques to deposit oxide films, allowing the control of many properties of the films by changing the partial pressure of the reactive gas, the components with the different targets and even sputtering power. Many reports have been published explaining the mechanisms involved in thin film growth using magnetron sputtering, but very often these refer to tungsten oxide thin films obtained from a metallic tungsten target. In contrast, the reports on tungsten oxide thin films obtained from a WO3 target are seldom reported. In 2009, Acosta et al. reported the studies on the optical properties of tungsten oxide thin films by non-reactive sputtering of WO3 target and found that the argon pressure had a strong influence on the optical properties of the film. It has been predicted that a large amount of oxygen vacancies, defects and disordered structures in the deposited films, which are very critical in determining the crystalline, optical, photochemical and electric properties of tungsten oxide thin film, would be produced when the sputtering plasma interacts with WO3 bulk.

 

 

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

  (1)The nanoscale tungsten powder with an average particle size of 19 nm was obtained by gradually reducing WO3, which was prepared by ultrasonic spray and thermochemical conversion process, into WO2.90 and W.

 

  (2)Compacting with a rubber die is a preferred method for making a tungsten green compact with the nanoscale powder, whereby a relative density of 46.2% was achieved.

 

  (3)The compact made from the nanoscale tungsten powder starts shrinkage at 1050℃, and the shrinkage rate is maximum at 1210℃. The shrinkage almost ends at 1500℃. In the case of the traditional tungsten powders, however, the compacts barely shrink.

 

  (4)After sintered in hydrogen at 1500℃, tungsten samples with a relative density of 96.4% and a particle size of 5.8 pm were prepared. As for the traditional tungsten powder, the relative density is only 68.2% after sintering.

 

 

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

In the past few years, an increasing interest has been put on the tungsten oxide films due to their potential applicanons in smart windows, gas sensors, photocatalytic reactions, and optoelectronic devices, etc. The unique properties of the tungsten oxide films were usually determined by the oxygen defects and the valence states of tungsten ions. Besides, it is very important to improve the properties of tungsten oxide films and other oxide films by controlling their morphologies and crystalline phases, which mainly depend on the preparation technologies and thermal treating temperatures and atmospheres.

 

 

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

Nanoscale tungsten powders were compacted with a steel die and a rubber die respectively. In the case of compaction with a steel die, the relative density of the resulted compact is 28.3% when the unit compacting pressure is 200 MPa. When the compacting pressure was higher than 200 MPa, some defects such as delamination and fracture were observed in the compacts.

 

The compacting pressure for a rubber die can be up to 300 MPa, resulting in a compact free of detects with a relative density of 46.2%. Even with a compacting pressure of 200 MPa, the relative density of the compact can also be up to 44.0%, which is remarkably more than that obtained by compacting with a steel die. It shows that the green density of nanoscale tungsten powder can be greatly improved by compacting with a rubber die.

 

 

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