Hot spray welding (coating) technology has made rapid progress. There have been high energy plasma spraying, vacuum plasma spraying, supersonic flame spraying, explosive spraying and other new technologies, which can improve the performance of the coating more than the existing oxygen one acetylene flame spraying. Moreover, the hard alloy hot spray welding (coating) powder is convenient to make, no matter which kind of technology is used, the raw material of the spray can not be carbonized.

In many countries' energy consumption, building energy consumption accounts for about 30-40% of national energy consumption, while energy lost through glass doors and windows accounts for more than 50% of building energy consumption. About 46% of the solar spectrum is near-infrared light. So, if the transmission of near-infrared light is reduced, electricity used for ventilation and cooling system would be cut down. Therefore, research and development of transparent thermal insulation coatings for energy efficient glass has important practical significance. It can be predicted that transparent thermal insulation coatings have considerable prospects due to their economical and energy-saving significance.

Tungsten and molybdenum are important non-ferrous metals. They are mainly used in alloy metallurgy, but also widely used in other fields such as chemical industry. As the price of tungsten and molybdenum products has increased in recent years, Recovering APT, tungsten and molybdenum from the slag in the production of ammonium paratungstate (APT) can create better economic benefits for enterprises.

Tungsten trioxide is an indirect band gap n-type semiconductor metal oxide, which has broad application prospects in electrochromism, semiconductor, gas sensors and photocatalysis. Nano-sized tungsten trioxide has excellent properties. It has strong absorption for electromagnetic waves, which makes it to be solar energy absorbing material and military stealth material. The huge specific surface area and surface effect make it a kind of excellent catalyst. In addition, as a transition metal compound, it also possesses semiconductor properties and is a sensing material with great potential.