Over the last decade, nanostructured tungsten oxide materials have attracted much interest due to their potential for catalyst, gas sensors, and electrochromic material applications. Several studies have been conducted by using various techniques, including the oxygen plasma processing, plasma sputtering, chemical solution, sol-gel techniques, electron beam evaporation deposition, electrochemical etching, and the chemical vapor deposition techniques. Most work concerned the synthesis of nanoparticles for catalytic applications based on chemical solution methods.

The nanostructured tungsten oxide materials were synthesized using a simple hot filament CVD technique. The details of the process were described elsewhere in our previous publications. The tungsten filament acted as a precursor for tungsten oxide, and no catalyst or other tungsten-containing compound precursor was used. Both AlN and A ceramic substrates were used. Prior to the experiments, the substrates were ultrasonically washed in the methanol solution for 5 minutes, and dried with helium. After placing the substrate, the chamber was pumped down to Torr and then fed with the Ar gas (purity: 75%) to ambient pressure. During deposition, the gas inside the chamber was in a static state. The distance between the hot filament and substrate remained unchanged. The substrate temperature was controlled by adjusting electrical current on the hot filament, which was different from our previous experiments where the substrate temperature was controlled by simply changing the distance between the substrate and the hot filament.

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A method is disclosed for forming a tungsten oxide film on a substrate by applying an alkyl amine tungstate compound thereon and removing at least a portion of the alkyl amine tungstate compound to form a tungsten oxide film.

In a preferred embodiment, a solution of alkyl amine tungstate compound is formed in a solvent to uniformly apply the alkyl amine tungstate compound; the solvent is removed by evaporation thereby forming a deposit; the deposit is heated for a time and at a temperature sufficient to at least partially pyrolyze the alkyl amine tungstate compound.

The alkyl amine tungstate compound desirably may be selected from the group consisting of bis (di-n-octylammonium) tetratungstate, and di (n-octadecylammonium) tetratungstate. Preferably, bis (di-n-octylammonium) tetratungstate is used.

The invention also provides tungsten oxide films which include suboxides of tungsten oxides (WO3); which have an average ratio of oxygen atoms to tungsten atoms equal to or less than 3:1; which are denser than films produced from currently known MOD precursor compounds; which have a color gradient, that is, regions of different color; and wherein the regions of color are electrochromic.

A method for forming a tungsten oxide film comprising the steps of:

a) applying onto an ITO coated substrate a solution containing an alkyl amine tungstate compound dissolved in 50:50 2-propanol:xylene solvent,

b) vaporizing said 50:50 2-propanol:xylene solvent from the applied solution to produce a deposit on said ITO coated substrate composed predominately of said alkyl amine tungstate compound, and

c) heating the deposit in the presence of an oxygen containing atmosphere for a time between about 20 and 25 minutes and at a temperature between about 450° C. and 510° C. to decompose said alkyl amine tungstate compound to produce a tungsten oxide film which in a reduced state has a transmittance between 800-1200 nm which is less than 25 percent and which in an oxidized state has a transmittance between 400-1200 nm which is greater than 80 percent.

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Several methods are used to form tungsten oxide films. The methods include sputtering, chemical vapor deposition, and plasma enhanced chemical vapor deposition, in which sub-atmospheric pressure must be maintained. In these methods, large, complex and expensive equipment is needed, and the methods involve significant energy consumption and relatively high operating costs. The films produced by current methods are tungsten oxide films of WO3, without suboxides, and which are colorless or faint yellow, single color films.

A facile and inexpensive method to produce thin films of nanostructured tungsten oxide is described. A nanocrystalline tungstite (WO3·H2O) film is spontaneously formed when a tungsten substrate is immersed in nitric acid at elevated temperatures. The resulting thin film is composed of plate-like tungstite crystals with edges preferentially directed out from the substrate surface. The tungstite can easily be transformed into WO3 by annealing. Patterned WO3·H2O/W structures can be obtained by a combination of lithographic techniques and etching. In this study, the effect of exposure time, acid concentration, and temperature on the microstructure of the films has been investigated. The potential of this inexpensive synthesis method to produce large-area coatings of nanostructured tungsten oxide as well as patterned films makes it interesting for several different applications, such as batteries, gas sensors, and photocatalysts.

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Tungsten carbide cutting tools surface coating technology in recent decades in response to market demand developed surface modification technology, which effectively solve the contradiction tool material hardness, wear resistance and strength, toughness between more effectively improve the life of tungsten carbide cutting tools, the tool to obtain excellent mechanical properties, and greatly improve the machining efficiency, is widely recognized as the ideal tool material speed cutting, dry cutting technology.

Dry cutting technology is a major innovation of traditional production methods, is a new clean manufacturing technology. All kinds of super-hard, high temperature materials and coating technology development tool, created extremely favorable conditions for dry cutting technology. Coated tungsten carbide cutting tools dry coating technology has become an effective way to dry machining. Dry cutting tungsten carbide coatings play a role in the following two main aspects: on the one hand, tungsten carbide coating has a thermal conductivity than the matrix tool and workpiece material is much lower, thus weakening the thermal effect of the tool substrate ; on the other hand, it can effectively improve the friction and adhesion of the cutting process, thereby reducing the cutting heat generated.


 

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Brazing of tungsten carbide cutting tools with high hardness and wear resistance, especially at high temperatures can still maintain its high hardness, has been widely used in manufacturing various metal cutting tools. Brazed tungsten carbide is firmly connected to one of the most successful method for steel substrates, but the tungsten carbide cutting tools welding technology is an important factor in causing weld cracking.

Brazed tungsten carbide cutting tools mainly for its simple and compact structure, good rigidity, greater flexibility in use, adaptability and other characteristics, are used in precision machining, FMS, and other various metal cutting machining. Brazed tungsten carbide cutting tools are mainly using high-frequency welding brazing equipment. Induction brazing by induction heating to provide heat, or working through the induction coil is energized rather than directly on the tungsten carbide cutting tools, electrical energy transfer by induction method to tungsten carbide cutting tools, and selectively heating the surface of the part to be welded to the brazing A method of soldering temperature. Equipment brazed tungsten carbide welding process used by high-frequency induction heating equipment, high frequency induction brazing machinery and water cooling system and control system.


 

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At present, China recycled metal production has maintained rapid growth for 10 consecutive years, renewable resources, recycling more than 40,000 companies, employing nearly 1,000 people, recyclables dismantling converted more than 5,000 enterprises, more than 640 distribution market. In recent years, mainly recycled metal production average annual growth of 27%, from 720,000 tons in 2000 to 7.75 million tons in 2010. By the end of 2010, non-ferrous metal has become an important part of the China Nonferrous Metals Industry, vigorously develop renewable non-ferrous metal industry, effectively easing the shortage contradiction Chinese native nonferrous mineral resources.

According to estimates, compared with the primary metal production, per ton recycled copper, recycled aluminum, secondary lead is equivalent to saving 1054 kg respectively 3443 kg, 659 kg of standard coal, water and 395 m3, 22 m3, 235 m3, reduce solid waste discharge 380 tons, 20 tons, 128 tons, recycled copper per ton, respectively, equivalent to reducing emissions of sulfur dioxide Secondary Lead 0.137 tons, 0.03 tons.

According to the China Nonferrous Metals Industry Association Recycling Metal Branch, at present, China's non-ferrous metal industry is regenerated important juncture in the restructuring, and already has a good industrial base: First, a significant effect of renewable non-ferrous metal industry restructuring, recycled metal processing park construction gradually scale, enterprises have developed rapidly, smelting and processing technology and equipment to improve the standard of significant technological progress and innovation to accelerate, formed from the scrap metal recycling, dismantling, smelting, processing and product applications complete industrial chain; the second is non-ferrous metal Product applications expanding renewable broad application prospects aluminum, secondary lead alloys, recycled copper industry has achieved good results; Third, private enterprises accounted for the main production of renewable non-ferrous metals, with mechanism of living, a new system, a strong sense of innovation and other advantages, to promote metal recycling industry has made important contributions; four is recycled metals industry has always been attached great importance to the national authorities and strong support, the current form of production, research and universities work together to promote industrial development efforts.




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Tungsten oxide (WO3) has been one of the most widely studied materials due to its multifunctional properties that have wide spectrum of applications in electrochromic devices, catalysers, gas sensors, optical switching devices, and so forth. Over the past three decades, intensive research has been carried out towards improving WO3-based electrochromic (EC) devices due to their important energy saving properties. A typical asymmetric EC device consists of an ion conducting (IC) layer, which also acts as a counter electrode and a WO3 electrochromic layer as the working cathode, sandwiched between two transparent conductive electrodes (TEs). When a low voltage (1–3 V) is applied across the TEs, Li+ ions from the counter electrode and electrons (e−) from the TE move to the EC WO3 layer. This double injection results in the formation of colored LixWO3 bronzes, with a controllable degree of coloration as a function of (Li ion concentration). When the applied voltages are reversed, leading to a bleached state.

Recent developments in the synthesis of transition metal oxides in the form of porous thin films have opened up opportunities in the construction of electrochromic devices with enhanced properties. In this paper, synthesis, characterization and electrochromic applications of porous WO3 thin films with different nanocrystalline phases, such as hexagonal, monoclinic, and orthorhombic, are presented. Asymmetric electrochromic devices have been constructed based on these porous WO3 thin films. XRD measurements of the intercalation/deintercalation of Li+ into/from the WO3 layer of the device as a function of applied coloration/bleaching voltages show systematic changes in the lattice parameters associated with structural phase transitions in LixWO3. Micro-Raman studies show systematic crystalline phase changes in the spectra of WO3layers during Li+ ion intercalation and deintercalation, which agree with the XRD data. These devices exhibit interesting optical modulation (up to ~70%) due to intercalation/deintercalation of Li ions into/from the WO3layer of the devices as a function of applied coloration/bleaching voltages. The obtained optical modulation of the electrochromic devices indicates that, they are suitable for applications in electrochromic smart windows.

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WO3-x thin films were deposited on induim tin oxide (ITO) glass substrates with various oxygen flow ratios from 0.55 to 0.7 by the reactive facing-target sputtering method, at a power density of 4 W/cm2 and room temperature. The structural properties of the WO3-x thin films were measured by X-ray diffractometry and Raman spectral analysis. As-deposited WO3-x thin films had an amorphous structure. In the Raman spectra, WO3-x thin films exhibited two strong peaks at 770 and 950 cm-1 attributed to the vibrations of W6+–O and W6+=O bonds, respectively. The electrochemical and optical properties of WO3-x thin films were measured by cyclic voltammetry and UV/vis spectrometry. The results showed the highest charge density at an oxygen flow ratio of 0.7 and the highest transmittance in the visible range. The maximum coloration efficiency was 30.82 cm2/C at an oxygen flow ratio of 0.7.

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Tungsten trioxide (WO3) has been studied for many years. It is one of the best materials for use in the fabrication of electrochromic (EC) devices, such as electrically tintable glass for use in buildings and automobiles. WO3 has the desirable characteristics of transparency, chemical stability—as in the stoichiometry doesn't change with time after deposition—and relatively low cost. Typically, WOx, where 3>x>2.75, is desired for the EC application for the following reasons: (1) in the x>3 region, the oxygen is rich such that the WOx film may not be bleachable after lithium atom insertion; and (2) in the region x<2.75, the film is no longer transparent.

The deposition of WO3 films is of considerably interest, not least because of their electrochromic properties. Physical vapor deposition (PVD) is one of the conventional methods used for depositing EC films. During the Physical Vapor Deposition (PVD) WOx deposition, the stoichiometry of the film (value of x) is controlled by the oxygen partial pressure. However, the value of x changes with the oxygen partial pressure too sharply such that it is very hard to control in the range of interest—see FIG. 1; in addition, the deposition rate is very low. See T. J. Vink, E. P. Boonekamp, R. G. F. A. Verbeek and Y. Tamminga, Lithium trapping at excess oxygen in sputter-deposited a-WO3 films, Journal of Applied Physics 85(3), pp. 1540-1544, 1 Feb. 1999. According to Vink et al.'s data, reproduced in FIG. 1, control of the oxygen partial pressure to achieve an O/W ratio (value of x) of around 2.85 is very difficult due to the rapid change of x with oxygen partial pressure—such a process would have a very narrow process window and consequently would likely be a process with poor yield.

The two factors—narrow process window and low deposition rate—make the prior art PVD WOx film deposition process unattractive for use in the EC industry. Clearly, there is a need for improved deposition methods which provide sufficient control of the x value to allow high yield deposition of EC WOx films with x in the desired range of 3>x>2.75. Furthermore, there is a need for a deposition method for these EC films which provides a high enough deposition rate to satisfy manufacturing throughput targets at relatively low cost.

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In the process of grinding fluid grinding tungsten carbide cutting tools can not only reduce the grinding temperature, but also serve to improve the quality of grinding and grinding efficiency effects, and therefore widely used in the processing. But when grinding tungsten carbide grinding fluid is possible to make use of tungsten carbide cobalt leaching. tungsten carbide cobalt binder material, it will greatly reduce the life of the leaching of tungsten carbide cutting tools; at the same time, high levels of cobalt grinding waste will pollute the environment, workers' health hazard. Therefore, the study of the mechanism of grinding tungsten carbide cutting tools cobalt leaching when looking for an effective way to reduce or avoid leaching of cobalt tool, has great significance.

To reduce the wear of tungsten carbide cutting tools, cutting tools to avoid leaching of cobalt element, reduce environmental pollution, to achieve green manufacturing, through the development of triethanolamine alternatives to inhibit leaching effect of grinding fluid cobalt, or use the mill containing triethanolamine After cutting fluid grinding tungsten carbide, tungsten carbide debris should be promptly separated from the grinding waste and avoid leaving a long soak cobalt leaching.

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