Tungsten carbide cutting tool coating performance largely depends on the quality of the coating process and the coating, the coating quality preparation include: coating density, texture, microstructure, structural defects, residual stress. Tungsten carbide cutting tool coating process parameters include a deposition temperature, arc current, N2 partial pressure, a negative bias, coating time, the degree of vacuum and the like.

1. The deposition temperature
Tungsten carbide cutting tool coating deposition temperature on the microstructure, hardness and adhesion plays a crucial role. Temperature is too low, non-uniform nucleation, is loose, thick tissue, film hardness, adhesion, poor abrasion resistance and other mechanical properties; temperature is too high, the substrate surface is overheating, is obtained coarse crystalline organization, lower hardness. Only a suitable temperature to obtain a dense columnar crystals, the atomic arrangement of the film hardness due to more regular, reduced porosity and increased reasons.

2. The arc source current
Under certain bias, arc source current determines the temperature and macroscopic mechanical properties of the matrix, the target current increases, the substrate temperature, the crystal growth from the column to a dense crystalline equiaxed growth and transformation, tungsten carbide cutting tool coating With the improvement of hardness.


 

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It was also found: the plating current distribution directly affect coating uniformity. The edge of the mold, the corner portion, R at the current density was significantly higher than other parts, and accordingly the amount of metal deposition, large coating thickness. Under normal circumstances, the coating thickness difference of the central and side corners, R at about 4μm. Current lead to uneven distribution of coating thickness difference reaches more than 15μm, severe because of local metal deposition coating amount excessive shedding.
    
Further, the mold shape, structure, material and the like also affect the coating quality.
    
Countermeasure
    
(1) Before blasting, inspection, eliminate trachoma mold matrix, porosity, pitting corrosion, adhesion and the like.
    
(2) When the first test blast sandy, if impurities, foreign matter, oil and other pollution, should be completely replaced immediately. Timely cleaning the mold surface remaining after blasting grit and other adhesive material.
    
(3) In addition to the oil before the oil to the surface inspection, if oil emulsifier gather timely spray to break up; if the mold surface after degreasing oily emulsion adhesion, must be clean.
    
(4) Acid activation time must be strictly controlled to avoid excessive corrosion die; at the same time, under good control mold groove depth, to prevent the electrode plates, connectors and other corrosion. Their corrosion will contaminate the bath, resulting in poor plating.
   
(5) When the bath preparation of high purity chemicals as much as possible, and timely analysis of impurities. In addition, the bath to regularly analyze, filter, and change them regularly.
    
(6) The shape of the mold structure, scientifically-designed according to current balance board can effectively suppress local deposition of metal is too thick, the coating quality assurance.
    
(7) Ensuring the mold production process to meet the premise of mold design optimization, particularly conducive to improve the coating quality.
    
(8) Replenish the anode, repair accessories, regular cleaning of the plating tank sludge, and "three wastes" comprehensive way.
    
(9) Purification, protection of the environment, comply with the technical rules, strengthening the operator responsible, to avoid environmental, mechanical impurities into the bath.




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Tungsten oxide, also known as tungsten trioxide or tungstic anhydride, WO3, is a chemical compound containing oxygen and the transition metal tungsten. It is obtained as an intermediate in the recovery of tungsten from its minerals.Tungsten ores are treated with alkalis to produce WO3. Further reaction with carbon or hydrogen gas reduces tungsten trioxide to the pure metal.

A novel composite based on tungsten oxide and fly ash was hydrothermally synthetized to be used as substrate in the advanced treatment of wastewaters with complex load resulted from the textile industry. The proposed treatment consists of one single step process combining photocatalysis and adsorption. The composite’s crystalline structure was investigated by X-ray diffraction and FTIR, while atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to analyze the morphology. The adsorption capacity and photocatalytic properties of the material were tested on mono- and multi-pollutants systems containing two dyes (Bemacid Blau – BB and Bemacid Rot – BR) and one heavy metal ion-Cu2+, and the optimized process conditions were identified. The results indicate better removal efficiencies using the novel composite material in the combined adsorption and photocatalysis, as compared to the separated processes. Dyes removal was significantly enhanced in the photocatalytic process by adding hydrogen peroxide and the mechanism was presented and discussed. The pseudo second order kinetics model best fitted the experimental data, both in the adsorption and in the combined processes. The kinetic parameters were calculated and correlated with the properties of the composite substrate.

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The tungsten oxide film may be deposited on the substrate by any suitable method including such conventional deposition techniques as, e.g., sputtering, chemical vapor deposition (CVD) and the spray method. As would be apparent to those skilled in the art in view of the present disclosure, the tungsten source employed in such methods will vary with the technique used. The process of depositing a film of tungsten oxide according to sputtering generally involves the application of a radio frequency voltage to a solid tungsten metal target exposed to an oxygen-containing atmosphere at reduced pressure. Chapman is hereby expressly incorporated by reference for its teachings of sputtering techniques. Another useful film deposition technique which may be employed to deposit a tungsten oxide film according to the present invention, is the well-known CVD process. It generally involves the flowing of gaseous reactants, one of which is a tungsten compound such as tungsten carbonyl, over a heated substrate. Thin Film Processes edited by J. L. Vossen and Werner Kern is herein expressly incorporated by reference for its teaching of such a process. Still other useful processes for depositing the tungstenoxide film on the surface of the substrate will be apparent to those skilled in the art in view of the present disclosure. The temperature of the substrate during the deposition process may vary and is not critical to the invention. For example, the tungstenoxide film may be deposited at room temperature or at an elevated temperature, the latter being the case when such films are deposited on a hot glass ribbon being produced by the well-known float glass process. The latter may involve temperatures in the range of 80° C. to about 700° C.

Generally, the tungsten oxide film is deposited on the substrate in a thickness of preferably between about 200 and 6000. The desired thickness of the film is determined by various factors, including reactant concentrations temperature and substrate velocity.

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Tungsten oxide films are of critical importance forelectrochromic device technology ,such as for smart windows capable of varying the throughput of visible light and solar energy.

Tungsten oxide films (WO(3)) are deposited by thermal evaporation techniques using the starting materials of tungsten (W) and tungsten oxide (WO(3)). By varying deposition parameters, three main types of WO(3) film exhibiting different optical properties form. These are blue, gray, and colorless films. The samples are characterized optically and morphologically. Blue-colored samples exhibit a broad selective absorption peak around 1000nm. Absorption of gray-colored samples spreads out in the visible region in an exponential form. The refractive indices of samples are between 1.9 and 2.1. The energy gap of blue and colorless samples is 3.32 eV, but that of the gray-colored samples is 3.18 eV and smaller. X-ray diffraction studies reveal that evaporated WO(3) films are amorphous. Fourier transform infrared spectra of samples were studied to evaluate bond properties. Colorless near-stoichiometric tungsten oxide films exhibit three absorption peaks in the 1000-600-cm(-1) window. These peak locations, in terms of cm(-1) window. These peak locations, in terms of cm(-1), are 669,737, and 813. In the colored samples, these three absorption peaks split into two peaks ~20 cm(-1) apart.

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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. WO3has 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 WOxfilm may not be bleachable after lithium atom insertion; and (2) in the region x<2.75, the film is no longer transparent.

A deposition method for electrochromic WOxfilms involves cyclic deposition of very thin poisoned and metallic tungstenoxide layers to build up a film with a desired general stoichiometry with x in the range of 3>x>2.75. The method may include: charging a deposition chamber with oxygen gas to poison a tungsten metal target; initiating sputtering of the target while reducing the oxygen partial pressure being supplied to the chamber and pumping the chamber; sputtering target for time t1+t2to form first and second tungstenoxide layers, where the first layer is deposited during time t1from a poisoned target and the second layer is deposited during time t2from a metallic target, and where the stoichiometry of the film comprising the first and second layers is a function of t1and t2; and, repeating until a desired film thickness is achieved.

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After a Cu substrate is contacted with tungstenoxide powders, thermal reduction treatment is carried out under hydrogen atmosphere. Namely, the present method includes the steps of putting a substrate of Cu, Ni, Fe, Co, Cr, W, or the like in an upper, middle, or lower portion of a tungsten oxide (WO3or WO2.9) layer and carrying out thermal treatment thereon under a hydrogen atmosphere.

Such a coating method is widely applicable to another species of the metal substrate such as Ni, Fe, Co, Cr, W, and the like as well as Cu. Therefore, the tungsten oxide thin film method according to the present method is applicable to any kind of metal substrates.

A tungsten thin film according to the present method can be coated 500 nm˜25 μm thick by carrying out thermal treatment for 10 minutes to six hours at a temperature range between 650˜1050° C.

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Disclosed is a tungsten film coating method using tungstenoxide powders including the steps of contacting the tungstenoxide powders with a metal substrate and carrying out thermal reduction treatment thereon at a temperature of at least 650° C. under a hydrogen atmosphere just to coat the tungsten film on the metal substrate. Accordingly, the present methodenables to provide a simple method of coating a tungsten thin film on a metal substrate using the phenomenon of tungsten migration through vapor phase when thermal reduction treatment is carried out on tungstenoxide powders without using previous chemical or physical vapor depositions requiring expensive precision equipments or causing environmental pollution.

First of all, tungstenoxide (WO3or WO2.9) powders having a grains size of 1˜10 μm are put on a metal substrate such as Cu, Ni, Fe, Co, Cr, W, or the like. When thermal reduction treatment is carried out thereon at 650° C. (temperature from which the metal substrate is coated with tungsten by reduction of the tungstenoxide powders) under a hydrogen atmosphere, the hydrogen gas reacts with oxygen contained in the tungstenoxide powders. Hence, steam is formed as well as composition of tungstenoxide is changed into WO2. Such WO2powders react with adjacent moisture, as shown in the following chemical equation 1, so as to turn into tungstenoxide of WO2(OH)2as a gas phase and hydrogen. The generated gaseous phase tungstenoxide {WO2(OH)2} moves to the neighboring metal substrate by diffusion, and then reacts with adjacent hydrogen again, as shown in the following chemical equation 2, so as to be reduced to solid phase tungsten. In this case, if the metal substrate is around, the reaction by the chemical equation 2 occurs on the metal substrate preferentially (heterogeneous nucleation and growth) so as to coat the metal substrate with a tungsten thin film a few nanometers (nm) to tens of micrometers (μm) thick.

WO2(S)+2H2O(g)WO2(OH)2(g)+H2(g) [Chemical Equation 1]
WO2(OH)2(g)+3H2(g)W(S)+4H2O(g) [Chemical Equation 2

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Tungsten oxide, also known as tungsten trioxide or tungstic anhydride, WO3, is a chemical compound containing oxygen and the transition metal tungsten. It is obtained as an intermediate in the recovery of tungsten from its minerals.Tungsten ores are treated with alkalis to produce WO3. Further reaction with carbon or hydrogen gas reduces tungsten trioxide to the pure metal.

The procsses disclosed is for preparing a film of fluorine-modified tungsten oxide on a substrate. The process comprises providing a tungsten oxide film on the substrate and then exposing the tungsten oxide film at an elevated temperature to a stream of a gaseous fluorocarbon. The exposure takes place for a time sufficient to modify the tungsten oxide with fluorine and form a film having modified infrared adsorption and reflectant properties.

Novel process is disclosed for preparing a fluorine-modified tungsten oxide. The process comprising depositing a tungsten oxide film on a substrate and subsequently exposing the film, at an elevated temperature, to a stream of a gaseous fluorocarbon compound for a time sufficient to decompose the compound and fluorine-modify the tungsten oxide. According to the present process, the resultant fluorine-modified tungsten oxide film has modified infrared absorption and reflection properties. The gaseous fluorocarbon compound can be provided diluted with other gases such as nitrogen or air when it is exposed to the tungsten oxide film on the substrate.

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Tungsten carbide cutting tool wide range of applications, both for machining cast iron, non-ferrous metal and non-metallic materials, also suitable for processing a variety of steel and heat-resistant alloys. Both used in the manufacture of tungsten carbide indexable cutter machine folder and welding tools, can also be manufactured in various sizes smaller overall complex tools, such as the overall end mills, reamers, drills, composite processing tool and hobbing knives. At present, with the development of ultra-fine grain tungsten carbide technology, application of tungsten carbide cutting tools is still expanding.

When using cemented tungsten carbide cutting tool machining a variety of workpiece materials, high temperatures can cause cutting tool and the surrounding medium the oxidation reaction, the oxidation wear is easy to form the tool. Metal cutting tools in the process of forming the cutting edge portion has been cut metal adhesion transfer constituted "BUE" BUE was peeling from the cutter blade portion along with tool wear; Tool diffusion also occurs in the cutting process wear is worn between the relative wear caused by surface diffusion of elements; generated during cutting phase at high temperature in different metals, and the emergence of thermal current, which occurred in the electrochemical wear.

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