From the narrow sense, the carbide we usually refer to is composed of the hard phase tungsten carbide (WC) and the binder phase cobalt (Co); in a broad sense, cemented carbide refers to the materials that refractory metal compound and a binder metal composed by ingredients, pressing alloy molding, sintering and a series of manufactured. Refractory metal carbides generally refers to the periodic table carbide article IV, V, VI family of W, Ti, Ta, V, Hf and other elements, of which the WC, TiC, TaC of the most widely used.

Cemented carbide has higher hardness, strength, red hardness, excellent chemical stability, perfect wear and ablation resistance and many advantages so that it has a broad application prospect, such as cutting tools, geological mining tools, molding, structural parts, wear parts, high temperature high pressure cavity and so on. Steel bonded carbide is one kind of cemented carbide. In addition, cemented carbide can be divided into common tungsten carbide based (WC - Co, WC- TaC - Co, WC – TiC - Co, WC – TiC – TaC - Co, WC- Ti – TaC – NbC - Co), titanium carbide or titanium carbonitride-based (commonly based on TiC or Ti(C,N) and uses Ni – Mo as the binder), chromium carbide based (commonly based on Cr3C2, uses Ni or Ni – W as the binder) and coated carbide (commonly based on tungsten carbide and deposits hard compound of few microns in thickness by CVD or PVD).

Steel bonded carbide a kind of cemented carbide that based on TiC or WC and uses steel as the binder. It is generally prepared using powder metallurgy method, after machining and heat treatment properties between conventional cemented carbide and steel, which is a new engineering material. Furthermore, according to the final structure of the binder phase, steel bonded carbide can be specifically divided into martensite-based, austenite-based and ferrite-based.

Tungsten alloy all-in-one laser printer shielding can be used for shielding the radiation released during using an all-in-one laser printer. All-in-one laser printer, also known as laser plain paper fax machine, is a fax machine that forms an image by the means of utilizing carbon powder to attach on the paper. All fax machines work by scanning the files to be sent and convert them into a series of black and white point information. These point information would be transformed into audio signals and then be transmitted through a traditional phone line. After the recipient's fax machine receiving the signals, it will print them out, so that the recipient will receive a copy of the original document sent. The difference in different categories of fax machines is the printing method. All-in-one laser printer mainly uses a se drum in the machine body to control the opening and closing of laser beam, thereby producing an image with a charge on the drum, then the carbon powder inside the fax machine will be attracted and attached to the paper to form text or image graphics.

With the development and the maturity of all-in-one laser printer technology, its powerful functionality is widely used in modern office applications. Due to its form of file output of laser printing, it will produce certain laser radiation during the printing process. Today, it is accepted that even low-power lasers with only a few milliwatts of output power can be hazardous to human eyesight when the beam hits the eye directly or after reflection from a shiny surface. At wavelengths which the cornea and the lens can focus well, the coherence and low divergence of laser light means that it can be focused by the eye into an extremely small spot on the retina, resulting in localized burning and permanent damage in seconds or even less time. The same with most electrical appliances, fax machine can also generate electromagnetic radiation which has a certain impact on the human body, by causing cardiovascular disease, diabetes, cancer mutation, miscarriage, infertility, birth defects, immune system and nervous system damage and the like. Therefore, the use of tungsten alloy all-in-one laser printer shielding is necessary.

Because tungsten alloy has a high density, such that its radiation shielding capability can reach very high. Therefore, tungsten alloy all-in-one laser printer shielding has a good radiation shielding performance. Placing a tungsten alloy all-in-one laser printer shielding at the periphery of laser machine can effectively shield the radiation generated during the use of fax machine, thereby reducing the radiation damage of office workers. In addition, compared with traditional materials (such as lead), tungsten alloy is non-toxic and will not pollute the environment, so it is an ideal radiation shielding material.

People usually use tungsten electrode for aluminum GTAW. As we know, tungsten electrode has many types, and each type is given an AWS classification and includes a painted stripe around one end so you can easily identify the type, including pure tungsten (EWP), 2% thoriated (EWTh-2), zirconiated (EWZr-1), ceriated (EWCe-2), lanthanated (EWLa-1), and rare earth（EW-G）tungsten electrode.

Pure tungsten electrode has a lot of shortages, so manufacturers usually add various additions to the tungsten electrode for improving electrode’s performance. First, doped with rare earth makes the tungsten less likely to sag or droop at high temperatures. Second, it makes electrode easier for the tungsten to emit electrons, which gives it a higher current-carrying capacity compared to pure tungsten.

In the past, people usually use 2 percent thoriated electrodes direct current electrode negative (DCEN) welding, but although more recently lanthanated and ceriated electrodes have become more popular for this type of welding. Because 2% thoriated tungsten electrode has radioaction and it will harm people’s health. On the other hand, When people started to weld aluminum by GTAW using alternating current (AC), they found out 2% thoriated electrodes really weren’t well perform for that type of welding. In AC GTAW much more energy of it is taken up by the tungsten than is taken up in DCEN welding. So in the past the electrode choices for AC using were limited to pure tungsten or zirconiated tungsten, which could carry more current than a pure tungsten electrode of the same size. Neither of these electrodes was used with a sharpened tip. Instead, they were allowed to form a round ball on the end. So during AC, people prefer to choose lanthanated and ceriated electrodes.

On the other hand, thoriated tungsten can produce to a very irregular in geometry, which produced a fluttery, irregular arc. So pure and zirconiated electrodes were preferred.

When inverter GTAW machines came on the scene, the balance control can be set much further toward electrode negative (EN), but it still getting good arc cleaning action. Since only a little electrode positive (EP) is used, the tungsten electrode stays much cooler. In fact, the best electrodes for AC inverter GTAW machines are generally ceriated, lanthanated, and rare-earth electrodes, which are all sharpened to a point and it can retain the point very well during use. Thoriated, zirconiated, and pure tungsten electrodes are not often used with AC inverter machines.

Tungsten electrode is an important part in welding field. So produce high quality tungsten electrode can not only improve electrode’s life, but also can improve welding performance. In the production process, manufacturers should well control production parameters, properly grinding and cutting electrode also will influence electrode’s performance. As we knew, improperly produced electrode will leads to arc wander, splitting, shedding, inconsistencies, or expensive mistakes and other problems happening in the welding process. Properly produced, ground and cutting and processing electrodes can improve arc starting and stability.

To produce tungsten electrode manufacturers usually uses powder metallurgic method. The detailed production processes are as follow: doping-mixing-pressing-pre-sintered-sintered- multistage swaging process -recrystallization annealing-drawing straightening and polishing. In the production process, every parameter will influence electrode’s performance, so we should continue to improve production technology for improving its welding performance.

On the other hand, tungsten electrode grinding and cutting is another factor influence electrode’s welding performance. And during grinding and cutting diamond wheels are recommended for all tungsten electrodes. While tungsten is a very hard material, the surface of a diamond wheel is harder, which makes for a smooth grind. Grinding with other types of wheels can create jagged edges, imperfections, or invisible poor surface finishes that contribute to weld inconsistency and defects.

There is electrons flow at a greater density on the surface of the electrode. So during grinding, there are some tips should follow. Firstly, electrodes can not grind or polish by crosswise, because the electrons on the surface will jump across the grinding marks. During the welding, the arc begins before the tip, spreads out, and usually wanders, and then tungsten electrode becomes overheated and wears out more quickly. Secondly, if electrodes longitudinal grinding with the grain, the electrons are led steadily to the extreme tip of the tungsten electrode. The arc starts straight and remains narrow, concentrated, and stable.

Tungsten Crucible is one of the important deep-processing tungsten products which is now widely used in smelting of rare earth for its excellent corrosion resistance and good anti-wear properties as well as a high temperature strength. The choice of tungsten crucible has an important influence on rare earth metal smelting. Thus, in the preparation of tungsten crucible for rare earth smelting, users should pay more attention to the followings.

The first is for the selection of tungsten powder. Tungsten powder is the main raw material for tungsten crucible, the grain size of tungsten powder plays a crucial role on the quality of the finished tungsten crucible. Inappropriate choice of the grain size of tungsten powder will make tungsten crucible have crack during the pressing. Therefore, the grain size of tungsten powder cannot too coarse. If too coarse, the space in the pressing process will be great which will reduce the density of pressed compact and easily lead to cracking. If the users choose too small grain size, movement of position and the amount of deformation between the tungsten powders will increase at the time of pressing. Due to the flabby of elastic stress, the finished tungsten crucible would have crack finally. Accordingly, the grain size of tungsten powder of tungsten crucible for rare earth would better between 2.5μm and 3.0μm. In addition, the oxygen content of the tungsten powder should be less than 0.1%.

Next is the control of pressure in processing. While pressing tungsten crucible with a strong pressure, tungsten powder will have a serious distortion. On the other hand, the strong pressure would increase the elastic stress, and finally, resulting in tungsten crucible cracking. If the pressure is too weak, tungsten crucible cannot enough reach, and it easy to have crack. In addition, the speed of pressure pool should be slow, if too fast, release of elastic stress of tungsten powder will accelerate which would lead to cracking of the tungsten crucible.

Finally is the notice of sintering process. When sintering pressure compact in the medium frequency induction furnace, the sintering temperature should be controlled between 2200 ℃ and 2250 ℃. And the holding time of 3-5 hours is the best. What’s more, the rising rate of sintering temperature cannot too fast or it would cause deformation of tungsten crucible, it is better to rise 80 ℃ or 100 ℃ for one hour.

Tungsten crucible formed by the above ways for rare earth smelting would have better properties and the best effect which can also greatly reduce industry costs.

Tungsten crucible is one of the metal tungsten products. It can be divided into sintering, stamping and spinning type. Sintering tungsten crucible is mainly applied to the powder metallurgy technology. Stamping and spinning type of tungsten crucible is made of tungsten rod by turning, the size of this type of tungsten crucible is generally smaller than the ordinary one. Tungsten crucible can be used in vacuum inactive gas under 2600℃. Tungsten has a high boiling point, a high melting point, high temperature strength as well as a excellent anti-wear performance. In addition, its coefficient of thermal expansion is small and quenching degree is good. So, tungsten crucible is widely used in smelting of rare earth, quartz glass, electronic painting, crystal growth and other industries.

Generally, the first step of the production process of tungsten crucible is the preparation of tungsten powder and then sifting them. Because the thickness of the tungsten powder has some differences, and in order to meet the requirement of finished tungsten crucible product, users should separate coarse tungsten powder and thin tungsten powder from the mixed tungsten powder with a mesh. And then blending the different tungsten powder which has the same chemical composition together. And then placed it in a closed container which is filled with liquid. Put the same pressure gradually on each surface by supercharging system, so that it can reduce the distance to increase density of material and improve the physical properties of material without any shape-shift. After that, lathe the rough blanks and then put them into a medium frequency furnace for sintering. The next step is the lathing of competitive products. Finally, inspecting the finished product package.

Besides the usual production process, tungsten crucible can also be formed by the following production processes into various types, including sintering, forging, chemical deposition, plasma spraying, a spinning method, rivet linking and welding in according with the requirement of users. Users select a different preparation process to make different types of tungsten crucible. On the other hand, demand of tungsten crucible is increasing year by year, so that states should research and develop different production processes to meet changing market demands. With the rapid development of tungsten industry, researchers should constantly improve the production process of tungsten crucible. In addition, in the manufacturing process of the tungsten crucible, users should pay attention to its pollution and increase the utilization of raw materials to protect the environment.

The color of yttrium oxide is white with a little yellow which is incompatible with water and alkali, and mainly dissolve in acid. Yttrium oxide is mainly formed by the decomposing of fergusonite, and after the extraction of mixed rare earth solution, dissolving it in acid, and extract again, and concentrate it directly. Finally burning it. Yttrium oxide tungsten crucible is a new type of tungsten crucible which has a high strength and has a strong corrosion resistance.

Tungsten crucible has many excellent properties. Such as high melting point, high temperature strength, a good thermal conductivity, and a small coefficient of thermal expansion. However, because the boundary of the tungsten granule is easily to be corroded, and therefore, the corrosion resistance of ordinary crucible tungsten should be improved. On the contrary, yttrium oxide tungsten crucible can solve this problem radically.

In the manufacturing process of yttrium oxide tungsten crucible, the 1μm yttrium oxide particles will penetrate into the boundaries of the tungsten crystal, distributing evenly around the tungsten crystal. The uniform penetration of yttrium oxide particles can suppress the molten metal and tungsten particles into chemical compound. And it can improve the corrosion resistance of the tungsten crucible. on the other hand, strength of bending resistance of this type tungsten crucible would reach 800MPa under 1000 ℃. Therefore, the yttrium oxide tungsten crucible has a stronger bending strength which is the five times than the pure tungsten crucible.

Except for the improvement of corrosion resistance, yttrium oxide tungsten crucible has a stronger thermostability by comparison with the general pure tungsten crucible. Under normal circumstances, yttrium oxide tungsten crucible can melt dysprosium, neodymium and other reactive rare earth metals, such as aluminum. When melting rare earth metals, yttrium oxide tungsten crucible cannot be corroded and melted.

In addition to the above features, in the manufacturing process of yttrium oxide tungsten crucible, users should pay attention to the protection of yttrium oxide toxicity. Yttrium oxide does harm for our eyes if it contact with the eyes. And it would cause some damage to the liver and lungs if accidentally taking it. Therefore, during the manufacturing process of yttrium oxide tungsten crucible users should be careful with the respiratory system and eyes. It would be better to choose the appropriate respirator and wear anti-chemical goggles and face mask and use safety appliance such as glove when apply, avoid directly touch.

Merely rely on raising the temperature of the tungsten blanks shrink to increase the density, which is difficult to control precisely. Such as the deviation of heat matching, it is the major influencing factor of conventional infiltration hermeticity. Some researchers try to ultrafine tungsten powder added to certain activators, such as nickel (Ni), cobalt (Co), iron (Fe), etc., and then mixed with copper powder. After pressing and activated sintering, the relative density of tungsten copper can reach 98 % or more, which can be a good solution to tungsten copper heat sink material hermeticity issue. But it added activator of Ni, Co, Fe and other elements will be Cu and W-phase and phase mutually dissolved, and magnetic Fe, Cu content changes will directly affect the conductivity and the thermal conductivity of the material, so not suitable in the heat sink industry applications.

Therefore, on this basis, the researchers conducted a process optimization, the tungsten powder mixed with a small amount of copper powder, copper powder can effectively preserve this part of the green bodies connected pores, when carried out at high temperature and pressure infiltration of liquid copper can be fully effective filled tungsten skeleton. This section is also known as copper induction of copper, its main role lies in two main aspects, one is to enhance the strength of tungsten blanks, and the other is infiltration process hermeticity guarantee.

Tungsten powder has high hardness, poor plasticity, generally under pressure prone to "arch effect" between the powder. Once the pressure is too large, blank-arch bridge will make a release force is rupture and delaminated, and thus the relative density of tungsten powder can only reach about 60%. But copper powder has good plasticity, which can effectively destroy the "arch effect" between the tungsten powder and plastically deformed. Both of them can fill each other, engage with each other, thereby increasing the density and strength of tungsten copper green. On the other hand, since the initial tungsten skeleton have a uniform distribution of copper, the part of copper changed into liquid and complement with the copper liquid out side the skeleton at 1350℃.