Tungsten copper liner is a kind of psudoalloy that composed of W and Cu, which is immiscible and forming compound with each other. So it is difficult to fabricate by common pressing-sintering process, the most widely used in tungsten copper products is powder metallurgy (PM), which includes infiltration and activated liquid-phase sintering. Infiltration presses tungsten powder into a compact, at a certain temperature pre-sinter the porous tungsten skeleton with density and strength. And then the low melting point of the molten liquid copper is infiltrated tungsten skeleton in order to obtain tungsten copper alloy with fully densified. The main mechanism is the liquid metal wetting porous matrix metal, under the effect of capillary forces along the inter-particle pore liquid copper flows and fills pores of the porous tungsten skeleton.

According to the sintering temperature, infiltration process can be specifically divided into sinter tungsten skeleton at high temperature + Cu infiltrated and sinter composite powder at low temperature + Cu infiltrated. Sinter tungsten skeleton at high temperature + Cu infiltrated presses tungsten powder into a compact before sinter and infiltrated Cu at 1800-2200℃. Since the tungsten powder at a high temperature to fully restore the remaining low-melting impurities and sub-oxides can be restored by evaporation gasification and thermal decomposition was removed, thus prepared tungsten copper shaped relative density of 99.2% comprehensive and excellent performance.

However, it also has some disadvantages, such as long production cycle, the control parameters are many and complex and high production cost. While sinter composite powder at low temperature + Cu infiltrated is mixed with a small amount of induced copper before sintering and infiltration. Generally, induced copper content of about 2.5% -3.5% and the granularity is similar to tungsten powder, which can effectively improve the compacting performance and the flowability of liquid Cu. But too much of the added amount of copper will result in enrichment-induced infiltration of copper, so that the overall the density of tungsten copper liner decreases.

Introduction
Thoriated tungsten electrode has low work function, stable welding performance and long service life, so in the early time it was widely used in welding industry.

Tungsten electrodes are used in tungsten inert gas (TIG) or plasma welding. During the welding process the electrode, arc and weld pool are protected from atmospheric contamination by an inert protective gas. A tungsten electrode is used in welding industry because it can withstand very high temperatures without melting or erosion. It is usually made by powder metallurgy and is formed to various sizes after sintering. Besides, according to different doped rare earth oxides, it can be divided into different types. Oxides used are primarily those of zirconium, thorium, lanthanum, yttrium or cerium, and doped quantity is usually 1%-4%. All these oxides greatly improve arc initiation, especially when direct current (DC) welding is employed.

Hazards
As we know thorium (Th) is slightly radioactive with a long half life and emits mainly alpha (α) particles, but occasionally some beta (β) and gamma (γ) radiation is emitted. Thoriated tungsten electrode was made by 2%thorium oxide, therefore, a low level radioactive material which contains in electrode, and it will cause small external radiation hazard and an internal hazard from ingestion or inhalation to welders. The external hazard estimated for a welder holding an electrode for a long time is a very small fraction of the maximum permissible radiation dose and it is concluded that the external radiation hazard is likely to be negligible. However, to achieve maximum arc stability the electrode tip should grind to a conical point before use and the shape is maintained during use by regular regrinding. During the grinding process, particles of electrodes may be produced with thoria on the surface. These dust particles that create the major hazard, as they may be inhaled. On the other hand, during welding, electrode will release hazardous substance, if welder ingestion or inhalation by accident it will harm to their health.

Storage
It is recommended that thoriated electrodes are stored in steel boxes with clearly labelled. When stored in closed boxes, there should no significant hazard in handling and storage. 10 pieces electrodes for one plastic box can be handled by welders safely without any special precautions.

With the continuous development of optical applications, the scope of application of optoelectronic products becomes more widely, and product requirements have gradually increased. A waterproofing membrane is a layer of material that prevents the passage of water. These materials are used in a huge range of products, but the term is generally used when referring to construction or clothing. Waterproof is often a matter of degree rather than certainty. In the vacuum coating process, the inorganic material would become the vapor and deposit on the substrate surface which is bombarded by ohmic heating or high energy electron gun. Because the microstructure film is uneven which would cause a large number of capillary voids during deposition, causing the lens surfaces absorb dust, water, oil. Finally, it will easily scratch the surface of the product, on the other hand, the dust would have a great impact on the optical performance of products. Thus, the waterproof film prepared by a wolfram crucible can overcome this deficiency partly.

First of all, put the high purity and amorphous oxides materials as carrier materials, and then form them into the final shape through freezing process or heating process by adhesive in a room temperature. After that, put the semi-finished product into a tungsten crucible which is put into a high temperature furnace and pressure inside the furnace, the heat treatment with the 850-1500 ℃ temperature. In the case of heat treatment, form oxide carrier materials with many hole and evenly shape through the changing of the shape. At the end of it, dropping waterproof material which contains an organic fluorine-silicon in a porous oxide carrier material, eventually forming a waterproof membrane.

As a carrier of semi-finished product, when heating, tungsten crucible would cost much less time to rise the temperature thanks to its high melting point, boiling points, and high thermal conductivity. Operation of wolfram crucible for waterproof membrane is simple and convenient which can also produce a lot of production in a short time. After using silica oxide carrier materials, people do not need to pay special attention to its recycling, manufacturers can generally handle it the same as the general waste, therefore, the cost is relative low. Wolfram crucible for waterproof membrane would make less time-consuming as well as high performance and the in the productions process it would not cause a great impact on the environment.

Manufacturing process of tungsten boat is generally stamping at a high temperature. Depending on the different requirements of the finished wolfram boat, Manufacturing process of it can be divided into stamping, welding, sintering, riveting. The following will talk more details about stamping tungsten boat. Stamping (also known as pressing) is the process of placing flat sheet metal in either blank or coil form into a stamping press where a tool and die surface forms the metal into a net shape. Stamping includes a variety of sheet-metal forming manufacturing processes, such as punching using a machine press or stamping press, blanking, embossing, bending, flanging, and coining.

First of all, tungsten plate should be blended into a certain angle, or bending the blended workpiece again. After that, it should be pressed into any hollow shape by mould, or bending the hollow mould workpiece further deformation. Afterward the hole or the outer edge of tungsten plate should be folded into a straight wall by mould. Forcing an outward radial force on the hollow member by mould, so that the local diameter can be expanded. After expansion, pressing the outside-in radial pressure on the hollow member so to narrow the local diameter. Next, putting the bloom into the die cavity, squeeze it out from the gap of mould to form the hollow or solid workpiece. Roll the panel into a ball peen whose shape approximate to a close one. Finally, press the bended or stretched workpiece into a right W-boat shape.

The main characteristic of the stamping W-boat is the high rate of final products but it would cause noise pollution. Because that this type of W-boat using the stamping equipment and stamping mould, the accuracy of size and shape the stamping wolfram crucible are much higher. What’s more, it has a long life time and it is not easily to be damaged, therefore, shape of the W-boat from the same production batch is almost the same which quality is also stable. On the other hand, pressure of stamping device is accurate, so that it will not damage the surface quality of the finished W-boat. However, there still exist some disadvantages of it. For example, during the stamping process, the device will produce noise and vibration which would have a great influence on operators. Furthermore, the mould is an essential material for stamping process, so the quality of the mould determines the quality of the W-boat.

Users can make reasonable adjustments to the size of the stamping W-boat as needed.

Along with widely using of radiation in medical, industrial, scientific communications, food, medicine and other fields, radiation hazards and how to achieve radiation protection also attract people's attentions. In physics, radiation is the emission or transmission of energy in the form of waves or particles（such as alpha particles, beta articles）through space or through a material medium. It is generally divided into ionizing radiation and non-ionizing radiation depending upon the energy of the radiated particles. Ionizing radiation (including α, β and γ radiation) has enough high-energy radiation to ionizing atoms, while the energy of non-ionizing radiation is lower than that of ionizing radiation, which can't ionize substances. In the medical field, radiation may be used to diagnose and treat diseases, such as physicians can use X-rays to find broken bones and locate cancer grow in vivo; in the field of science, radioactive atom is used as tracer; and in modern communication systems the form of radiation is mainly electromagnetic radiation.

With the increasing use of radiation in our lives, its harm cannot be neglected any longer. Most electronic devices have electromagnetic radiation that have a great harm on human health. For example, long-term irradiation during pregnancy will cause fetal malformations. Long-term exposure to radiation also can also make human body discomfort, resulting in human organs and system damage, lead to leukemia, cancer, eye diseases, reproductive system damage, aplastic anemia and other diseases. Therefore, the radiation protection is a must. Radiation protection can be reached by putting a shielding between humans and the radiation source or around the radiation source in order to achieve the effect of weakening the intensity of radiation to avoid human suffering from radiation damage. Common shield material are lead shielding, tungsten alloy shielding, depleted uranium, of which tungsten alloy is the best radiation shielding material.

Tungsten alloy is a tungsten-based alloy that adds other elements. It is found naturally on Earth almost exclusively in chemical compounds. It has the highest melting point of all the elements and also has strength at high temperature, high creep resistance and good thermal conductivity and electron emission performance. Compared with other shielding materials, tungsten has a higher density, while the radiation shielding performance of a metal material is closely related to its density, the higher the density is, the better the shielding performance is, and therefore tungsten alloy shielding has a good radiation shielding effectiveness. In addition, tungsten alloy shielding is a non-toxic, environmental protection and friendly shielding metal alloy shielding, neither pollute the environment, nor endanger human health. 

Tungsten carbide consists of refractory metal carbide as the matrix and binder metal fabricated by powder metallurgy, which has many differences in mechanical properties with common steel (cast iron, cast steel, carbon steel, etc.). Especially the difference in linear expansion coefficient is the key factor of affecting the connecting property directly, which is easy to produce internal stress in the joints. If the stress exceeds the tensile strength of the cemented carbide, carbide will lead to cracking. In addition, due to the particularity of cemented carbide, the common methods are hot charging, casting, hot isostatic pressing, welding and cementing method in which the WC composite cast iron and soldering processes and solder wettability is poor.

Hot charging method uses the inner interference to thermal inner and outer layers together. The process requires tungsten carbide must have a certain thickness of the outer ring to avoid ring cracking under tension effect. So the biggest defect of the process is the consumption of tungsten carbide, which can not save the cost. The cementation method, as the name suggests is to use an epoxy resin adhesive polymer inner and outer ring are bonded together. But since he adhesive properties of the physical and chemical limits such composite roll through the process of the preparation can not be used at high temperature and pressure environment, under the alternating stress and mechanical stress joint action, is extremely prone to surface cracking phenomenon.

Thus, the three methods currently used mainly casting, hot isostatic pressing and welding. Casting is a method of pre-plating the outer layer of metal carbide as a buffer layer, using the casting method in conjunction with the iron carbide into a composite outer roll. CIC (cast in carbide) can casting carbide ring and ductile iron and form a strong metallurgical connection, so that the stress distribution can be dispersed cemented carbide. Tungsten carbide outer ring can with high hardness and excellent wear resistance withstand pure rolling force, and ductile iron with good toughness can deliver the rolling moment by the connection with tungsten carbide ring. But there are also casting some technical problems, such as the casting process is difficult to obtain precise control, so that will cause the quality of the composite roll stability can not be guaranteed.

With the rapid development of technology, the corresponding requirements of rolling industry are also increasing. Roller is the important part of mill, which uses a pair or a set of roller to roll the steel. It mainly endures static and dynamic loads during rolling, abrasion and temperature changes. Common roll hardness testing are Shore and Leeb hardness testing, both of which are rebound hardness testing, surface hardening hardness can reach HS45-105.

However, the roller made by single material has been difficult to meet the changing requirements of rolling today. Although using coating process can guarantee the achievement of specified performance requirements, there are some matching problems in the binding strength between coating layer and the matrix, the coefficient of thermal expansion and other parameters. Furthermore, the higher cost is also the obstacle in the way of promoting.

Composite roller has uniform structure, high density and stable rolling properties, which has become one of the hotspot of many relevant researchers at home and abroad. Tungsten carbide composite roller by steel joining process, on the one hand, it has the advantages of tungsten carbide, such as high hardness, high density, excellent wear resistance and corrosion resistance and low coefficient of thermal expansion; on the other hand, it makes full use of the strength and toughness of steel, which makes tungsten carbide composite roll can meet the most of rolling industry.

Theoretically, connection of different materials is usually difficult than the connection of the same material. This is due to the quality of the connection of different materials not only be affected by the performance of physical and chemical properties of the material itself, which to a greater extent also depends on the performance of the two materials match or not. Tungsten carbide consists of refractory metal carbide as the matrix and binder metal fabricated by powder metallurgy, which has many differences in mechanical properties with common steel (cast iron, cast steel, carbon steel, etc.).