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01

1970-01

Technical Parameters of Tantalum

Tantalum has a boiling point of 5427 ℃ and a melting point of 2996 ℃. It is a refractory metal, and its melting point is higher than that of other commonly used metals. Tantalum will react with oxygen at 300 °C in the air, nitrogen at 700 °C, and 350 °C in hydrogen-containing gas.,which  starts to react with hydrogen at 350 ℃ in hydrogen-containing gas, and starts to react with nitrogen at 300 ℃ in ammonia gas, and brittle compounds will be formed. Therefore, if tantalum equipment and containers are exposed to air during operation, the operating temperature should generally not exceed 250 °C. If they are not in contact with the environment such as air, it can be considered whether they can be used at higher temperatures. The welding and heat treatment of tantalum should be carried out in vacuum or under the protection of inert gas, that is, the thermal process above 300 ℃ should be carried out under the protection of vacuum or inert gas. Tantalum is commonly used in inert gas shielded welding, and the purity of argon gas should not be lower than 99.999%. Not only the welding pool should be protected by inert gas, but also the welding seam and heat-affected zone during cooling after welding should be protected by inert gas when the temperature is above 250 ℃. Therefore, a protective tow cover is required. It is best to stop supplying inert gas when the temperature drops below 200 °C. It should be ensured that the surface of the welded joint and each weld is silver-white or light yellow. The light blue should be ground off and no dark blue, off-white or white powder should appear.Tantalum is mainly used as a corrosion-resistant material. Ta 2 O 5 film is formed on the surface of tantalum, which has good corrosion resistance. Generally speaking, the corrosion resistance of tantalum is better than that of titanium, zirconium and niobium, and it can be considered as the engineering material with the best corrosion resistance. It often has excellent corrosiveness in strong corrosive media such as nitric acid, aqua regia, hydrochloric acid, phosphoric acid, and organic acid, but it cannot be considered that tantalum can resist corrosion in any corrosive media, For example, in some temperature and concentration of fuming sulfuric acid, hydrofluoric acid, hydrosilicic acid, fluorosilicic acid, fluoroboric acid, sodium hydroxide, potassium hydroxide, potassium nitrite, aluminum chloride, aluminum fluoride, chlorine, bromine (in methanol) and other medium solutions, they have been used or tested with poor corrosion resistance or corrosion resistance. Tantalum and tantalum alloy pressure processing materials can adopt the brand of vacuum arc or vacuum electron beam melting and the brand of powder metallurgy. Due to the unstable mechanical properties, low plasticity and poor welding performance of powder metallurgy products, they are generally not used in pressure vessels, but only in the fluid parts of fluid machinery.Tantalum and tantalum alloys have been widely used in pressure vessels, but there is no specific content in the official pressure vessel standard specifications of various countries. Pure tantalum is mainly used for pressure vessels, which has good corrosion resistance and plasticity. Ta-2.5W and Ta-10W tantalum alloys are used only when higher strength is required. Oxygen, nitrogen, hydrogen and carbon in tantalum can form an interstitial solid solution in tantalum. When the content exceeds the solubility, a second phase will appear, reducing the plasticity of tantalum. The addition of tungsten to tantalum will increase the melting point of tantalum and increase the high temperature strength of tantalum.

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01

1970-01

Why do you think titanium alloy is awesome when you hear it? What kind of material is it?

In some TV programs or on the Internet, we can often see how expensive it is to build an aircraft carrier. This is because the construction of an aircraft carrier needs to involve many technical fields and related materials. Therefore, it is not enough to build an aircraft carrier with money, and a strong industrial base and material research and development capabilities are required. It has been reported that a single rivet on the deck of an aircraft carrier can be used to replace a car, which shows how expensive it is. This kind of rivet is not an ordinary rivet. It is a rivet made of titanium alloy material. This kind of expensive titanium alloy rivet is not full of armor plates, but only where the fighter jets are taking off and landing.    Because the fighter jet will spray a high temperature of more than 1000 degrees Celsius when it takes off, which requires the deck to be able to withstand high temperature, and the welding technology for high temperature resistant materials is immature, so the assembly between the decks needs to be completed by titanium alloy rivets.Titanium alloy is an alloy based on titanium and added with other elements. Titanium alloy material has the characteristics of light weight, high strength, small elasticity, high temperature resistance and corrosion resistance. It is mainly used in aero-engine, rocket and missile components. (Titanium is also used in general industry, and there are many grades of titanium. Different industries will choose the appropriate grade of titanium according to requirements.) Titanium alloy is a relatively young metal. It has a history of 60 or 70 years since it was developed. After entering the 20th century, traditional steel and aluminum can no longer meet the needs of aerospace, navigation and other fields. Titanium alloy material developed by American company in 1954 Whenever it is mentioned that a product uses titanium alloy as material, it will attract the attention of many people, because titanium alloy is particularly expensive. In the eyes of many people, titanium alloy is synonymous with high-end metal materials. Such precious materials are generally used in aircraft engines, and it is also an ideal material for some sophisticated weapons and equipment. But in fact, titanium, the main metal that makes up titanium alloy, is not rare. The content of titanium element accounts for 0.45% of the total mass of the earth's crust, second only to iron, aluminum, magnesium and other metal elements. At present, there are more than 140 kinds of titanium minerals known, and the reserves are also very rich. In nature, titanium exists in minerals such as ilmenite and rutile. Pure titanium is silver gray. At the same time, it is also a light metal. The density of titanium is only 4.54 grams per cubic centimeter and the melting point is 1668 degrees Celsius. It has plasticity.What really make titanium popular are its own characteristics. As a light metal, titanium has a high ratio of weight to strength among all elements, and its weight is 44% lighter than steel, but its mechanical strength is similar to steel, 3 times stronger than aluminum. Titanium has strong anti-corrosion ability. Titanium will be covered with a dense oxide film at room temperature, which is similar to aluminum. Its non-toxic and non-magnetic characteristics are also very suitable for industrial production. Liquid titanium can be dissolved with almost all metals, so it can form alloys with a variety of metals. By adding a certain proportion of other metal elements, the smelted titanium alloy can not only ensure light weight, high strength, corrosion resistance, but also have greater strength or stronger high temperature resistance, and even have memory ability. Titanium is a metal that is compatible with human body and is also used in medical fields, such as heart stents, orthopedic titanium plates, etc. Titanium alloys are also widely used in some eyeglass frames, watch frames, and some sporting goods in daily life. This will involve the smelting technology of metals. Titanium alloys are extremely harsh to the smelting environment, and titanium has low chemical activity under high temperature conditions, so the smelting of titanium alloys must be carried out at high temperature. Generally, the smelting temperature of titanium alloys should be above 800 degrees Celsius, and it should also be operated in a vacuum environment. This smelting environment is much higher than that of steel and other metals. As the saying goes, what is rare is more expensive, and titanium alloy has become the so-called rare metal, which leads to its high price. Although the output of titanium alloy is low and the price is expensive, it does not mean that it is used less, especially in some cutting-edge weapons and equipment and national key equipment, the use of titanium alloy in various countries is also very bold. At present, titanium alloy materials are widely used in the aerospace industry, so titanium alloy is also called "space metal". They are light in weight, high in strength and high temperature resistance, and are especially suitable for the manufacture of aerospace vehicles. Many components that used aluminum alloy in the past have changed to titanium alloy. With the development of technology, the current speed of aircraft is more than 3 times the speed of sound. Such a fast supersonic flight will cause the aircraft to rub against the air and produce a lot of heat. Generally, when the flight speed is less than twice the speed of sound, aluminum alloy can be used for the fuselage. When the flight speed is more than twice the speed of sound, aluminum alloy can't stand it, so titanium alloy with better high temperature resistance and performance must be used. When the speed of flight exceeds three times the speed of sound, more titanium alloy will be used for the fuselage. Some internal pressure hull, torpedo chamber and other parts of the attack nuclear submarine are made of titanium alloy. Titanium alloy material is non-magnetic, corrosion-resistant and extremely strong, which can effectively resist the shock wave of bombs. In addition, it can dive deeper. For example, China's "Jiaolong" manned cabin uses titanium alloy material, which can dive to the deep sea of more than 7000 meters, which is equivalent to a pressure of 7,000 tons per square meter. The pressure is astonishing. Now, in addition to the extensive use of titanium alloys in high-precision equipment such as aviation, rocket engines, submarines, warplanes, etc., titanium alloys are also widely used in conventional or individual soldier equipment, such as howitzers, bulletproof helmets, etc.

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01

1970-01

Tungsten Electrode

Tungsten electrodes have high melting point, corrosion resistance, high density, good thermal and electrical conductivity.Due to the properties of tungsten, it is well suited for TIG welding and other electrode materials for this type of work. Adding rare earth oxides to tungsten metal to stimulate its electron work function improves the welding performance of tungsten electrodes: the arc starting performance of the electrode is better, the stability of the arc column is higher, and the electrode burnout rate is smaller. Common rare earth additives include cerium oxide, lanthanum oxide, zirconium oxide, yttrium oxide and thorium oxide.In tungsten electrodes, more importantly, they also have different tungsten content, and the final color is also different. When welding, choose the right tungsten electrode to make welding easier and it is important to get a high-quality weld. Some important factors to consider in making the right choice are the type of power source (inverter or transformer), welding material (steel, aluminum or stainless steel) and material thickness.Cerium Tungsten ElectrodeCerium oxide is added to tungsten to produce cerium tungsten electrodes. The specific data are as follows:Type   Dopant    Doping Amount    Other Doping Amount    Electron Work Function   Color Coating HeadWC20 CeO2 1.80~2.20%<0.20% 2.7~2.8 GreyCerium tungsten has the following advantages over thorium tungsten material:Non-radiative, low melting rate, long welding life, good arc starting. Therefore, cerium tungsten is the best substitute for thoriated tungsten in low current welding environment.Cerium tungsten electrodes are mainly used in low current DC welding. Cerium tungsten has excellent arc starting performance at low current, so it has become the standard of most rail pipe welding equipment manufacturers, in addition, it is also used in other low current applications such as welding of fine parts.Cerium tungsten is not suitable for applications under high current conditions, because under such conditions, the oxide will quickly move to the high heat area, that is, the top of the electrode weld, which will cause damage to the uniformity of the oxide. The above-mentioned benefits brought by the uniform distribution of the material will no longer exist.Lanthanum Tungsten ElectrodeLanthanum oxide is added to tungsten to produce tungsten-lanthanum electrodes. The specific data are as follows:Type   Dopant    Doping Amount    Other Doping Amount    Electron Work Function   Color Coating Head WL10 La2O3 0.80~1.20%<0.20% 2.6~2.7 BlackWL15 La2O3 1.30~1.70%<0.20% 2.8~3.0 GoldenWL20 La2O3 1.80~2.20%<0.20% 2.8~3.2 Sky BlueBetter mechanical cutting performance, better creep resistance, high recrystallization temperature and good ductility.Lanthanum-tungsten electrode is already the most popular electrode material in the world, especially the lanthanum-tungsten electrode with a content of 1.5% (different from 2.0%)Scientific research shows that 1.5% lanthanum tungsten has the conductivity closest to that of 2.0% tungsten thorium. Therefore, welders can easily change the electrode without changing the parameters of the equipment.In 1998, there was a famous field test, which was to weld 2.0% tungsten thorium electrode, 2.0% tungsten cerium electrode and 1.5% lanthanum tungsten electrode provided by the two manufacturers at 70 A and 150 a current and 300 V DC respectively. As a result, in these two cases, 1.5% lanthanum tungsten electrode showed its excellent welding performance, and also reflected its characteristics of low burn rate.Lanthanum tungsten electrode is also suitable for AC welding tasks, and its performance is excellent.Thorium Tungsten ElectrodeThorium oxide is doped in tungsten to produce thorium tungsten electrode. Specific data are as follows:Type   Dopant    Doping Amount    Other Doping Amount    Electron Work Function   Color Coating Head WT10 ThO2 0.90~1.20% YellowWT20 ThO2 1.8~2.2% RedWT30 ThO2 2.80~3.20% PurpleWT40 ThO2 3.80~4.20% OrangeCompared with pure tungsten materials, thorium tungsten has the following characteristics:*Lower Electronic Function * Higher Crystallization Temperature * Better Conductivity * Good Mechanical Cutting Performance.Thorium tungsten electrode is a widely used tungsten electrode material, which has superior welding performance than pure tungsten, so it is widely used in the field of DC welding.Thorium tungsten electrode is easy to operate and can work well even under overload current.Nevertheless, people are gradually turning their attention to other types of tungsten electrodes, such as tungsten cerium and tungsten lanthanum, not only because they show excellent performance in most applications, but also, importantly, they do not emit radiation harm. Because the thorium oxide in thorium tungsten electrodes produces a small amount of radiation, some welders are reluctant to approach them.When welding with thorium tungsten electrodes, it is necessary to maintain a good ventilation environment, and the discarded welding joints should be properly disposed of.Zirconium Tungsten ElectrodeZirconium oxide is doped into tungsten to produce zirconium-tungsten electrodes. The specific data are as follows:Type   Dopant    Doping Amount    Other Doping Amount    Electron Work Function   Color Coating Head WZ3 ZrO2 0.20~0.40%<0.20% 2.5~3.0 BrownWZ8 ZrO2 0.70~0.90%<0.20% 2.5~3.0 WhiteLike pure tungsten electrodes, zirconium tungsten electrodes can only be welded in an alternating current environment.The zirconium tungsten electrode has good welding performance in the alternating current environment. Especially in the case of high load current, the superior performance of zirconium-tungsten electrodes is irreplaceable by other electrodes.During welding, the end of the zirconium-tungsten electrode can be kept in a spherical shape to reduce the phenomenon of tungsten infiltration, and has good corrosion resistance.Due to the emergence of other alternative products, the demand for zirconium-tungsten electrodes will tend to decrease. The main alternative is tungsten lanthanum electrodes.Yttrium Tungsten ElectrodeWhen yttrium tungsten electrode is welded, the arc beam is slender and the degree of compression is large, and its penetration depth is relatively large at medium and large currents. It is mainly used in the military industry and aerospace industry. Zirconium oxide is doped into tungsten to produce zirconium-tungsten electrodes. The specific data are as follows:Type   Dopant    Doping Amount    Other Doping Amount    Electron Work Function   Color Coating HeadWY YO2 1.80~2.20%<0.20% 2.0~3.9 Blue

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01

1970-01

Tungsten Copper Alloy

Tungsten-copper alloy combines the advantages of metal tungsten and copper, among which tungsten has a high melting point (tungsten melting point is 3410 ° C, copper melting point is 1080 ° C), high density (tungsten density is 19.34g/cm3, copper density is 8.89 g/cm3) ; Copper has excellent electrical and thermal conductivity, tungsten-copper alloys (generally ranging from WCu7 to WCu50) have uniform microstructure, high temperature resistance, high strength, arc ablation resistance, and high density; moderate electrical and thermal conductivity, widely used in military high temperature resistant materials , Electrical alloys for high-voltage switches, electrical processing electrodes, and microelectronic materials are widely used in aerospace, aviation, electronics, electric power, metallurgy, machinery, sports equipment and other industries as parts and components.Tungsten copper alloys are used as nozzles, gas rudders, air rudders, and nose cones of missiles and rocket engines in aerospace. The main requirements are high temperature resistance (3000K~5000K) and high temperature airflow scouring ability. It mainly uses copper to volatilize at high temperatures. The resulting sweating and cooling effect (the melting point of copper is 1083°C) reduces the surface temperature of tungsten copper and ensures that it can be used under extreme conditions of high temperature.Tungsten copper alloy is widely used in high-voltage switch 128kV SF6 circuit breaker WCu/CuCr, high-voltage vacuum load switch (12kV 40.5KV 1000A), and arrester. High-voltage vacuum switch is small in size, easy to maintain, and has a wide range of applications. Use in flammable, explosive and corrosive environments. The main performance requirements are arc ablation resistance, anti-welding resistance, small cut-off current, low gas content, and low thermal electron emission capability. In addition to the conventional macro performance requirements, porosity and microstructure properties are also required. Therefore, special processes are required, and complex processes such as vacuum degassing and vacuum infiltration are required.1. High-performance materials for aerospaceTungsten copper material has the properties of high density, perspiration cooling performance, high temperature strength and erosion resistance. Wait.2. Vacuum contact materialThe contact material must have very good machinability and thermal shock resistance. Due to arcing during contact and breaking, the temperature of the contact material will rise by several thousand degrees Celsius in a fraction of a second. The W-Cu contact material produced by our company is widely used due to its excellent physical properties.Advantages: high ablation resistance, high toughness, good electrical and thermal conductivity. Good machining performance.3. Electrodes for EDMWhen machining cemented carbide products with EDM, the copper or graphite electrodes wear out quite quickly due to the special properties of WC. For EDM machining of this material, the W-Cu electrodes produced by our company are the most suitable.Product performance: high electrical corrosion rate, low loss rate, precise electrode shape, excellent processing performance, and good surface quality of WC. 4. Electronic packaging materialsW-Cu electronic packaging material has both the low expansion properties of tungsten and the high thermal conductivity properties of copper. What is particularly valuable is that its thermal expansion coefficient and thermal conductivity can be designed by adjusting the composition of the material. The application brings great convenience. We use high-purity and high-quality raw materials, and obtain W-Cu electronic packaging materials and heat sink materials with excellent performance after pressing, high-temperature sintering and infiltration. Materials suitable for packaging with high-power devices, such as substrates, lower electrodes, etc.; high-performance lead frames; thermal control boards and radiators for military and civilian thermal control devices. Advantages: thermal expansion coefficient and high thermal conductivity matching with different substrates; excellent high temperature stability and uniformity; excellent processing performance;

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01

1970-01

Vacuum electroplating tungsten wire production and application fields

Composition of vacuum electroplating:There are several types of vacuum evaporation, sputtering and ion plating. They all deposit various metal and non-metal films on the surface of plastic parts by distillation or sputtering under vacuum conditions. In this way, a very thin surface coating can be obtained, and it has high speed and good adhesion. Advantages, but the price is also high, there are fewer types of metals that can be operated, and it is generally used as a functional coating for higher-end products, such as internal shielding. There are two common electroplating processes for plastic products: water electroplating and vacuum ion plating. Vacuum ion plating, also known as vacuum coating. The practice of vacuum electroplating is now a relatively popular practice, and the products produced have a strong sense of metal and high brightness. Compared with other coating methods, it has lower cost and less pollution to the environment, and is now widely used in various industries. Application scope of vacuum electroplating:Common products such as ABS material, ABS+PC material, PC material. At the same time, due to the complex process flow, high environment and equipment requirements, the unit price is more expensive than water electroplating.Now a brief introduction to its process flow:Surface cleaning→Destaticize→Spray primer→Bake primer→Vacuum coating→Spray finish→Bake finish→PackVacuum electroplating tungsten wire production:The general practice of vacuum electroplating is to spray a layer of primer on the material first, and then do the electroplating. Since the material is a plastic part, air bubbles and organic gases will remain during injection molding, and moisture in the air will be absorbed during placement. In addition, because the surface of the plastic is not smooth enough, the surface of the directly plated workpiece is not smooth, the gloss is low, the metal feeling is poor, and there will be air bubbles, blisters and other bad conditions. After spraying a layer of primer, a smooth and flat surface will be formed, and the generation of bubbles and blisters existing in the plastic itself will be eliminated, so that the effect of electroplating can be exhibited.

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Copyright: Luoyang Mengchang Metal Materials Co., Ltd.  Record No.:Yu ICP No. 2022014492-1