Tungsten Needles and Tungsten Rhenium Needles Used in the Construction of Probe Cards

Tungsten needle, also named tungsten pin, mainly refer to thin tungsten rod or thin tungsten rod with sharp tip. Their properties are basically the same, but uses are different. Mostly, their diameters are usually below 2mm and lengths range from 15mm to 100mm. 

For thin tungsten rod, it is mainly used as an electrode for argon arc welding. During welding, an arc will be generated between the tungsten electrode and the workpiece, and under the action of the arc heat, the filler metal will melt with the workpiece to form a weld.

Tungsten rod with pointed tip can be simply understood as pure tungsten or tungsten alloys with pointed tips at one end or both ends, which are mainly used as instrument probes, such as digital four-probe testers. The distance between the four tungsten needles in the digital four-probe tester cannot be too long or too short, and each one has a different function.

The rods with pointed tip are usually called tungsten probes. Most integrated circuits are tested using cantilever blade and epoxy ring probe cards. Contact resistance, balanced contact force and card life are directly dependent on probe material and shape. Therefore, a critical design step for any card is the specification of the probes.

In blade cards, probes are soldered to metal or ceramic blades, which in turn are mounted to a printed wiring board (PWB) to match the contact land pattern of the device under test. For epoxy ring cards, the probes are arranged in a contact pad pattern, embedded in the epoxy ring, and the bake-hardened assembly is bonded and soldered to the PWB.

The use of tungsten rhenium (WRe) needles in probe card construction has grown considerably over the past two years. Traditionally, tungsten (W) probes have been used for many reasons - excellent stiffness, hardness and wear properties.

The growing acceptance of WRe as an alternative probe material seems to be mainly due to the good user experience. Chinatungsten/CTIA GROUP found both tungsten and WRe materials were effective in scrubbing the contact pads. But due to its higher hardness, the WRe probe exhibits excellent resistance to tip fouling and better overall lifetime characteristics.

Chinatungsten/CTIA GROUP are professional manufacturers of tungsten for more than two decades, please feel free to contact us if you have any purchasing plans for tungsten and tungsten rhenium needles. 

If you have any inquiry of tungsten needles, please feel free to contact us:
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A New Production Method to Make Tungsten Target

Tungsten target, also known as tungsten sputtering target, is a typical pure tungsten product with high purity, high melting point, high density, high deflection strength, good thermochemical stability, low resistance, non-toxic and non-radioactive characteristics. It is widely used in flat panel displays, solar cells, integrated circuits, automotive glass, medical equipment and other industries. 

The researcher with the patent number CN102513789A provides a method for producing it and steps are as follows:

Provide target blanks; machine the surface of the blanks; put the machined blanks into a vacuum jacket and vacuumize, and the vacuuming step is done through a degassing tube; forge the blanks in the vacuum jacket; the blanks in the vacuum envelope are calendered; after the calendering, cooling is performed and the vacuum envelope is removed.

Notes on this method:

1) After the described vacuuming, also need to carry out the step of heat treatment for the first time to the vacuum envelope: after being carried out to a temperature of 200 ℃～500 ℃, carry out the insulation step. During the heating and heat preservation process, the vacuum was continuously pumped so that the vacuum degree in the vacuum envelope was at least 10^-3Pa, and then the forging step was performed on the tungsten target material blank in the vacuum envelope.

2) A second heat treatment of the blank is required before the forging step is performed on the blank in the vacuum jacket. The temperature of the second heat treatment is 900 ° C ~ 1500 ° C, and is kept at this temperature for 1h ~ 5h.

3) After the forging step is performed on the tungsten blank in the vacuum envelope and before the calendering step is performed on the blank in the vacuum envelope after forging, a third heat treatment is also performed on the blank in the vacuum envelope. The temperature of the 3rd heat treatment is 900 DEG C～1500 DEG C, and is kept at this temperature for 0.8h～1h.

Compared with the prior art, the production method has the following advantages: no mold is required, the problems of cracks and easy surface oxidation when the billet is processed and extended in the air can be avoided, and the internal structure is uniform and the grain size is consistent. The tungsten targets required by sputtering targets have the advantages of easy processing and low rejection rate.

If you have any inquiry of tungsten target, please feel free to contact us:
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Tungsten foil for Electric light Source Parts and Electric Vacuum Devices

Tungsten foil is a kind of thin tungsten sheet with thinner thickness of 0.05mm to 0.3mm and more narrow width of 50mm to 400mm. With more than 99.95% purity, it owns excellent thermal, mechanical, chemical and electrical properties, and is widely used in many fields. 

Regarding its physical and chemical properties, it is a silver-gray metal sheet with metallic luster, with a melting point of about 3410 °C, a boiling point of about 5660 °C, a relative density of 19.35g/cm3, and characteristics of low vapor pressure, small evaporation rate, low plastic-brittle transition temperature, low resistivity, good chemical stability, creep resistance, heat resistance and toughness. 

Under normal temperature and pressure, it will not react with air, water, concentrated hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid and aqua regia, but will dissolve in the mixed acid of hydrofluoric acid and concentrated nitric acid. In addition, under heating conditions, it will weakly react with mineral acids (excluding hydrofluoric acid) such as concentrated hydrochloric acid, sulfuric acid, and nitric acid.

From the perspective of production method, tungsten metal foil is first purified by recrystallization method of ammonium paratungstate, and heated in a porcelain crucible. After the ammonia volatilizes, tungsten oxide can be obtained, and then the tungsten oxide is reduced with hydrogen to prepare tungsten powder, and then the tungsten powder is processed, etc. The tungsten slab is prepared by static pressing and sintering at high temperature. Finally, the tungsten slab is rolled by a rolling mill, and then the foil is cut and formed by a shearing machine.

In terms of usage, the foil can be used to manufacture electric light source parts, electric vacuum devices, medical shielding parts, current collectors for aluminum ion batteries, heating elements and heat shields for electric vacuum furnaces/high temperature furnaces. In addition, it can also be stamped into a tungsten boat, which can be applied to vacuum-coated utensils.

Meanwhile, in addition to molybdenum foils, tantalum foils, nickel foils and titanium foils that can be used as current collectors for batteries, tungsten foils can also be used. Studies have shown that tungsten foil has stable electrochemical performance in the voltage window range of 0-2.5v.

If you have any inquiry of tungsten foil, please feel free to contact us:
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Non-sag Tungsten Wire Replaces High Carbon Steel Wire as Base Material of Diamond Wire Saw

Diamond wire saw, also known as diamond wire, refers to a cutting wire that uses electroplating process or resin bonding method to fix diamond abrasive on metal wire. It is mainly used to cut high hard and brittle materials such as single crystal silicon, polycrystalline silicon, sapphire, magnetic materials and cemented carbide, etc.

Compared with free abrasive wire saws, it has the advantages of higher processing efficiency, lower energy consumption, and better cutting quality; compared with circular saws and band saws, it can not only flexibly change the cutting direction, but also process more complex geometric shapes. However, this does not mean that the wire saw does not have any shortcomings. The current wire saw with carbon steel wire as the busbar/base material has the shortcomings of large wire diameter, high wire breakage rate and short service life. Therefore, in order to make up for the deficiencies of the existing wire saws, manufacturers began to use non-sag tungsten wire to replace high carbon steel wire as the base material of diamond wire.

For the production of diamond wire saws based on tungsten wire, researchers with the patent number CN113275659A proposed a new manufacturing method. The process is as follows: (1) Optimal black tungsten wire, which goes through pay-off → three-stage electropolishing → water washing → drying → Take up the wire to prepare silver-white metallic luster tungsten wire; (2) The tungsten wire treated in step (1) is successively paid off → secondary degreasing → pickling → impact nickel → sanding → sand fixing → heat treatment → After taking up the wire, a tungsten-based diamond wire saw with a wire diameter of 30~40um can be prepared.

Thanks to the characteristics of tungsten, the tungsten-based diamond wire saw can be much cost-effectively than before and now most enterprises are trying to use the new kind of wire despite the supply of this wire is very tight. Chinatungsten Online can supply this tungsten wire. If you have got the purchasing plan, please feel free to contact us. 

If you have any inquiry of non-sag tungsten wire, please feel free to contact us:
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EB Tungsten Filament Price on September 23, 2022

The latest price of φ0.8mm EB tungsten filament is USD 2.00/PC, EXW XIAMEN, CHINA on September 23, 2022. 

Tungsten filaments, also called cathodes or electron emitters or electron sources, are mainly made of high-quality tungsten. Of all pure metals, tungsten has the highest melting point (3422°C), the lowest vapor pressure at temperatures above 1650°C, and the highest tensile strength. Tungsten also has the lowest coefficient of thermal expansion of all pure metals. This combination of properties makes tungsten an ideal material.

Tungsten can be used in both thermionic electron guns and field-emission (CFE) electron guns. Electron beams come from filaments made of various materials. The most common is the tungsten hairpin gun, which is widely used in scanning electron microscopes, transmission electron microscopes, and microprobe systems. This filament is a tungsten ring that acts as a cathode. Apply voltage to the loop to heat it up. The anode, which is positive relative to the filament, forms a strong attraction to electrons. This causes electrons to be accelerated towards the anode. Some accelerate near the anode and down the column to the sample.

An electron gun works at a high temperature, which is required for thermionic emission. For this, a filament or the cathode should be of a material that has a high melting point in order for it to continuously emit electrons. Tungsten filament is folded with various shapes to help in focusing the electron beam.

If you have any inquiry of EB tungsten filament, please feel free to contact us:

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Cerium Tungsten Electrode Price on September 23, 2022

The latest price of φ3.2x175mm cerium tungsten electrode is USD 2.00/PC, EXW XIAMEN, CHINA on September 23, 2022. 

Cerium tungsten electrode (WC20) is alloyed with about 2% cerium oxide. It is a non-radioactive, refractory or non-consumable metal electrode material, which is the preferred substitute for thorium tungsten electrodes. Regular diameter of the electrode is between 0.5mm and 12.0mm, and the length is 150mm and 175mm.

The addition of this small percentage of cerium oxide increases the electron emission qualities of the electrode which gives them a better starting characteristic and a higher current carrying capacity with no spitting. With the increase of cerium oxide content, the ablation resistance and arc starting of cerium tungsten electrode will increase; with the increase of use time, the welding performance will gradually decrease.

The electrode has excellent arc starting properties at low current, and can operate successfully with AC or DC electrode negative. If used on higher current applications, the cerium oxide may be concentrated to the excessively hot tip of the electrode. In addition, WC20 is also used in inert gas shielded arc welding, hydrogen atom welding, argon arc surfacing, pulse argon arc welding, plasma welding, plasma cutting, plasma spraying, plasma melting, etc. The welding materials can be carbon steel, stainless steel, silicon copper, copper, bronze, titanium and so on.

If you have any inquiry of cerium tungsten electrode, please feel free to contact us:

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Why Fine Tungsten Wire Can Be Used for Window Heating?

Tungsten is the most widely used refractory metal with up to 3410℃ melting point. It also has good electrical and thermal conductivity under the conditions of low thermal expansion, low vapor pressure and high temperature, so tungsten is widely used to make filaments of various incandescent lamps and tungsten halogen lamps and electrodes of gas discharge lamps.

In addition, tungsten wire can be used as a heating material for high temperature furnaces, heating elements for electronic tubes and reinforcing ribs for composite materials. The main reason for using this metal wire as heating wire is that only the melting point of tungsten exceeds 3400 degrees Celsius, and it has advantages of good winding performance and no sagging. 

Heated glass is used to prevent fogging and freezing in the windows of cars, trucks and ships. To make it heatable, the heating wire is very important. Usually, the heating wire uses tungsten as raw material. This type of wire requires very tight tolerance for the diameter to ensure consistent mechanical properties and a defined "split level". A minimum of 99.95% purity is also required, which is the perfect prerequisite for a reproducible and controllable process.

To prevent reflections in glass, it is necessary to produce fine tungsten wires with a graphite surface for window heating. These wires are available in standard diameters from 12 µm to 58 µm, corresponding to a resistance rating of 630 - 40 Ohm/m.

The unique properties of our ultra-fine tungsten wire allow us to provide you with the highest quality precision wire. The fine means a diameter of 0.015mm. By comparison: the average diameter of a human hair is 0.075mm, which is almost six times as thick as a human hair.

Meanwhile, we also supply wires on standardized coils, sealed with a desiccant package to prevent oxidation during storage as much as possible. We supply fine tungsten wire for all types of window heating.

If you have any inquiry of tungsten wire, please feel free to contact us:
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