How to Extend the Service Life of Molybdenum Wires

Molybdenum wires are pressed and sintered from our high purity molybdenum powders to compact ingots by powder metallurgy and then drawing. As a leading molybdenum manufacturer, we are capable of providing wires with a range of diameter from 20 microns to 2mm. 

Many end-users would require a good quality of products. How to extend the service life of these wires? Here are some tips: 

1.Installation 

Wires made of molybdenum are easily deformed and broken. Therefore, they can not be bended during installation. If bended, cut it off to avoid wire breakage during operation. The cutting fluid should also be replaced in time during use because it will turn black after a long time of use, which will directly affect the performance of products.

2.Operation 

When the wire is discharged during operation, it will also be damaged. However, due to the good mechanical properties of molybdenum, the damage is small. Therefore, it would be better to using low-energy processing parameters to reduce the damage. After running for a period of time when the color of wire becomes write, workpieces can be cut with normal high current. In addition, after replacing the wire, running new wire for 5-10 minutes before cutting the workpiece, so that the internal stress of the molybdenum wires can be released. 

When the moly wire breaks during the operation of the cutting machine, most of the broken ends are within a dozen to dozens of turns after the reversing of the wire barrel. It can be seen that the metal wire at both ends of the head and tail is easier to be broken. Therefore, in the cutting process, the wire barrel is reversed to form a switch control block and move a little outward or inward at regular intervals.

3. Maintenance

Routine maintenance of molybdenum wire can also improve the service life, such as: daily storage, placement and time. It should be stored in a ventilated and cool place with low humidity, and the temperature is 20℃~25℃ to avoid oxidation. In addition, it should not be placed for more than 6 months. While using it, check whether the packaging is damaged or deformed.

If you have any inquiry of molybdenum wires, please feel free to contact us:

Email: sales@chinatungsten.com/sales@xiamentungsten.com

Tel.: +86 592 5129696/+86 592 5129595

Fax: +86 592 5129797

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Types of Silicon Carbide Heating Elements for Producing Lithium Ion Battery Components

Silicon carbide (SiC) heating elements are non-metal high temperature heating element made from high-quality green silicon carbide. Compared with metal electric heating elements, this element has the advantages of high temperature, oxidation resistance, corrosion resistance, long life, and convenient installation and maintenance. 

The operating temperature of the silicon carbide heating elements can go up to 1550°C in an oxidizing atmosphere, or inert gas atmospheres of argon or helium. in a reducing atmosphere, the maximum obtainable operating temperature is 1350°C. Nowadays, they are widely used in various high-temperature electric furnaces and electric heating equipment in magnetic materials, powder metallurgy, lithium ion battery components, ceramics, glass, metallurgy and machinery industries.

Our silicon carbide electric heating elements adopt a new production process for the availability of an excellent heat and cold resistance ratio, energy saving and long life. Meanwhile, they can avoid the damage to the furnace body caused by the excessive temperature of the cold zone. Chinatungsten Online manufactures the following types of SiC heaters. 

1.Equal-diameter Silicon Carbide Rod

It has the advantages of low resistance, long service life, and energy saving, which is commonly used in rare earth phosphors, electronics, magnetic materials, powder metallurgy, precision casting and other industries, as heating elements for pusher furnaces, mesh belt furnaces, trolley furnaces, and box furnaces.

2. Thick-end SiC Rod

It is an electric heating element composed of a hollow tubular heating part and a thickened end. Meanwhile, it is hard and brittle, resistant to rapid cold and heat, and will not deform under high temperature. Mostly used in test furnaces. 

3. U-Shaped Alpha Silicon Carbide Rods

The rod is composed of two equal diameter silicon carbide rods sharing a cold end, and can be connected to the power cord at one end of the kiln. Its surface can be used in the temperature of about 1500 ℃. Given that, it is mostly applied in kilns with high furnace temperature and high furnace temperature uniformity requirements.

4. Gun-shaped SiC Rod

This shape of element is improved from the U-shaped rod by extending 40mm to 60mm length at the U-shaped end to support the rod body. It is matched with double heating element rod to be used in the glass bottle industry to produce soda-lime flat glass. 

5. W-shaped Silicon Carbide Rod

The special rod is composed of a common silicon carbide rod connected to one end of three high-purity silicon carbide rods. The joint is also made of the same material, and the structure of the rod is exactly the same so that it can be used for horizontal installation in a float glass cell. Besides that, it can be directly connected to the three-phase power supply and the furnace top can be connected in one direction.

6. H-shaped Silicon Carbide Heating Elements

This heating element is commonly used for heating and heat preservation of forehearths and pot sections in the glass industry. As a non-linear resistor, its resistor has a large dispersion at room temperature.

7. Reaction Bonded Single Spiraled Heating Elements

Single spiraled element is an electronic component specially processed by precise calculation and design on the basis of equal diameter SiC rod. Its using temperature can reach 1500 ℃, used for heating of kilns with special needs. Its characteristics are: more power saving, simple operation, high temperature and long life.

8. Reaction Bonded Double Spiraled Heating Elements

The double spiraled element is an electronic component specially processed by precise calculation and design on the basis of the U-shaped heater. It is designed to meet the small space in the furnace and the normal U-shaped rod cannot be installed in the electric furnace. It is mainly used for the heating of kilns with special needs. Its characteristics are: power saving, simple operation, high temperature and long life. 

If you have any inquiry of silicon carbide heating elements, please feel free to contact us:

Email: sales@chinatungsten.com/sales@xiamentungsten.com

Tel.: +86 592 5129696/+86 592 5129595

Fax: +86 592 5129797

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Why Should We Do a Protective Coating for Molybdenum-copper Alloy (MoCu alloy)?

Molybdenum-copper alloy (MoCu alloy) is a pseudo-alloy composed of two insoluble metals molybdenum and copper. As a result, it gains characteristics both of these two metals, such as high thermal conductivity, low thermal expansion coefficient, non-magnetic, low gas content, good machining performance and special high temperature performance.

What is the protective coating?

In order to improve the high temperature resistance and welding performance of finished products, there can be a layer of coating on the surface, usually nickel or gold. Displacement plating, chemical roughening, chemical nickel plating, or cyanide gold plating are the most common used methods. 

We use scanning electron microscope and EDS to analyze its morphology and composition of the coating, and test welding and high temperature resistance by gold-tin welding according to GJB1941-94. The results show that the displacement plating method achieves the uniformity of the chemical properties of element Mo and element Cu at the interface of the Mo-Cu alloy substrate, and avoids the problem of excessive internal stress in the deposited crystal due to different chemical activities; chemical roughening increases the specific surface area at the interface of the substrate, increases the number of "mechanical bites" at the interface of the coating and the substrate, and improves the bonding strength of the coating and the substrate.

The high temperature resistance of the gold plating layer obtained on the surface of the MoCu substrate is ≥350℃, and the void ratio after welding is ≤30%, which meets the requirements of welding technical indicators. 

Molybdenum-copper alloy has high thermal conductivity, up to about 200W/m·K, and has the advantages of small thermal expansion coefficient and easy machining. It is used in spacecraft phased array antenna T/R module bottom plate and high-power microwave shell and power device carriers and other fields that have good application prospects. However, its surface wettability is poor and cannot meet the soldering functional requirements of solders such as PbSnAg, SnAgCu and AuSn.

In order to improve the weldability, it is necessary to coat a gold plating layer with excellent welding performance on the surface. however, as the surface composition of the molybdenum-copper alloy is composed of two metal elements with relatively different chemical properties, and the content of chemically inert Mo element is as high as 85%, it is difficult to coat the gold coating on the surface.

In aerospace products, the solders used in the early days were mainly low melting point solders such as PbSnAg and InSn. The peak temperature during the soldering process was all below 230°C, so the high temperature resistance of the gold coating is relatively low. With the development of T/R module housing and chip packaging technologies, high melting point solders represented by AnSn have been widely used. The peak soldering temperature is as high as 300℃. 

During the high-temperature soldering process, the gold plating layer and the molybdenum copper alloy substrate will expand due to thermal expansion. The thermal stress caused by the coefficient mismatch increases, resulting in quality problems such as skinning and blistering of the gold coating. Therefore, in order to meet the welding requirements of spacecraft stand-alone load products, higher requirements are put forward for the preparation and high temperature resistance of the gold coating on the surface of the MoCu alloy.

There are many grades for moly copper alloy, such as Mo85Cu15, Mo80Cu20, Mo70Cu30, Mo60Cu40, Mo50Cu50, Mo40Cu60. Different grades match different densities, thermal conductivities and coefficients of thermal expansion. Other customized grades also can be customized.

Chinatungsten is a professional manufacturer of molybdenum for more than two decades, if you have got any purchasing plan for related products, please feel free to contact us, we will offer you our most favorable prices and qualitied products. 

If you have any inquiry of MoCu plates, please feel free to contact us:

Email: sales@chinatungsten.com/sales@xiamentungsten.com

Tel.: +86 592 5129696/+86 592 5129595

Fax: +86 592 5129797

Scan QR code of Chinatungsten Wechat platform to follow up the daily latest price and market of tungsten, molybdenum and rare earth.