Tungsten polymers are used to produce catheters and other devices that are inserted into the body for diagnostic or interventional procedures are commonly filled with substances opaque to x-rays, thereby rendering the devices visible under fluoroscopy or x-ray imaging. These fillers, or radiopacifiers—tungsten(typically dense metal powders)—affect the energy attenuation of photons in an x-ray beam as it passes through matter, reducing the intensity of the photons by absorbing or deflecting them. Because these materials exhibit a higher attenuation coefficient than soft tissue or bone, they appear lighter on a fluoroscope or x-ray film. This visibility provides the contrast needed to accurately position the device in the affected area. Image contrast and sharpness can be varied by the type and amount of radiopacifier used, and can be tailored to the specific application of the device.

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Extrusion, which is a process used to create objects of a fixed cross-sectional profile. Tungsten alloy material can be pushed or pulled through a die of the desired cross-section in extrusion process. The extrusion process may also increase the strength of tungsten alloy shielding.

The process begins by heating the stock material (for hot or warm extrusion). It is then loaded into the container under the press. A dummy block is placed behind it where the ram then presses on the material to push it out of the die. Afterward the extrusion is stretched in order to straighten it. If better properties are required then it may be heat treated. The extrusion ratio is defined as the starting cross-sectional area divided by the cross-sectional area of the final extrusion. Compared with forging, one of the main advantages of the extrusion process is that this ratio can be very large while still producing with quality. For the extrusion process, only one compression can cause extrusion ratio is about 60%~80%. In forging process, one compression cause extrusion ratio is no more than 20% ,otherwise the scrap rate will be greatly enhanced.

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A particularly dense material with excellent shielding properties is needed to ensure that the surrounding tissue is protected and the radiation guided only to the intended locations--high density tungsten alloys are widely used as medical and industrial radiation shielding applications.

Tungsten alloys are used for radioactive source containers, gamma ray protection, radiation shields, x-ray shielding and source holders for oil-well, logging, and industrial instrumentation. We can also use our tungsten alloys to make collimators and shielding for cancer therapy machines, and as syringe protection for radioactive injections.

There is no licensing required for tungsten alloy materials. Tungsten alloys are stable at high temperatures. You can use one-third less material than lead for the same energy-absorbing effectiveness, meanwhile it is non-toxic.

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Ammonium paratungstate (APT) is one of the materials for the preparation of lanthanum tungsten electrode, which is a kind of white crystalline salt. After World War II, there are literatures showing that the anion in (NH₄)₁₀(W₁₂O₄₁) ·5H₂O has been proved to be [H₂W₁₂O₄₂]¹⁰⁻, holding two hydrogen atoms inside the cage. Tungsten-oxygen cage, the focus of the anion, requires 42 oxygen molecules. Therefore, the correct formula expression for ammonium paratungstate is (NH₄)₁₀[H₂W₁₂O₄₂] ·4H₂O. On the contrary to the paratungstate A ion, whose anion is [W₇O₂₄]⁶⁻, the paratungstate B ion is [H₂W₁₂O₄₂]¹⁰⁻ ion, which is similar to the paramolybdate ion. However, the existence of the paratungstate A ion can’t be confirmed by NMR (Nuclear Magnetic Resonance) spectroscopy.

Before 1930, there had been some argument about the exact composition of the salt, and someone had proposed the two structures at that time: (NH₄)₁₀W₁₂O₄₁ and (NH₄)₆W₇O₂₄. And O.W. Gibbs had said that” the alkali tungstate are unusually complex. Salts of essentially different formula is so close in composition ratio that the differences lie very near the unavoidable errors of analysis. The analysis is hardly sufficiently close to deciding the question on purely analytical grounds." 

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