while foams of silicon carbide can be used very advantageously as a temperature-resistant and corrosionresistant insulating material and filter material or catalyst support. Pipes, crucibles, bricks or the like of these mixtures are suitable for use as high temperature materials because of their good chemical resistance.

Silicon carbide continuous filaments can be manufactured in accordance with a known process by exposing a carbon filament, manufactured according to conventional processes, to a silicon tetrachloride gas atmosphere at 800 1,200C (U.S. Pat. No. 3,433,725). According to a further known process, silicon carbide continuous filaments are obtained by coating a thin tungsten filament with silicon carbide, which is formed on the tungsten surface, kept at 1,200 to 1,300C, by pyrolysis of methyldichlorosilane (F. Galasso, et al., Appl. Phys. Lett. 9 (1966) 37). The disadvantage of these processes is that relatively thick silicon carbide fibers result which are difficult to handle, and their high manufacturing cost prevents a broad application.

Shaped articles such as, for example, pipes, crucibles or bricks can be manufactured according to known processes by sintering pulverulent silicon carbide, with addition of silicon powder, in appropriate molds, in most cases with the use of high pressures and temperatures, in the presence of nitrogen. In these cases, the silicon nitride formed acts as a sintering aid.

It is furthermore known to manufacture silicon carbide coatings on suitable shaped articles by pyrolysis of a mixture of slicon tetrachloride, toluene and hydrogen (K. Moers, Z. anorg. allg. Chem. 198 (1931) 243).

Foams of silicon carbide can be manufactured according to the process of U.S. Pat. No. 3,100,688, by reacting a mixture of finely divided silicon dust and carbon dust with dilute hydrofluoroic acid and heating the foam thereby formed, after drying, to a temperature of between l,400 and 2,200C under an inert gas.

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Compared to traditional radiation shielding materials, tungsten alloys provide excellent value. A high-density alloy can provide the same energy absorption as lead using 1/3 less material! Unlike lead, you’ll also reduce administration costs by eliminating the need to obtain special licensing—it’s not required.

Experts find that radiation exposure could be reduced by maxing shielding. The density of a material is related to its radiation stopping ability. Higher density means better stopping power and shielding. Due to a higher density, tungsten alloy has a much higher stopping power than lead. It is greater linear attenuation of gamma radiations means that less is required for equal shielding. Alternatively equal amounts of tungsten alloy shielding provide diminished exposure risks than equivalent lead shielding.

Tungsten alloy is a suitable raw material for radiation protection, as its combination of radiographic density (more than 60% denser than lead), machinability, good corrosion resistance, high radiation absorption (superior to lead), simplified life cycle and high strength. It can provide the same degree of protection as lead whilst significantly reducing the overall volume and thickness of shields and containers. Besides, compared with lead or depleted uranium in the past, tungsten alloy is more acceptable in this case, for they are non-toxic.

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Black SiC is a man made mineral with a high thermal conductivity rating of 100 W/m-K. It is extremely hard, around a Mohs 9.1 or 2550 Knoop. It has high strength at elevated temperatures. For example, at 1000oC, SiC is 7.5 times stronger than Al203 (aluminum oxide). Black SiC will contain some free silicon and carbon and thus is not as pure as green SiC. Black will range in purity from 97-99% pure, depending on grit size. Green SiC is made from Silica sand and coke, and is extremely pure. Hexagonally shaped, it breaks into very sharp particles. Our green SiC is 99.5% pure, exceeding JIS, ISO, & FEPA standards.

Green SiC is harder than black, coming in at a 9.4 Mohs and 2600 on the Knoop scale. Green is often the media of choice when it comes wire sawing. The micronization process of manufacturing our green SiC is controlled by a computer. Then the material is water classified/separated - this produces a very tight particle size distribution, as well as a reduction in fines, as preferred for accurate wire sawing applications. Unless your application requires an extremely pure SiC, by default, black is preferred due to its more economic pricing.

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Tungsten alloy is ideal for shielding against X-rays and gamma radiation. The very high density of tungsten shielding (more than 60% denser than lead) allows a reduction in the physical size of shielding components, without compromising their rigidity or the effectiveness of the shielding characteristics.

Whether you need to protect sensitive electronic equipment or delicate human tissue, the energy-absorbing properties of T&D’s tungsten alloys make them exceptional choices for radiation shielding applications, in both medical and industrial settings.

1) Shielding in medical

multi leaf collimator

shielding protection tank for medical radiation

shielding syringe for liquid medicine radiation

tungsten alloy containers, such as tank, box for storing radioactive materials

autocollimator and tungsten collimation bar for medical lineal accelerator, nuclear industry and container system inspection

shielding for Co60 and other radiation

gamma radiography shield

2) Shielding in industry

shielding block

flaw detector

large container inspection devices

radioactive source containers

Nuclear shielding wall etc.

Tungsten Alloy Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-alloy.com
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