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Low Cost Synthesis of Silicon Carbide Nanopowders

Among modern ceramic materials, silicon carbide (SiC) and silicon nitride (Si3N4) has been successfully used in a variety of high-tech applications. SiC provides the effective combination of mechanical properties. It is widely used as an abrasive material and structure. It has high hardness, chemical inertness, than the melting temperature of the steel wear and oxidation of it for serious conditions such as high temperature sealing valve, rocket nozzle and wire drawing die and extrusion die for bearing applications because of its good wear resistance and corrosion resistance. In the tube by SiC to find its thermal properties and creep resistance of high temperature and hot electron exchange. The heating element from SiC. They can produce a high temperature of 1650 DEG C and medium in the air or inert considerable life. However, with any contact with water or hydrocarbon gas, can influence their age.

Silicon nitride has comparatively lower oxidation resistance and higher thermal conductivity than SiC. Major applications of silicon nitride are as automotive and gas turbine engine parts. It has high strength, fracture toughness and refractoriness which are required properties for ball bearings, anti-friction rollers. It performs remarkably when exposed to molten metal and/or slag.

A combined form of silicon carbide and nitride has been developed as silicon carbide grains bonded in silicon nitride matrix. This Si3N4-bonded silicon carbide is used for some critical applications where very high thermal shock resistance is required. For instance, in particular case of flame-out engine start-up, temperature reaches from ambient to 1600 °C in few seconds followed by an abrupt decrement to 900 °C in less than one second. Si3N4-bonded silicon carbide exclusively endures these conditions.

Traditional methods to produce these ceramic materials are energy intensive and hence expensive. For example, the Acheson process, which is the most widely adapted method to produce commercial-grade SiC, essentially takes 6 – 12 kWh to yield one kg of SiC. An inexpensive method, that uses low cost agro-industrial byproduct, is the pyrolysis of rice husks, first carried out by Lee and Cutler in 1975. Since then many researchers have discussed and used various process routes and modifications to obtain Silicon Carbide Nanopowders and/or silicon nitride, either in particulate or in whisker form, from rice husks.

Morphological studies on RH reveal that micron size silica particles are distributed in cellulosic part of RH. When these silica particles are made to react with carbon in biomass part of RH under specific experimental conditions, silicon carbide can result. Moreover, besides silicon carbide, modifications in process mechanism lead to formation of some other industrially useful products, viz. silicon nitride, silicon oxynitride (Si2N2O), ultra-fine silica, and solar-cell grade silicon.

Related reading: nano particles nano oxides

 

 

 

 

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Use Up Raw Materials First In The US

In the United States we have abundant raw materials and natural resources. Many in the United States of America the mines have been closed, the raw materials we too much from other countries, must arrive here at a very high cost. Many of the raw materials we get from other nations are not as good as the raw materials we have here and that is a real problem.

Likewise in the future many of the raw materials we have in the United States we will not need because the likelihood of us making things out of steel and copper are not too probable. We will have Nano diamond powder tubes may have carbon, fiber optics, special composites and super alloys made from exotic metals or that have be re-engineered at the molecular level. Because this is the obvious future, we should use our own raw materials in the United States first.

Many economists and the old way of thinking believe we should use raw materials from other nations first and then when they ran out we would be last with our own raw materials and not have anything to worry about. However technology and the rapid advances in research and development has shown us that in the future we will not need these raw materials anyway.

Our goal should be to use our own raw materials in the United States first and work on innovation, research and development was prospected materials in the future to make things better, with their own raw materials. As long as we can use our own in a responsible and environmentally friendly way of raw material that is meaningful to the ground here for the first time to use our materials to use their own. Please consider take this into consideration in 2006.

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The History Of Static Electricity

History

People have dealt with and managed the problems of static electricity for hundreds of years.For example, at the beginning of the fifteenth Century, military fortress, static control program implemented in the treatment of black powder to prevent ignition from electrostatic discharge (ESD). In early 1860, Vin Mills in the American use grounding and flame ionization techniques to eliminate static electricity steel tube and paper in the drying process of network. When American Navy sent the first nuclear submarine in the 50’s of the last century in the Arctic, typical of the antistatic agent used to reduce electrostatic influence to navigation equipment. Over the years, as electronic devices become smaller, faster, therefore, more vulnerable to the destructive effect of static electricity. In order to ensure the normal operation of electrical equipment to the electrostatic, Navy needs some form of control. Because the navy task, static control and increasing awareness of the whole world. Then, static control, industrial development, products and equipment control of electrostatic and electrostatic discharge.

Definitions

According to Grolier’s encyclopedia, Static Electricity is electricity at rest or the accumulation of electric charge, as opposed to an electric current which is the movement of electricity. The flow or movement of people and/or materials in and through the environment causes separation and therefore static electricity. A familiar example is when a person walks across a carpeted floor. Static Electricity is generated simply by the contact and separation of the soles of shoes from the carpeted floor. ESD occurs when the electrostatic charge is transferred from a material that carries the charge to an electrostatic sensitive device. In the example above this ESD is the shock felt after walking across the carpeted floor and then touching a door knob. It is this ESD, which comes in varying degrees, that can be most damaging to electrical devices and other industrial, commercial and consumer products.

Examples

Static Electricity, a natural phenomenon, and consequently ESD are the primary causes of multiple number of problems affecting industry, business and personal life. These problems can be as simple as the shock resulting from walking across a carpet; as costly as the destruction of sensitive electronic components or jamming of machinery; and as dangerous as the ignition of combustible vapors, powders or dust. Typical problems caused by static;

Attraction of dust, dirt and bacteria to all environmental surfaces, as well as to products and product packages Damage or destruction of sensitive electronic components and sub-assemblies during manufacture, testing, packaging, shipping or receiving.

Computer and electronic office equipment data errors memory loss, system failures and other glitches.

Charge generation on surfaces of tote boxes and carriers used to process and store electronic components can create a potential for discharge. Jamming or slipping of paper, plastics or other material during printing, packaging or converting. Ignition of combustible vapors, dust or solvents causing fire or explosion. Irregularities caused by static in high quality printing, heat sealing, silk screening, lamination and other applications.

Work benches and production surfaces in electronic manufacturing and repair facilities will triboelectric charge components, assemblies, or their handling containers in contact and separation with a surface thereby creating a discharge

FACTS

1. Almost any material can generate static electricity. The ability to store or dissipate the charge depends on the type of material

2. Static can cause damage to sensitive devices resulting in instant failure. In contrast, static damage can also go undetected for a period of times resulting in product failure once the product is in service.

3. Electrostatic fields are associated with charged objects

4. The degree of severity of ESD events is contingent upon the type of discharge which occurs.

Electrical Characteristics of Materials

In order to understand how to control the generation of static electricity and the prevention of ESD, one must know the different electrical characteristics of materials that can generate static electricity. There are four varying degrees of electrical resistance.

Conductive Silver Powders allows a charge to flow across or through its volume easily. Surface Resistivity < 106 ohms/sq The miracle of the products have been provide solutions for static control in the past 20 years in India.Our high quality products to help prevent the electrostatic discharge damage sensitive electronic components.Our products include electrostatic prevention personnel grounding, anti-static work surface, anti-static packaging.

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Tungsten Carbide Cobalt Nanopowder Insert Recycling:

Tungsten carbide cobalt nanopowder, also known as cemented carbide, is a relatively precious material which is critical to many manufacturing processes. Metal machining process must use tungsten carbide insert tool tip AS, AS hard alloy hardness and wear resistance of a hot ideal shaping, boring, and the metal workpiece. Face Mills the most modern, tool and cutter old lathe used for cutting tools

The only downside of using carbide inserts for such a wide range of machining processes is that the tungsten material used in creating tungsten carbide alloys is both scarce and expensive. With most tungsten reserves in the US and other Western countries exhausted, China supplies over 80% of the tungsten used worldwide. In 2005, the International Tungsten Industry Association estimated that at the current rate of global consumption, all tungsten reserves will be used up within 140 years. Tungsten carbide inserts are typically treated as disposable materials, even though only the cutting edges of the inserts are worn when they’re disposed.

Rather than disposing of inserts, many manufacturers are turning to recycling companies which purchase used tools.

Why Recycle Carbide Inserts?

Financial Benefits
Tungsten carbide is an expensive material, and most recycling companies are willing to pay for used scrap. By turning used inserts over to recycling facilities, manufacturers can recoup at least a portion of their expenses, lowering their overall material costs. Rates for scrap tungsten carbide fluctuate widely, depending on current market values.

Environmental Benefits
Because carbide inserts contain heavy metals, disposing of them in traditional ways can be quite harmful to the environment. Heavy metals may leech into the soil over time, contaminating ground water. By recycling these, these harmful effects can be largely avoided and global tungsten reserves can be preserved for future generations.

How to Find a Tungsten Carbide Insert Recycling Facility

As more manufacturers are becoming aware of the financial and environmental benefits of recycling inserts, more and more carbide scrap recycling facilities are becoming available around the world. Major worldwide toolmaking companies, including Sandvik Coromant, Kennametal and ATI Stellram, offer their own recycling services for customers. While these companies typically offer recycling services to their own customers, they generally offer a reimbursement for the carbide scrap.

Independent tungsten carbide insert and scrap recycling facilities offer an alternative which in many cases may be more financially beneficial to manufacturers. Carbide recycling providers such as Carbide Recycling Company and Machine Tool Recyclers, Inc. tend to offer the highest and most recent going rate for tungsten carbide, so manufacturers may get more in return for their scrap carbide.

Another option is to require manufacturers and their suppliers to help find the best hard alloy recyclers. Some manufacturers may provide internal circulation, or may have some other use of the waste. Turning with carbide blade back to their interests of suppliers, manufacturers can get a credit for future procurement suppliers.