2016年4月13日星期三

What Is Graphite ?

Graphite, also called plumbago or black lead. Graphite has a layered structure that consists of rings of six carbon atoms arranged in widely spaced horizontal sheets. Graphite thus crystallizes in the hexagonal system, in contrast to the same element crystallizing in the octahedral or tetrahedral system as diamond. Such dimorphous pairs usually are rather similar in their physical properties, but not so in this case. Graphite is dark gray to black, opaque, and very soft (with a hardness of 1 1/2 on the Mohs scale), while diamond may be colourless and transparent and is the hardest naturally occurring substance. Graphite has a greasy feel and leaves a black mark, thus the name from the Greek verb graphein, “to write.” For detailed physical properties of graphite, see native element (table).
Graphite is formed by the metamorphosis of sediments containing carbonaceous material, by the reaction of carbon compounds with hydrothermal solutions or magmatic fluids, or possibly by the crystallization of magmatic carbon. It occurs as isolated scales, large masses, or veins in older crystalline rocks, gneiss, schist, quartzite, and marble and also in granites, pegmatites, and carbonaceous clay slates. Small isometric crystals of graphitic carbon (possibly pseudomorphs after diamond) found in meteoritic iron are called cliftonite.
Graphite is used in pencils, lubricants, crucibles, foundry facings, polishes, arc lamps, batteries, brushes for electric motors, and cores of nuclear reactors.Graphite products such as graphite rods, graphite blocks, graphite plates etc. It is mined extensively in China, India, Brazil, North Korea, and Canada.
Graphite was first synthesized accidentally by Edward G. Acheson while he was performing high-temperature experiments on carborundum. He found that at about 4,150 °C (7,500 °F) the silicon in the carborundum vaporized, leaving the carbon behind in graphitic form. Acheson was granted a patent for graphite manufacture in 1896, and commercial production started in 1897. Since 1918 petroleum coke, small and imperfect graphite crystals surrounded by organic compounds, has been the major raw material in the production of 99 to 99.5 percent pure graphite.

Graphite Industry Moves Toward The High-end 

2016年4月10日星期日

Graphite Industry Moves Toward The High-end

Development of low-end of chinese graphite industry is seriously hurt resource protection and industrial upgrading. with the rapid development of modern science and technology and the country's new materials, the field of new energy broaden continuously, graphite industry is facing the same fate with rare earth: due to the low threshold which leads to over-exploitation of resources, the low end of the industry, low deep processing technology, a few companies monopoly control, lack of unified planning and regulation, and all these situation restrict the healthy development of graphite industry.
According to the records of Bureau of Customs, datas show that China graphite is major exporting to japan, south Korea, the united states, india, russia, japan and south korea import large quantities of graphite material from china, the price per ton only a few thousand dollars, after its purification process re-export to china, the price per ton of 10 million -20 million.
In Inner Mongolia, Shandong, Heilongjiang, Hubei, Hunan and other places of rich graphite, graphite industry is basically still in the process of mining the primary stage of the production of raw materials, graphite products, quality and technical level are all backward, so as to form a waste of resources, environmental pollution , and the cycle of low efficiency, and lack of funds, lack of information, lack of talent is also fatal factors to these graphite companies, china graphite companies are most are still at a loss.

Advantages Of Carbon-Carbon Composite Material 

2016年4月6日星期三

Advantages Of Carbon-Carbon Composite Material

Carbon-carbon composite material is a material made of high strength carbon fiber and carbon matrix after the process of graphitization, it can be widely used in various types of structures, heaters and containers under high temperature environments.
Compared to graphite materials and other materials,What are the main advantages of carbon-carbon composites material?
1)High intensity (five times stronger than steel);
2)High temperature resistance (still maintain excellent mechanical and electrical properties at 2000 ℃);
3) Thermal shock resistance;
4) Low thermal expansion coefficient;
5) Small heat capacity;
6) Low density (1.7);
7) Excellent corrosion resistance and radiation performance.
It can be mainly used in industries such as aerospace、auto industry、chemical, textile and machinery manufacturing and medical field etc.

The Graphite Material of Photovoltaic Industry 

2016年3月24日星期四

The Graphite Material of Photovoltaic Industry

As we know, graphite is widely applied , As technology has improved,high density, high strength, good isotropic graphite has become more and more useful, which is iso-graphite, iso-graphite is widely used in solar photovoltaic industry.
In the monocrystal or polycrystalline furnace, the most common products are graphite crucible, heating element, guide cylinder, graphite tray, heat shield an so on.
  Graphite hot zone of guide cylinder
  Graphite hot zone of heating element
  Polycrystalline graphite sabot
  Polycrystalline graphite parts

Graphite materials have excellent characteristics that other metal materials can not be replaced in solar photovoltaic industry, such as heating evenly, good earthquake-resistance,and prolong machinery  life-cycle at the same time.
Whether at home or abroad, the isostatic pressure graphite is preferable for graphite hot zone.Which is an important materials.

Graphite Plate Is Better Material In Vacuum Furnace 

2016年3月20日星期日

Graphite Plate Is Better Material In Vacuum Furnace

Graphite plates used for vacuum furnace, which is generally resistant to 2,000 degrees celsius, the other materials are not up to such a high temperature.and graphite is the most electrically conductive non-metallic minerals in the nature, its temperature can reach 30 degrees celsius temperatures, and it is the best conductive material, so it's applied to vacuum furnace、heat treatment furnace. Ceramics can also be resistant to several thousand degrees, but the ceramics are not non-conductive, so they are just used to make protective sleeve, not the heating rods.
Graphite plates used in vacuum furnace,if they are different materials selected, its life is different, oxidation time will be also different. in general, poor material of graphite rod, after heating, the oxidation will speed and be not durable, and then the surface oxidised, it will become broken easily. so high density graphite plate is the best choice. as top graphite plates supplier, XRD Graphite Manufacturing Co.,Ltd offers high purity graphite、high density graphite and high strength graphite.

Tough Graphite Mold Market 2016

2016年3月14日星期一

Tough Graphite Mold Market 2016

Now, with the global scarcity of resources, raw material price increases much more than before, so the cost of graphite mold rises too. some of graphite molds suppliers can not afford the cost and "close the door". some large companies have started new ideas of graphite mold market to find a new way.
Graphite mold enterprises are facing heavy pressure:
1、The rapid rise in prices of raw materials make graphite mold rises price at almost months or even one or two months, some large graphite mold companies had to cut profits.
2、Due to the impact of national policies,huge domestic graphite mold industry is also facing increasingly intense competition.
3、From the consumer in terms of market players, consumers have become more rational than before, a very sought-after price promotion also has lost the power.
Cooperation and competition of graphite mold suppliers:
For graphite mold companies, they must identify the market position、customer orientation、brand positioning, establish a unique brand personality, enhance their competitiveness and occupy and expand the market.
In addition, the agreement between the future market needs related companies coexist to form groups to occupy the market. This requires companies to be good to share the benefits with others, so that companies can win-win.
Graphite mold market forms a new pattern of brand segmentation:
Brand integration, capital operation, the enterprise alliance is the more active,these are notable feature of graphite mold industry this year, such as graphite molds for silvergraphite molds for coppergraphite molds for glass etc.the industry reshuffle soon, the competition will force the brands companies segment customers in the market, new pattern segment formed in the brand.

How To Prolong The Service-life Of Graphite Plate 

2016年3月6日星期日

How To Prolong The Service-life Of Graphite Plate

Graphite plate is widely used in many industries, so the maintenance is importmant for customers. as one of top graphite plates suppliers-XRD graphite makes a few considerations and advices as follows:
1)The amount of current increased to Graphite plate, the higher temperature of the appearance for graphite plate. It recommends to use as small as possible load density (power).
2)Parallel connection for the grpahite plates, avoiding to be broken for the rapid increase of resistor.  
3)After the graphite plate heated in the air, the appearance of graphite plate will constitute a dense silicon oxide film, playing the effect of extending service-life.
4)When graphite plates used continuously, resistor need to be added slowly to delay service-life.
5)the higher temperature,the shorter service-life for graphite plates. in the furnace of 1400℃ or above,oxidation rate will accelerate to shortened the service-life. so try not to let the temperature of the graphite plate surface too high when used in the process.