Polyether ether ketone, the English name polyetheretherketone (referred to as PEEK), it is a linear aromatic polymer compound molecular main chain containing chain links. Unit consisting of an oxygen – p-phenylene – oxo – carbonyl – p-phenylene, are semi-crystalline thermoplastics.
Product Name: polyether ether ketone (PEEK) resin is an excellent special engineering plastics, specialty engineering plastics compared with other more significant advantage, being resistant to high temperature of 260 degrees, excellent mechanical properties, self-lubricating, good resistance chemical corrosion, fire-retardant, peeling resistance, abrasion resistance, intolerance strong nitric acid, concentrated sulfuric acid, anti-radiation, superior mechanical properties can be used in high-end machinery, nuclear engineering and aviation and other technology.
Polyetheretherketone PEEK (short)
Substance: linear aromatic polymer compound
Polyether ether ketone resin
Special engineering plastics
Features
Radiation resistance, insulation and stability
performance
PEEK material properties of a wide range of excellent application
table of Contents
1 Product Features
2 Performance
3 Application
▪ Applied Research
▪ Current use
4 PEEK Processing
5 corresponding indicators
6 sheet bar
7 properties of the table
8 polyetheretherketone
Product Features
Radiation resistance, insulation resistance and stability, hydrolysis resistance, compressive strength, corrosion resistance, and its composite materials into mechanical parts with self-lubricating effect.
. Temperature, good thermal stability, high heat resistance (compared with PPS fine), HDT at 315 degrees Celsius, UL continuous use temperature of 260 degrees Celsius.
1: Mechanical properties of PEEK are both toughness and rigidity and balance of plastic. Particularly its excellent alternating stress fatigue resistance is the most outstanding of all plastics, can be comparable with the alloy material.
2: Self-lubricating PEEK has outstanding sliding characteristics in all plastics, suitable for the stringent requirements of low coefficient of friction and resistance to abrasion purposes. Especially carbon fiber, graphite certain percentage of each modified PEEK blended self-lubricating properties better.
3: chemical resistance (corrosion resistance) PEEK has excellent chemical resistance in ordinary chemicals, can be dissolved or damaged only concentrated sulfuric acid, its corrosion resistance and nickel steel similar.
4: flame retardant polymer PEEK is very stable, 1.45mm thick sample, without any flame retardant can achieve the highest standards.
5: peeling resistance PEEK excellent peeling resistance, and therefore can be made of or coated with a thin wire, can be used in harsh conditions.
6: fatigue resistance PEEK has the best fatigue resistance in all resin.
7: radiation resistance capability is strong resistance to high radiation, exceeding the best general-purpose polystyrene resin in radiation resistance. It can still maintain high performance made a good insulating ability when γ radiation dose of 1100Mrad.
8: Hydrolysis of PEEK and its composites from chemical influence of water and high-pressure steam, products made of this material for use in high temperature and high pressure water continuously will maintain the outstanding characteristics.
PEEK Product Features
PEEK (polyether ether ketone) Plastics is an aromatic crystalline thermoplastic polymer material having a melting point of 334 ℃, with high mechanical strength, high temperature, impact resistance, flame retardant, acid hydrolysis, abrasion resistance, fatigue, resistance to radiation and good electrical properties.
High temperature
PEEK resin has a high melting point (358 ℃) and glass transition temperature (1 43 ℃), continuous use temperature of 260 ℃, its 30% GF or CF-reinforced grades of load heat distortion temperature up to 316 ℃.
Mechanical properties
PEEK (polyether ether ketone) Plastics resin has good toughness and rigidity, it has alloy material comparable alternating stress on excellent fatigue resistance.
Smoky
Standard measuring soot produced by the burning plastic is ASTM E662, this standard is used by the US National Bureau of Standards (NBS) smoke laboratories than the optical density units, measuring soot produced by the combustion of the sample standard shapes visible dim level, Under this test can be sustained combustion (flame) or combustion interrupt (no flame) the situation, in plastic PEEK has the lowest Smoky.
Fugitive gas
PEEK and many of the same organic material, during pyrolysis, PEEK mainly produce carbon dioxide and carbon monoxide, using a British Standard BSS 7239 test craft can detect extremely low concentrations of gas escape, this detection process requires 1 m3 of space complete combustion of 100 g sample and analyze the gas generated therein, the toxicity index is defined as the concentration of the gas under normal conditions produce a comprehensive and 30 minutes can make a lethal dose of the ratio, PEEK450G index was 0.22, and the acid was not detected gas.
stability
PEEK plastic materials having excellent dimensional stability properties, which some are very important for some applications. Changes in temperature, humidity and other environmental conditions, little effect on the size of PEEK parts, dimensional accuracy is required to meet the high demand working conditions.
1.PEEK plastic materials injection molding shrinkage, which controls PEEK injection molded part dimensional tolerance range is very good, so that the dimensional accuracy of PEEK parts is much higher than common plastic;
2. The thermal expansion coefficient, as the temperature changes (by changes in ambient temperature during operation or cause friction and heat), the dimensional change PEEK parts is small;
3.PEEK thermal hydrolysis characteristics prominent in the hot and humid environment, low water absorption, similar to general-purpose plastics such as nylon size due to water absorption leaving significant change will not happen;
Insulation stability
PEEK (polyether ether ketone) Plastics resin has good electrical insulation properties, and keep to a high temperature range. The dielectric loss at high frequencies is small
Radiation resistance and peel resistance
PEEK (polyether ether ketone) Plastics resin with good radiation resistance and peel resistance, it can be used magnet wire made of a special purpose.
Now the sterilizer and wireless authentication system, sometimes used peek, fairly stainless steel effect.
performance
PEEK resin is ideal for electrical insulation, high temperature, high pressure and high humidity and other harsh working conditions, can still maintain good electrical insulation properties, and therefore the field of electronic information is becoming the second largest application area PEEK resin. It can be used in the manufacture of ultra-pure water delivery pipes, valves and pumps.
PEEK resin can also withstand autoclaving cycles up to 3000 times at 134 ℃, this feature so that it can be used to produce high sterilization requirements, surgical and dental equipment to be used repeatedly. PEEK not only light weight, non-toxic, corrosion resistance, etc., or is currently working with the closest human skeleton material, combine with the body, so instead of the human skeleton is made of metal which is another important application in the medical field with a PEEK resin. Domestic production of PEEK material development is very rapid.
PEEK resin is the late 1970s by the British former ICI has developed, since its inception, has been used as an important strategic defense industry materials, many countries have restrictions on exports.
Polyether ether ketone (PEEK) as a new type of semi-crystalline aromatic plastic engineering plastics, with extremely good physical and mechanical properties, in many specific areas can replace metal, ceramics and other traditional materials, reduce the quality in terms of performance, improve outstanding contributions, to become one of today’s most popular high-performance engineering plastics. PEEK high temperature thermal performance is very prominent, long-term use at 250 ℃, instantaneous temperature up to 315 ℃; its rigidity, dimensional stability, low coefficient of linear expansion, close to the aluminum material; PEEK good chemical stability, acid, alkali and almost all organic solvents have a strong corrosion resistance, and flame retardant, anti-radiation and other properties; PEEK resistance to sliding wear and fretting wear loss of excellent performance, especially under 250 ℃ can be maintained high wear resistance and low friction coefficient; moreover, PEEK shooting easy extrusion and injection molding. With some excellent performance, PEEK in aerospace, machinery, petroleum, chemical, nuclear, rail transportation and other fields have a wide range of applications, even in 200-degree steam, which pull stretch strength, quality and appearance does not change significantly, may long-term use. It has a very high alternating stress effect good fatigue resistance, and long-term load resistance, wear resistance. Has excellent flame resistance, there is self-extinguishing, does not contain a flame retardant in the resin, the molecule is also halogen-free, so it will not filthy environment when burned, oxygen index of 24-35, flame rating of UL94V & mdash; 0. In addition to PEEK can be dissolved in concentrated sulfuric acid and concentrated nitric acid yellow, but on the other solvents are stable, but if the crystal is not sufficient, it will produce a crack in the acetone solvent class.
PEEK molding process may be injection molding, extrusion, blow molding, pressing and so on.
Uses: It is an excellent overall performance of engineering plastics, films can cast or directional, used wire coating line, nuclear engineering components, H or C grade electrical insulating material, a flexible printed circuit board, the heat pump cabinet or rack , oil couplings, valves, heat or metal anti-corrosion coatings, monofilaments, bandaging aspects belt, sieve, subways, mining, oil, electrical industry, nuclear engineering, chemical engineering equipment.
application
It peek has been widely used in the aerospace, automotive, electrical and electronics, medical and food processing.
Applied Research
PEEK has excellent properties, fields of application will also be with the domestic applied research and more widely, the current domestic set up in Chongqing 1973 and new materials research center that specializes in the research PEEK in applications. The research center is at all levels of government leadership and care was established in Chongqing, committed in the automotive sector, electrical and electronic fields, transportation and other areas of research, in terms of the current application of walking in the forefront of the country.
Currently used
Currently in the sterilizer and wireless authentication system, sometimes used peek, fairly stainless steel effect.
PEEK Ties
Polyether ether ketone resin (Polyether Ether Ketone, called PEEK resin) is 4,4-difluoro-benzophenone and hydroquinone in the presence of an alkali metal carbonate, diphenyl sulfone as a solvent to a condensation reaction prepared a new type of semi-crystalline aromatic engineering thermoplastics. It belongs to high-temperature thermoplastics with high glass transition temperature (143 ℃) and melting point (343 ℃), load thermal deformation temperature up 316 ℃ (30% glass fiber or carbon fiber reinforced grade), long-term at 250 ℃ use, such as PI, PPS, PTFE, PPO, etc. Compared with other high-temperature plastic, use temperature limit was nearly 50 ℃; PEEK resin not only has excellent heat resistance than other high-temperature plastic, and has high strength, high modulus, high fracture toughness, and excellent dimensional stability; PEEK resin at a high temperature to maintain high strength, bending strength it amounted to about 200 ℃, 24MPa, 250 ℃ under the bending strength and compressive strength is still 12 ~ 13MPa; PEEK resin of greater rigidity, good dimensional stability, low coefficient of linear expansion, very close to the aluminum material; has excellent chemical resistance, in the usual chemicals, only concentrated sulfuric acid to dissolve or destroy it, it corrosion resistance and nickel steel similar, while its own flame retardant, under fire conditions and toxic gas release less smoke, anti-radiation and strong; PEEK resin toughness, good for alternating stress fatigue resistance is all The most outstanding of plastic, can be comparable with the alloy material; PEEK resin has outstanding tribological properties, resistance to sliding wear and fretting wear performance is excellent, especially to maintain high wear resistance and low friction coefficient at 250 ℃; PEEK resin easy extrusion and injection molding, excellent processing performance, high forming efficiency. In addition, PEEK also has a self-lubricating, easy processing, insulation and stability, hydrolysis resistance and other excellent properties, making it in the aerospace, automotive, electrical and electronics, medical and food processing with a wide range of applications, development and utilization prospects are very broad.
PEEK processing
PEEK material by injection molding method and stick plate machined form or ideal. PEEK products in designer mode or when small quantities of PEEK parts by injection mode is not economical. Often use machine processing methods to produce. PEEK and other plastic materials can be the same as using the same equipment and technology for the processing and finishing deburring, since PEEK material has good wear resistance and good physical properties generally recommended to use carbide, diamond tools and drills to operate [1] .
PEEK product parts in the processing time generally want to peek peek rod or plate pre-patenting, you can remove the parts of the stress and residual stress. In the machining time local temperature increase will cause the material to produce more of the stress can be the product of the second patenting treatment to remove stress.
Corresponding indicators
PEEK is Polyetheretherketone short, the Chinese name is polyether ether ketone resin, is a high-end specialty plastics. Polyether ether ketone / PEEK
Low creep.
· High modulus of elasticity.
· Excellent friction properties.
· Special wear.
· Resistance to various aggressive media, FDA approved, non-toxic.
· Very good chemical resistance.
· Retardant.
Polyether ether ketone and polyphenylene sulfide (PPS), polysulfone (PSF), polyimide (PI), polyarylate (PAR), liquid crystal polymer (LCP) are together known as the six major special engineering plastics.
Sheet bar
PEEK rods, plates
PEEK material made with pure PEEK plate PEEK plates at all levels in the best toughness, impact best. PEEK can use the most convenient way for disinfection sterilization (steam, dry heat, ethanol, and Y-rays), and manufacture of PEEK material composition in line with EU and US FDA regulations for food to be in nature, these features make it suitable in the medical, pharmaceutical and food processing industry has been very widely used.
PEEK material form
Polyether ether ketone
PEEK refers to a linear macromolecule polymer main chain aryl ketone and ether linkages composition, which is currently the only mass-produced varieties polyaryletherketone, the English name for polyetherether ketone, abbreviated PEEK, Molecular Structure of
Molecular structure of polyether ether ketone
Molecular structure of polyether ether ketone
PEEK has a heat resistance of thermosetting plastics, thermoplastics chemical stability and moldability. PEEK is also excellent in heat resistance. Heat distortion temperature of 160 ℃, when 20% to 30% glass fiber reinforced, heat distortion temperature can be increased to 280 ~ 300 ℃. PEEK good thermal stability, in the air 420 ℃. 2h circumstances under weightlessness only 2%, 500 ℃ when 2.5%, 500 ℃ only produce significant thermal weightlessness. Polyether ether ketone long-term use temperature of about 200 ℃, at this temperature, can still maintain a high tensile strength and flexural modulus, it is a very strong material, have excellent long-term creep resistance and fatigue resistance.
Electrical insulating properties of PEEK is very good, the volume resistivity of about 10 ~ 10Ω · cm. It still has a small dielectric constant and dielectric loss in the high frequency range. For example, when 10Hz, in the room it was only 3.2 dielectric constant, the dielectric loss of only 0.02.
Chemical stability PEEK is also very good, with the exception of concentrated sulfuric acid, almost any chemical reagents are very stable, even at high temperature, can still maintain excellent chemical stability. In addition, it has excellent resistance to hot water and steam resistance. It can steam a long time in the 200 ~ 250 ℃.
PEEK has good flame resistance, in a normal environment is difficult to burn, even burning, smoke emission and emission of harmful gases is very low, even lower than PTFE and other low-fuming amount of polymer. In addition. It also has excellent resistance to radiation. Α-rays, β-rays, γ-rays resistance polymer material is the best present. It is covered with wire products can withstand 1.1 × 10Gy of γ-rays.
Above the melting point of PEEK has good melt flow properties and thermal stability. Thus with typical thermoplastic molding processability, and therefore can be used injection molding, extrusion, blow molding, lamination molding method, etc., but also spinning, film formation. Although PEEK melt processing temperature range of 360 ~ 400 ℃, but because of its thermal decomposition temperature is above 520 ℃, so it still has a wide working temperature range.
Although the history of PEEK is only a short period of twenty years, but because of its outstanding heat resistance, chemical resistance, radiation resistance and high strength, ease of processing, so that it now has nuclear industry, chemical industry, electronics, machinery and instrumentation, automotive and aerospace fields has been widely used. Especially as thermal performance thermoplastic resin, it can be used as the base material of high performance composites.
modified
Pure performance PEEK material is difficult to meet the different needs of different industries, so in need of special working environment modified PEEK, its main means there is modification, copolymerization, composite reinforced modified, tamped modified nano modification and surface modification technologies. It can be increased by modifying certain aspects of performance PEEK, such as abrasion resistance, impact strength, so as to expand the scope of application of PEEK, reducing the cost of materials, improved processing properties of PEEK.
Common modified PEEK
Wave fiber modification: 10% wave fiber modification, 20% wave fiber modification, 30% wave fiber modified
PEEK grades:
Trademark
Features and uses
150CA20
Injection molding, extrusion grade, 20% carbon fiber reinforced, high temperature, rigidity, excellent strength for engineering products
150CA30
30% carbon fiber reinforced, high temperature, good stiffness and strength, for mechanical, electrical, automotive, chemical and other engineering products good chemical resistance
150CA40
Injection molding, extrusion grade, 40% carbon fiber reinforced, high rigidity, high temperature, for engineering components
150P
Coating grade, low viscosity, powder, unreinforced, crystalline, above UL94V-0, temperature 160 ℃, suitable for metal coating
380G
Extrusion and coating grade. The viscosity of the mixture pellets, unreinforced, crystalline, UL94V-0, using a temperature above 160 ℃. Suitable for general use extruded monofilament and engineering components, particularly metal wire coating
380P
Extrusion and coating grade. Viscosity, powder, unreinforced, crystalline, UL94V-0, the above temperature 160 ℃, suitable for general use extruded monofilament and engineering components, such as a metal wire coating
450CA30
Injection enhanced levels. A mixture of aggregates, 30% carbon fiber reinforced, with good rigidity and load bearing performance, temperature above 250 ℃, the maximum can reach 315 ℃, UL94V-0, good toughness, high strength, good chemical resistance, fast molding cycle.
150FC30
Injection molding, extrusion grade, 30% carbon fiber reinforced, high stiffness, high temperature, good lubrication, used as engineering components
450G
Injection molding grade, non-reinforced, high viscosity, a mixture of aggregates, crystalline, UL94V-0, using a temperature above 160 ℃, high strength
450P
Injection molding grade, powder, characteristics and uses with 450G
450GL20
Reinforced injection molding grade. A mixture of aggregates, 20% glass fiber reinforced, heat resistance and flexural modulus 450G grade high strength and stiffness, use
450GL30
At a temperature of 250 ℃, to UL94V-0. Suitable for mechanical, chemical, electrical and other engineering products, but also for extruded products.
D150CA30
New products and enhance injection molding grade. Glass fiber and carbon fiber reinforced mixture pellets, good mobility, good heat resistance, continuous use temperature of 250 ℃, up more than 300 ℃. Suitable for mechanical, electrical and other high-quality thin-walled engineering products
D150G
New products, injection molding grade. Mixing the pellets, good mobility, good heat resistance, temperature 250 ℃, stable mechanical properties.
D150GL30
New products, injection enhanced levels. 30% glass fiber reinforced, mixed pellets.
D450HT15
New products, a good variety of performance for heavy-duty applications engineering products, can replace more traditional metal
D450HF30
450GL10
New products, enhance injection molding grade, 10% glass fiber, strength and rigidity, high heat resistance, is a mixture of pellets
KX3
New products, injection molding grade. Mixture pellets. Suitable bearings and other engineering products
LC1006
Injection enhanced level, 30% carbon fiber reinforced, high temperature, rigidity and strength, for mechanical, electrical, chemical, automobile and other lubrication good
LF1006
Injection enhanced level, 30% chopped fiber, characteristics and uses with LC1006
LFL4036
Injection enhanced level, 45% chopped fiber and PTFE, high temperature resistance, rigidity and strength, for mechanical, electrical, automotive, chemical and other products
LL4530
Injection enhanced level, 20% silicone resin-modified, high temperature, rigidity and strength, for mechanical, electrical, automotive, chemical and other lubricating products
PDX79737
Injection enhanced level, 30% chopped glass fiber reinforced, high temperature, good rigidity and strength. Suitable for mechanical, electrical, automotive, chemical products
PDX79738
Injection enhanced level, 30% carbon fiber, characteristics and uses above PDX79737
PDX81319
Injection enhanced level, 15% carbon fiber, characteristics and uses above PDX79737
PDX81336
Injection enhanced level, 45% carbon fiber and PTFE filled enhancements, the other with PDX79737
PDX81338
Injection enhanced level, 20% PTFE filled, high temperature, rigidity and strength, for mechanical, electrical, chemical, automotive and chemical coupling of engineering products
PDX87229
> 20% short glass fiber filled, high temperature, rigidity and strength, for mechanical, electrical, chemical, automotive and other engineering products hydrolytic stability
PDX87461
> 15% short glass fiber filled, high temperature, rigidity and strength, for mechanical, electrical, chemical, automotive and tensile properties of engineering products
WA40
Injection enhanced level, 40% of aluminum shavings filling enhanced, high temperature, rigidity and strength, for mechanical, electrical, automotive, chemical and other good lubricating products
WC-1006
Injection enhanced level, 30% carbon fiber reinforced, high temperature, rigidity and strength, for mechanical, electrical, automotive, chemical and other anti-static products
Deutsche
30% glass fiber reinforced PEEK
PEEK Product Features
PEEK (polyether ether ketone) Plastics is an aromatic crystalline thermoplastic polymer material having a melting point of 334 ℃, with high mechanical strength, high temperature, impact resistance, flame retardant, acid hydrolysis, abrasion resistance, fatigue, resistance to radiation and good electrical properties.
High temperature
PEEK resin has a high melting point (334 ℃) and glass transition temperature (1 43 ℃), continuous use temperature of 260 ℃, its 30% GF or CF-reinforced grades of load heat distortion temperature up to 316 ℃.
Mechanical properties
PEEK (polyether ether ketone) Plastics resin has good toughness and rigidity, it has alloy material comparable alternating stress on excellent fatigue resistance.
Flame retardant
Flammable material that is obtained after high energy ignition sustain combustion capacity from oxygen, nitrogen mixture. Measurement recognized standards for the flammability UL94, method is to ignite a predetermined shape of a vertical sample, and then measured the material is automatically turned off the time it takes. PEEK test results for V-0, which is the optimal level of flame retardance.
stability
PEEK plastic materials having excellent dimensional stability properties, which some are very important for some applications. Changes in temperature, humidity and other environmental conditions, little effect on the size of PEEK parts, dimensional accuracy is required to meet the high demand working conditions.
1.PEEK plastic materials injection molding shrinkage, which controls PEEK injection molded part dimensional tolerance range is very good, so that the dimensional accuracy of PEEK parts is much higher than common plastic;
2. The thermal expansion coefficient, as the temperature changes (by changes in ambient temperature during operation or cause friction and heat), the dimensional change PEEK parts is small;
3. size stability, dimensional stability means the use of plastic or a dimensionally stable during storage performance engineering plastics products, changes of this size is mainly because the polymer molecules activation energy increase, so that there is a segment extent of curl caused;
4.PEEK thermal hydrolysis characteristics prominent in the hot and humid environment, low water absorption, similar to general-purpose plastics such as nylon size due to water absorption leaving significant change will not happen;
Insulation stability
PEEK (polyether ether ketone) Plastics resin has good electrical insulation properties, and keep to a high temperature range. The dielectric loss at high frequencies is small
Radiation resistance and peel resistance
PEEK (polyether ether ketone) Plastics resin with good radiation resistance and peel resistance, it can be used magnet wire made of a special purpose.
Currently in the sterilizer and wireless authentication system, sometimes used peek, fairly stainless steel effect.
Application
Since PEEK (polyether ether ketone) Plastics resins have many advantages over, so in the petrochemical, electronic and electrical, instrumentation, mechanical automotive, medical, aerospace, military and nuclear power, and many other fields has been widely used. For example: It is now more mature domestic applications are: air compressor piston rings, thrust collar, choke ring, valves, valve bacteria, star wheel, sealing rings, valve seats, bearing cage, non-oil lubricated bearings , magnetic pump isolation sets, electrodes, gears, screws, wire, radiation shutters, microwave digestion tank, the wafer carrier and the like.
Polyether ether ketone (PEEK) resin is an excellent special engineering plastics, compared with other special engineering plastics has many significant advantages, high temperature resistance, excellent mechanical properties, self-lubricating, good resistance to chemical corrosion, fire-retardant, peeling resistance, radiation resistance, insulation resistance and stability, hydrolysis resistance and ease of processing, in the fields of aerospace, automotive, electrical and electronics, medical and food processing are widely used. Application-performance PEEK resin was first obtained wide applications in the aerospace field, instead of aluminum and other metal materials of various aircraft parts. The automotive industry since the PEEK resin has good abrasion resistance and mechanical properties, as a raw material manufacture the engine cover, with its manufacture of various parts bearings, gaskets, seals, clutch ring gear in the car’s transmission, brakes and air conditioning systems are widely used.
PEEK resin is ideal for electrical insulation, high temperature, high pressure and high humidity and other harsh working conditions, can still maintain good electrical insulation properties, and therefore the field of electronic information is becoming the second largest application area PEEK resin, manufacture ultra-pure water delivery pipes, valves and pumps in the semiconductor industry, used to manufacture the wafer carrier, electronic insulating film and a variety of connected devices. As a semi-crystalline engineering plastics, PEEK is insoluble in almost all solvents concentrated sulfuric acid, which used to produce compressor valves, piston rings, seals and a variety of chemical used pump, valve components. PEEK resin can also withstand autoclaving cycles up to 3000 times at 134 ℃, this feature so that it can be used to produce high sterilization requirements, surgical and dental equipment to be used repeatedly. PEEK not only light weight, non-toxic, corrosion resistance, etc., or is currently working with the closest human skeleton material, combine with the body, so instead of the human skeleton is made of metal which is another important application in the medical field with a PEEK resin. PEEK resin domestic production, rapid development in the late 1970s by the British former ICI has developed, since its inception, has been used as an important strategic defense industry materials, many countries have restrictions on exports.