Composite materials - future materials. Composite materials with a metal die. Classification of composite materials, страница 4

Эпоксифенольные карбоволокниты КМУ-1 the l hardened by a carbon ribbon, and КМУ-1у on a harness, висскеризованном threadlike chips, can is long to work at temperature to 200 °С.

Карбоволокниты КМУ-3 and КМУ-2 l receive on эпоксианилиноформальдегидном connecting, they can be operated at temperature to 100 °С, they are most technological. Карбоволокниты КМУ-2 and КМУ-2 the l on the fundamentals полиимидного connecting can be applied at temperature to 300 °С.

Карбоволокниты differ a high statistical and dynamic fatigue resistance, save this property at normal and very low temperature (high heat conduction of a filament prevents a self-heating of a material at the expense of an internal friction). They water- and chemically proof. After effect on air of x-ray radiation and Е almost do not vary.

Heat conduction углепластиков in 1,5-2 times above, than heat conduction of fibreglasses. They have following electrical performances: = 0,0024ч0,0034 Om·sm (along filaments);? = 10 and tg = 0,001 (at a current frequency of 10 Hz).

Карбостекловолокниты contain along with coal glass fibres that reduces the price of a material.

2.4 Karbovoloknity with a carbon die

Koksovannye materials receive from usual polymeric карбоволокнитов, exposed pyrolysis in inert or regenerative atmosphere. At temperature 800-1500 °С are organised карбонизированные, at 2500-3000 °С графитированные карбоволокниты. For deriving пироуглеродных materials упрочнитель gives all the best under the shape of an article and is located in the oven in which gaseous hydrocarbon (methane) is passed. At a certain condition (temperature 1100 °С and residual pressure 2660 Pases) methane decays and organised pyrolitic carbon is besieged on filaments упрочнителя, linking them.

Organised at pyrolysis connecting coke has a high adhesive strength with a carbon filament. In this connection the composite material possesses high mechanical and абляционными properties, firmness to thermal blow.

Карбоволокнит with a carbon die of type KUP-VM on values of strength and impact strength at 5-10 time exceeds special graphites; at heat in inert atmosphere and vacuum it saves strength to 2200 °С, on air is oxidated at 450 °С and demands a sheeting. The coefficient of friction of one карбоволокнита with a carbon die on another is high (0,35-0,45), and deterioration is small (0,7-1 microns on тормажение).

2.5 Borovoloknity

Бороволокниты represent compositions from polymeric connecting and упрочнителя - boric filaments.

Бороволокниты differ high strength at squeezing, shear and a cut, low creeping, high hardness and a coefficient of elasticity, heat conduction and electroconductance. The cellular microstructure of boric filaments ensures high strength at shear on boundary of section with a die.

Besides a continuous boric filament apply complex боростеклониты in which some parallel boric filaments are braided стеклонитью, betraying формоустойчивость. Application боростеклонитей facilitates a master schedule of manufacture of a material.

As dies for deriving боровлокнитов use modified эпоксидные and полиимидные the connecting. Бороволокниты КМБ-1 and КМБ-1к are intended for long operation at temperature 200 °С; КМБ-3 and КМБ-3к do not demand a high pressure at processing and can work at temperature not from above 100 °С; КМБ-2к it is efficient at 300 °С.

Бороволокниты they possess high fatigue resistances, stands to effect of radiation, water, organic dilutants and горючесмазочных materials.

As boric filaments are semiconductors бороволокниты possess heightened heat conduction and electroconductance:? = 45 кДж / (m?);? = 4? 10С (along filaments); = 1,94? 10 Ohm? Sm;? = 12,6ч20,5 (at a current frequency of 10 Hz); tg? = 0,02? 0,051 (at a current frequency of 10 Hz). For бороволокнитов strength at squeezing in 2-2,5 times more than for карбоволокнитов.

Physicomechanical properties бороволокнитов are reduced the previous table.

2.6 Organovoloknity