When to use Nextel™ 312 Fibers
3M™ Nextel™ Ceramic Textiles and Composites provide innovative solutions in industries from aerospace to petroleum refining to metal processing. The outstanding thermal protection provided by Nextel™ Fabrics, Tapes and Sleevings allows engineers and manufacturers to handle high temperature applications up to 2500°F (1371°C).
Nextel™ Composite Fibers
The family of 3M™ Nextel™ Fibers was developed to serve a variety of needs. 3M™ Nextel™ Fibers 312, 440, and 550 are designed for non-structural applications where their primary purpose is to insulate or to act as a flame barrier. To aid in the selection of the proper fiber for each of these different applications, the fibers are tested in a manner appropriate to their end use.
3M™ Nextel™ 312 Ceramic Fiber Typical Properties
3M™ Nextel™ Roving 312 – Typical Properties
3M™ Nextel™ Plied Yarn 312 – Typical Properties
Note: All yields are based upon sized rovings and yarns. The allowable range in add-ons for sizing is 1.1 to 3.0% by weight. The allowable tolerance on final twist is ± 30%.
3M™ Nextel™ 312 Roving Strength Maximum Temperature Limit
* Strain rate = 12.5 mm/min
Fiber Weight Loss Nextel™ 312 Ceramic Fiber Roving
Roving samples were subjected to 2192°F (1200°C) for fifteen hours. Fibers were weighed before and after the fifteen hour exposure in order to determine weight loss. The fiber evolves B2O3 at temperatures greater than 2012°F (1100°C).
Shrinkage on Nextel™ 312 Fiber
Roving samples were held at each temperature for fifteen hours. After that time they were measured for shrinkage. All fiber compositions showed less than three percent shrinkage after fifteen hours at 2372ýF (1300ýC). Fiber compositions other than Nextel™ Roving 312 showed shrinkage of less than 1.5% at these conditions.
Nextel™ Ceramic Fiber 312 Moisture Absorption
The 3M™ Nextel™ Ceramic Fibers 312 absorb very little moisture due to their smooth, non-porous surface. Fibers exposed to 100% relative humidity for several hours at room temperature had 0.08% weight gain.
Electrical Insulation Resistance on 3M™ Nextel™ Braided Sleeving 312 (unsized)
Insulation resistance of 3M™ Nextel™ Braids on Type K thermocouple wire was measured as the temperature was increased from ambient to over 1832°F (1000°C). With 12 inch (30,5 cm) sections exposed to the test temperature, the remainder of the 18 inch (45,7 cm) thermocouple specimen extended through the oven wall and was connected to an ohmmeter. All wires were open-ended. A typical curve of insulation resistance as a function of temperature is shown in the figure below for thermocouple wires insulated with unsized yarn. The values of insulation resistance will change depending on thickness, length of thermocouple wire and braid construction.
IR Absorbance and Transmittance 3M™ Nextel™ Ceramic Fiber 312
A small flake of alumina-boria-silica (3:1:2) fired to 1742 F (950 C) was used to determine the transmittance and absorbance of 3M™ Nextel™ Ceramic Fiber 312 in the infrared region. The thickness of the flake was determined from the interference pattern to be 22.4 m thick. The following graph shows that in the shortwave number region (4000-3000 cm-1) the transmission loss is small and appears essentially due to reflection. Weak absorption shows between 2700 and 1700 cm-1. Beyond 1700 cm-1 absorption becomes strong and finally complete beyond 1400 cm-1. Absorbance can be calculated from the relationship A=log10 (100)/(%T).
Cryogenic Testing on 3M™ Nextel™ Woven Tape 312
Five samples of 3M™ Nextel™ Woven Tape 312 1 inch (2,54 cm) wide were cut to 6 inch (15,2 cm) lengths for testing in liquid nitrogen.
Samples were heat cleaned at 1472degF (800degC) for one hour to remove the sizing before testing.
Samples were placed in liquid nitrogen to soak for three minutes. Samples were then removed and tested for strength retention.
A second set of five samples was dipped into liquid nitrogen ten times and then tested for strength retention.
Radiation Resistance & Microwave Measurement - 3M™ Nextel™ Ceramic Fiber 312 Radiation Resistance
Exposure to radiation from a Cobalt 60 source did no noticeable damage to the 3M™ Nextel™ Fiber 312. A total of 1 x 107 rads at an exposure rate of 2.1 x 10 5 rads/hour did not change the tensile strength of the fibers, yarns or fabrics made from the fibers.
Power Transmission and Reflection for 3M™ Nextel™ Fabric panels 18 inch x 18 inch (45.7 cm x 45.7 cm) at 10 GHz.
*Sample held with styrofoam panels, angles of incidence 0°.
3M™ Nextel™ Woven Fabric 312 – Thermal Optical Properties*
The optical properties of fibers on the exterior of the space craft controls the amount of solar heating that will occur in orbit. For instance, a low absorptivity would be desired if one were designing components for a spacecraft mission. This would reflect most of the sun’s energy and protect the craft and the instruments from high temperatures.
Optical measurements were made on 3M™ Nextel™ Woven Fabrics 312 using a Gler Dunkle DB-100 Emissometer and MS-251 Solar Reflectometer machines. The average absorptance () and emittance () are as follows:
NASA Nonmetallic Material Testing*
Flammability, Toxicity and Thermal Vacuum Stability testing on 3M™ Nextel™ Woven Fabrics was performed using procedures specified in NHB 8060.1B and SP-R-0022A.
Flammability: Passed test in 30% oxygen and 10 psia environment.
Toxicity: Passed Test.
Thermal Vacuum Stability: Heat cleaned fabric passed test. Sized 3M™ Nextel™ Fabric outgassed volatile condensable materials of 0.15%, which exceeded the required limit of 0.1 weight %.
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Further information on 3M™ Nextel™ 312 Ceramic Textiles
Further information on other 3M™ Nextel™ Ceramic Textiles
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