A method for preparing bn-si3n4 multiphase ceramic continuous fiber by composite organic precursor method
A technology of organic precursors and multiphase ceramics, applied in the fields of fiber chemical characteristics, textiles and papermaking, can solve the problem of high thermal cracking temperature of BN wave-transparent ceramic fibers, and achieve excellent mechanical properties and dielectric properties
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
Method used
Image
Examples
preparation example Construction
[0022] 1. Preparation of composite organic precursors
[0023] Generally, polyborazane and polysilazane with a low degree of polymerization are viscous liquids at room temperature, and fibrils cannot be obtained simply by mixing them together. The present invention selects polyborazane precursors and polysilazane precursors both containing NH-functional groups as raw materials, and mixes and pretreats the two precursors through a specific process to make the two precursors moderately crosslinked, and obtains BN- Si 3 N 4 composite organic precursors.
[0024] The selected polyborazane structural unit is shown in formula (1), and it is a viscous liquid at room temperature; the polysilazane structural unit is shown in formula (2), and it is a viscous liquid at room temperature. Among them, the molecular weight range of 400-1000 in the polyborazane raw material accounts for > 60%; the molecular weight range of 700-3000 in the polysilazane raw material accounts for > 60%.
[0...
Embodiment 1
[0032] Under the protection of an inert gas, 47.5 grams of polyborazane and 2.5 grams of polysilazane organic precursor were mixed into the flask, mixed at 200 ° C and vacuum degree -0.099 MPa for 5 hours and small molecules were removed, and the softening point was obtained. Composite organic precursors at 65±1°C.
[0033] The resulting composite organic precursor was melt-spun at 120±2° C. to obtain continuous fibrils with a diameter of about 15 microns. Take 2g fibrils, in N 2 Continuous non-melting fibers were obtained by electron beam radiation crosslinking under atmosphere; in NH 3 at 0.5°C / min to 1000°C and keep the temperature constant for 1h; in N 2The temperature was raised to 1600°C at a rate of 0.5°C / min, and the temperature was kept constant for 1 hour to obtain white ceramic fibers.
[0034] The scanning electron fiber photo of the obtained white ceramic fiber is as figure 1 As shown, the fibers have a smooth surface and an average diameter of 13 μm. The obt...
Embodiment 2
[0037] Under the protection of an inert gas, mix 45 grams of polyborazane and 5 grams of polysilazane organic precursor into the flask, mix at 220 °C and -0.099 MPa for 3 hours and remove small molecules, and obtain a softening point of 75 ± Composite organic precursors at 1 °C.
[0038] The resulting composite organic precursor was melt-spun at 135±2°C to obtain continuous fibrils with a diameter of about 15 microns. Take 2g of fibrils, at 100℃, NH 3 Constant temperature under atmosphere for 2h, then at 200℃, NH 3 Atmospheric constant temperature 2h obtains continuous non-melting fiber; Then in NH 3 at 0.5°C / min to 1000°C and keep the temperature constant for 1h; in N 2 The temperature was raised to 1600°C at a rate of 0.5°C / min, and the temperature was kept constant for 3 hours to obtain white ceramic fibers.
[0039] The obtained fiber was ground into powder, and the powder was tested by X-ray diffractometer. The results showed that the fiber was composed of BN and Si ...
PUM
| Property | Measurement | Unit |
|---|---|---|
| softening point | aaaaa | aaaaa |
| tensile strength | aaaaa | aaaaa |
| diameter | aaaaa | aaaaa |
Abstract
Description
Claims
Application Information
Login to View More