Composite high-temperature molybdenum disilicide-base material and preparation method thereof

A technology of molybdenum disilicide and composite materials, which is applied in the field of high-temperature structural materials, and can solve problems such as inability to inherit Mo powder, increase process cost, and voids

Inactive Publication Date: 2009-09-16
李琎 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But there are also many essential disadvantages, such as MoSi 2 The phase melts into a liquid phase at the moment of formation, resulting in relatively coarse grains, which cannot inherit the shape of Mo powder; during the sintering process, MoSi 2 The temperature of the phase rises sharply and melts, causing the gasification of low-volatility impurities and the detachment of adsorbed gases. ...

Method used

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  • Composite high-temperature molybdenum disilicide-base material and preparation method thereof
  • Composite high-temperature molybdenum disilicide-base material and preparation method thereof
  • Composite high-temperature molybdenum disilicide-base material and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0060] Prepare a high-temperature composite hollow disc with an outer diameter of 50 mm, an inner diameter of 30 mm, and a thickness of 6 mm.

[0061] In kerosene medium, Mo with an average particle size of 1 μm 2 N powder and Si powder are evenly mixed, and the weight of Si powder is Mo 2 28% by weight of N powder. Vacuumize the reactor, then feed hydrogen to make the pressure of hydrogen in the reactor a positive pressure (the main purpose is to remove the atmospheric medium in the reactor), keep the flow of hydrogen, add the above mixed powder into the reactor, stir Powder;. The reactor was heated to 450°C at a rate of 5°C / min. HCl gas was introduced to make the concentration of HCl in the reactor 50%, and then the reactor was closed. Heating the reactor to 1050°C and keeping it warm for 5 hours, the Mo 2 Siliconization of N powder into Mo 5 Si 3 — Si 3 N 4 Composite powder, where Si 3 N 4 The volume content is about 27%.

[0062] Add the composite powder and ...

Embodiment 2

[0066] A high-temperature composite material sheet with a length and width of 80 mm and a thickness of 1.2 mm was prepared.

[0067] Mo with an average particle size of 0.5 microns 2 The N powder was treated three times by silicification, nitriding, and silicification to become Mo 5 Si 3 ~ Si 3 N 4 Composite powder, where Si 3 N 4 The volume content is about 54%. The first silicidation process is basically the same as that in Example 1, except that the silicidation temperature is 950° C. and the holding time is 4 hours. After the siliconization treatment, put the powder directly into the kerosene without contacting with the air. Ball mill the powder for 4 hours to eliminate agglomeration. The reactor was evacuated, and then nitrogen was introduced to make the pressure of nitrogen in the reactor a positive pressure. Keep the nitrogen flowing, add the above powder into the reactor, and stir the powder. The reactor was heated to 450°C at 5°C / min. Close the reactor an...

Embodiment 3

[0072] Prepare a high-temperature composite material square with a side length of 20 mm and a thickness of 5 mm.

[0073] The preparation method of composite powder and mixed powder is the same as that of Example 1. YSZ powder (yttria-stabilized zirconia powder) with an average particle size of 160 microns is added as a strengthening phase, and the amount added is 20% of the weight of the mixed powder. After uniform mixing, the mixture is pressed into a blank with a side length of 26 mm and a thickness of 8.5 mm

[0074] The sintering process was carried out under nitrogen. Heating to 1300°C for 10 minutes to uniform the blank temperature, heating to 1450°C for 30 minutes for liquid phase sintering, and then heating to 1500°C for 60 minutes to nitride the remaining Si phase. The blank was molded under a nitrogen atmosphere at 1500°C to a thickness of 5.2 mm to eliminate internal pores. Machining removes the surface defect layer to obtain the finished product.

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Abstract

The invention relates to a composite high-temperature molybdenum disilicide-base material and a preparation method thereof. The method can prepare the composite high-temperature material under lower production cost, which has the highest room temperature toughness equivalent to that of high-temperature alloys, higher high temperature intensity, high temperature creep resistant performance and certain plastic processing performance; the substrate of the composite high-temperature material is a composite substrate composed of MoSi2 and Si3N4, wherein the average crystal grain size of the MoSi2 is smaller than 2 microns, and the average grain diameter of the Si3N4 particulates is smaller than 1 microns. The method adopts the following technical proposal: Mo2N powder or powder of Mo5Si3 or Mo3Si are used as initial powder to obtain composite powder Mo3Si-Mo5Si3-Si3N4 or Mo5Si3-MoSi2-Si3N4 after being processed by siliconization or nitridation-siliconization, the composite powder is further enhanced and mixed with materials such as Si powder, SiC powder and the like, and is pressing molded, and then a blank is sintered under the temperature of 1415 to 1550 DEG C, and finally the sintered blank is plastic deformed, thus obtaining a required dense article of the composite high-temperature material.

Description

technical field [0001] The invention relates to a high-temperature structural material, in particular to a molybdenum disilicide-based high-temperature composite material and a preparation method thereof. Background technique [0002] High-temperature structural materials are key materials in equipment such as aero-engines, thermal power generating units, gas turbines, and internal combustion engines, and their performance largely determines the thermal efficiency and overall performance of such equipment. Studies have shown that the high temperature strength and high temperature creep resistance of oxide ceramics are low, and non-oxide ceramics, such as Si 3 N 4 , SiC, etc., have poor sintering performance, so that a large amount of sintering aids that reduce the high-temperature performance of the material must be added during sintering, or the production process is extremely complicated, while intermetallic compounds have low room temperature toughness, low high-temperat...

Claims

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Application Information

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IPC IPC(8): C04B35/58C04B35/622
Inventor 李琎苏健
Owner 李琎
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