CN102432013A - Preparation method of beta-nano-SiC - Google Patents

Abstract

A preparation method of beta-nano-SiC comprises the following steps of: mixing starch or cane sugar with soluble glass according to the mass ratio of 1:1-5, or mixing starch or cane sugar with nitrate according to the mass ratio of 1:0.01-0.5, then mixing with soluble glass with the mass ratio of starch to soluble glass being 1:1-5, standing for 5-30 minutes after uniformly mixing, dying the mixture at the temperature of 60-120 DEG C for 5-20 hours to obtain a dried substance; carrying out a carbothermal reduction reaction for 3-20 hours by heating the dried substance to 1100-1400 DEG C under the protection of argon gas, and naturally cooling to room temperature after the reaction so as to obtain a primary reaction product; roasting the primary reaction product at the temperature of 600-800 DEG C for 1-5 hours, and removing unreacted carbon; immersing for 12-48 hours by using a mixed acid composed of hydrochloric acid and hydrofluoric acid at the volume ratio of 1:1-5, removing superfluous silica from the product, washing, filtering and drying to finally obtain beta-nano-SiC. The preparation method provided by the invention requires low cost, has a simple technology, and is suitable for large-scale industrial production.

Description

A kind of preparation method of β-nanometer silicon carbide

Technical field

The present invention relates to a kind of preparation method of β-nanometer silicon carbide.

Background technology

Silit (SiC) is a kind of broad-band gap (2.3ev) semiconductor material; Have a series of excellent properties; Strong etc. like good, the good thermal conductivity of high physical strength, chemicalstability and electroconductibility, thermostability; In the electronics of high temperature, high frequency, large-power semiconductor device and nanoscale and optoelectronic areas, have huge potential using value, can also be widely used in the toughener of pottery, metal and polymeric matrix composite material.In addition, silicon carbide nano material can use under severe condition such as high temperature, high pressure, deep-etching, is the ideal material of support of the catalyst in the present chemical reaction.Therefore, develop the technological very important of a kind of low-cost mass preparation silicon carbide nano material.

The main method of preparation nanometer silicon carbide has at present: microwave method, arc discharge method, laser ablation method, chemical Vapor deposition process, heating vaporization and collosol and gel carbothermic method.Compare with other method, the collosol and gel carbothermic method is because raw materials cost is cheap, and conversion unit is simple, is the technology that is hopeful to carry out scale operation most.

Have many use organometallicss, synthetic resins and superfine silicon dioxide, the siliceous macromolecular compound of report wait synthesis of nano silit at present.Chinese patent (publication number: CN1762801A) proposed a kind of preparation method of synthesizing silicon carbide nano wire for example; This method is a carbon source with resol or sucrose or polyoxyethylene glycol, and methyl silicate or tetraethoxy or silicon sol are that silicon source and rare earth metal salt are raw material; Periodical Advanced Functional Materials 16 (2006) 561-567 have reported and have utilized mesopore silicon oxide (SBA-15) as hard template, are the mesoporous silicon carbide of the synthetic high-ratio surface of raw material with the Polycarbosilane; Chinese patent (publication number CN 1962433A) discloses the method that a kind of preparation contains the silicon carbide nanometer line of non-crystalline state ball-like structure in half a lifetime, and this method is a raw material with sucrose and silicon sol; Chinese patent (publication number: CN 101386409A) disclose a kind of method for preparing silicon carbide nanometer line, contained SiO with silicon ore deposit, quartz, useless optical fiber etc. ₂Waste material be raw material, be reductive agent with carbon, bamboo charcoal, coal etc., through the vacuum carbothermal reduction synthesizing silicon carbide nano wire.Do not see at present the report that uses cheap water glass and starch or the synthetic β-nanometer silicon carbide of sucrose.

Summary of the invention

The object of the present invention is to provide simple, the with low cost and ability mass preparation β-method of nanometer carborundum of a kind of technology.

The present invention accomplishes according to the following steps:

(1), carbon silicon two-component mixture preparation: with starch or sucrose and water glass by mass ratio 1: 1-5 mixes; Perhaps earlier starch or sucrose and nitrate salt by mass ratio 1: 0.01-0.5 mixes, and presses starch again and mixes with water glass with water glass mass ratio 1: 1-5, leaves standstill after mixing 5-30 minute, is placed in 60-120 ℃ time dry 5-20 hour then, obtains dry thing;

(2), carbothermic reduction: dry thing under argon shield, is warming up to 1100-1400 ℃ and carried out carbothermic reduction reaction 3-20 hour, naturally cool to room temperature after the reaction, obtain the primary reaction product;

(3), thermal treatment: the primary reaction product at 600-800 ℃ of following roasting 1-5 hour, is removed unreacted carbon;

(4), pickling: using volume ratio is 1: the mixing acid of the hydrochloric acid of 1-5 and hydrofluoric acid composition soaked 12-48 hour, removed unnecessary silicon-dioxide in the product, through washing, filtration, oven dry, finally obtained β-nanometer silicon carbide again.

Aforesaid nitrate salt is nickelous nitrate or Xiao Suangu.

The present invention compares with existing method has following advantage:

1, replaces tetraethoxy or silicon sol with water glass cheap and easy to get, therefore significantly reduced the preparation cost of silit;

2, directly be mixed with the silicon-carbon two-component mixture with water glass and starch or sucrose, have advantage simple to operate, that preparation cycle is short, thereby help the rapid large-scale production of nanometer silicon carbide.

3, raw material sources are abundant and with low cost, required equipment is simple, operating procedure is simple, production cost is low, temperature of reaction is lower, with short production cycle, product purity is high, easy realization of large-scale production.

Description of drawings

Fig. 1 is that the present invention prepares β-nanometer silicon carbide XRD figure.

Embodiment

Embodiment 1

1, takes by weighing the service water glass that 10 gram starch and 11 restrain and mix, left standstill after stirring 5 minutes, then 70 ℃ of dryings 12 hours.

2, desciccate is put into tube type high-temperature furnace, feed argon gas, be warming up to 1200 ℃, isothermal reaction naturally cooled to room temperature after 10 hours under argon gas atmosphere.

3, gained reaction product oxidation 3 hours in 700 ℃ of air; Using volume ratio again is that 1: 1.5 the hydrochloric acid and the mixing acid of hydrofluoric acid soaked 12 hours; After washing, filter, to make diameter be 3-50nm in oven dry, length is at micron-sized silicon B-carbide nanofiber.

Embodiment 2

1, takes by weighing the service water glass that 15 gram sucrose and 30 restrain and mix, left standstill after stirring 15 minutes, then 90 ℃ of dryings 10 hours.

2, desciccate is put into tube type high-temperature furnace, feed argon gas, be warming up to 1300 ℃, isothermal reaction naturally cooled to room temperature after 6 hours under argon gas atmosphere.

3, gained reaction product oxidation 5 hours in 600 ℃ of air, using volume ratio again is that 1: 2 the hydrochloric acid and the mixing acid of hydrofluoric acid soaked 15 hours, after washing, filter, to make diameter be 10-90nm in oven dry, length is at micron-sized silicon B-carbide nano wire.

Embodiment 3

1, takes by weighing the service water glass that 25 gram starch and 100 restrain and mix, left standstill after stirring 25 minutes, then 110 ℃ of dryings 9 hours.

2, desciccate is put into tube type high-temperature furnace, feed argon gas, be warming up to 1330 ℃, isothermal reaction naturally cooled to room temperature after 7 hours under argon gas atmosphere.

3, gained reaction product oxidation 2 hours in 800 ℃ of air, using volume ratio again is that 1: 3 the hydrochloric acid and the mixing acid of hydrofluoric acid soaked 24 hours, after washing, filter, to make diameter be 20-200nm in oven dry, length is at micron-sized silicon B-carbide nano wire.

Embodiment 4

1, take by weighing 20 gram sucrose and 1 gram nickelous nitrate mixing and ball milling after, the service water glass with 60 grams mixes again, leaves standstill after stirring 20 minutes, then 100 ℃ of dryings 7 hours.

2, desciccate is put into tube type high-temperature furnace, feed argon gas, be warming up to 1300 ℃, isothermal reaction naturally cooled to room temperature after 8 hours under argon gas atmosphere.

3, gained reaction product oxidation 4 hours in 700 ℃ of air, using volume ratio again is that 1: 4 the hydrochloric acid and the mixing acid of hydrofluoric acid soaked 36 hours, after washing, filter, oven dry makes the silicon B-carbide nano particle that diameter is 3-80nm.

Embodiment 5

1, take by weighing 30 gram starch and 9 gram Xiao Suangu mixing and ball milling after, the service water glass with 105 grams mixes again, leaves standstill after stirring 30 minutes, then 120 ℃ of dryings 10 hours.

2, desciccate is put into tube type high-temperature furnace, feed argon gas, be warming up to 1350 ℃, isothermal reaction naturally cooled to room temperature after 10 hours under argon gas atmosphere.

3, gained reaction product oxidation 3 hours in 800 ℃ of air, using volume ratio again is that 1: 3.5 the hydrochloric acid and the mixing acid of hydrofluoric acid soaked 30 hours, after washing, filter, oven dry makes the silicon B-carbide nano particle that diameter is 3-80nm.

Claims (2)

1. the preparation method of a β-nanometer silicon carbide is characterized in that comprising the steps:

(1), carbon silicon two-component mixture preparation: with starch or sucrose and water glass by mass ratio 1: 1-5 mixes; Perhaps earlier starch or sucrose and nitrate salt by mass ratio 1: 0.01-0.5 mixes, and presses starch again and mixes with water glass with water glass mass ratio 1: 1-5, leaves standstill after mixing 5-30 minute, is placed in 60-120 ℃ time dry 5-20 hour then, obtains dry thing;

(2), carbothermic reduction: dry thing under argon shield, is warming up to 1100-1400 ℃ and carried out carbothermic reduction reaction 3-20 hour, naturally cool to room temperature after the reaction, obtain the primary reaction product;

(3), thermal treatment: the primary reaction product at 600-800 ℃ of following roasting 1-5 hour, is removed unreacted carbon;

(4), pickling: using volume ratio is 1: the mixing acid of the hydrochloric acid of 1-5 and hydrofluoric acid composition soaked 12-48 hour, removed unnecessary silicon-dioxide in the product, through washing, filtration, oven dry, finally obtained β-nanometer silicon carbide again.

2. the preparation method of a kind of β-nanometer silicon carbide as claimed in claim 1 is characterized in that said aforesaid nitrate salt is nickelous nitrate or Xiao Suangu.

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