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Silicon powder surface deoxidizing method

A technology of silicon powder and absolute ethanol, which is applied in chemical instruments and methods, silicon compounds, inorganic chemistry, etc., can solve the problems of hindering the removal of residual oxides, eroding and damaging silicon substrates, increasing the effect of oxygen removal, etc., and achieves rapid removal reactions , reduced contact angle, and easy handling

Inactive Publication Date: 2013-04-24
UNIV OF SCI & TECH BEIJING
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  • Summary
  • Abstract
  • Description
  • Claims
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Problems solved by technology

However, during the HF etching process, due to the poor wettability of the silicon surface, especially as the reaction progresses, the wettability drops sharply, further hindering the removal of residual oxides, and the oxygen removal efficiency is low (M.C. Gomes, A.C. Fernandes, B.S. Almeida, R.M. Almeida, J. Mater. Sci. 1995, 30, 3893-3896.)
In addition, in the process of HF erosion, passivation is easy to occur, and the efficiency of oxygen removal decreases. HF2- is beneficial to eliminate this phenomenon, but with the increase of HF concentration, The concentration of 2- decreases (D.M. Knotter, J. Am. Chem. Soc. 2000, 122, 4345-4351), thus increasing the oxygen scavenging effect by increasing the HF concentration won't work
Although K. Yamamura et al. added an appropriate amount of HNO3 to HF, although the oxygen removal efficiency was improved, HNO3 would also severely corrode and damage the silicon substrate (K. Yamamura, T. Mitani, Surf. Interface Anal., 2008, 40, 1011-1013)

Method used

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Experimental program
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Embodiment approach 1

[0014] The commercial silica fume has a purity of 99.999 wt%, an average particle size of 6.23 μm, and an oxygen content of 2900 ppm. figure 1 is the XPS spectrum of original commercial silicon powder Si2p, SiO 2 The peak area ratio is 79.3%, it can be seen that the surface oxidation of silicon powder is serious. The nominal composition of deaeration liquid is by volume percentage, HF: 4%, C 2 h 5 OH: 2%, the rest is deionized water. Prepare the required oxygen removal solution in proportion and place it in a constant temperature water bath at 50°C, take out an appropriate amount of original commercial silicon powder to be treated and put it into the oxygen removal solution, stir continuously for 30 minutes, and then wash and filter with deionized water through a vacuum filter for 5 Once, vacuum-dried at 50°C, and then immediately vacuum-packed and stored. After testing, the oxygen content in the silicon powder dropped to (242±30) ppm after oxygen removal. figure 2 It is...

Embodiment approach 2

[0017] The commercial silica fume has a purity of 99.9 wt%, an average particle size of 26.67 μm, and an oxygen content of 3500 ppm. The nominal composition of deaeration liquid is by volume percentage, HF: 15%, C 2 h 5 OH: 3%, the rest is deionized water. Prepare the required oxygen removal solution in proportion and place it in a constant temperature water bath at 50°C, take out an appropriate amount of original commercial silicon powder to be treated and put it into the oxygen removal solution, stir continuously for 30 minutes, and then wash and filter with deionized water through a vacuum filter for 5 Once, vacuum-dried at 50°C, and then immediately vacuum-packed and stored. After testing, the oxygen content in the silicon powder dropped to (440±50) ppm after oxygen removal.

[0018]

Embodiment approach 3

[0020] The commercial silica fume has a purity of 99.9 wt%, an average particle size of 26.67 μm, and an oxygen content of 3500 ppm. The nominal composition of deaeration liquid is by volume percentage, HF: 1%, C 2 h 5 OH: 0.5%, the rest is deionized water. Prepare the required oxygen removal solution in proportion and place it in a constant temperature water bath at 50°C, take out an appropriate amount of original commercial silicon powder to be treated and put it into the oxygen removal solution, stir continuously for 30 minutes, and then wash and filter with deionized water through a vacuum filter for 5 Once, vacuum-dried at 50°C, and then immediately vacuum-packed and stored. After testing, the oxygen content in the silicon powder dropped to (700±40) ppm after oxygen removal.

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Abstract

The invention discloses a silicon powder surface deoxidizing method, and belongs to technical field of powder surface treatment. The silicon powder surface deoxidizing method is characterized by improving silicon powder surface wetting ability by adding a neutral solvent of absolute ethyl alcohol into hydrofluoric acid and controlling the proportion and the concentration of the absolute ethyl alcohol, and promoting H+, HF2- and H2F2 and the like to rapidly diffuse towards silicon atoms. The silicon powder deoxidizing technology includes: preparing needed deoxidizing liquid by using hydrogen fluoride (HF), the absolute ethyl alcohol and deionized water according to a proportion, placing the deoxidizing liquid in a water bath with a constant temperature from 25 DEG C to 60 DEG C, fetching out a proper amount of silicon powder to be processed, then placing the silicon powder into the deoxidizing liquid, ceaselessly stirring for 15-60 minutes, using deionized water to wash and filter the silicon powder for 3-8 times through a vacuum filter, drying the silicon powder at a temperature of 25-70 DEG C in a vacuum, and immediately sealing the silicon powder for preservation in the vacuum. The silicon powder surface deoxidizing method has the advantages of being high in deoxidizing efficiency, and simultaneously the deoxidizing liquid contains no hazardous substance such as sulfuric acid, causes no damage on a silicon substrate, and furthermore the powder after being processed is good in uniformity and dispersibility, simple in technology and easy to control.

Description

[0001] Technical field [0002] The present invention belongs to the field of powder surface treatment technology, involving the removal of silicon powder surface oxygen. Background technique [0003] As an indispensable basic raw material, silicon powder is widely used in powder metallurgical manufacturing, such as sintering preparation of difficult melting alloys, ceramics, composite materials, etc.However, due to higher surface activity, silicon powder is easily oxidized, and SIO is formed on the surface of silicon particles 2 , SIO and other oxide films.The oxide of silicon is relatively stable, and it is difficult to be restored even in the high temperature sintering process, which affects the quality of sintering materials.In addition, the surface of the surface will reduce the liquidity of the silicon powder, which is easy to cause the density of the material to decrease, and adversely affects the comprehensive mechanical properties of the material. [0004] At present, si...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/037
Inventor 张来启潘昆明王珏林均品梁永锋
Owner UNIV OF SCI & TECH BEIJING
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