CN105586004A

CN105586004A - Preparation method of aluminum-modified silica sol

Info

Publication number: CN105586004A
Application number: CN201511028790.5A
Authority: CN
Inventors: 施荣华; 朱小华; 李家荣; 陈雪琴
Original assignee: Jiangsu Tianheng Nano Science And Technology Co Ltd
Current assignee: Jiangsu Tianheng Nano Science And Technology Co Ltd
Priority date: 2015-12-31
Filing date: 2015-12-31
Publication date: 2016-05-18

Abstract

The invention provides a preparation method of aluminum-modified silica sol. In the silica sol preparation process, an aluminum element containing alkaline solution is added, and pH of a silica sol reaction solution is maintained in the range from 9.0 to 10.0. With the adoption of the technical scheme, compared with silica sol and aluminum-modified silica sol in the prior art, the aluminum-modified silica sol has the advantages that the polishing speed is increased, the quality of the polished surface meets the customer demands, and the aluminum-modified silica sol has good application prospect.

Description

A kind of preparation method of Ludox of aluminium modification

Technical field

The present invention relates to a kind of preparation method of grinding medium for chemico-mechanical polishing, specifically, relate to a kind of preparation method of Ludox of aluminium modification.

Background technology

Ludox polishing fluid is mainly the polishing of the sapphire cover plates such as the Sapphire Substrate used for large scale integrated circuit, LED and mobile phone, wrist-watch, and its market scale is huge, also very large to the demand of Ludox polishing fluid. But the Ludox that prior art is produced has the problems such as polishing speed is low, polished surface quality is unstable, cannot meet the requirement in market completely. By the analysis of causes, be mainly because abrasive hardness is large, easily reunite, cause polishing damage; And the chemical inertness of abrasive material is strong, when sapphire, silicon chip etc. are carried out to polishing, the surface quality after polishing time length and polishing is poor.

At present, both at home and abroad for these problems, start Ludox to carry out study on the modification, to improve the decentralization of Ludox, thereby improve the surface quality after its polishing speed and polishing. The research of al-modified silica sol is mainly to utilize aluminium salt as the form that aluminum nitrate, alchlor, aluminum sulfate etc. exist with Al3+, and Ludox is carried out to modification. This kind of aluminum salt modified Ludox poor stability, easily departs from adsorption layer, cannot preserve for a long time.

And Chinese patent [CN20140673957] provides a kind of scheme of al-modified silica sol, be get NaOH stir under the heating for dissolving that is added to the water, continue to be warming up to 90-100 DEG C, add again the mixture of Si powder and Al powder, react and be chilled to room temperature after 5-8 hour, filter, obtain milky colloidal sol. This scheme, the physical parameters such as the particle diameter of uncontrollable last colloidal sol, and Si powder and Al powder are active strong, wayward, are not suitable for suitability for industrialized production completely.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art part, a kind of preparation method of Ludox of aluminium modification is provided.

The preparation method of the Ludox of aluminium modification of the present invention adds the aqueous slkali containing aluminium element in Ludox preparation process, with the pH that maintains Ludox reactant liquor at 9.0-10.0.

The compound method of the described aqueous slkali containing aluminium element is as follows: sodium metaaluminate, tetrahydroxy are closed to one or more in sodium aluminate, aluminium oxide, be scattered in organic base, inorganic base or both mixed bases.

Described contains in the aqueous slkali of aluminium element, and the molar fraction that contains the compound of aluminium element is 0.1-1%, and the mass fraction of alkali is 5-10%.

Described dispersing mode comprises one or more in dispersed with stirring, ultrasonic dispersion.

Described inorganic base is selected from one or more in NaOH, potassium hydroxide, ammoniacal liquor, sodium carbonate, sodium acid carbonate.

Described organic base is selected from one or more in TMAH, tetraethyl ammonium hydroxide, triethanolamine, monoethanolamine.

The preparation method of the Ludox of aluminium modification of the present invention, comprises the following steps:

1) the alkaline silicon dioxide colloidal sol using even, the big or small 30-40nm of particle diameter, proportion as 1.05-1.15 is as crystal seed, and 10-15 times of deionized water diluted, and regulating pH value by the potassium hydroxide solution of mass fraction 5-6% is 11.0-12.5;

2) by step 1) gained mixed liquor heats, and heating and temperature control is at 100-200 DEG C, and in heating process, continuing to add proportion is the silicic acid that 1.02-1.04, pH value are 2.0-3.0, to maintain liquid level constant;

3) preparation is containing the aqueous slkali of aluminium element; By step 2) mixed liquor carry out continuous heating, the heat time is 40-60h, in course of reaction, add the aqueous slkali containing aluminium element, with the pH that maintains reactant liquor between 9.0-10.0, when silicon dioxide gel proportion reaches 1.250-1.300, stop heating, reaction finishes.

Described mode of heating comprises steam heating, electrical heating or oil bath heating.

Proportion in the present invention is relative density, with respect to the density of water.

Owing to having adopted above technical scheme, polishing speed promotes to some extent compared with the Ludox of the present invention and Ludox in prior art and the modification of prior art aluminium, and surface quality after polishing meets customer demand, therefore has very much application prospect.

Detailed description of the invention

Embodiment 1

In the present embodiment, the preparation method of the Ludox of aluminium modification comprises the steps:

1) even with particle diameter, 30-40nm size, the alkaline silicon dioxide colloidal sol that proportion is 1.15 is as crystal seed, and 15 times of deionized waters are diluted, and regulating pH value by mass fraction 6% potassium hydroxide solution is 12.5;

2) by step 1) gained mixed liquor heats, and temperature is controlled at 105 DEG C, continues to add the silicic acid that proportion is 1.04, pH value is 3.0, to maintain liquid level constant in heating process;

3) preparation is containing the aqueous slkali of aluminium element: by meta-aluminic acid by dispersed with stirring to the mixed solution of NaOH and triethanolamine; What be made into contains in the aqueous slkali of aluminium element, and sodium metaaluminate molar fraction is that 1%, NaOH and triethanolamine mass fraction are 10%;

By step 2) mixed liquor carry out continuous heating, the heat time is 60h, in course of reaction, the aqueous slkali that added 100ml to contain aluminium element every 3 hours, with the pH that maintains reactant liquor between 9.0-10.0. Make silicon dioxide gel proportion reach at 1.300 o'clock, stop heating, reaction finishes. Finally obtaining Ludox pH is 9.8, and particle diameter is 120nm.

Embodiment 2

1) even with particle diameter, 30-40nm size, the alkaline silicon dioxide colloidal sol that proportion is 1.05 is as crystal seed, and 10 times of deionized waters are diluted, and regulating pH value by mass fraction 5% potassium hydroxide solution is 12.5;

2) by step 1) gained mixed liquor heats, and temperature is controlled at 100 DEG C, and in heating process, continuing to add proportion is that 1.02, pH value is 2.0 silicic acid, to maintain liquid level constant;

3) preparation is containing the aqueous slkali of aluminium element: by meta-aluminic acid, by dispersed with stirring to tetramethyl ammonium hydroxide solution; What be made into contains in the aqueous slkali of aluminium element, and the molar fraction of sodium metaaluminate is 0.1%, and the mass fraction of TMAH is 5%;

Mixed liquor in step (2) is carried out to continuous heating, and the heat time is 40h, and in course of reaction, the aqueous slkali that added 150ml to contain aluminium element every 3 hours, with the pH that maintains reactant liquor between 9.0-10.0. Make silicon dioxide gel proportion reach at 1.250 o'clock, stop heating, reaction finishes. Finally obtaining Ludox pH is 9.0, and particle diameter is 80nm.

Embodiment 3

1) even with particle diameter, 30-40nm, the alkaline silicon dioxide colloidal sol that proportion is 1.07 is as crystal seed, and 12 times of deionized waters are diluted, and regulating pH value by mass fraction 5.5% potassium hydroxide solution is 12.5;

2) by step 1) gained mixed liquor heats, and temperature is controlled at 102 DEG C, and in heating process, continuing to add proportion is that 1.025, pH value is 2.5 silicic acid, to maintain liquid level constant;

3) preparation is containing the aqueous slkali of aluminium element: by meta-aluminic acid, by dispersed with stirring to NaOH solution; What be made into contains in the aqueous slkali of aluminium element, and the mass fraction that the molar fraction of sodium metaaluminate is 0.2%, NaOH is 6%;

Mixed liquor in step (2) is carried out to continuous heating, and the heat time is 48h, and in course of reaction, the aqueous slkali that added 120ml to contain aluminium element every 3 hours, with the pH that maintains reactant liquor between 9.0-10.0. Make silicon dioxide gel proportion reach at 1.285 o'clock, stop heating, reaction finishes. Finally obtaining Ludox pH is 9.5, particle diameter 108nm.

Comparative example 1

In this comparative example, the preparation method of Ludox comprises the steps:

Get 3.0gNaOH, under stirring, join heating for dissolving in 550mlH2O, continue to be warming up to 90-100 DEG C, add again the mixture of 28.0gSi powder and 0.10gAl powder, react after 5-8 hour, be chilled to room temperature, filter and obtain 120g milky colloidal sol by reduced pressure concentration, this aluminium modification sol SiO2 content is that 50.0%, pH value is 10.65, and aluminium content is 833ppm.

Comparative example 2

Even with particle diameter, big or small 35nm, the alkaline silicon dioxide colloidal sol that proportion is 1.07 is as crystal seed, and 12 times of deionized waters are diluted, and regulating pH value by mass fraction 5.5% potassium hydroxide solution is 12.5; Gained mixed liquor heats, and temperature is controlled at 102 DEG C, and in heating process, continuing to add proportion is that 1.025, pH value is 2.5 silicic acid, to maintain liquid level constant;

In the NaOH solution that is 6% by mass fraction, in course of reaction, added the NaOH solution of 120ml every 3 hours, with the pH that maintains reactant liquor between 9.0-10.0. The mixed liquor continuous heating time is 48h, makes silicon dioxide gel proportion reach at 1.285 o'clock, stops heating, and reaction finishes. Finally obtaining Ludox pH is 9.6, particle diameter 112nm.

Table one: under identical condition, the Ludox in embodiment is carried out respectively to polishing experiments, polishing speed is as following table.

As can be seen from the above table, the polishing speed of the al-modified silica sol that embodiment 1-3 prepares, faster 23.7% than the polishing speed of the Ludox of prior art aluminium modification, than the normal Ludox polishing speed fast 30.3% that there is no aluminium modification.

Above-described embodiment, is more typical embodiment of the present invention, is not used for limiting the scope of the present invention, changes or modifies with the equivalence of doing described in the claims in the present invention therefore all, includes within the claims in the present invention scope.

Claims

1. a preparation method for the Ludox of aluminium modification, is characterized in that, adds the aqueous slkali containing aluminium element in Ludox preparation process, with the pH that maintains Ludox reactant liquor at 9.0-10.0.

2. the preparation method of the Ludox of aluminium modification according to claim 1, it is characterized in that, the compound method of the described aqueous slkali containing aluminium element is as follows: sodium metaaluminate, tetrahydroxy are closed to one or more in sodium aluminate, aluminium oxide, be scattered in organic base, inorganic base or both mixed bases.

3. the preparation method of the Ludox of aluminium modification according to claim 1, is characterized in that, described contains in the aqueous slkali of aluminium element, and the molar fraction that contains the compound of aluminium element is 0.1-1%, and the mass fraction of alkali is 5-10%.

4. the preparation method of the Ludox of aluminium modification according to claim 2, is characterized in that, described dispersing mode comprises one or more in dispersed with stirring, ultrasonic dispersion.

5. the preparation method of the Ludox of aluminium modification according to claim 2, is characterized in that, described inorganic base is selected from one or more in NaOH, potassium hydroxide, ammoniacal liquor, sodium carbonate, sodium acid carbonate.

6. the preparation method of the Ludox of aluminium modification according to claim 2, is characterized in that, described organic base is selected from one or more in TMAH, tetraethyl ammonium hydroxide, triethanolamine, monoethanolamine.

7. the preparation method of the Ludox of aluminium modification according to claim 1, is characterized in that, described preparation process comprises the following steps:

2) step 1) gained mixed liquor is heated, heating and temperature control is at 100-200 DEG C, and in heating process, continuing to add proportion is the silicic acid that 1.02-1.04, pH value are 2.0-3.0, to maintain liquid level constant;

8. the preparation method of the Ludox of aluminium modification according to claim 7, is characterized in that, described mode of heating comprises steam heating, electrical heating or oil bath heating.