Method of preparing hydrated calcium silicate nano-film

Abstract

A method of preparing a hydrated calcium silicate (C—S—H) nano-film. The method includes: 1) synthesizing a hydrated calcium silicate powder having a calcium to silicon ratio (Ca/Si) of 0.5-3.0; 2) calcining the C—S—H powder obtained in 1) for 2-3 hours under a temperature of 150-250° C., cooling to approximately 25° C., and pressing the C—S—H powder under a pressure of 100-200 megapascal, to yield a target material; 3) fixing a substrate on a sample table of a magnetron sputtering apparatus, placing the target material obtained in 2) in a target position of the magnetron sputtering apparatus, pre-sputtering the target material for 5-10 minutes, rotating the substrate at a constant speed, sputtering the target material for 30-300 minutes, to yield a nano-film; and 4) soaking the nano-film obtained in 3) into in a saturated aqueous solution of calcium hydroxide at approximately 25° C. for 1-3 days.

Claims

1. A method, comprising: 1) synthesizing a hydrated calcium silicate (C—S—H) powder having a calcium to silicon ratio (Ca/Si) of 0.5-3.0; 2) calcining the C—S—H powder obtained in 1) for 2-3 hours under a temperature of 150-250° C., cooling to approximately 25° C., and pressing the C—S—H powder under a pressure of 100-200 megapascal, to yield a target material having a diameter of between 50 and 60 mm and a thickness of between 4 and 6 mm; 3) fixing a substrate on a sample table of a magnetron sputtering apparatus, placing the target material obtained in 2) in a target position of the magnetron sputtering apparatus, maintaining a distance between the substrate and the target material to 2-10 cm; evacuating a sputtering chamber of the magnetron sputtering apparatus to a pressure of not more than 10.sup.−3 pascal, injecting argon or helium into the sputtering chamber, wherein a flow rate of the argon or helium is controlled to be 10-100 sccm to keep the pressure in the sputtering chamber at 0.5-2.5 pascal; setting a magnetron sputtering power to 50-200 W, pre-sputtering the target material for 5-10 minutes, turning on a rotation system of the sample table and rotating the substrate at a constant speed, sputtering the target material for 30-300 minutes, to yield a nano-film; and 4) soaking the nano-film obtained in 3) in a saturated aqueous solution of calcium hydroxide at approximately 25° C. for 1-3 days, to yield a hydrated calcium silicate nano-film.

2. The method of claim 1, wherein the C—S—H powder in 1) has a formula of (CaO)x.Math.SiO.sub.2.Math.H.sub.2O, in which x ranges from 0.5 to 3.0.

3. The method of claim 1, wherein in 2), the C—S—H powder is calcined under a temperature of 200° C. for 2.5 hours.

4. The method of claim 1, wherein in 2), the C—S—H powder is pressed under a pressure of 150 megapascal to yield the target material; in 3), the substrate comprises glass, silicon, metal or metal oxide; the distance between the substrate and the target material is 5 cm; the flow rate of the argon or helium is 50 sccm; the pressure of the sputtering chamber is 1.5 pascal; the magnetron sputtering power is 150 W; a pre-sputtering time of the target material is 8 minutes; and a sputtering time of the target material is 150 minutes.

5. The method of claim 1, wherein in 4), the nano-film prepared in 3) is immersed in the saturated aqueous solution of calcium hydroxide at 25° C. for 2 days.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a SEM image of cross-section of a C—S—H nano-film in Example 1 (the thickness of the nano-film is not marked) of the disclosure;

(2) FIG. 2 is a SEM image of cross-section of a C—S—H nano-film in Example 1 (the thickness of the nano-film is marked) of the disclosure;

(3) FIG. 3 is a SEM image of cross-section of a C—S—H nano-film in Example 2 (the thickness of the nano-film is not marked) of the disclosure;

(4) FIG. 4 is a SEM image of cross-section of a C—S—H nano-film in Example 2 (the thickness of the nano-film is marked) of the disclosure; and

(5) FIG. 5 is a flow diagram showing a method of preparing a C—S—H nano-film by means of magnetron sputtering as taught in the disclosure.

DETAILED DESCRIPTION

(6) To further illustrate, embodiments detailing a method of preparing a hydrated calcium silicate (C—S—H) nano-film are described below. It should be noted that the following embodiments are intended to describe and not to limit the disclosure.

(7) A method of preparing a C—S—H nano-film comprises the following steps: 1) synthesizing a hydrated calcium silicate (C—S—H) powder having a calcium to silicon ratio (Ca/Si) of 0.5-3.0; 2) calcining the C—S—H powder obtained in 1) for 2-3 hours under a temperature of 150-250° C., cooling to approximately 25° C., and pressing the C—S—H powder under a pressure of 100-200 megapascal, to yield a target material having a diameter of between 50 and 60 mm and a thickness of between 4 and 6 mm; 3) fixing a substrate on a sample table of a magnetron sputtering apparatus, placing the target material obtained in 2) in a target position of the magnetron sputtering apparatus, maintaining a relative distance between the substrate and the target material to 2-10 cm; evacuating a sputtering chamber of the magnetron sputtering apparatus to a pressure of not more than 10.sup.−3 pascal, injecting argon or helium to the sputtering chamber, wherein a flow rate of the argon or helium is controlled to be 10-100 sccm to keep the pressure in the sputtering chamber at 0.5-2.5 pascal; setting a magnetron sputtering power to 50-200 W, pre-sputtering the target material for 5-10 minutes, turning on a rotation system of the sample table and rotating the substrate at a constant speed, sputtering the target material for 30-300 minutes, to yield a nano-film; 4) soaking the nano-film obtained in 3) into in a saturated aqueous solution of calcium hydroxide at approximately 25° C. for 1-3 days, to yield a hydrated calcium silicate nano-film.

(8) The preparation method described in certain embodiments of the disclosure can adjust the size of the C—S—H nano-film by adjusting the sputtering power, sputtering time, substrate size and distance between the substrate and the target material. During the magnetron sputtering process, no impurity is introduced, and the deposition rate of C—S—H on the substrate is stable, the nano-films prepared are homogeneous and pure, which makes it can be conveniently used for subsequent experiments, including the observation of morphology and the measurement of various mechanical properties.

(9) In one embodiment, the C—S—H powder in 1) has a formula of (CaO)x.SiO.sub.2.H.sub.2O, in which x ranges from 0.5 to 3.0.

(10) In one embodiment, in 2), the C—S—H powder is calcined under a temperature of 200° C. for 2.5 hours.

(11) In one embodiment, in 2), the C—S—H powder is pressed under a pressure of 150 megapascal to yield the target material; in 3), the substrate comprises glass, silicon, metal or metal oxide; the relative distance between the substrate and the target material is 5 cm; the flow rate of the argon or helium is 50 sccm; the pressure of the sputtering chamber is 1.5 pascal; the magnetron sputtering power is 150 W; a pre-sputtering time of the target material is 8 minutes; and a sputtering time of the target material is 150 minutes.

(12) In one embodiment, in 4), the nano-film prepared in 3) is immersed in the saturated aqueous solution of calcium hydroxide at 25° C. for 2 days.

EXAMPLE 1

(13) The method of preparing a C—S—H nano-film by means of magnetron sputtering is carried out according to the following steps.

(14) 1. Synthesize the C—S—H powder with calcium to silicon ratio of 0.5.

(15) 2. The synthetic C—S—H powder is calcined for 2.0 hours under the condition of 150° C., then cool the powder to room temperature (25° C.).

(16) 3. The powder obtained in the last step is pressed into target under the condition of 100 megapascal.

(17) 4. Adjust the distance between the substrate and the target to 2 cm.

(18) 5. Evacuate the chamber and keep the pressure within the chamber under 5.0×10.sup.−4 Pa

(19) 6. The flow rate of argon is set to 10 sccm, and the pressure within the chamber is ensured around 0.5 pascal.

(20) 7. The magnetron sputtering power is set to 55 W, and start pre-sputtering, pre-sputtering time is 5 minutes.

(21) 8. Start depositing C—S—H film on the substrate, the duration of the process is 120 minutes. During the process, the substrate maintains a uniform rotation.

(22) 9. Soak the C—S—H nano-film into distilled water at room temperature for 1 days.

EXAMPLE 2

(23) The method of preparing a C—S—H nano-film by means of magnetron sputtering is carried out according to the following steps.

(24) 1. Synthesize the C—S—H powder with calcium to silicon ratio of 1.5.

(25) 2. The synthetic C—S—H powder is calcined for 3 hours under the condition of 175° C., then cool the powder to room temperature (25° C.).

(26) 3. The powder obtained in the last step is pressed into target under the condition of 200 megapascal.

(27) 4. Adjust the distance between the substrate and the target to 4 cm.

(28) 5. Evacuate the chamber, and keep the pressure within the chamber under 5.0×10.sup.−4 Pa.

(29) 6. The flow rate of argon is set to 20 sccm, and the pressure within the chamber is ensured around 1.5 pascal.

(30) 7. The magnetron sputtering power is set to 100 W, and start pre-sputtering, pre-sputtering time is 5 minutes.

(31) 8. Start depositing C—S—H film on the substrate, the duration of the process is 30 minutes. During the process, the substrate maintains a uniform rotation.

(32) 9. Soak the C—S—H nano-film into distilled water at room temperature for 2 days.

EXAMPLE 3

(33) The method of preparing a C—S—H nano-film by means of magnetron sputtering is carried out according to the following steps.

(34) 1. Synthesize the C—S—H powder with calcium to silicon ratio of 2.0.

(35) 2. The synthetic C—S—H powder is calcined for 2.0 hours under the condition of 200° C., then cool the powder to room temperature (25° C.).

(36) 3. The powder obtained in the last step is pressed into target under the condition of 150 megapascal.

(37) 4. Adjust the distance between the substrate and the target to 5 cm.

(38) 5. Evacuate the chamber, and keep the pressure within the chamber under 1.0×10.sup.−4 Pa.

(39) 6. The flow rate of argon is set to 50 sccm, and the pressure within the chamber is ensured around 1.5 pascal.

(40) 7. The magnetron sputtering power is set to 150 W, and start pre-sputtering, pre-sputtering time is 8 minutes.

(41) 8. Start depositing C—S—H film on the substrate, the duration of the process is 150 minutes. During the process, the substrate maintains a uniform rotation.

(42) 9. Soak the C—S—H nano-film into distilled water at room temperature for 2 days.

EXAMPLE 4

(43) The method of preparing a C—S—H nano-film by means of magnetron sputtering is carried out according to the following steps.

(44) 1. Synthesize the C—S—H powder with calcium to silicon ratio of 2.0.

(45) 2. The synthetic C—S—H powder is calcined for 2.0 hours under the condition of 150° C., then cool the powder to room temperature (25° C.).

(46) 3. The powder obtained in the last step is pressed into target under the condition of 175 megapascal.

(47) 4. Adjust the distance between the substrate and the target to 8 cm.

(48) 5. Evacuate the chamber, and keep the pressure within the chamber under 1.0×10.sup.−4 Pa.

(49) 6. The flow rate of argon is set to 10 sccm, and the pressure within the chamber is ensured around 2.5 pascal.

(50) 7. The magnetron sputtering power is set to 200 W, and start pre-sputtering, pre-sputtering time is 8 minutes.

(51) 8. Start depositing C—S—H film on the substrate, the duration of the process is 300 minutes. During the process, the substrate maintains a uniform rotation.

(52) 9. Soak the C—S—H nano-film into distilled water at room temperature for 3 days.

EXAMPLE 5

(53) The method of preparing a C—S—H nano-film by means of magnetron sputtering is carried out according to the following steps.

(54) 1. Synthesize the C—S—H powder with calcium to silicon ratio of 3.0.

(55) 2. The synthetic C—S—H powder is calcined for 2.0 hours under the condition of 250° C., then cool the powder to room temperature (25° C.).

(56) 3. The powder obtained in the last step is pressed into target under the condition of 200 megapascal.

(57) 4. Adjust the distance between the substrate and the target to 10 cm.

(58) 5. Evacuate the chamber, and keep the pressure within the chamber under 1.0×10.sup.−4 Pa.

(59) 6. The flow rate of argon is set to 10 sccm, and the pressure within the chamber is ensured around 2.5 pascal.

(60) 7. The magnetron sputtering power is set to 250 W, and start pre-sputtering, pre-sputtering time is 10 minutes.

(61) 8. Start depositing C—S—H film on the substrate, the duration of the process is 300 minutes. During the process, the substrate maintains a uniform rotation.

(62) 9. Soak the C—S—H nano-film into distilled water at room temperature for 3 days.

(63) It will be obvious to those skilled in the art that changes and modifications may be made, and therefore, the aim in the appended claims is to cover all such changes and modifications.