Study On The Manufature Of Nano-films

The pursuit of the task is to research some new techniques of the preparation of nano-films. Through consulting and analyzing a large number of literature in or out of our country, we discover that there is a prevalent problem: powder body will reunite in the process of preparation of nano material. This paper explore a set of new techniques of the preparation of nano-films by applying some work experience and accumulated knowledge. We also settle the problem of the colloid reuniting and deposition films reuniting.Through studying sol and the ultrasonic decentralization theory, we design and experiment the preparation project in the method of ultrasonic-sol (take CdS for example), and find a classic project through exploring the functions of sol concentration, the mode and time of ultrasonic, the effect of surfactant and pH one by one. The following is the classic project. First, put SDS into two tubes of reaction original solution respectively, ultrasonic irradiating for 20 minute in order to mix the solution equable. Under the ultrasonic irradiation, keep the temperature of water area at 20℃,make the Na2S act with the original Cd(NO3)2 solution, and then continue to irradiating for 120 minutes, keeping the pH between 5 and 7. The article bats around dynamics character of disperse powder body made from nano colloid through liquid posture synthesize, introduces at length the basic theory of ultrasonic cavitation effect from the process of cavitating, the value of cavitation threshold, the breakdown time of ultrasonic cavitation froth and various physics parameter affecting ultrasonic cavitation, points out that powder body reuniting is a prevalent problem in the process of preparation of colloid by ultrasonic-sol method, opens out the agglomerating-separating phenomena and affecting ingredient when colloid particle reacts under the ultrasonic, discusses dynamics stability of the nano-colloid and reckons the dynamics reason of nano colloid and its stability theoretically. We can draw an conclusion from the example of CdS: in the water, the sedimentation speed of 1nm CdS nano colloid is 1.25×10-12(m/s) , and it takes 252.2 years to descend 10mm in the water.We advance a novel method of the preparation of nano-films—electric field deposition method and successfully design the experiment device of this method. Comparing the result of the traditional electrodeposition method with current electric field deposition method, the new technology can effectively hurdle the influence of the harmful electrode reactions on the process of deposition and deposited films, and can prepare even nano-films of 25nm with low interstice ratio. The article compares the effect of electrodeposition with that of electric field deposition from electric current density, temperature, and pH value, and expounds the superiority of electric field deposition— the method is affected less in the process of electric field deposition, and can avoid many disadvantages of the former technology. Meanwhile, the author brings forth the design of the overlapping method to obtain nano-films, which is made by overlapping nano-films layers and insulation layers layer by layer. Overlapping method applies out electric field to electrodeposit, and uses the insulation layer to prevent the crystal particle between the layers from growing. Through analyzing the STM scan result of each layer, we can draw a conclusion: obtaining by electric field deposition, the height of monolayer of nano-films is 25nm,and the thickness of three deposition films layers is 80.4nm, which verifies that the overlapping method can avoid the reuniting under agglomeration because of its special technique design and technique means.