A kind of selective coating for absorbing solar light and heat
[technical field]
The utility model belongs to the solar facilities field, relates in particular to a kind of use on the flat type solar heat collector surface, is used to absorb the coating for selective absorption of solar energy.
[background technology]
Solar water heater is exactly the radiant heat energy that absorbs the sun.It is a maturation and product of the future the most the most in China's solar thermal utilization.The New-type water heater product of environmental protection, safe, energy-conservation, health is provided for the common people.Modal solar water heater has three kinds: passive solarenergy water heater, flat solar water heater and solar vacuum-tube water heater.The heat collector and the water tank of stagnation type solar water heater are integrated.Simple in structure, cheap.But it is poor to be incubated, the use of can not spending the night, and more can not use winter.The flat solar water heater is made up of flat plate collector, water storage box, circulation pipe, support.Structural shape such as it is flat box type that absorber has that board-like, the full copper pipe of copper aluminum composite pipes is board-like, the stainless steel punch forming is welded.And solar thermal collector, critical component wherein is exactly a plate core of solar heat-collecting, adopts the compound board-like material of copper aluminium to make now mostly.Coating for selective absorption of sunlight spectrum is applied to solar thermal collector thermal-arrest surface, mainly constitute by infrared high reflection layer, absorbed layer and antireflection layer, wherein the effect of antireflection layer is to reduce body surface to reflection of incident light, and the increment surface increases absorption efficiency to the absorption of light; Infrared high reflection layer reduces heat collector inside to external radiation, reduces heat loss; Absorbed layer is used to absorb sunshine, provides thermal source to heat collector.In the photo-thermal conversion of solar energy, the refractive index of the medium in the absorbed layer of coating for selective absorption is low as far as possible, the refractive index of antireflection layer is also low as far as possible, could obtain photo-thermal conversion efficiency higher solar energy coating for selective absorption like this, but the sedimentation rate that also will pay attention to medium simultaneously can not be low excessively, in order to avoid influence production efficiency.And in the preparation process of coating, adopt reactive magnetron sputtering or radio frequency reaction and medium frequency reactive sputtering method, and utilize metal or nonmetal target, because target is poisoned, cause the sedimentation rate of antireflection layer very low, production efficiency is reduced greatly.Because the production efficiency of antireflection layer is low, the most solar thermal collectors on market do not adopt the sunshine coating for selective absorption that is provided with antireflection layer at present.Studied with extensive use coating for selective absorption at present for the solar selectively absorbing coating that uses in the vacuum environment low temperature range, the advantage of this film system and process is, the work of the single target magnetically controlled DC sputtering of A1 plated film, equipment is simple to operate, the rete absorptivity is higher, to using the more suitable of all-glass vacuum tube in low temperature range, but uses because its infrared emittance rises with temperature obviously raises for middle temperature and high temperature, cause the heat collector heat waste to increase, the thermal efficiency obviously descends.In order to improve the heat endurance of high temperature scope of application coating for selective absorption, reduce infrared emittance, research and development high-temperature stable metal double target co-sputtering deposition technology, this coating have stratified film structure, make in high temperature range hot property stable, absorption/emission is smaller.But; The key of this coating and process is to adopt high-temperature stable metal such as W, MO, SS, and must adopt the bipolar electrode target co-sputtering; Cause sedimentation rate low, production cycle length, complex process, target rare expensive, cost is high.So need a kind of absorptivity very high now, emissivity is very low, and good coating for selective absorption of heat endurance and technology of preparing.But there is not to occur to overcome the technical solution of above shortcoming so far in the industry.
[utility model content]
The purpose of this utility model provides a kind ofly has good solar selectively absorption characteristic, and the firm selective absorption film of rete, and this rete has higher binding strength and good weatherability, is to have higher production efficiency in production simultaneously.
In order to reach above-mentioned technical purpose, the technical solution that the utility model adopts comprises following technology contents: a kind of selective coating for absorbing solar light and heat, this coating is by multiple layer metal and nonmetal being composited, above-mentioned selective solar is characterized in that attached on the metal plate: the order that described coating is adhered on metal plate is followed successively by bottom-aluminium nitride composite bed-aluminium nitride composite bed-alundum (Al (second layer aluminium and N in this
2After reacting gas, whether generate new aluminium nitride compound substance)
Described bottom is a kind of in stainless steel, molybdenum or the nickel.
The thickness of described bottom-aluminium nitride composite bed-aluminium nitride composite bed-alundum (Al is 80nm-120nm.
The thickness of described bottom-aluminium nitride composite bed-each layer of aluminium nitride composite bed-alundum (Al is bottom 15nm-25nm; Aluminium nitride composite bed 25nm-35nm; Aluminium nitride composite bed 25nm-35nm; Alundum (Al 15nm-25nm.
The optimum thickness of described bottom-aluminium nitride composite bed-each layer of aluminium nitride composite bed-alundum (Al is bottom 20nm; Aluminium nitride composite bed 30nm; Aluminium nitride composite bed 30nm; Alundum (Al 20nm.
Described aluminium nitride composite bed coating need add nitrogen when answering sputter sending out in vacuum chamber, the addition of nitrogen is the 20sccm-40sccm handkerchief.
Described stainless steel is for using the SUS304 stainless steel.
By adopting above-mentioned technical solution, the utility model has obtained following technological merit and effect: the utility model is by adopting stainless steel-aluminium nitride composite bed--and the composite film of aluminium nitride composite bed-alundum (Al is as the coating for selective absorption of flat type solar heat collector, this composite film has extraordinary solar selectively energy, wherein metal back layer adopts stainless steel, molybdenum or nickel as metal back layer respectively, above-mentioned several metal can have very strong in conjunction with fastness on copper or aluminium sheet, thereby strengthens the fixedly fastness of whole absorbing membranous layer; Above-mentioned in addition stainless steel, molybdenum or nickel all have extraordinary properties of infrared reflection, thermal emissivity that can very effective reduction rete, with aluminium nitride as absorbed layer, and the nitrogen and the oxygen reaction that in magnetron sputtering and in the vacuum chamber, charge into, form the reactive sputtering film, reactive sputtering goes out the gradual change absorbing membranous layer of different metal volume ratio, by suitable adjustment thicknesses of layers and metal volume fraction are set, form interference of light absorbing membranous layer, strengthened the absorption of rete greatly, thereby strengthened the absorptivity of above-mentioned rete greatly visible light; The superiors at above-mentioned rete pass through reactive sputtering alundum (Al rete or silica coating in addition; can utilize the stable performance of alundum (Al or silica; rete under it is played the effect of antireflective and sealing; the protection absorbed layer can not be subjected to the moisture content in the atmosphere, the corrosion that salt grades; increased substantially the weatherability of rete; significant prolongation the service life of above-mentioned rete; has the microcosmic surface porous because of this rete simultaneously; can prevent visible reflection of light, therefore also have antireflecting function.
[description of drawings]
Fig. 1 is a film layer structure schematic diagram of the present utility model.
[specific embodiment]
Below the utility model is described in detail:
The utility model is the improvement of making at the coating process of the heat collection chip material that uses in the existing flat type solar heat collector, heat collecting sheet commonly used now is generally sheet copper or aluminium sheet, so the solar selectively absorbing coating in the utility model is exactly with above-mentioned two kinds of technological improvements that material base material commonly used is made.This coating is by multiple layer metal and nonmetal being composited, and above-mentioned selective solar coating is attached on the metal plate, and this metallic plate just sheet copper or aluminium sheet.As shown in Figure 1, the order that described coating is adhered on metal plate 5 is followed successively by metal back layer 4-aluminium nitride composite bed 3-aluminium nitride composite bed 2-alundum (Al 1, according to different metallic characters, the metal back layer 4 in the utility model is a kind of in stainless steel, molybdenum or the nickel.The composite film that uses this different materials to make, solar selectively absorbing coating just, mainly be above-mentioned several metals and aluminium and copper by behind the reactive sputtering, can stablize and firm attached on aluminium or the copper base material, set up a firm basis of adhering to for whole composite film like this.These several metal materials also have stronger properties of infrared reflection in addition, can reduce the thermal emissivity of composite film, improve the hot property of solar panels core, promptly, the energy of the visible light of absorption is stayed as much as possible to the high-absorbility of visible light with to the height reflection of infra-red radiation.Metal back layer 4 described in the utility model, the thickness of the material of metal back layer (comprise stainless steel, molybdenum, nickel any one)-aluminium nitride composite bed 3-aluminium nitride composite bed 2-alundum (Al 1 is 80nm-120nm.This above-mentioned thickness is a more rational thicknesses of layers of screening.The thickness of every tunic layer that above-mentioned rete is produced when carrying out reactive sputtering is respectively that metal back layer 4 is 15nm-25nm; Aluminium nitride composite bed 3 absorbed layers are 25nm-35nm; Aluminium nitride composite bed 2 is 25nm-35nm; Alundum (Al 1 is 15nm-25nm.This above-mentioned thickness range can be adjusted according to the technical indicators such as purposes of concrete instructions for use and solar facilities.But Zui Jia film layer structure metal back layer 20nm in the ordinary course of things; Aluminium-nitrogen-aluminium has 60nm altogether; Alundum (Al 20nm.
The process of above-mentioned rete is that at first with metal base 5, just sheet copper or aluminium sheet carry out surface preparation, put it into then in the pretreatment chamber 10
-2Under the vacuum condition of Pa, feed Ar gas 60sccm, regulate vacuum, open cathodic power source at 0.6pa through mass flowmenter, cathodic power source 480v, electric current 4.5A, the ion etching before being coated with, the processing time is 10-25 minute.With Ar ion gun bombarding base material 5 surfaces, current density 0.8A/cm
2Make the solid impurity of above-mentioned sheet copper or surface of aluminum plate obtain good cleaning, carry out that ion etching is general only need be carried out a surface and get final product, also on a surface, carry out at least because be coated with solar selectively absorbing coating.Carrying out ion etching, can to make base material 5 be that the surface of sheet copper or aluminium sheet is cleared up completely, improves the adhesive force when being coated with rete, improves rete service life.
After carrying out base material 5 surface preparations, can begin the process that is coated with of rete, this process realizes by the vacuum magnetic control reactive sputtering.Above-mentioned treated sheet copper or aluminium sheet are put into the vacuum sputtering chamber, under the vacuum condition of 0.5Pa, be coated with metal back layer 4 by magnetron sputtering, adopt stainless steel target or nickel target or molybdenum target to carry out, feed nitrogen 42sccm, the maintenance operating air pressure is 0.5pa, electric current 5A, the magnetron sputtering time is 5 minutes.Reach 20nm at thickness and can enter being coated with of next rete.
The base material that this has been coated with metal back layer is put into vacuum chamber equally, is coated with absorbed layer by reactive sputtering, adopts the aluminium target to carry out magnetron sputtering, aerating oxygen 30sccm during sputter, nitrogen 20sccm, the maintenance operating air pressure is 0.5pa, electric current 5A, the magnetron sputtering time is 7 minutes.Reach 30nm at thickness and can enter being coated with of next rete.In the sputter absorbed layer, can also feed the gas that other can feed.Being coated with different films when being, feed different gas, according to the sequencing in the film system.
The base material that this has been coated with metal back layer is put into vacuum chamber equally, is coated with absorbed layer by reactive sputtering, adopts the aluminium target to carry out magnetron sputtering, aerating oxygen 25sccm during sputter, nitrogen 15sccm, the maintenance operating air pressure is 0.5pa, electric current 5A, the magnetron sputtering time is 10 minutes.Reach 30nm at thickness and can enter being coated with of next rete.
At last this is coated with the alundum (Al 1 of metal back layer, base material 5 has been put into vacuum chamber, be coated with the ceramic layer on surface by reactive sputtering, adopt the aluminium target to carry out magnetron sputtering, aerating oxygen 45sccm during sputter, the maintenance operating air pressure is 0.5pa, electric current 5A, the magnetron sputtering time is 5 minutes.Reach 20nm at thickness and can enter being coated with of next rete.
Foregoing description can only be counted as preferred embodiment.Those those of skill in the art in the art and those manufacturings or use people of the present utility model should recognize other multiple variation pattern of the present utility model.Therefore, it being understood that the above-mentioned illustrated embodiment usefulness that only presents a demonstration, it can't be construed as limiting scope of the present utility model, scope of the present utility model according to the principle of Patent Law, comprise that the claim that the principle of equivalent is explained limits.