Patent Application: US-201414513271-A

Abstract:
the invention relates to a coating composition consisting of an oxide compound . the invention also relates to a method for producing a coating composition consisting of an oxide compound and to a method for coating substrates composed of metal , semiconductor , alloy , ceramic , quartz , glass or glass - type materials with coating compositions of this type . the invention further relates to the use of a coating composition according to the invention for coating metal , semiconductor , alloy , ceramic , quartz , glass and / or glass - type substrates .

Description:
the series of images in fig1 to 3 clearly shows the influence of the action of the laser depending on the duration of action , in this case given by the speed at which the laser was moved across the sample . in detail , fig1 shows an untreated al / al 2 o 3 composite structure before the laser treatment . neither a uniform surface nor a structuring of the surface can be discerned . fig2 shows an al / al 2 o 3 composite structure after brief laser treatment . this gives rise to the formation of new morphologies and structures , in this case to nanowires and fractal structures . fig3 shows an al / al 2 o 3 composite structure treated to complete conversion . only a small number of defects can be discerned and the surface appears to be uniform . fig4 shows the broad absorption of the al / al 2 o 3 composite structure ( thickness : 200 - 400 nm ). the absorption in a broad wavelength range permits the use of lasers in a broad wavelength range . fig5 and fig6 show an x - ray diffraction analysis of different al / al 2 o 3 composite structures which were treated for different periods of time on two different substrates . it is clearly possible to discern the arising and the increase of the signals of the α - al 2 o 3 crystal structure , while the signals of the metallic aluminum decrease . this shows an increasing crystallization and formation of α - al 2 o 3 . fig7 shows the selective conversion in specific regions depending on the energy . on the al / al 2 o 3 composite structure shown , strip - shaped regions were produced with the treatment intensity increasing toward the left , said regions being separated in each case by untreated strips , in accordance with the method according to the invention . it is clearly possible to discern the precise resolution and the accuracy with which the method according to the invention enables the targeted production of structures on surfaces . fig8 shows the water permeability of differently treated al / al 2 o 3 composite structures . while the untreated al / al 2 o 3 composite structure ( top , squares ) exhibits a high permeability to water and is therefore not suitable as protection against corrosion , the completely converted al / al 2 o 3 composite structure according to the invention exhibits no permeability ( bottom , triangles ). by contrast , an al 2 o 3 coating having defects ( middle , circles ) has a significantly higher permeability . this shows how important it is to precisely control the conversion conditions for the production of durable and secure protective layers . fig9 shows the measurement of the hardness of a completely converted al / al 2 o 3 composite structure with the aid of nano intendation . a hardness of 28 (+/− 2 ) gpa was measured in this case . the precursor aluminum tert - butoxydihydride ( al ( tbu ) h 2 ) was deposited onto a metallic substrate ( steel , copper , nickel or platinum ) or alternatively onto glass or ceramics in a cvd apparatus under argon at a temperature of 600 ° c . the furnace was heated inductively , wherein a conductive sample holder was used in the case of glass . the pressure in the reactor was approximately 6 . 0 × 10 − 2 mbar . the volatile decomposition products of the precursor ( including hydrogen and isobutene ) were detected by a connected mass spectrometer . for an al / al 2 o 3 composite structure having a layer thickness of approximately 1 μm , the duration of the inflow of precursor was approximately 10 minutes . larger thicknesses were able to be obtained with a longer duration ( 30 to 90 minutes ). the al / al 2 o 3 composite structure obtained is dark to black in coloration owing to its absorption . the local heating was carried out with the aid of a laser . firstly , an air - cooled co 2 laser having a wavelength of 10 . 6 μm was used , which laser was focused by means of a biconvex znse lens having a focal length of 120 mm . the exposure diameter was 10 - 12 mm and the conversion width of the laser on the substrate was approximately 20 - 25 μm . the intensity of the laser was varied between 1 w / cm 2 and 5 w / cm 2 . this laser is absorbed by the al / al 2 o 3 composite structure and the aluminum oxide layer . an argon ion laser having wavelengths in the range of visible light was furthermore used , which laser was focused with the aid of a biconvex lens having the focal length of 120 mm . the exposure diameter was 10 - 12 mm and the conversion width of the laser on the substrate was approximately 20 - 25 μm . the wavelengths of 514 nm , 488 nm , and also a wavelength range of 450 nm to 532 nm ( mixed line ) were used for the irradiation of the al / al 2 o 3 composite structure . the intensity was varied between 0 . 4 w / cm 2 and 2 w / cm 2 . this laser is absorbed only by the al / al 2 o 3 composite structure and not by the aluminum oxide layer obtained upon complete conversion . a pulsed laser was used in the case of fragile substrates , in particular in the case of some glasses and ceramics . in this case , it was possible to treat thin , and very thin layers of al / al 2 o 3 composite structure without influencing the substrate . lasers having the wavelengths of 266 nm , 355 nm , 532 nm or 1064 nm were used for this purpose . the intensity was kept low and was 200 joules for a pulse length of 4 - 8 ns . the exposure diameter was 10 - 12 mm and the conversion width of the laser on the substrate was approximately 20 - 25 μm . the treatment was carried out both with an individual pulse and with a repetition of pulses with a rate of 10 hz . a small penetration depth of the laser of just 200 - 300 nm was able to be achieved as a result . this permitted the production of very thin oxide layers (& lt ; 300 nm and even & lt ; 200 nm ) with particularly high protection against corrosion and having a hardness of 28 (+/− 2 ) gpa . pradhan et al . “ crystallinity of al 2 o 3 films deposited by metalorganic chemical vapour deposition ”, surface and coating technology , 176 ( 2004 ), 382 - 384 triantafyllids et al . “ surface treatment of alumina - based ceramics using combined laser sources ”, applied surface science , 186 ( 2002 ), 140 - 144 zheng et al . “ effect of core - shell composite particles on the sintering behaviour and properties of nano - al 2 o 3 / polystyrene composite prepared by sls ”, materials letters , 60 , ( 2006 ), 1219 - 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