Method for preparing amorphous SiOC coating by adopting chemical vapor deposition process
Technical Field
The invention belongs to the technical field of coating preparation, and particularly relates to a method for preparing an amorphous SiOC coating on the surface of a metal workpiece such as stainless steel, carbon steel, titanium alloy and the like by adopting a chemical vapor deposition process, which is mainly used for improving the wear resistance, corrosion resistance and high temperature resistance of the metal workpiece.
Background
The stainless steel, titanium alloy and other materials have strong corrosion resistance and good biocompatibility, so the material is widely applied to medical instruments. When some medical devices are applied to high-speed friction conditions, after a certain period of time, the medical devices are seriously abraded and even abrasive dust falls off, so that the medical devices can cause fatal damage to human bodies.
In the SiOC coating, the contents of silicon and oxygen elements are high, the content of carbon elements is low, and the carbon elements exist in two forms, namely, the silicon and the silicon enter a Si-O-Si network structure in a doping form, and the carbon and the silicon are combined to replace the position of an oxygen atom; alternatively, the carbon element is dispersed in the form of amorphous free carbon in the structural gap. Because of this, the presence of carbon greatly enhances the SiO2The amorphous SiOC coating has higher hardness, excellent corrosion resistance and high-temperature use performance, and meanwhile, the amorphous SiOC coating has better biocompatibility and is one of the preferable materials for improving the friction resistance of high-speed friction contact parts in medical devices, the deposition temperature of the amorphous SiOC coating is lower than the melting point of stainless steel or titanium alloy, and the amorphous SiOC coating with the thickness of more than 1 mu m can be deposited on the surface of the amorphous SiOC coating.
Disclosure of Invention
The invention aims to provide a method for preparing an amorphous SiOC coating by adopting a chemical vapor deposition process, which solves the problem that stainless steel, carbon steel and other alloys are easy to wear during high-speed rolling friction, thereby effectively improving the friction resistance of metal materials such as stainless steel and the like.
In order to achieve the purpose, the invention adopts the following technical scheme:
a method for preparing amorphous SiOC coating by chemical vapor deposition process comprises introducing gas into reaction cavityThe system is selected from organosilane-C2H5OH-H2Ar system, the organosilane being selected from one or a mixture of Hexamethyldisiloxane (HMDSO), Hexamethyldisilane (HMDS), Tetraethoxysilane (TEOS), comprising the following steps:
(1) polishing away oxide skin on the surface of a metal matrix by using abrasive paper to ensure that the surface is smooth and has no burrs, wherein the metal matrix is stainless steel, carbon steel or other alloys;
(2) ultrasonically cleaning the metal substrate with the polished surface by adopting an organic solvent or a cleaning solution for 10-20 minutes, and drying the metal substrate by using nitrogen for later use;
(3) mixing single or two types of organosilane and absolute ethyl alcohol according to a volume ratio of 0.1-5, and uniformly stirring to obtain a precursor raw material;
(4) when the amorphous SiOC coating is deposited on the metal substrate, the flow rate of a mixed liquid of organic silane and absolute ethyl alcohol is 0.1-5 g/min, the flow rate of argon gas is 100-5000 sccm, the flow rate of hydrogen is 10-1000 sccm, the deposition temperature is 1000-1200 ℃, the working pressure is 10-1000 Pa, the deposition time is 0.5-4 h, and the deposition is finished and cooled along with a furnace.
According to the method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process, hexamethyldisiloxane or tetraethoxy-archasilane is used as organic silane alone, or mixed liquid of hexamethyldisiloxane and hexamethyldisilane in a volume ratio of 1-20 is used as organic silane, or mixed liquid of tetraethoxy-disiloxane and hexamethyldisilane in a volume ratio of 1-20 is used as organic silane.
In the method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process, preferably, in the step (3), the volume ratio of the organosilane to the absolute ethyl alcohol is 1: 1, mixing, and uniformly stirring a mixed solution of organosilane and absolute ethyl alcohol before use.
In the method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process, preferably, in the step (4), the flow rate of the mixed liquid of the organosilane and the absolute ethyl alcohol is 0.8 g/min.
In the method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process, preferably, in the step (4), the flow rate of argon gas is 3000 sccm.
In the method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process, preferably, in the step (4), the hydrogen gas flow is 200 sccm.
In the method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process, preferably, in the step (4), the deposition temperature is selected to be 1100 ℃.
In the method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process, the working pressure in the step (4) is preferably 600 Pa.
The method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process preferably has the deposition time of 2h in the step (4).
According to the method for preparing the amorphous SiOC coating by adopting the chemical vapor deposition process, the thickness of the amorphous SiOC coating deposited on the surface of the metal substrate is 0.1-50 mu m, and the amorphous SiOC coating is compact and well combined with the substrate; the hardness range of the amorphous SiOC coating is 6 GPa-15 GPa, and the friction coefficient range is 0.02-0.2.
The design idea of the invention is as follows:
because stainless steel, carbon steel and other alloys have lower hardness and poorer high-speed friction resistance, the amorphous SiOC coating can improve the friction resistance of the coating. According to the invention, a layer of compact amorphous SiOC coating with the thickness of 0.11-50 μm is deposited on the surface of the SiOC coating by adopting a chemical vapor deposition process, wherein O atoms in an Si-O network structure of the amorphous SiOC coating are partially replaced by C atoms to form Si-C bonds, and the C atoms which are not bonded form free C and are distributed in the Si-O network structure to form a compact structure, so that the SiOC coating has excellent friction resistance, corrosion resistance, oxidation resistance and the like.
The invention has the advantages and beneficial effects that:
(1) the amorphous SiOC coating prepared by the invention can effectively improve the friction-resistant service performance of stainless steel, carbon steel and other alloys;
(2) the amorphous SiOC coating prepared by the method has a compact structure and is well combined with a substrate;
(3) the amorphous SiOC coating prepared by the method has excellent mechanical property, the performance of the amorphous SiOC coating can be adjusted within a certain range, and the amorphous SiOC coating is suitable for most of use environments and is not limited to the background.
(4) According to the invention, the precursor raw material organosilane singly uses hexamethyldisiloxane or tetraethoxy-archasilane, or uses a mixed solution of hexamethyldisiloxane and hexamethyldisilane according to a certain volume proportion, or uses a mixed solution of tetraethoxy-siloxane and hexamethyldisilane according to a certain volume proportion, so that the gasification temperature is low, and the organic silane precursor is nontoxic, harmless and free of corrosive gas.
(5) The organosilane is independently used, hexamethyldisiloxane can be selected, and hexamethyldisiloxane and hexamethyldisilane can be selected for mixed use, so that the cost is relatively low. When the organosilane is mixed for use, the volume ratio of the hexamethyldisiloxane to the hexamethyldisilane is determined according to practical requirements, and when the friction environment requires that the hardness of the amorphous SiOC coating is higher, the volume ratio of the hexamethyldisilane can be properly improved.
Drawings
FIG. 1 is a surface topography map of a stainless steel surface after 2h of amorphous SiOC coating friction wear deposited by chemical vapor deposition.
The specific implementation mode is as follows:
in the specific implementation process, the invention adopts a thermal excitation type chemical vapor deposition system, and Hexamethyldisiloxane (HMDSO), Hexamethyldisilane (HMDS), Tetraethoxysilane (TEOS) and absolute ethyl alcohol (C) are selected2H5OH), hydrogen (H)2) And an argon (Ar) gas system, controlling the proportion of organosilane to absolute ethyl alcohol, and depositing an amorphous SiOC coating with a compact structure and a thickness of 0.1-50 mu m on the surface of stainless steel, carbon steel or other alloys under the conditions of working pressure of 10-1000 Pa and temperature of 1000-1200 ℃, wherein the hardness range of the amorphous SiOC coating is 6 GPa-15 GPa, the friction coefficient range is 0.02-0.2, the method is suitable for most of use environments, and the hardness of the amorphous SiOC coating is adjusted according to different friction pairs.
The following further describes the embodiments of the present invention, and it should be noted that the description of the embodiments is provided to help understanding of the present invention, but the present invention is not limited thereto. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.
The experimental procedures in the following examples were carried out by conventional methods unless otherwise specified, and the experimental materials used in the following examples were commercially available by conventional methods unless otherwise specified.
Example 1
In this embodiment, the method for preparing the amorphous SiOC coating by the chemical vapor deposition process is as follows:
(1) 316L stainless steel is selected as a substrate, and 400#, 800# and 2000# sandpaper are used for sequentially polishing away oxide skin on the surface of the 316L stainless steel, so that the surface is smooth and has no burrs.
(2) Ultrasonically cleaning 316L stainless steel with polished surface by isopropanol and ethanol for 15 minutes respectively, and drying by nitrogen for later use.
(3) Mixing Hexamethyldisiloxane (HMDSO) and absolute ethyl alcohol according to a certain volume ratio of 1, and uniformly stirring to obtain a precursor raw material.
(4) When an amorphous SiOC coating is deposited on a 316L stainless steel substrate, the flow rate of a mixed solution of hexamethyldisiloxane and absolute ethyl alcohol is 0.5g/min, the flow rate of argon gas is 3000sccm, the flow rate of hydrogen is 200sccm, the deposition temperature is 1000 ℃, the working pressure is 600Pa, and the deposition time is 2 h. And (5) after the deposition is finished, cooling along with the furnace.
(5) After friction experiments of 316L stainless steel without the amorphous SiOC coating deposited on the surface and 316L stainless steel with the amorphous SiOC coating deposited on the surface, the friction coefficients were obtained, as shown in Table 1, under the friction conditions of 100g loading force and 30min experiment time.
TABLE 1 coefficient of friction for surface deposited and undeposited amorphous SiOC coated 316L stainless steels
| Sample (I)
|
Coefficient of friction
|
| 316L stainless steel without amorphous SiOC coating deposited on surface
|
0.54
|
| 316L stainless steel with amorphous SiOC coating deposited on surface
|
0.09 |
Example 2
In this embodiment, the method for preparing the amorphous SiOC coating by the chemical vapor deposition process is as follows:
(1) 316 stainless steel is selected as a substrate, and 400#, 800# and 2000# sandpaper are used for sequentially polishing away oxide skins on the surface of the 316 stainless steel so as to enable the surface to be smooth and have no burrs.
(2) Ultrasonically cleaning the polished 316 stainless steel by respectively adopting isopropanol and ethanol for 15 minutes, and drying by using nitrogen for later use.
(3) Tetraethoxysilane (TEOS) and absolute ethyl alcohol are mixed according to a certain volume ratio of 1, and the mixture is uniformly stirred to be used as a precursor raw material.
(4) When the amorphous SiOC coating is deposited on a 316 stainless steel substrate, the flow rate of a mixed solution of hexamethyldisilane and absolute ethyl alcohol is 0.8g/min, the flow rate of argon gas is 3000sccm, the flow rate of hydrogen is 400sccm, the deposition temperature is 1100 ℃, the working pressure is 600Pa, and the deposition time is 1.5 h. And (5) after the deposition is finished, cooling along with the furnace.
(5) After friction experiments of 316 stainless steel without the amorphous SiOC coating deposited on the surface and 316 stainless steel with the amorphous SiOC coating deposited on the surface, the friction coefficients were obtained, as shown in Table 2, under the friction conditions of 100g loading force and 30min experiment time.
TABLE 2 weight gain of samples after 100h high temperature oxidation of TiAl alloys with surface deposited and non-deposited amorphous SiOC coatings
| Sample (I)
|
Coefficient of friction
|
| 316 stainless steel without amorphous SiOC coating deposited on surface
|
0.47
|
| 316 stainless steel with amorphous SiOC coating deposited on surface
|
0.13 |
Example 3
In this embodiment, the method for preparing the amorphous SiOC coating by the chemical vapor deposition process is as follows:
(1) 316L stainless steel is selected as a substrate, and 400#, 800# and 2000# sandpaper are used for sequentially polishing away oxide skin on the surface of the 316L stainless steel, so that the surface is smooth and has no burrs.
(2) Ultrasonically cleaning 316L stainless steel with polished surface by isopropanol and ethanol for 15 minutes respectively, and drying by nitrogen for later use.
(3) Mixing a mixed solution (volume ratio is 1: 5) of Hexamethyldisiloxane (HMDSO) and Hexamethyldisilane (HMDS) and absolute ethyl alcohol according to a certain volume ratio, wherein the volume ratio is 1, and uniformly stirring the mixture to obtain a precursor raw material.
(4) When the amorphous SiOC coating is deposited on a 316L stainless steel substrate, the flow rate of a mixed liquid of organosilane and absolute ethyl alcohol is 1g/min, the flow rate of argon gas is 5000sccm, the flow rate of hydrogen is 600sccm, the deposition temperature is 1050 ℃, the working pressure is 800Pa, and the deposition time is 1 h. And (5) after the deposition is finished, cooling along with the furnace.
(5) After friction experiments of 316L stainless steel without the amorphous SiOC coating deposited on the surface and 316L stainless steel with the amorphous SiOC coating deposited on the surface, the friction coefficient was obtained, as shown in Table 3, under the friction condition of 100g loading force and the experiment time of 30 min.
TABLE 3 coefficient of friction for 316L stainless steels with surface deposited and undeposited amorphous SiOC coatings
| Sample (I)
|
Coefficient of friction
|
| 316L stainless steel without amorphous SiOC coating deposited on surface
|
0.54
|
| 316L stainless steel with amorphous SiOC coating deposited on surface
|
0.16 |
As shown in FIG. 1, it can be seen from the surface morphology of the amorphous SiOC coating deposited on the stainless steel surface for 2h by the chemical vapor deposition process that the coating has less wear and less wear after 1h of the rubbing experiment, and the coating is not abraded to the substrate, and the coating has good bonding after the rubbing experiment.
The embodiment result shows that the invention provides the method for preparing the amorphous SiOC coating by the chemical vapor deposition process suitable for the metal materials such as stainless steel and the like, and the amorphous SiOC coating has the advantages of good chemical stability, good wear resistance, strong oxidation resistance and strong creep resistance, and has good bonding force with stainless steel, carbon steel and other alloy matrixes. The amorphous SiOC coating has no particle peeling off when in actual use. The amorphous SiOC coating can obviously improve the frictional wear performance of the stainless steel and prolong the service life of the metal material.