CN105779937A - Method for depositing amorphous diamond thick film on steel substrate by using multi-energy ion beams - Google Patents

Abstract

A method for depositing an amorphous diamond film with a thickness of more than 20 μm on a steel substrate by using multi-energy ion beams belongs to the field of hard wear-resistant coating preparation. The purpose of the present invention is to use the magnetic filter cathode arc deposition technology to obtain a multi-energy mixed ion beam by applying a pulsed negative bias on the target, reduce the internal stress of the film, and prepare a steel substrate with high hardness and low temperature at low temperature. Friction coefficient, excellent anti-wear performance, thick film of amorphous diamond above 20μm. Specifically involved: steel substrates, low temperature, magnetically filtered cathodic arc deposition techniques, multi-energy ion beams, large volume targets and metal-free transition layers. The magnetic filter cathodic arc deposition equipment used in the present invention has independent intellectual property rights, and the equipment is easy to operate, and the prepared amorphous diamond thick film is suitable for the application of high-hardness and wear-resistant coating deposition in industrial parts such as tool bearings.

Description

A Method for Depositing Amorphous Diamond Thick Film on Steel Substrate by Multi-energy Ion Beam

technical field

The invention belongs to the field of hard wear-resistant coatings, in particular to a method for preparing thick amorphous diamond films on steel substrates by using multi-energy ion beams.

technical background

Amorphous diamond (amorphous diamond, aD), also known as tetrahedral amorphous carbon (tetrahedral amorphous carbon, ta-C), refers to a hydrogen-free diamond-like carbon with a SP ³ hybridization content exceeding 80%. Compared with amorphous carbon (aC), amorphous diamond has the advantages of high SP ³ hybridization content and dense film; compared with hydrogenated amorphous carbon (aC:H), amorphous diamond has lower deposition temperature and better Excellent photothermal stability and higher mechanical, optical and electrical performance indicators; compared with diamond films, amorphous diamond has the advantages of adjustable structure and properties, preparation at room temperature, smooth surface, and large deposition area, so it has With higher practical application value, it is widely used in various fields such as machinery, electronics and microelectronics, biomedicine and aerospace, especially in the field of military industry. DLC coating plays an extremely important role.

At present, the preparation technology of amorphous diamond is roughly divided into chemical vapor deposition and physical vapor deposition, specifically PECVD method, sputtering method, ion plating, laser pulse deposition and vacuum arc deposition. The preparation of amorphous diamond by these existing methods requires high temperature, and the steel substrate will undergo phase transformation at high temperature, which prevents the deposition of amorphous diamond on the steel substrate. The thickness of the prepared amorphous diamond film is generally several hundred nanometers. On the one hand, due to the poor bonding force of the film base, the method of metal transition layer is usually used to improve the bonding force. On the other hand, due to the high internal stress of the amorphous diamond film layer, the non-crystalline Crystalline diamond films are prone to cracking under such high internal stress.

In view of the above situation, the present invention introduces a method for depositing an amorphous diamond thick film on a steel substrate at low temperature using the magnetic filter cathodic arc technology. By applying pulsed negative bias to the substrate, the energy of the carbon ion beam reaching the substrate is no longer a single energy, but a mixture of high energy and low energy, which can effectively reduce the internal stress of the film to 2-3GPa, and solve the problem caused by high stress. To solve the problem that the film cannot grow thick, prepare an amorphous diamond thick film with a thickness of up to 20 μm, a hardness higher than 5000HV, and a good bonding force.

Contents of the invention

The purpose of this invention is to introduce a method of depositing amorphous diamond thick film on steel substrate at low temperature by using the magnetic filter cathodic arc technology of multi-energy ion beam. Different from the traditional plasma preparation of amorphous diamond technology, during the whole preparation process, a pulsed negative bias is applied to the target to obtain a multi-energy ion beam, so that the ion energy reaching the surface of the film is no longer single, but mixed. Energy, reduce the internal stress of the film, so that it can grow thick. The formation process of the amorphous diamond film in the present invention includes a graded layer and a deposition layer. The graded layer is an amorphous state formed by bombarding the surface with high-energy carbon ions, which can improve the bonding force of the film base. Through the use of double elbows, large particles and neutral particles are filtered out to improve membrane purity. By controlling the strength of the upper and lower magnetic fields, the positive bias of the bend, the magnitude of the negative bias on the target, and the duty cycle of the negative bias, the technical indicators such as the thickness, hardness, friction coefficient, internal stress, and bonding force of the amorphous diamond film are optimized. .

The invention has the following advantageous effects: the temperature of the entire deposition process is low, lower than the phase transition temperature of steel, and the amorphous diamond film can be successfully deposited on the steel substrate, improving the surface performance of the steel piece without affecting the quality of the steel piece itself. performance. Prepare a high-energy gradient layer. The gradient layer is amorphous and well combined with the steel substrate. At the same time, the transition layer and the deposition layer use the same graphite cathode, eliminating the need for complex operations of changing sources for other metal transition layers. Apply pulse bias voltage on the target, so that the ion energy reaching the substrate is a multi-energy ion beam in a mixed state, which effectively reduces the internal stress of the amorphous diamond film. The pulse negative bias applied to the target in the invention can be adjusted in size and duty ratio, so as to achieve the purpose of controlling the energy of the ion beam reaching the steel substrate. The magnetic filtration plasma deposition amorphous diamond thick film technology provided by the present invention is simple to operate, and the prepared thick film has the characteristics of high hardness, wear resistance, low friction coefficient, high binding force, etc., and is suitable for use on the surface of workpieces such as tools and bearings. deposition and other fields.

Description of drawings

The above-mentioned features and advantages of the present invention will become clearer and easier to understand by describing the accompanying drawings and specific embodiments.

Fig. 1 is the schematic diagram of amorphous diamond thick film structure of the present invention,

Explanation of reference numerals: 201-substrate, 202-gradient layer, 203-deposition layer;

Fig. 2 is the structure schematic diagram of the magnetic filtration deposition device of the double elbow of the present invention;

Description of reference numerals: 101-steel substrate, 102-graphite cathode source, 103-inlet (not used in this method), 104-inlet (not used in this method), 105-negative bias, 106-magnetic Filter elbow, 107-magnetic filter coil, 108-observation window, 109-pump interface;

Fig. 3 is the stainless steel substrate amorphous diamond film layer schematic diagram of the present invention;

Fig. 4 is the Raman test schematic diagram of the stainless steel substrate amorphous diamond film layer of the present invention;

Fig. 5 is the Vickers hardness test result of the amorphous diamond film layer of the present invention;

Fig. 6 is a schematic diagram of the friction and wear test of the alloy steel substrate amorphous diamond film layer of the present invention.

detailed description

In conjunction with the description of the accompanying drawings, taking graphite as the arc source and stainless steel as the substrate as an example, the technical process for preparing an amorphous diamond thick film by magnetic filtration plasma deposition of the present invention is introduced in detail. The implementation steps are as follows:

1. Substrate cleaning:

Sequentially use ethanol and acetone to ultrasonically clean the stainless steel substrates for 20 minutes respectively.

2. Film layer preparation:

(a) Transition layer: fix the substrate stainless steel on the target, facing the outlet of the magnetic filter elbow, close the chamber, evacuate, start the arc source, start to apply negative bias to the sample, and turn on the magnetic field and positive bias of the elbow. The purity of the isolated source graphite is 99.9%, the vacuum degree is below 10-3GPa, the arc current is 100A, the arc voltage is about 24V, the magnetic current of the curved tube close to the isolated source is 1.50A, and the magnetic current of the curved tube close to the chamber is 2.00A. The positive bias voltage of the elbow is 15V, and the energy of the ion beam is adjusted from high energy to deposition energy gradually. The whole process takes about 10 minutes.

(b) Deposition layer: After finishing the gradient layer, adjust the negative bias voltage to 200V to 400V, keep other parameters unchanged, and continue to deposit. When the arc source graphite continues to break the arc, replace the arc source, repeat step (a), adjust the negative bias voltage to 200V to 400V, and continue deposition. The total deposition time is 20 hours.

In order to illustrate the performance of the amorphous diamond thick film, reference can be made here to Figures 3, 4, 5 and 6, which are respectively a schematic diagram of the thickness of the amorphous diamond film deposited on a stainless steel substrate in the present invention, a schematic diagram of the Raman test peak split results, and a friction diagram. Schematic diagram of wear test results, Figure 5 shows the Vickers hardness test results of amorphous diamond film. As shown in FIG. 3 , the thickness of the amorphous diamond film is 20 μm. From FIG. 5 , it can be known that the average Vickers hardness of the amorphous diamond film layer is 9000 HV. Here, the Raman analysis in Figure 4 is to indicate the sp ³ bond content in the amorphous diamond layer, the ratio of the D peak area to the G peak area reflects the size of the graphite cluster, and the ID/IG is 0.354 through peak fitting, indicating that graphite The cluster size is small, indicating a high SP3 bond content in the membrane. , Figure 6 is a schematic diagram of the friction coefficient of the amorphous diamond thick film on the friction and wear equipment (dry friction, the object is a silicon carbide ball). It can be seen from the figure that the average friction coefficient of the film layer is 0.0882.

Compared with the prior art, the embodiments of the present invention have the following advantages:

1) The deposition temperature is low, and it can be deposited without changing the properties of the steel substrate.

2) Compared with the general method for preparing amorphous diamond film, this method does not need a metal transition layer, which greatly simplifies the equipment.

3) The use of pulsed magnetic filtration double elbow deposition on the pulsed target can obtain a thick film of amorphous diamond with high sp ³ bond content, high film hardness, small friction coefficient and small wear.

It should be noted that the above content is a further detailed description of the present invention in conjunction with specific embodiments, and it cannot be considered that the specific embodiments of the present invention are limited thereto. Various improvements and modifications are made on the basis of the invention, and these improvements or modifications fall within the protection scope of the present invention. Those skilled in the art should understand that the above specific description is only for the purpose of explaining the present invention, and is not intended to limit the present invention. The protection scope of the present invention is defined by the claims and their equivalents.

Claims (6)

1. use the magnetic filtering cathode arc deposition technique of multi-energy ion beam, the method preparing the amorphous diamond thick film without intermediate metal in steel substrate under low temperature.

2. steel substrate according to claim 1, it is characterised in that: the method can in the various metal substrate such as rustless steel, steel alloy, high-speed steel, titanium alloy deposited amorphous diamond film.

3. low temperature according to claim 1, it is characterised in that: whole deposition process is all be carried out below at 100 DEG C.

4. amorphous diamond film according to claim 1, it is characterised in that: coefficient of friction is extremely low, and film surface smoothness is high, and extreme hardness, thickness is up to more than 20 μm.

5. multi-energy ion beam according to claim 1, it is characterized in that: the target laying substrate adds back bias voltage, this back bias voltage is not direct current, but pulse, the plasma beam energy making arrival substrate is not single, but mixed tensor, the internal stress of so prepared diamond-film-like is reduced.

6. technology without intermediate metal according to claim 1, it is characterised in that: intermediate metal need not be added again in substrate and deposition layer, but use the graphite arc source that synsedimentary layer is identical to do a graded bedding, it is not necessary to change source.