Coating process and stepped alloy wear-resistant coating thereof

Abstract

The invention discloses a coating process and a stepped alloy wear-resistant coating thereof. The stepped alloy wear-resistant layer comprises a bonding layer and a functional layer, wherein the functional layer is composed of a compact layer, a sub-functional layer and a main functional layer. The wear resistance of the functional layer in the stepped alloy wear-resistant coating increases in a stepped manner from the bottom layer to the top layer, and the wear resistance of the outermost layer is optimal, so that the service life of the drill bit can be fully prolonged; the wear resistance is gradually reduced and the toughness is gradually increased from the top layer to the bottom layer, so that the internal stress of the film layer is reduced and the impact resistance is gradually increased. The coating formed on the surface of the workpiece through the coating process has the advantages of being not prone to falling off and good in abrasion resistance, and the process is easy to operate and easy to popularize and use.

Description

Technical Field

[0001] The invention relates to the technical field of drill bit coating, in particular to a coating process and a stepped alloy wear-resistant coating. Background Art

[0002] Cutters and drill bits are one of the indispensable parts in mechanical processing, and the materials used are mainly cemented carbide and high-speed steel. These two materials have the characteristics of high hardness and wear resistance, but in actual use, due to the special use of cutters and drill bits, they are prone to breakage and excessive wear, which requires continuous replacement of cutters and drill bits, thereby increasing processing costs and affecting processing efficiency.

[0003] In order to solve this technical problem, a protective coating is usually formed on the surface of the cutter head and drill bit in the prior art to improve its hardness and wear resistance. When forming the coating on the surface of the cutter head and drill bit, sputtering coating is mostly adopted. The formed coating is mostly only a single-layer coating. This single-layer coating has poor bonding strength with the surface of the workpiece, and the coating is easy to fall off after long-term use. At the same time, the coating has the disadvantages of high brittleness, poor impact resistance, low hardness, and poor wear resistance. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a coating process and a stepped alloy wear-resistant coating. The coating formed on the drill bit surface by this process has the characteristics of not being easy to fall off and having good wear resistance. The process is simple to operate and easy to promote and use.

[0005] The technical solution of the present invention is: The present invention provides a coating process for forming a stepped alloy wear-resistant coating on a workpiece, characterized in that it comprises the following steps: S1: Workpiece pretreatment: sandblast and ultrasonically clean the workpiece, then evenly clamp the workpiece on the coating equipment turntable and put it into the furnace, adjust the turntable revolution speed to 2-4rpm / min, evacuate the vacuum chamber to 2-4Pa, and turn on the heater to raise the temperature to 480℃-600℃; Further, in the S1 workpiece pretreatment step, the sandblasting medium includes: aluminum oxide and silicon carbide; Furthermore, the S1 workpiece pretreatment step also includes, after the workpiece is evenly clamped on the coating equipment rotary rack and placed into the furnace, H2 is introduced with a flow rate of 200 sccm to decontaminate the workpiece surface again.

[0006] S2: performing glow etching on the surface of the workpiece to activate the substrate surface; Furthermore, in the step S2, when glow etching is performed on the surface of the workpiece, Ar gas is introduced with a flow rate of 100-150 sccm, the vacuum degree of the furnace chamber is 2-4 Pa, a negative bias voltage of 150V-200V is applied to the substrate, and glow etching is performed for 15-25 minutes.

[0007] S3: preparing an adhesive layer: using at least one first target material to form an adhesive layer by coating the surface of the workpiece; Furthermore, when preparing the bonding layer in step S3, N2 gas is introduced, the coating pressure is adjusted to 2-4 Pa, the negative bias voltage is adjusted to 20V-60V, the target current is 150A-200A, and the deposition time is 25-30min.

[0008] S4: Preparation of stepped functional layers: Using at least one first target material, preparing a dense layer on the surface of the adhesive layer; Furthermore, in the step S4 of preparing the stepped functional layer, when preparing a dense layer on the surface of the next layer, the coating pressure is 2-4Pa, the negative bias voltage is adjusted to 80V-150V, the N2 flow rate is 450-550sccm, the target current is 150-200A, and the deposition time is 25-30min.

[0009] In the present invention, the first target material is used when preparing the bonding layer and the dense layer. Except for the different negative bias values ​​used, other process adjustments are the same. First, the wear resistance of the material components in the first target material in the present invention is lower than that of the third target material in the present invention, but the toughness is higher than that of the third target material. The first target material is used as the bonding layer and is deposited on the surface of the workpiece, and the bonding force between the first target material and the workpiece is better; wherein, the wear resistance of the material components in the third target material used in the present invention is higher than that of the first target material and the second target material, and the wear resistance of the material components in the first target material and the second target material is equivalent.

[0010] Secondly, the bonding layer in the present invention adopts a negative bias voltage of a lower dense layer as a condition for depositing the coating, so that when the first target material is deposited on the surface of the workpiece, the particles formed by the first target material on the surface of the workpiece are coarser, the film layer is looser, and the adhesion between the film layer and the surface of the workpiece is excellent; then, a dense layer is deposited on the bonding layer, and under the condition that other parameters remain unchanged, the negative bias voltage is increased to make the particles of the dense layer finer than those of the bonding layer, the film layer is denser, and the wear resistance of the film layer is higher than that of the bonding layer; that is, the bonding layer and the dense layer are two-layer structures with the same components but different densities, wherein the bonding layer mainly functions to increase the bonding force between the coating and the surface of the workpiece, and wherein the dense layer, on the one hand, enhances the wear resistance of the entire film layer, so that the bonding layer has good adhesion on the workpiece and has certain wear resistance; on the other hand, because the dense layer has both high toughness and certain wear resistance, it has a good transition buffer connection effect for the deposition of the sub-functional layer with step-by-step increase in wear resistance of the present invention.

[0011] On the surface of the dense layer, a sub-functional layer formed by depositing the second target material and the third target material and a main functional layer formed by depositing the third target material are prepared: a. Using N second targets and M third targets, and all the second targets and third targets are fully opened at the same time, coating the surface of the dense layer to form at least one sub-functional layer; wherein the wear resistance of the third target is higher than that of the second target, M<N and M≥1 and is an integer; b. While keeping the third target material turned on, after closing at least one second target material, coating the surface of the previous sub-functional layer to form another sub-functional layer; c. Based on step b, step b is repeated in sequence until only the third target is left open, and the coating forms the top main functional layer, completing the coating of the stepped functional layer.

[0012] Furthermore, when preparing the sub-functional layer and the main functional layer, N2 gas is introduced with a N2 flow rate of 450-550sccm, the coating pressure is adjusted to 2-4Pa, the negative bias voltage is adjusted to 20V-60V, the target current is 150-200A, and the deposition time is 15-20min.

[0013] Firstly, each sub-functional layer and main functional layer contains highly wear-resistant material components. If the density of the deposited film is too high or the deposited thickness is too large, the internal stress of the film will be relatively large and the film layer will easily crack. Therefore, when depositing the above-mentioned film layer, the present invention adopts a negative bias voltage smaller than that for preparing the bonding layer, and the film deposition time is also shorter than that for preparing the bonding layer.

[0014] Secondly, each sub-functional layer is composed of a material component with higher toughness (the second target material) and a material component with higher wear resistance (the third target material), so that it has both high wear resistance and toughness. Therefore, the total internal stress of the multi-layer second target material and third target material sub-functional layer formed by deposition is low, making it less likely to crack during use.

[0015] Furthermore, the materials of the first target material and the second target material are consistent, the first target material and the second target material are single element target materials or mixed element target materials, and the wear resistance of the material components of the first target material and the second target material are comparable.

[0016] Therefore, the entire stepped functional layer formed by the above five functional layers has a step-like increase in wear resistance from bottom to top, and the outermost layer has the best wear resistance, which can fully extend the service life of the drill bit; the wear resistance gradually decreases from the outer layer to the inner layer, but the toughness gradually increases, so that the internal stress of the film layer is reduced and the impact resistance is gradually increased.

[0017] The present invention also provides a step-type alloy wear-resistant coating formed by the above coating process, comprising a bonding layer and a functional layer, wherein the bonding layer is bonded to the surface of the plated workpiece, and the functional layer is bonded to the surface of the bonding layer; The functional layer comprises: a dense layer, several sub-functional layers and a main functional layer, and the proportion of wear-resistant components in the several sub-functional layers increases from the bottom layer to the upper layer; The bonding layer and the dense layer are both formed by depositing the first target material; each sub-functional layer is formed by depositing the second target material and the third target material; and the main functional layer is formed by depositing the third target material. Furthermore, the composition of the bonding layer and the dense layer is consistent with the composition of the first target material; and the bonding layer and the dense layer are single element coatings or mixed element coatings.

[0018] Furthermore, the following layer is an AlTiN layer, which includes 40%-45% Al, 25%-30% Ti and 25%-35% N in atomic percentage, and the film thickness is 0.6-0.8 μm; The dense layer is an AlTiN dense layer, which comprises 40%-45% Al, 25%-30% Ti and 25%-35% N in atomic percentage, and the film thickness is 1.2-1.6μm; The sub-functional layer is a multilayer AlTiN and TiSiN layer, the total thickness of the film is 0.6-0.8μm; The second main functional layer is a TiSiN layer, which includes 40%-50% Ti, 7%-10% Si, and 40%-50% N in atomic percentage, and the film thickness is 0.3-0.5 μm.

[0019] The first target and the second target used in the present invention are both AlTi targets, and the third target is a TiSi target.

[0020] The beneficial technical effects of the present invention are as follows: the present invention provides a coating process and a stepped alloy wear-resistant coating. Firstly, the present invention obtains a film layer of suitable density and thickness by adjusting the negative bias voltage and deposition time in the coating process according to the wear resistance and toughness of different target materials; the coating layer formed on the surface of the workpiece by the process has the characteristics of not easy to fall off and good wear resistance, and the process is simple to operate and easy to promote and use.

[0021] Secondly, the step-type alloy wear-resistant layer of the present invention includes: a bonding layer and a functional layer, and the functional layer includes a dense layer, a sub-functional layer and a main functional layer. The bonding layer and the dense layer are two-layer structures with the same composition but different densities, wherein the bonding layer mainly functions to increase the bonding force between the coating and the workpiece surface, and the dense layer, on the one hand, enhances the wear resistance of the entire film layer, so that the bonding layer has good adhesion on the workpiece and has a certain wear resistance.

[0022] Thirdly, each sub-functional layer is composed of a material component with higher toughness (the second target material) and a material component with higher wear resistance (the third target material), so that it has both high wear resistance and toughness. Therefore, the total internal stress of the multi-layer sub-functional layer formed by the deposition of the second target material and the third target material is low, making it less likely to crack during use.

[0023] Fourthly, the functional layer in the stepped alloy wear-resistant coating of the present invention has a step-like increase in wear resistance from the inner layer to the outer layer, and the outermost layer has the best wear resistance, which can fully extend the service life of the drill bit; the wear resistance gradually decreases from the outer layer to the bottom layer, but the toughness gradually increases, so that the internal stress of the film layer is reduced and the impact resistance is gradually increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the bonding force between the step-type alloy wear-resistant coating deposited on Example 1 and its corresponding workpiece tested by the indentation method, wherein a1 is an indentation test diagram under a load of 60KG, a2 is an indentation test diagram under a load of 100KG, and a3 is an indentation test diagram under a load of 150KG; Figure 2 Schematic diagram of the bonding force between the step-type alloy wear-resistant coating deposited on comparative example 1 and its corresponding workpiece by indentation test, wherein b1 is an indentation test diagram under a load of 60KG, b2 is an indentation test diagram under a load of 100KG, and b3 is an indentation test diagram under a load of 150KG; Figure 3Schematic diagram of the bonding force between the step-type alloy wear-resistant coating deposited on comparative example 2 and its corresponding workpiece by indentation method test, wherein c1 is an indentation test diagram under a load of 60KG, c2 is an indentation test diagram under a load of 100KG, and c3 is an indentation test diagram under a load of 150KG; Figure 4 d1 is an indentation test diagram of the bonding force between the step-type alloy wear-resistant coating deposited on the comparative example 3 and its corresponding workpiece, wherein d2 is an indentation test diagram under a load of 100 kg, and d3 is an indentation test diagram under a load of 150 kg; Figure 5 is an appearance diagram of the hard tool in Example 1; Figure 6 is the coating morphology of the hard tool in Example 1 (magnification × 50.0); Figure 7 is another angle morphology of the coating of the hard tool in Example 1 (magnification × 50.0); Figure 8 is the morphology of the coating of the hard tool in Example 1 at other angles (magnification × 50.0); Fig. 9 is the coating morphology of the hard tool in Example 1 (magnification × 100.0); Fig.10 This is another angle morphology image of the coating of the hard tool in Example 1 (magnification × 100.0).

[0025] In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and examples. The following examples are used to illustrate the present invention but are not used to limit the scope of the present invention.

[0026] The step-type alloy wear-resistant coating of this embodiment 1 is composed of a bonding layer and a functional layer, and the functional layer includes: a dense layer, a multi-layer sub-functional layer and a third target main functional layer. In this embodiment 1 and comparative examples 1-3, the first target and the second target are both AlTi targets (Plansee, TiAl 33 / 67 at%), and the third target is a TiSi target (Plansee, TiSi 80 / 20 at%). In practical applications, the materials of the first target and the second target are consistent or inconsistent, and the first target and the second target can be single element targets or mixed element targets.

[0027] The coating equipment used in the present embodiment 1 and comparative examples 1-3 is: arc ion coating machine (Balzers Kila); the workpiece used in the present embodiment 1 and comparative examples 1-3 is a cemented carbide tool.

[0028] Example 1 S1: Workpiece pretreatment: First, the workpiece is sandblasted and cleaned. The sandblasting media includes: aluminum oxide and silicon carbide, so that the surface of the workpiece obtains a certain degree of cleanliness and different roughness, and increases the adhesion between it and the coating; then the workpiece is ultrasonically cleaned and the surface moisture is removed; then the workpiece is evenly clamped on the coating equipment turntable and put into the furnace, the turntable speed is adjusted to 3rpm / min, the vacuum chamber is evacuated to 3Pa, and the heater is turned on and heated to 480℃; H2 is introduced, and the H2 flow rate is adjusted to 200sccm, and the above workpiece is gas flushed to clean the surface of the above workpiece again.

[0029] S2: Glow etching the surface of the workpiece: introduce Ar gas, adjust the Ar flow rate to 100 sccm, set the furnace chamber vacuum to 3 Pa, apply a negative bias voltage of 200 V to glow etch the surface of the workpiece, and glow etch for 20 minutes to activate the substrate surface.

[0030] S3: preparing the bonding layer: using a first target material, i.e., AlTi target material, when preparing the bonding layer, N2 gas is introduced, the N2 flow rate is 500sccm, the coating pressure is adjusted to 3 Pa, the negative bias voltage is 40V, the target current is 150A, the deposition time is 30min, and a layer of AlTiN bonding layer A1 is formed on the surface of the workpiece by coating; The bonding layer prepared by the above steps is an AlTiN layer, which includes 40% Al, 28% Ti and 32% N in atomic percentage, and the film thickness is 0.8 μm.

[0031] S4: Preparation of stepped functional layers: Prepare a dense layer on the surface of the AlTiN adhesive layer; In this embodiment 1, when preparing the dense layer, an AlTi target is used, the coating pressure is 3Pa, the negative bias voltage is 80V, the N2 flow rate is 500sccm, the target current is 150A, and the deposition time is 30min, and a layer of AlTiN dense layer A2 is formed on the surface of the workpiece by coating; The dense layer prepared by the above steps is an AlTiN dense layer, which includes 42% Al, 28% Ti and 30% N in atomic percentage, and the film thickness is 1.5 μm.

[0032] In addition, according to the requirements of drill bit coating, AlTi target material can be further used to further increase the negative bias voltage to form another AlTiN dense layer on the surface of the previous AlTiN dense layer. In this specific embodiment 1, the negative bias voltage is only increased once, that is, only one AlTiN dense layer is formed.

[0033] Preparation of multi-layer sub-functional layers and main functional layers: In this embodiment, three second target materials (P2, P4, P6) and one third target material (P8) are used, wherein the target materials of P2, P4, and P6 are the same as the target material of the first target material, all of which are AlTi targets and the content of each target component is the same; wherein the target material composition of P8 is TiSi, and the wear resistance of the target material of P8 is higher than that of the target materials of P2, P4, and P6.

[0034] a. Open P2, P4, P6 and P8, N2 flow rate 500sccm, coating pressure 3Pa, negative bias voltage 40V, target current 150A, deposition time 20min; form the first sub-functional layer A3 on the aforementioned AlTiN dense layer A2, at this time, in the first sub-functional layer A3, the TiSi target deposition component accounts for 25% of all the components in the layer, and the AlTi target deposition component accounts for 75% of all the components in the layer; b. Only one second target (such as P2) is turned off, and P4, P6 and P8 are left turned on. The three targets are coated using the same coating process parameters as in step a above, and a second sub-functional layer A4 is formed on the first sub-functional layer A3. At this time, in the second sub-functional layer A4, the TiSi target deposition component accounts for 33.3% of all components in the layer, and the AlTi target deposition component accounts for 66.7% of all components in the layer; c. Continue to turn off one second target (such as P4), leaving P6 and P8 turned on, and the two targets are coated using the same coating process parameters as in step a above, forming a third sub-functional layer A5 on the second sub-functional layer A4. At this time, in the third sub-functional layer A5, the TiSi target deposition component accounts for 50% of all the components in the layer, and the AlTi target deposition component accounts for 50% of all the components in the layer; At this point, the coating of the entire multi-layer sub-functional layer in Example 1 is completed; The multi-layer functional sub-layer prepared by the above steps is AlTiN and TiSiN layer, and the film thickness is 0.5μm; d. Continue to turn off one second target material (such as P6), leaving only the third target material P8 open, and use the same coating process parameters as in the above step a to perform coating, and form a main functional layer A6 on the third sub-functional layer A5, that is, a TiSiN main functional layer A6. At this time, in the TiSiN main functional layer A6, the TiSi target material deposition component accounts for 100% of the content of all components in the layer.

[0035] The main functional layer prepared by the above steps is a TiSiN layer, which includes 45% Ti, 10% Si and 45% N in atomic percentage, and the film thickness is 0.5 μm.

[0036] At this point, the coating of the entire stepped functional layer in Example 1 is completed.

[0037] Among them, when specifically selecting the target material of each target material, the above-mentioned second target materials P2, P4, and P6 may also be different from the material of the first target material, and the materials of the three second target materials may also be completely different; it is also possible that two of the target materials P2, P4, and P6 have the same material, and the materials of the two same target materials may be the same as or different from the material of the first target material; but the wear resistance of the materials of the above-mentioned second target materials is lower than the wear resistance of the third target material P8.

[0038] The hard cutting tool coated with a stepped alloy wear-resistant coating corresponding to Example 1 is obtained through the above steps.

[0039] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that no AlTiN dense layer is prepared, and the other process parameters and coating structures are the same, which will not be repeated here.

[0040] In addition, since the AlTiN dense layer is not prepared in Comparative Example 1, in order to ensure that the total thickness of the film layer on the workpiece of Comparative Example 1 is equivalent to the total thickness of the film layer of Example 1, the AlTiN layer of the next layer of Comparative Example 1 is subjected to thick plating treatment, that is, the hard tool coated with a stepped alloy wear-resistant coating corresponding to Comparative Example 1 obtained by the steps described in Comparative Example 1 includes: Next, an AlTiN layer B1 is formed, with a thickness of 2.2 μm; The sub-functional layer is a multi-layer AlTiN and TiSiN layer B2-B4, and the total thickness of the film layer is 0.5μm; The main functional layer is the TiSiN layer B5, and the film thickness is 0.5 μm.

[0041] The atomic percentages of each film layer in Comparative Example 1 refer to those in Example 1 and are not described again here.

[0042] Comparative Example 2 Compared with Example 1, Comparative Example 2 differs in that the prepared multilayer sub-functional layers are different. In Example 1, the wear resistance of the multilayer sub-functional layers increases in a step-like manner from bottom to top, while in the multilayer sub-functional layers of Comparative Example 2, the wear resistance decreases in a step-like manner from bottom to top; in addition, other coating processes and coating structures are the same.

[0043] The multilayer sub-functional layer of Comparative Example 2 is prepared on the surface of the AlTiN dense layer of Comparative Example 2, and the specific preparation method is as follows: In this comparative example 2, three third target materials (P8, P10, P12) and one second target material (P2) are used, wherein the materials of the P8, P10, and P12 targets are all TiSi targets, and the content of each target component is the same; the material composition of the P2 target is AlTi, and the wear resistance of the P8, P10, and P12 targets is higher than that of the P2 target.

[0044] a2. Open P8, P10, P12 and P2, set the N2 flow rate to 500 sccm, the coating pressure to 3 Pa, the substrate negative bias voltage to 40 V, the target current to 150 A, and the deposition time to 20 min; form the first sub-functional layer C3. At this time, in the first sub-functional layer B3, the TiSi target deposition component accounts for 75% of all the components in the layer, and the AlTi target deposition component accounts for 25% of all the components in the layer; b2. Only one third target (such as P8) is turned off, and P10, P12 and P2 are left turned on. The three targets are coated using the same coating process parameters as in step a2 above, and a second sub-functional layer C4 is formed on the first sub-functional layer C3. At this time, in the second sub-functional layer C4, the TiSi target deposition component accounts for 66.7% of all the components in the layer, and the AlTi target deposition component accounts for 33.3% of all the components in the layer; c2. Continue to turn off a third target (such as P10), leaving P12 and P2 turned on, and the two targets are coated using the same coating process parameters as in the above step a2 to form a third sub-functional layer B5 on the second sub-functional layer B4. At this time, in the third sub-functional layer C5, the TiSi target deposition component accounts for 50% of the total content of the layer, and the AlTi target deposition component accounts for 50% of the total content of the layer; At this time, the coating of the multi-layer sub-functional layer in Comparative Example 2 is completed; d2. Turn off P10, P12 and P2, leaving only the third target P8 open, and use the same coating process parameters as in the above step a2 to perform coating, forming a TiSiN main functional layer C6 on the third sub-functional layer C5. At this time, in the TiSiN main functional layer C6, the deposited component of the TiSi target accounts for 100% of the content of all components in the layer. At this point, the coating of the entire stepped functional layer of Comparative Example 2 is completed.

[0045] The hard cutting tool coated with a stepped alloy wear-resistant coating corresponding to Comparative Example 2 is prepared by the steps described in Comparative Example 2, comprising: Next, an AlTiN layer C1 is formed, with a thickness of 0.8 μm; AlTiN dense layer C2, thickness 1.5 μm; The sub-functional layer is a multi-layer AlTiN and TiSiN layer C3-C5, and the total thickness of the film is 0.5μm; The main functional layer is TiSiN layer C6, and the film thickness is 0.5 μm.

[0046] The atomic percentages in each film layer in Comparative Example 2 refer to those in Example 1 and are not described again here.

[0047] Comparative Example 3 Compared with Example 1, Comparative Example 3 differs in that the prepared multi-layer sub-functional layers are different, and the other coating processes and coating structures are the same.

[0048] The sub-functional layer of Comparative Example 3 is a multi-layer alternating second target material or third target material interlaced layer, which is prepared on the surface of the AlTiN dense layer D2 of Comparative Example 3, and the specific preparation method is as follows: a3. Open the third target, i.e., the TiSi target, adjust the N2 flow rate to 500 sccm, the coating pressure to 3 Pa, the substrate negative bias voltage to 40 V, the target current to 150 A, and the deposition time to 20 min to form the first TiSi sub-functional layer D3. At this time, in the first TiSi sub-functional layer D3, the TiSi target deposition component accounts for 100% of the content of all components in this layer.

[0049] b3. Turn off the TiSi target, turn on the second target, i.e., the AlTi target, adjust the N2 flow rate to 500 sccm, the coating pressure to 3 Pa, the negative bias voltage to 40 V, the target current to 150 A, and the deposition time to 20 min to form the second AlTi sub-functional layer D4. At this time, in the second AlTi sub-functional layer D4, the AlTi target deposition component accounts for 100% of the content of all components.

[0050] The above steps a3 and b3 are cycled once to obtain the third TiSi sub-functional layer D5 and the fourth AlTi sub-functional layer D6. At this time, the coating of the multi-layer second target material and the third target material sub-functional layer in Comparative Example 3 is completed.

[0051] Then, a TiSi main functional layer D7 is prepared on the surface of the fourth AlTi sub-functional layer C6. At this point, the entire coating of Comparative Example 3 is completed.

[0052] The hard cutting tool coated with a stepped alloy wear-resistant coating corresponding to Comparative Example 3 is prepared by the steps described in Comparative Example 3, comprising: Next, an AlTiN layer D1 is formed, with a thickness of 0.5 μm; AlTiN dense layer D2, thickness 1.5 μm; The sub-functional layer is a multi-layer AlTiN and TiSiN layer D3-D6, and the main functional layer is a TiSiN layer D7. The total thickness of the sub-functional layer and the main functional layer is 1.2 μm.

[0053] The atomic percentages in each film layer in Comparative Example 3 refer to those in Example 1 and are not described again here.

[0054] The present invention uses an indentation method to test the bonding strength between the step-type alloy wear-resistant coating deposited on Example 1 and Comparative Examples 1-3 and its corresponding workpiece. Among them, 60KG, 100KG, and 150KG in the figure are the loads of this indentation test. The test results are as follows Figure 1-Figure 4The indentation test equipment used in this test is a Calotester ball mill from TRIBOTECHNIC, France, and an Olympus metallographic microscope.

[0055] The indentation method is a very common method for measuring the interfacial bonding strength of coatings. It uses non-stress parameters to estimate the interfacial bonding strength between the film layer and the substrate. That is, the film surface is subjected to an indentation test under different loads. When the load is large enough, transverse cracks will occur at the interface between the film layer and the substrate. When the cracks expand to a certain stage, the film layer will fall off. The minimum load at which film damage can be observed is called the critical load.

[0056] Therefore, from Figure 1-Figure 2 It can be seen that the film layers on the workpieces of Example 1 and Comparative Example 1 have good bonding strength with the workpieces. When the load is 60-150KG, there are no obvious cracks on the film layers on the workpieces of Example 1 and Comparative Example 1. Figure 3-4 It can be seen that when the load is 150KG, the film layer falls off in Comparative Example 2, and when the load is 100KG, the film layer falls off in Comparative Example 3. The bonding strength between the film layer on the workpiece of Comparative Examples 2-3 and the workpiece is worse than that of Example 1 and Comparative Example 1.

[0057] Figure 5-Figure 10 This is a topographical image of the hard tool of Example 1. Figure 5-Figure 10 As shown, the hard tool of Example 1 has uniform morphology, normal coating, and no film explosion. Wear resistance test of Example 1 and Comparative Examples 1-3.

[0058] The cutting life of the cemented carbide tools of Example 1 and Comparative Examples 1-3 was tested, and the results are shown in Table 1. The specific test method is as follows: Tool model: APMT1604PDER-DL Cutting material: Ductile iron 200 Shape of cut material: bearing base Cutting speed: V = 1200m / min Feed: F=1000mm / min Cutting depth: Ap=1mm Coolant: No

[0059] It can be seen from Table 1 that Example 1 has better wear resistance than Comparative Examples 1-3, which is beneficial to improving product quality and extending the service life of workpieces.

[0060] The present invention also provides a step-type alloy wear-resistant coating formed by the above coating process, comprising a bonding layer and a functional layer, wherein the bonding layer is bonded to the surface of the plated workpiece, and the functional layer is bonded to the surface of the bonding layer; The functional layer comprises: a dense layer, a plurality of functional layers and a main functional layer, and the proportion of wear-resistant components in the plurality of sub-functional layers increases from the bottom layer to the upper layer; The composition of the bonding layer and the dense layer of the present invention is consistent with the composition of the first target material; and the bonding layer and the dense layer are single-element coatings or mixed-element coatings.

[0061] In the step-type alloy wear-resistant coating formed by the above-mentioned coating process provided by the present invention: The following layer is an AlTiN layer, which includes 40% Al, 28% Ti and 32% N in atomic percentage, and the film thickness is 0.8 μm; The dense layer is an AlTiN dense layer, in atomic percentage, including 42% Al, 28% Ti and 30% N, the film thickness is 1.5μm; The sub-functional layer is a multilayer AlTiN and TiSiN layer, the total thickness of the film is 0.5μm; The second main functional layer is a TiSiN layer, which includes 48% Ti, 7% Si, and 45% N in atomic percentage, and the film thickness is 0.5 μm.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the technical principles of the present invention, and these improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A coating process for forming a stepped alloy wear-resistant coating on a workpiece, characterized in that: The steps include: S1: Workpiece pretreatment: sandblast and ultrasonically clean the workpiece, then evenly clamp the workpiece on the coating equipment rotating rack and put it into the furnace, adjust the rotating rack speed to 2-4rpm / min, evacuate the vacuum chamber to 2-4Pa, and turn on the heater to raise the temperature to 480℃-600℃; S2: performing glow etching on the surface of the workpiece to activate the substrate surface; S3: preparing an adhesive layer: using at least one first target material to form an adhesive layer on the surface of the workpiece; S4: Preparation of stepped functional layers: Using at least one first target material, preparing a dense layer on the surface of the adhesive layer; On the surface of the dense layer, a sub-functional layer formed by depositing the second target material and the third target material and a main functional layer formed by depositing the third target material are prepared: a. Using N second targets and M third targets, and all the second targets and third targets are fully opened at the same time, coating the surface of the dense layer to form at least one sub-functional layer; wherein the wear resistance of the third target is higher than that of the second target, M<N and M≥1 and is an integer; b. While keeping the third target material turned on, after closing at least one second target material, coating the surface of the previous sub-functional layer to form another sub-functional layer; c. Based on step b, step b is repeated in sequence until only the third target is left open, and the coating forms the top main functional layer, completing the coating of the stepped functional layer.

2. The coating process according to claim 1, characterized in that: In the workpiece pretreatment step S1, the sandblasting medium includes: aluminum oxide and silicon carbide.

3. The coating process according to claim 1, characterized in that: The S1 workpiece pretreatment step also includes evenly clamping the workpiece on the coating equipment rotary rack and placing it into the furnace, introducing H2 to decontaminate the workpiece surface again.

4. The coating process according to claim 1, characterized in that: In the step S2, when glow etching is performed on the surface of the workpiece, Ar gas is introduced, the Ar gas flow rate is 100-150 sccm, the vacuum degree of the furnace chamber is 2-4 Pa, a negative bias voltage of 150V-200V is applied, and glow etching is performed for 15-25 minutes.

5. The coating process according to claim 1, characterized in that: When preparing the bonding layer in the S3 step, N2 gas is introduced with a N2 flow rate of 450-550 sccm, the coating pressure is adjusted to 2-4 Pa, the negative bias voltage is adjusted to 20V-60V, the target current is 150A-200A, and the deposition time is 25-30min.

6. The coating process according to claim 1, characterized in that: In the step S4 of preparing a stepped functional layer, when preparing a dense layer on the surface of the next layer, the coating pressure is 2-4 Pa, the negative bias voltage is adjusted to 80 V-150 V, the N2 flow rate is 450-550 sccm, the target current is 150-200 A, and the deposition time is 25-30 min; When preparing the sub-functional layer and the main functional layer, N2 gas is introduced with a N2 flow rate of 450-550sccm, the coating pressure is adjusted to 2-4Pa, the negative bias voltage is adjusted to 20V-60V, the target current is 150-200A, and the deposition time is 15-20min.

7. The coating process according to claim 1, characterized in that: The first target material and the second target material are made of the same material, and the first target material and the second target material are single element target materials or mixed element target materials.

8. A step-type alloy wear-resistant coating formed by any coating process in claims 1 to 7, characterized in that: It comprises a bonding layer and a functional layer, wherein the bonding layer is bonded to the surface of the plated workpiece, and the functional layer is bonded to the surface of the bonding layer; The functional layer comprises: a dense layer, several sub-functional layers and a main functional layer, and the proportion of wear-resistant components in the several sub-functional layers increases from the bottom layer to the upper layer; The adhesive layer and the dense layer are both formed by depositing the first target material; each sub-functional layer is formed by depositing the second target material and the third target material; and the main functional layer is formed by depositing the third target material.

9. The step-type alloy wear-resistant coating according to claim 8, characterized in that: The composition of the bonding layer and the dense layer is consistent with the composition of the first target material; and the bonding layer and the dense layer are single-element coatings or mixed-element coatings.

10. The step-type alloy wear-resistant coating according to claim 8, characterized in that: The following layer is an AlTiN layer, which includes 40%-45% Al, 25%-30% Ti and 25%-35% N in atomic percentage, and the film thickness is 0.6-0.8 μm; The dense layer is an AlTiN dense layer, which comprises 40%-45% Al, 25%-30% Ti and 25%-35% N in atomic percentage, and the film thickness is 1.2-1.6μm; The sub-functional layer is a multilayer AlTiN and TiSiN layer, the total thickness of the film is 0.6-0.8μm; The main functional layer is a TiSiN layer, which includes 40%-50% Ti, 7%-10% Si, and 40%-50% N in atomic percentage, and the film thickness is 0.3-0.5 μm.

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