CN109632542B - Method for measuring hardness of hard coating - Google Patents
Method for measuring hardness of hard coating Download PDFInfo
- Publication number
- CN109632542B CN109632542B CN201811625665.6A CN201811625665A CN109632542B CN 109632542 B CN109632542 B CN 109632542B CN 201811625665 A CN201811625665 A CN 201811625665A CN 109632542 B CN109632542 B CN 109632542B
- Authority
- CN
- China
- Prior art keywords
- coating
- pmma
- hardness
- indentation
- hard coating
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N3/40—Investigating hardness or rebound hardness
Abstract
The invention belongs to the technical field of physical measurement, and particularly relates to a method for measuring hardness of a hard coating. The measuring method of the invention comprises the following steps: arranging a thermoplastic organic material coating on the hard coating of the sample to be detected; and heating and softening the thermoplastic organic material coating, pressing an indentation on the thermoplastic organic material coating, cooling, measuring the size of the indentation, and calculating the hardness of the hard coating. According to the invention, the organic material coating with certain plasticity is arranged on the hard coating to reduce the impact effect of the pressure head on the coating at the periphery of the indentation, so that the fragmentation degree of the pressure head is reduced; meanwhile, the coating which is not directly pressed by the pressure head is wrapped by the plastic organic material coating, and even if the adhesive layer below the coating fails, the coating cannot fall off in large scale. The method can reduce the number of cracks around the indentation pressed by the pressure head during hardness measurement and the size of the cracks, and simultaneously has certain amplification on the size of the indentation, so that the hardness measurement fluctuation of the hard coating is small.
Description
Technical Field
The invention belongs to the technical field of physical measurement, and particularly relates to a method for measuring hardness of a hard coating.
Background
The hard cutting tool is sprayed with the titanium nitride, the titanium aluminum nitride and other hard coatings, so that the performances of the hard cutting tool, such as service life, cutting speed, machining precision and the like, can be improved. Hardness is a key parameter for hard tools and hard coatings. In the prior art, hardness measurement for hard tools is well established, but hardness measurement of hard coatings on hard tools is difficult. Since the indenter does not allow penetration of the coating onto the substrate when the hardness is measured, and the coating thickness is typically in the order of microns, the vickers hardness of a typical 3 μm coating thickness (d 3 μm) is measured using a diamond indenter at an angle of 136 °, even if the indenter happens to penetrate the coating, the length L of the indentation diagonal is calculated as follows: l2 × (d × tan (136/2))/sin 45, i.e. in the maximum case the diagonal length L is only 21 μm. Therefore, when the hardness of the coating is tested on a conventional Vickers hardness machine, even if the indenter is allowed to just press through the coating, the length of the diagonal line of the indentation is relatively short, and in a microscopic image of a hardness tester, human error is large and accurate measurement is difficult. And the hard coating has serious edge breakage phenomenon of indentation when being subjected to a hardness test. Although the quality of the hard coating and the quality of the hard tool are both excellent, the interface between the hard coating and the hard tool is a weak point, and the condition that the coating is easy to fall off exists, which is often observed in the practical use process of the tool, and the falling off phenomenon also exists in the hardness measurement. The uneven peeling of the coating at the indentation edge makes it more difficult to determine the indentation edge (i.e. the starting point of the diagonal), and the inconsistency of the measured indentation size is often very obvious when different operators or the same operator perform tests at different times, which results in very large test fluctuation for a coating with a very small indentation size.
At present, the precision of the hardness measurement process of the hard coating is improved by a common microhardness tester. However, adding a microhardness meter first requires cost; secondly, the absolute hardness of the coating is rarely required to be accurately measured in actual production, the coating hardness is calibrated every year only by sending the coating hardness to qualified test units in China for measurement, and the stability of the coating hardness, namely the change condition of the relative hardness, is more important in daily production; thirdly, the requirement on the technical level of operators is high when a microhardness meter is adopted to measure hardness, and only a few units in China have good measuring capability at present. And the edge collapse phenomenon of the indentation still exists in the process of measuring the hardness of the hard coating by a microhardness tester, so that the test fluctuation is still large.
Disclosure of Invention
The invention aims to provide a method for measuring the hardness of a hard coating, which can effectively reduce the fluctuation in the process of measuring the hardness of the hard coating.
A method of measuring the hardness of a hard coating comprising the steps of:
(1) arranging a thermoplastic organic material coating on the hard coating of the sample to be detected;
(2) and heating and softening the thermoplastic organic material coating, pressing an indentation on the thermoplastic organic material coating, cooling, measuring the size of the indentation, and calculating the hardness of the hard coating.
The hard coating is relatively brittle and the indenter presses against the hard coating during the hardness test causing the coating to chip into pieces in the plane of the coating. At the same time, the hard coating, which is broken into pieces, is unevenly detached in a direction perpendicular to the plane of the coating, due to insufficient bonding force of the adhesive layer between the coating and the tool substrate. The coating in the center of the indentation completely collapses and does not affect the indentation measurement, but the coating at the edge of the indentation is fractured into a plurality of independent pieces surrounding the indentation, most of the coating pieces are regularly fractured at the edge of the indentation, but some coating pieces are fractured and shed outside the indentation, and some coating pieces extend into the fracture of the indentation, so that the determination of the edge of the indentation is difficult. The measuring method of the invention adopts the organic material coating with certain plasticity to reduce the impact effect of the pressure head on the coating at the periphery of the indentation and reduce the fragmentation degree of the pressure head; meanwhile, the coating which is not directly pressed by the pressure head is wrapped by the plastic organic material coating, and even if the adhesive layer below the coating fails, the coating cannot fall off in large scale.
The method for measuring the hardness of the hard coating can realize the hardness test of the hard coating by utilizing the existing Vickers hardness tester in the production process, monitor the hardness change condition of the hard coating in the production process and reduce the production cost without using a microhardness tester. The method can effectively reduce the number of cracks around the indentation pressed by the pressure head during hardness measurement and the size of the cracks, has certain amplification on the size of the indentation, and combines the two effects to ensure that the hardness measurement fluctuation of the coating is small.
Preferably, the method for measuring the hardness of the hard coating comprises the following steps:
(1) arranging a PMMA coating on the hard coating of the sample to be detected;
(2) and heating the PMMA coating to 65-85 ℃ by adopting infrared rays, then pressing an indentation on the PMMA coating, cooling, measuring the size of the indentation, and calculating the hardness of the coating.
The organic material adopts polymethyl methacrylate (PMMA), and the hardness of PMMA is far lower than that of a hard coating, so that the hardness measurement result is not influenced. PMMA is a thermoplastic material, the plasticity of PMMA can be accurately controlled by controlling the heating temperature, a PMMA layer with certain plasticity attached to the hard coating can be used as a fixing agent of the hard coating, namely, PMMA at the position touched by a pressure head is only allowed to fall off together with the hard coating, and the PMMA can be adhered to the hard coating without being directly impacted by the hard coating, so that the large block of PMMA is prevented from falling off. PMMA still has the advantage that difficult fracture when receiving the impact, has certain fragility simultaneously, therefore PMMA coating has accurate fracture nature, receives the accurate fracture in the place that the pressure head is assaulted promptly. For the above reasons, the PMMA coating can be provided to avoid the indentation edge from being not easily defined.
Through verification, the PMMA (viscosity average molecular weight of 100-200K) has proper brittleness/plasticity at 65-85 ℃, can effectively buffer the impact of a pressure head on a coating around an indentation, and has certain brittleness to obtain a clear indentation edge interface. When the hardness of the hard coating is measured, PMMA is heated, and the adhesion and wrapping effect of PMMA on the hard coating in the measurement process can be improved. During the measurement process, when the pressure head is pressed down, the PMMA can firstly form a pressure hole, and then when the pressure head continues to feed downwards, the PMMA is pressed and shrinks towards the periphery of the pressure mark. Generally, the elasticity of PMMA is slightly larger than that of a hard coating below, if the temperature is too high, PMMA rebounds to the center of an indentation in the horizontal plane direction after a pressure head is removed, extends into the indentation of the hard coating beyond the edge of the indentation of the hard coating, and is not beneficial to accurate measurement. Therefore, the heating temperature of PMMA should not exceed 85 ℃, and the expansion difference between PMMA and the hard coating is reduced.
When the organic coating is heated, the objective table of the hardness tester is reformed to arrange the heating wires with proper shapes on the objective table, which is the best way for uniformly heating the organic coating, but the objective table is damaged in actual implementation, so that the hardness measurement of other products (such as hard cutters except the hard coating and the like, which need to accurately measure the hardness of each sheet) can be influenced, and the objective table is reformed, so that the processing difficulty exists, and the workload is large. Therefore, the invention adopts an infrared non-contact heating mode, an infrared lamp is arranged near the hard coating sample to be measured, and the organic coating is heated by utilizing infrared rays.
The thickness of the PMMA coating is 50-300 mu m, so that the PMMA coating has certain strength, and the hard coating which is not impacted by a pressure head is prevented from falling off.
The PMMA coating in the step (1) comprises a first PMMA coating and a second PMMA coating below the first PMMA coating, the first PMMA coating comprises PMMA and conductive filler, and the second PMMA coating comprises PMMA and titanium oxide.
The conductive filler may make the first PMMA coating conductive. In order to prevent the underlying hard coating from rising too high in temperature when the PMMA coating is heated, a second PMMA coating containing titanium oxide is first applied over the hard coating. The titanium oxide particles are excellent infrared reflective particles, and the raw material is readily available. The second PMMA coating is used as a bottom mirror of the whole PMMA coating, and infrared rays which are about to penetrate through the PMMA coating are returned to the PMMA coating again in the heating process, so that the infrared absorption efficiency of PMMA is further improved, and the heating degree of the infrared rays on the hard coating is reduced.
And (3) cutting the PMMA coating into a PMMA belt containing the indentation after the cooling in the step (2), and then applying current to two ends of the PMMA belt to perform melting treatment on PMMA burrs generated in the indentation pressing process.
After the indentation is obtained, performing melt flow treatment on PMMA at the edge of the indentation, removing the PMMA burrs at the edge, and obtaining a round and crack-free PMMA edge, so that the indentation edge of the hard coating is easier to define. The PMMA can be melted by a heat source heating method, such as resistance wire baking, infrared hot air baking and the like. However, the heating by a heat source is difficult to be carried out locally and accurately, and if the PMMA is melted and flowed in a large area, the flowed PMMA is excessively invaded into indentation pits, and indentation openings are seriously reduced and deformed, so that the measurement accuracy of the hardness is influenced. Therefore, the PMMA coating with certain conductivity can be obtained by adding the conductive filler into the PMMA coating, after the indentation is obtained, current is applied to two ends of the PMMA belt, and the PMMA at the edge of the indentation slightly generates melting flow by utilizing the increased resistance at the indentation (the conductor cross section area is reduced by the indentation), so that the crack of the PMMA coating which originally only has a small amount of cracks is further eliminated, and the identification of the edge of the indentation is more facilitated.
Preferably, the conductive filler is at least one of flake graphite and needle coke, and the particle size of the conductive filler is 50-200 μm. The conductive fillers are all carbon materials, so that the PMMA coating is colored, the color difference between the PMMA coating and the cutter substrate in indentation is obvious, and the edge can be more easily identified under a microscope. In addition, the carbon material has a splitting effect on the matrix, and is beneficial to tidy fracture of the PMMA coating. Meanwhile, the carbon material can change the PMMA coating from transparent to black, increase the absorption of infrared heat in the hardness measurement process, reduce heat perspective, enable the heat of an external heat source to be applied to the PMMA coating as efficiently as possible, and simultaneously reduce the heating degree of the lower hard coating.
Since the PMMA band has a small size, the particle size is preferably 200 μm or less in order to uniformly disperse the conductive filler particles in the coating layer having such a small size, and the particle size is preferably 50 μm or more in order to have a certain particle size to facilitate interparticle crossing. The conductive filler particles and the PMMA form a composite material, cross contact is easy to occur between the conductive particles, and when the content of the carbon powder is greater than a percolation threshold value, jump conduction of the PMMA/conductive filler composite material is realized.
In order to apply current to the PMMA belt conveniently, the width of the PMMA belt is 3-8 mm, and the length of the PMMA belt is 15-25 mm.
To avoid affecting the hard coating hardness measurements, the thickness of the second PMMA coating layer does not exceed 400 nm.
The cooling time in the step (2) is more than 40 min. The long cooling time is adopted because the thermal expansion coefficient of organic materials such as PMMA is large, if the cooling is insufficient, the PMMA around expands towards the indentation, so that the measurement of the length of the indentation is short, the hardness value is high, the temperature is fully reduced to the room temperature before each measurement, and the hardness of the hard coating with accuracy and high consistency can be obtained.
And (3) in order to obtain a clear indentation edge, cleaning is carried out after cooling in the step (2), wherein the cleaning is carried out on the hard coating and PMMA coating scraps at the indentation by using a deplating solution, and polyvinylpyrrolidone is added into the deplating solution. The deplating liquid is dripped on the indentation, and the coating around the indentation is protected by PMMA, so that large-area destructive deplating can not be caused. The polyvinyl pyrrolidone can increase the viscosity of the deplating solution, and prevent the deplating solution from undercutting along cracks of the hard coating due to capillary action, so that the edges of the indentations are broken and difficult to define.
Drawings
FIG. 1 is an indentation of a cemented carbide tool at a pressure of 0.2kg in the prior art;
FIG. 2 is an indentation of a cemented carbide tool at a pressure of 0.5kg according to the prior art;
FIG. 3 is an indentation of a titanium nitride hard coating at a pressure of 0.2kg in the prior art;
FIG. 4 is an indentation of a titanium nitride hard coating at a pressure of 0.5kg in the prior art;
FIG. 5 is a schematic diagram of the process of measuring the hardness of a hard coating according to the present invention;
fig. 6 is a schematic view of a method for measuring hardness of a hard coating layer according to example 1 of the present invention.
Detailed Description
The conductive filler added to the first PMMA coating layer of the present invention may be, in addition to flake graphite or needle coke, a material that easily makes cross contact between particles to allow hopping conduction between particles.
The first PMMA coating layer of the present invention is formed by the following method: dissolving polymethyl methacrylate in glacial acetic acid or acetone, preparing a PMMA solution with the mass concentration of 15-18%, and sealing and standing for more than 2 hours; and then adding a conductive filler into the PMMA solution, fully stirring, and then spin-coating on a hard cutter at a rotating speed of 1500-2000 rpm. Due to the high resistance of PMMA, the amount of conductive filler added to the first PMMA coating of the present invention is above its percolation threshold to achieve conductivity of the PMMA coating.
The second PMMA coating layer of the present invention is formed by the following method: dissolving polymethyl methacrylate in glacial acetic acid or acetone, preparing a PMMA solution with the mass concentration of 15-18%, and sealing and standing for more than 2 hours; adding titanium oxide particles (the amount of the added titanium oxide particles is 10-20% of the mass of the PMMA solution) into the PMMA solution, fully stirring, and then spin-coating on a hard coating cutter at the rotating speed of 2000-2500 rpm.
Before the first PMMA coating and the second PMMA coating are coated in a spin mode, the surface of the hard coating cutter is activated and wetted, and the adhesion of PMMA to the surface of the cutter is increased.
The deplating liquid adopted in cleaning in the process of measuring the hardness of the hardness coating is a mixed liquid of hydrofluoric acid and nitric acid which is added with polyvinylpyrrolidone and has the volume ratio of 1: 1. The mass of the polyvinylpyrrolidone is 0.5-1.5% of the total mass of the deplating liquid. In order to prevent the size of the indentation from being enlarged, the cleaning time is less than 2 min. The preferable reaction time is 30 to 120 s. More preferably, the reaction time is 60 to 100 seconds.
After obtaining the indentation, a calculation is performed to obtain the relative hardness of the hard coating. The indentation size, i.e. the diagonal length, the opening diagonal length of the PMMA coating in the present invention is the diagonal length of the indentation. The length is larger than the diagonal length of the opening of the hard coating below the length, and conversion is needed to obtain the hardness of the hard coating. Specifically, the calculation formula of the absolute vickers hardness is still used as a basis, and appropriate correction is carried out:
wherein the content of the first and second substances,
c is a correction coefficient, and is corrected to be 0.13 after long-term test, and the value of the correction coefficient is slightly larger than a conventional value of 0.102; f is Newton force of pressing down of the pressure head; alpha is the included angle of the opposite surfaces of the pressure head, and is generally 136 degrees; l is the length of the diagonal of the indentation; d is the coating thickness. That is, in the above formula for calculating the vickers hardness of the hard coat layer, the body (the part in parentheses) is still the conventional vickers hardness calculation formula, but a correction value k is added in the front, because the thicker the PMMA coating layer is, the larger the opening size l is, and correction is required, without changing the hardness of the hard coat layer. After adding the PMMA coating, the opening size l is increased and the thicker the PMMA, the larger l, the easier the measurement. Of course, the thickness of the PMMA coating should take into account both the strength and the plasticity/brittleness of the layer.
The invention is further described with reference to the following figures and specific embodiments.
As shown in fig. 1 and 2, the indentation generated during the hardness measurement of the prior art hard tool is clear, and the diagonal length is about 36 μm (1400HV, 1kg pressure); as shown in fig. 3 and 4, the coating layer of the indentation edge generated during the hardness measurement of the hard coating in the related art is peeled off, and the indentation edge is difficult to be determined.
In the process of measuring the hardness of the hard coating according to the present invention, after applying the PMMA coating on the cutter, the PMMA coating is heated using an infrared lamp and then pressed with an indentation, as shown in fig. 5. When the indenter is pressed down, PMMA will form an indent first, and then continue to feed downward, forming an indentation on the hard coating.
Example 1
In this embodiment, the titanium nitride hard alloy coating is used as the test coating, and as shown in fig. 6, the method for measuring the hardness thereof includes the following steps:
(1) taking a hard tool coated with a titanium nitride hard alloy coating, and cleaning to remove oil stains;
(2) dissolving polymethyl methacrylate (PMMA) in glacial acetic acid to prepare a PMMA solution with the mass concentration of 15%, and sealing and standing for 3 hours;
(3) adding titanium oxide particles (the amount of the added titanium oxide particles is 10 percent of the mass of the PMMA solution) into the PMMA solution, fully stirring, and then spin-coating the mixture on a hard coating blade at the rotating speed of 2000 revolutions per minute to form a second PMMA coating with the thickness of 300 nm;
(4) adding the wetted flake graphite (the particle size of the flake graphite is 100 microns, and the mass of the added flake graphite is 15% of the mass of the PMMA solution) into the PMMA solution, fully stirring, and spin-coating on the hard cutter obtained in the step (3) at the rotating speed of 1500 revolutions per minute to form a first PMMA coating with the thickness of 80 microns;
(5) drying the hard cutter obtained in the step (4) in a drying oven at 50 ℃ for 2 h;
(6) placing a cutter on a test bench, heating PMMA to 70 ℃ by infrared rays to obtain proper brittleness/plasticity, and pressing a pressure head under the pressure of 0.1kg (for a hardness meter with the pressure range of 0.1-1 kg) to obtain an indentation;
(7) cooling for 50min, and cutting the PMMA coating by using a blade to form a PMMA belt with the length and the width of 5 multiplied by 20mm and containing the indentation;
(8) applying current to two ends of the PMMA belt to heat PMMA burrs at the indentation part to slightly melt and reflow, so that the PMMA which only has a small amount of cracks originally is further cracked;
(9) dropping a deplating solution at the indentation, reacting for 30s, and then ultrasonically cleaning, thereby removing hard coating chips in the indentation and facilitating observation and measurement; wherein the deplating liquid is a mixed liquid of hydrofluoric acid and nitric acid which are added with polyvinylpyrrolidone thickening agent and have the volume ratio of 1:1, and the mass of the added polyvinylpyrrolidone thickening agent is 0.5 percent of the mass of the deplating liquid;
(10) the indentation size was measured and the relative hardness was calculated.
Example 2
In the embodiment, the alumina hard alloy coating is used as a test coating, and the hardness measurement method comprises the following steps:
(1) taking a hard tool coated with an alumina hard alloy coating, and cleaning to remove oil stains;
(2) dissolving polymethyl methacrylate (PMMA) in acetone to prepare a PMMA solution with the mass concentration of 16%, and sealing and standing for 3 hours;
(3) adding titanium oxide particles (the amount of the added titanium oxide particles is 15% of the mass of the PMMA solution) into the PMMA solution, fully stirring, and then rotationally coating the mixture on a hard coating blade at the rotating speed of 2200 revolutions per minute to form a second PMMA coating with the thickness of 100 nm;
(4) adding needle coke subjected to wetting treatment into the PMMA solution (the particle size of the needle coke is 50 microns, the mass of the added needle coke is 20% of the mass of the PMMA solution), fully stirring, and spin-coating on the hard cutter obtained in the step (3) at the rotating speed of 1800 revolutions per minute to form a first PMMA coating with the thickness of 200 microns;
(5) drying the hard cutter obtained in the step (4) in a drying oven at 53 ℃ for 1.5 h;
(6) placing a cutter on a test bench, heating PMMA to 83 ℃ by infrared rays to obtain proper brittleness/plasticity, and pressing a pressure head under the pressure of 0.1kg (for a hardness meter with the pressure range of 0.1-1 kg) to obtain an indentation;
(7) cooling for 60min, and then cutting the PMMA coating to form a PMMA belt with the length and width of 5 multiplied by 20mm and containing the indentation;
(8) applying current to two ends of the PMMA belt to heat PMMA burrs at the indentation part to slightly melt and reflow, so that the PMMA which only has a small amount of cracks originally is further cracked;
(9) dropping a deplating solution at the indentation, reacting for 60s, and then ultrasonically cleaning, thereby removing hard coating chips in the indentation and facilitating observation and measurement; the deplating liquid is a mixed liquid of hydrofluoric acid and nitric acid which are added with a polyvinylpyrrolidone thickening agent and have a volume ratio of 1:1, and the mass of the added polyvinylpyrrolidone thickening agent is 1% of that of the deplating liquid;
(10) the indentation size was measured and the relative hardness was calculated.
Example 3
In this embodiment, the method for measuring the hardness of the titanium carbide hard alloy coating is used as a test coating, and comprises the following steps:
(1) taking a hard tool coated with a titanium carbide hard alloy coating, and cleaning to remove oil stains;
(2) dissolving polymethyl methacrylate (PMMA) in glacial acetic acid to prepare a PMMA solution with the mass concentration of 18%, and sealing and standing for 4 hours;
(3) adding titanium oxide particles (the amount of the added titanium oxide particles is 10 percent of the mass of the PMMA solution) into the PMMA solution, fully stirring, and then spin-coating the mixture on a hard coating blade at the rotating speed of 2500 revolutions per minute to form a PMMA bottom layer with the thickness of 300nm and containing the titanium oxide particles;
(4) adding the wetted flake graphite (the particle size of the flake graphite is 200 microns, and the mass of the added flake graphite is 30% of the mass of the PMMA solution) into the PMMA solution, fully stirring, and then rotationally coating the flake graphite on the hard cutter obtained in the step (3) at the rotating speed of 2000 rpm to form a PMMA coating containing a conductive additive, wherein the thickness of the PMMA coating is 280 microns;
(5) drying the hard cutter obtained in the step (4) in a drying oven at the temperature of 55 ℃ for 1 h;
(6) placing a cutter on a test bench, heating PMMA to 65 ℃ by infrared rays to obtain proper brittleness/plasticity, and pressing a pressure head under the pressure of 0.1kg (for a hardness meter with the pressure range of 0.1-1 kg) to obtain an indentation;
(7) cooling for 70min, and then cutting the PMMA coating to form a PMMA belt with the length and width of 5 multiplied by 20mm and containing the indentation;
(8) applying current to two ends of the PMMA belt to heat PMMA burrs at the indentation part to slightly melt and reflow, so that the PMMA which only has a small amount of cracks originally is further cracked;
(9) dropping a stripping solution at the indentation, reacting for 120s, and then ultrasonically cleaning, thereby removing hard coating chips in the indentation and facilitating observation and measurement; wherein the deplating liquid is a mixed liquid of hydrofluoric acid and nitric acid which are added with polyvinylpyrrolidone thickening agents and have the volume ratio of 1:1, and the mass of the added polyvinylpyrrolidone thickening agents is 1.5 percent of the mass of the deplating liquid;
(10) the indentation size was measured and the relative hardness was calculated.
Example 4
In the embodiment, the aluminum-titanium nitride hard alloy coating is used as a test coating, and the hardness measurement method comprises the following steps:
(1) taking a hard tool coated with a nitrogen-aluminum-titanium hard alloy coating, and cleaning to remove oil stains;
(2) dissolving polymethyl methacrylate (PMMA) in acetone to prepare a PMMA solution with the mass concentration of 16%, and sealing and standing for 3 hours;
(3) drying the hard cutter obtained in the step (2) in a drying oven at the temperature of 55 ℃ for 1 h;
(4) placing a cutter on a test bench, heating PMMA to 70 ℃ by infrared rays to obtain proper brittleness/plasticity, and pressing a pressure head under the pressure of 0.1kg (for a hardness meter with the pressure range of 0.1-1 kg) to obtain an indentation;
(5) cooling for 50 min;
(6) dropping a deplating solution at the indentation, reacting for 100s, and then ultrasonically cleaning, thereby removing hard coating chips in the indentation and facilitating observation and measurement; wherein the deplating liquid is a mixed liquid of hydrofluoric acid and nitric acid which are added with polyvinylpyrrolidone thickening agents and have the volume ratio of 1:1, and the mass of the added polyvinylpyrrolidone thickening agents is 0.8 percent of the mass of the deplating liquid;
(7) the indentation size was measured and the relative hardness was calculated.
Test examples
To verify the feasibility of the hardness measurement according to the invention, the hardness data of the titanium nitride coating measured several times according to the measurement method of example 1 of the invention and the micro-hardness of the titanium nitride coating measured outstandingly were compared, the comparison results being shown in table 1.
Table 1 hardness test results
As can be seen from Table 1, the measurement results of the present invention have small differences in the absolute value of hardness and microhardness, but the hardness change trend of the coating can be well reflected, and the measurement results after repeated times are within the error range. That is, the comparison results show that the hardness measurement method of the invention can satisfy the stability monitoring of the hardness of the coating in daily coating production.
Claims (10)
1. A method of measuring the hardness of a hard coating comprising the steps of:
(1) arranging a thermoplastic organic material coating on the hard coating of the sample to be detected;
(2) heating and softening the thermoplastic organic material coating, then pressing an indentation on the thermoplastic organic material coating, cooling, measuring the size of the indentation, and calculating the hardness of the hard coating; wherein, when the thermoplastic organic material coating is pressed with the impression, the hard coating is also pressed with the impression, the impression does not penetrate the hard coating, and the size of the impression pressed on the thermoplastic organic material coating is larger than that of the impression pressed on the hard coating.
2. The method of measuring hard coating hardness according to claim 1, comprising the steps of:
(1) arranging a PMMA coating on the hard coating of the sample to be detected;
(2) heating the PMMA coating to 65-85 ℃ by adopting infrared rays, then pressing an indentation on the PMMA coating, cooling, measuring the size of the indentation, and calculating the hardness of the hard coating; wherein, when the thermoplastic organic material coating is pressed with the impression, the hard coating is also pressed with the impression, the impression does not penetrate the hard coating, and the size of the impression pressed on the thermoplastic organic material coating is larger than that of the impression pressed on the hard coating.
3. The method for measuring the hardness of a hard coating according to claim 2, wherein the thickness of the PMMA coating is 50-300 μm.
4. The method of measuring hard coating hardness according to claim 2, wherein step (1) the PMMA coating comprises a first PMMA coating and a second PMMA coating thereunder, the first PMMA coating comprises PMMA and conductive filler, and the second PMMA coating comprises PMMA and titanium oxide.
5. The method for measuring the hardness of a hard coating according to claim 4, wherein the PMMA coating is cut into a PMMA tape containing an indentation after the cooling in the step (2), and then the PMMA burr generated in the indentation pressing process is melted by applying a current to two ends of the PMMA tape.
6. The method of measuring hard coating hardness according to claim 4, wherein the conductive filler is at least one of flake graphite, needle coke; the particle size of the conductive filler is 50-200 mu m.
7. The method for measuring the hardness of a hard coating according to claim 5, wherein the PMMA tape has a width of 3 to 8mm and a length of 15 to 25 mm.
8. The method of measuring hard coating hardness according to claim 4, wherein the thickness of the second PMMA coating is no more than 400 nm.
9. The method for measuring the hardness of a hard coating according to claim 1 or 2, wherein the cooling time in step (2) is 40min or more.
10. The method for measuring the hardness of the hard coating according to claim 1 or 2, wherein the step (2) is followed by cleaning, wherein the cleaning is performed by using a deplating solution to clean the scraps at the indentation, and the deplating solution is added with polyvinylpyrrolidone.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811625665.6A CN109632542B (en) | 2018-12-28 | 2018-12-28 | Method for measuring hardness of hard coating |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811625665.6A CN109632542B (en) | 2018-12-28 | 2018-12-28 | Method for measuring hardness of hard coating |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109632542A CN109632542A (en) | 2019-04-16 |
| CN109632542B true CN109632542B (en) | 2021-07-23 |
Family
ID=66079111
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811625665.6A Active CN109632542B (en) | 2018-12-28 | 2018-12-28 | Method for measuring hardness of hard coating |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109632542B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1693875A (en) * | 2004-05-09 | 2005-11-09 | 中国科学院金属研究所 | Continuous loading vickers |
| CN2890890Y (en) * | 2006-04-14 | 2007-04-18 | 哈尔滨工业大学 | Micro-nanometer scale mechanical property tester |
| CN1963447A (en) * | 2006-11-01 | 2007-05-16 | 北京科技大学 | Apparatus for testing transformation temperature between toughness and brittleness, rupture toughness at different temperature and rigidity |
| JP2009064040A (en) * | 2008-12-08 | 2009-03-26 | Ricoh Co Ltd | Image forming apparatus |
| CN101466542A (en) * | 2006-06-26 | 2009-06-24 | 赢创罗姆有限责任公司 | Transparent plastic composite |
| CN102393341A (en) * | 2011-08-03 | 2012-03-28 | 湘潭大学 | Device for testing hardness, fracture toughness and residual stress of brittle material with indentation method |
| CN104075941A (en) * | 2014-06-12 | 2014-10-01 | 湘潭大学 | In-situ synchronous test method and device for fracture toughness and residual stress of fragile material |
| CN104568623A (en) * | 2014-08-13 | 2015-04-29 | 南京汉旗新材料科技有限公司 | Method for measuring hardness of biomass material |
-
2018
- 2018-12-28 CN CN201811625665.6A patent/CN109632542B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1693875A (en) * | 2004-05-09 | 2005-11-09 | 中国科学院金属研究所 | Continuous loading vickers |
| CN2890890Y (en) * | 2006-04-14 | 2007-04-18 | 哈尔滨工业大学 | Micro-nanometer scale mechanical property tester |
| CN101466542A (en) * | 2006-06-26 | 2009-06-24 | 赢创罗姆有限责任公司 | Transparent plastic composite |
| CN1963447A (en) * | 2006-11-01 | 2007-05-16 | 北京科技大学 | Apparatus for testing transformation temperature between toughness and brittleness, rupture toughness at different temperature and rigidity |
| JP2009064040A (en) * | 2008-12-08 | 2009-03-26 | Ricoh Co Ltd | Image forming apparatus |
| CN102393341A (en) * | 2011-08-03 | 2012-03-28 | 湘潭大学 | Device for testing hardness, fracture toughness and residual stress of brittle material with indentation method |
| CN104075941A (en) * | 2014-06-12 | 2014-10-01 | 湘潭大学 | In-situ synchronous test method and device for fracture toughness and residual stress of fragile material |
| CN104568623A (en) * | 2014-08-13 | 2015-04-29 | 南京汉旗新材料科技有限公司 | Method for measuring hardness of biomass material |
Non-Patent Citations (1)
| Title |
|---|
| 影响薄膜（涂层）硬度测试的因素;李清河;《分析检测》;20010930;全文 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109632542A (en) | 2019-04-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US20200223750A1 (en) | S-shaped stress profiles and methods of making | |
| TWI679183B (en) | Strengthened glass with deep depth of compression | |
| CN102494997B (en) | Detection method for interface bonding strength of particle reinforced metal matrix composite material | |
| TW201619088A (en) | Glasses and glass ceramics including a metal oxide concentration gradient | |
| CN103808651B (en) | A kind of method of testing of historical relic's protection material adhesive power | |
| CN107389447B (en) | Tensile sample manufactured by metal additive | |
| JP2013542159A (en) | Glass plate | |
| CN109632542B (en) | Method for measuring hardness of hard coating | |
| CN108548775A (en) | Enamel coating electrode and preparation method, corrosion resistance test method | |
| CN106680200A (en) | Method for detecting interface bonding strength of composite materials | |
| CN103105332B (en) | Method for testing cracking toughness of materials by orthogonal cutting process | |
| CN105092332A (en) | Dressing tool and method of specimen used for testing rheological properties of pitch | |
| CN110229640B (en) | Preparation and self-monitoring method of self-sensing composite material adhesive | |
| Lim | The impact of wafer back surface finish on chip strength | |
| CN110455572B (en) | Ceramic electronic component metallographic section and preparation method thereof | |
| CN107091786A (en) | A kind of method for the micro-vickers hardness for measuring glass substrate | |
| CN107807025A (en) | A kind of method for prefabricating of metal material cycles left life-span specimen surface crackle | |
| JP2005257514A (en) | Coating film adhesion strength measuring method | |
| CN208109562U (en) | A kind of X fluorescence spectrometer melts model machine aluminous refractory mold support automatically | |
| CN105729302A (en) | Clamp for preparing dental micro-tensile specimen and process for clamp | |
| CN113406393B (en) | Device and method for testing volume resistivity of conductive gel | |
| CN114654179B (en) | Preparation method of force measuring gasket of gas turbine bearing bush | |
| CN110470200A (en) | A method of detection diamond compact takes off cobalt depth | |
| CN110561284B (en) | Grinding tool for processing single crystal sapphire and preparation process thereof | |
| Rohumaa et al. | The impact of log heating on veneer quality and plywood performance |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |