Thermal spraying-Low pressure plasma spraying Ni-CO-Cr-Al-Y-Ta alloy coating
Some standard content:
ICS25.220.20
National Standard of the People's Republic of China
GB/T18681--2002
Thermal spraying
Low pressure plasma spraying
Nickel-Cobalt-Chromium-Aluminum-Molybdenum alloy coating
Thermal spraying--Low pressure plasma sprayingNi-Co-Cr-AI-Y-Ta alloy coating2002-03-10Promulgated
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
2002-08-01Implementation
GB/T18681—2002
Appendix A of this standard is an informative appendix. This standard is proposed by the China Machinery Industry Federation. Former
This standard is under the jurisdiction of the National Technical Committee for Standardization of Metallic and Non-metallic Coatings. The responsible drafting units of this standard are: Guangzhou Nonferrous Metals Research Institute, China Southern Aviation Power Machinery Company. The main drafters of this standard are: Hong Ruijiang, Zhou Kesong, Wu Ying, Diao Chupeng, Dai Dahuang. 160
1 Scope
Thermal spraying low-pressure plasma spraying
Nickel-cobalt-chromium-aluminum-yttrium-molybdenum alloy coating
GB/T18681—2002
This standard specifies the technical requirements and test methods of low-pressure plasma sprayed nickel-cobalt-chromium-aluminum-yttrium-molybdenum (NiCoCrAlYTa) alloy coatings.
This standard is applicable to low-pressure plasma sprayed NiCoCrAlYTa coatings for high-temperature parts of aircraft engines that resist high-temperature oxidation and hot corrosion.
This standard is also applicable to MCrAlY (M represents Ni, Co, NiCo, etc.) low-pressure plasma sprayed coatings. 2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For all referenced documents with dates, all subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, parties that reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all referenced documents without dates, the latest versions are applicable to this standard. GB/T6462 Microscope measurement method for cross-sectional thickness of metal and oxide coatings (eqvISO1463) GB/T6524 Determination of particle size distribution of metal powders - Light transmittance method (ne9ASTMB430) GB/T8642 Determination of bonding strength of thermal spray coatings - Vickers and Knoop microhardness tests for metal coatings and other related coatings (negISO4516) GB/T9790
GB/T13277
General quality grades of compressed air
Corrosion of metals and alloys - Removal of corrosion products on corrosion specimens (idtISO8407) GB/T16545
HB5258: Test method for determination of oxidation resistance of steel and high-temperature alloys 3 Terms and definitions
Low pressure plasma spraying (LPPs) Plasma spraying carried out in a low pressure isolation chamber. 3.2
Transferred arc cleaning uses a transferred arc to clean the surface of the workpiece, making it clean and activated, and preheating the workpiece to the temperature required for spraying. 3.3
Inspection batch (abbreviation: batch)
Powder or workpieces collected for sampling inspection. In powder inspection, it refers to the total amount purchased at one time. In workpiece inspection, it refers to the delivery quantity at one time. 4 Equipment
Low-pressure plasma spraying equipment should have the following basic conditions: 4.1 The vacuum chamber pressure should be automatically controlled to ensure the stability of the vacuum chamber pressure: the vacuum pipeline should be equipped with a dust filter to reduce dust pollution to the vacuum unit and the atmospheric environment. 161
GB/T18681—2002
4.2 The spray gun operating system should have a three-degree-of-freedom operating machine; for workpieces with complex shapes, such as the spraying of turbine engine blades, a six-degree-of-freedom robot is required.
5 Powder
The chemical composition and particle size requirements of NiCoCrAIYTa powder are shown in Table 1. Each batch (time) of powder purchased should be retested before spraying. Only powder that meets the requirements can be used for spraying. Its chemical composition can be confirmed by ICP method (inductively coupled plasma-atomic emission spectrometry), and the particle size distribution of powder is determined according to GB/T6524. Table 1 NiCoCrAIYTa powder composition and particle size Chemical composition
Mass fraction (%)
Particle size range/μm
6 Workpiece pretreatment
6.1 Workpiece surface state before spraying
The surface of the workpiece to be sprayed must be free of dust, oil and oxide scale, and its roughness should match the surface roughness requirements of the sprayed coating. If there are special needs, it must be determined by negotiation between the supply and demand parties. 6.2 Cleaning the workpiece
Soak it in chlorine solvent or other degreasing agent, and remove oil by ultrasonic cleaning for 5min~10min. The water film on the surface of the part is continuous and the oil is completely removed, then clean it with anhydrous alcohol.
6.3 Sandblasting
6.3.1 Shield and protect the surface of the non-spraying area. 6.3.2 According to the roughness requirements, select clean, dry white corundum with a particle size of 100 to 140 as the spray abrasive. 6.3.3 The oil and water content of the compressed air shall comply with the third level regulations specified in GB/T13277. The air pressure is 0.2MPa~0.3MPa. If there are special needs, it shall be determined through negotiation between the supply and demand parties. 6.3.4 The sandblasting angle is 60°~90°, and the sandblasting distance is 50mm~100mm. 6.3.5 Use clean compressed air to blow off the dust or abrasive adhering to the surface of the substrate. 6.4 Workpiece marking
Register according to the workpiece number. For workpieces with strict requirements on thickness and weight gain, such as the first and second stage blades of turbine engines, they should be weighed one by one and registered.
6.5 Shielding and protection
Put the workpiece into the spraying tooling, shield and protect the non-spraying parts and tooling. 7 Transfer arc cleaning
7.1 Pre-vacuum degree
After the workpiece is installed, close the vacuum chamber and start the vacuum system to make the pressure in the vacuum chamber ≤6.7Pa. 7.2 Vacuum chamber working pressure
When the vacuum chamber reaches the pre-vacuum degree, close the exhaust valve and fill the vacuum chamber with argon gas to increase the pressure to 6kPa~10kPa. 7.3 Spray gun power
Start the spray gun and control the arc power at 15kW~30kW, and adjust it according to the size of the transfer arc current. 7.4 Transfer arc current
Adjust the transfer arc power supply so that its current reaches a certain level, with the principle that the edges and corners of the workpiece will not be burned. 162
7.5 Workpiece preheating temperature
After the workpiece is cleaned by the transfer arc, its temperature should reach 700℃～900℃. 7.6 Waiting time for spraying
After the workpiece is cleaned by the transfer arc, it should be sprayed as soon as possible, and the interval time should not exceed 15s. 8 Spraying process
8.1 Vacuum chamber working pressure
GB/T18681-2002
After the transfer arc cleaning is completed, argon gas should continue to be filled into the vacuum chamber to increase the vacuum chamber pressure to 8kPa～12kPa. 8.2 Spraying process parameters
Appropriate spraying parameters should be selected, including arc current, arc voltage, spraying distance, nozzle type, plasma gas pressure and flow rate, powder feeding rate, etc. Through metallographic analysis, the parameters corresponding to the number of unmelted particles, microcracks, porosity and the number of second phases or inclusions at the interface contained in the coating shall prevail. 8.3 Workpiece Cooling
After the workpiece is sprayed, the vacuum chamber should continue to maintain the inert atmosphere, and the workpiece should cool naturally with the furnace. 9 Workpiece Disassembly
The workpiece and tooling should be able to be easily disassembled, and no collision is allowed during the operation. If the above situation occurs, it should be studied and handled by technical personnel and quality management personnel.
10 Coating Rework
10.1 Removal of coating.
10.1.1 Bath liquid for removing coating: hydrochloric acid (chemically pure) and water (deionized water) are mixed in a volume ratio of 1:1. 10.1.2 Bath liquid temperature: 50℃ (for un-diffused coating); bath liquid temperature: 70℃ (for diffused coating). 10.1.3 Soaking time: 1.5h~2.5h.
10.1.4 Shield and protect the key parts of the non-spraying area. 10.1.5 Continuously stir the bath liquid to make the temperature uniform. 10.2 After removing the coating, rinse, brush and dry the parts. 10.3 Re-treat the surface and spray the coating. Follow the provisions of Chapters 6, 7 and 8.
11 Post-treatment of coating
11.1 Diffusion treatment
After spraying, the coating that has passed the preliminary inspection should be diffused.Diffusion treatment conditions are shown in Table 2. For diffusion treatment of other materials, refer to the heat treatment conditions of the alloy.
Table 2 Diffusion treatment conditions
Workpiece material brand
Treatment temperature and time
1080±5℃, 4h and 870℃±5℃32h1080℃±5C.4h
1080C±5C.4h and 870C±5C, 32h
1020℃±5℃, 2h and 980℃±5℃.2hVacuum chamber pressure
1.33×10-Pa~1.33X10-Pa
GB/T18681—2002
11.2 Post-processing
In most cases, due to size requirements or surface roughness requirements, the coating needs to be fine-processed after spraying and heat treatment. The required size can be achieved by grinding, and the processing parameters are shown in Table 3; the coating can be made to achieve the required surface roughness by liquid sandblasting or vibration finishing, and the liquid sandblasting process is shown in Table 4; the vibration finishing conditions can be formulated by the technical department based on the specific shape and size of the parts with reference to Table 4.
Table 3 Grinding parameters of NiCoCrAIYTa coating Grinding wheel
No. 60 SiC grinding wheel
Abrasive used
No. 120 corundum sand
12 Technical requirements of coatingwwW.bzxz.Net
12.1 Appearance
Part speed/(m/min)
60~150
Grinding wheel speed/(m/s)
Lubricant
Water mixture
Table 4 Liquid sandblasting process parameters of NiCoCrAIYTa coating Air pressure/MPa
Sandblasting distance/mm
80~-100
The sprayed coating should have a uniform appearance, and there should be no cracks, delamination, peeling or blistering on the coating, and no improper masking. 12.2 Thickness
The coating thickness shall meet the requirements of the design drawings.
12.3 Weight gain
Roughness Ra/μm
Time/s
For parts with weight gain requirements, the weight gain range should be determined by discussion between the supply and demand parties based on the test results. Since there is a certain correspondence between the weight gain value and the thickness distribution of the coating, the weight gain value can also be used as the basis for coating acceptance. 12.4 Bonding strength
The average bonding strength of the sprayed coating should be greater than 50MPa. 12.5 Cupping test
It is carried out on the test piece, and the coating without diffusion treatment should not delaminate. Capillary cracks or cracks in the coating near the test area are allowed. 12.6 Metallographic structure
The coating structure is uniform, the coating and the substrate should be well bonded, and there are no defects such as cracks and voids at the interface. Porosity <2%, the number of unmelted particles <2%, and the maximum particle diameter <10um. After diffusion treatment, there should be an obvious diffusion zone at the coating/substrate interface. The metallographic structure conforms to the typical structure shown in Figure 1.
Diffusion layer
Figure 1 Metallographic structure of the coating after diffusion treatment (X400) 164
12.7 Hardness
GB/T18681-2002
Microhardness of the coating: 530HVO.2~580HVO.2 in the sprayed state, ≥420HV0.2 after diffusion treatment. 12.8, Chemical composition of coating
The purpose is to test the correctness of the powder used, and the chemical composition of the coating material should be consistent with the chemical composition of the powder material. 12.9 Anti-oxidation/corrosion performance
The anti-oxidation/corrosion performance of the coating should meet the design requirements. 13 Coating quality inspection method
13.1 Appearance inspection
The coating surface can be observed by visual inspection or a magnifying glass of less than 10 times, and 100% inspection. Focus on checking the edge of the coating to see if there is any peeling or spray leakage.
13.2 Coating thickness inspection
13.2.1 Spray one test piece or test piece for each batch of parts before and after spraying. 13.2.2 Determine the location and direction of the dissection based on the size and shape of the test piece or test piece for inspection. 13.2.3 Perform a microscope inspection of the coating thickness according to GB/T6462. 13.3 Weight gain measurement
Weigh the parts after spraying and compare them with the original weight to calculate the weight gain of the workpiece, accurate to 1mg, and 100% inspection. 13.4 Coating bonding strength measurement
Before each batch of parts is formally sprayed, perform a bonding strength test on the test piece or test piece for inspection according to GB/T8642. 13.5 Cupping test method
Perform before spraying each batch of parts. Use a 100mm×70mm×1.3mm test piece, the test piece material is GH3030 or 1Cr18Ni9Ti. Spray the coating on one side of the test piece, the coating thickness is 50μm~100μm, and the minimum spraying area should be 45mmX45mm. During the test, use a 22mm steel ball indenter to press down from the uncoated side, and the indenter presses down to a depth of 5mm. After the cupping test, visually inspect the coating in the deformed area or use a magnifying glass of less than 10 times. 13.6 Metallographic Inspection
13.6.1 Spray one test piece or test piece for inspection before and after each batch of parts is sprayed. 13.6.2 Determine the anatomical location and direction of the test piece or test piece for inspection based on its size and shape. 13.6.3 Clamp (embed) the sample, and grind it lightly with the pre-grinding disc and sandpaper in turn. The grinding direction is about 45 degrees to the coating. Each time the sandpaper is changed, the sample is rotated 90%
13.6.4 Use coating etchant to display the coating microstructure. The etchant composition is: nitric acid: acetic acid: water: hydrofluoric acid = 33:33:33:1 (volume ratio) or nitric acid: hydrochloric acid: glycerol = 1:3:5 (volume ratio). The above reagents are all chemically pure, and the water is deionized water. Use it as soon as it is prepared. 13.6.5 Observe the coating structure, interface state, measure porosity, unmelted particle size and number. 13.7 Coating hardness
Carry out simultaneously with metallographic inspection. Measure according to GB/T9790. 13.8 Coating chemical composition test
Carry out on the test piece after each batch of parts is sprayed. Use X-ray fluorescence spectroscopy or electron probe analysis or scanning electron microscope energy error analysis to measure and confirm whether the powder used is accurate. 13.9 Anti-oxidation performance test of coating
The anti-oxidation performance test of coating is carried out according to HB5258. 13.10 The high-temperature gas corrosion resistance test of coating is carried out on the gas corrosion tester. 1h is a cycle, in which heating in the tester for 55min and compressed air cooling outside the furnace for 5min. 165
GB/T18681—2002
Test temperature: 900℃±10℃.
13.10.2 Fuel flow rate: 0.2 L/h.
13-10.3 Oil-gas ratio: 1/45.
13.10.4Seawater concentration: 10-5, can be increased to 5×10-5 if necessary13.10.5Test time: 150h, can be increased to more than 200h if necessary. 13.10.6After the coating test, the corrosion products formed on the surface of the sample shall be removed according to GB/T16545. After the corrosion products are removed, it shall be ensured that no traces of corrosion products can be found by visual inspection or inspection with a ten-fold magnifying glass. Check the weight loss, appearance and metallographic structure of the coating before and after the magic corrosion, and record the test results.
Appendix A
(Informative Appendix)
References
GB/T18681—2002
The test method for the high temperature gas corrosion resistance of the coating refers to the enterprise standard of the Aviation Materials Research Institute of China Aviation Industry Corporation: Q/6S365-1983
3 High temperature gas corrosion test method.2 Post-processing
In most cases, due to size requirements or surface roughness requirements, the coating needs to be finished after spraying and heat treatment. The required size can be achieved through grinding, and the processing parameters are shown in Table 3; the coating can be treated with liquid sandblasting or vibration finishing to achieve the required surface roughness, and the liquid sandblasting process is shown in Table 4; the vibration finishing treatment conditions can be formulated by the technical department based on the specific shape and size of the parts with reference to Table 4.
Table 3 Grinding parameters of NiCoCrAIYTa coating Grinding wheel
No. 60 SiC grinding wheel
Abrasive used
No. 120 corundum sand
12 Technical requirements of coating
12.1 Appearance
Part speed/(m/min)
60~150
Grinding wheel speed/(m/s)
Lubricant
Water mixture
Table 4 Liquid sandblasting process parameters of NiCoCrAIYTa coating Air pressure/MPa
Sandblasting distance/mm
80~-100
The sprayed coating should have a uniform appearance, and there should be no cracks, delamination, peeling or blistering on the coating, and no improper masking. 12.2 Thickness
The coating thickness shall meet the requirements of the design drawings.
12.3 Weight gain
Roughness Ra/μm
Time/s
For parts with weight gain requirements, the weight gain range should be determined by discussion between the supply and demand parties based on the test results. Since there is a certain correspondence between the weight gain value and the thickness distribution of the coating, the weight gain value can also be used as the basis for coating acceptance. 12.4 Bonding strength
The average bonding strength of the sprayed coating should be greater than 50MPa. 12.5 Cupping test
It is carried out on the test piece, and the coating without diffusion treatment should not delaminate. Capillary cracks or cracks in the coating near the test area are allowed. 12.6 Metallographic structure
The coating structure is uniform, the coating and the substrate should be well bonded, and there are no defects such as cracks and voids at the interface. Porosity <2%, the number of unmelted particles <2%, and the maximum particle diameter <10um. After diffusion treatment, there should be an obvious diffusion zone at the coating/substrate interface. The metallographic structure conforms to the typical structure shown in Figure 1.
Diffusion layer
Figure 1 Metallographic structure of the coating after diffusion treatment (X400) 164
12.7 Hardness
GB/T18681-2002
Microhardness of the coating: 530HVO.2~580HVO.2 in the sprayed state, ≥420HV0.2 after diffusion treatment. 12.8, Chemical composition of coating
The purpose is to test the correctness of the powder used, and the chemical composition of the coating material should be consistent with the chemical composition of the powder material. 12.9 Anti-oxidation/corrosion performance
The anti-oxidation/corrosion performance of the coating should meet the design requirements. 13 Coating quality inspection method
13.1 Appearance inspection
The coating surface can be observed by visual inspection or a magnifying glass of less than 10 times, and 100% inspection. Focus on checking the edge of the coating to see if there is any peeling or spray leakage.
13.2 Coating thickness inspection
13.2.1 Spray one test piece or test piece for each batch of parts before and after spraying. 13.2.2 Determine the location and direction of the dissection based on the size and shape of the test piece or test piece for inspection. 13.2.3 Perform a microscope inspection of the coating thickness according to GB/T6462. 13.3 Weight gain measurement
Weigh the parts after spraying and compare them with the original weight to calculate the weight gain of the workpiece, accurate to 1mg, and 100% inspection. 13.4 Coating bonding strength measurement
Before each batch of parts is formally sprayed, perform a bonding strength test on the test piece or test piece for inspection according to GB/T8642. 13.5 Cupping test method
Perform before spraying each batch of parts. Use a 100mm×70mm×1.3mm test piece, the test piece material is GH3030 or 1Cr18Ni9Ti. Spray the coating on one side of the test piece, the coating thickness is 50μm~100μm, and the minimum spraying area should be 45mmX45mm. During the test, use a 22mm steel ball indenter to press down from the uncoated side, and the indenter presses down to a depth of 5mm. After the cupping test, visually inspect the coating in the deformed area or use a magnifying glass of less than 10 times. 13.6 Metallographic Inspection
13.6.1 Spray one test piece or test piece for inspection before and after each batch of parts is sprayed. 13.6.2 Determine the anatomical location and direction of the test piece or test piece for inspection based on its size and shape. 13.6.3 Clamp (embed) the sample, and grind it lightly with the pre-grinding disc and sandpaper in turn. The grinding direction is about 45 degrees to the coating. Each time the sandpaper is changed, the sample is rotated 90%
13.6.4 Use coating etchant to display the coating microstructure. The etchant composition is: nitric acid: acetic acid: water: hydrofluoric acid = 33:33:33:1 (volume ratio) or nitric acid: hydrochloric acid: glycerol = 1:3:5 (volume ratio). The above reagents are all chemically pure, and the water is deionized water. Use it as soon as it is prepared. 13.6.5 Observe the coating structure, interface state, measure porosity, unmelted particle size and number. 13.7 Coating hardness
Carry out simultaneously with metallographic inspection. Measure according to GB/T9790. 13.8 Coating chemical composition test
Carry out on the test piece after each batch of parts is sprayed. Use X-ray fluorescence spectroscopy or electron probe analysis or scanning electron microscope energy error analysis to measure and confirm whether the powder used is accurate. 13.9 Anti-oxidation performance test of coating
The anti-oxidation performance test of coating is carried out in accordance with HB5258. 13.10 The high-temperature gas corrosion resistance test of coating is carried out on a gas corrosion tester. 1h is a cycle, in which heating in the tester for 55min and compressed air cooling outside the furnace for 5min. 165
GB/T18681—2002
Test temperature: 900℃±10℃.
13.10.2 Fuel flow rate: 0.2 L/h.
13-10.3 Oil-gas ratio: 1/45.
13.10.4Seawater concentration: 10-5, can be increased to 5×10-5 if necessary13.10.5Test time: 150h, can be increased to more than 200h if necessary. 13.10.6After the coating test, the corrosion products formed on the surface of the sample shall be removed according to GB/T16545. After the corrosion products are removed, it shall be ensured that no traces of corrosion products can be found by visual inspection or inspection with a ten-fold magnifying glass. Check the weight loss, appearance and metallographic structure of the coating before and after the magic corrosion, and record the test results.
Appendix A
(Informative Appendix)
References
GB/T18681—2002
The test method for the high temperature gas corrosion resistance of the coating refers to the enterprise standard of the Aviation Materials Research Institute of China Aviation Industry Corporation: Q/6S365-1983
3 High temperature gas corrosion test method.2 Post-processing
In most cases, due to size requirements or surface roughness requirements, the coating needs to be finished after spraying and heat treatment. The required size can be achieved through grinding, and the processing parameters are shown in Table 3; the coating can be treated with liquid sandblasting or vibration finishing to achieve the required surface roughness, and the liquid sandblasting process is shown in Table 4; the vibration finishing treatment conditions can be formulated by the technical department based on the specific shape and size of the parts with reference to Table 4.
Table 3 Grinding parameters of NiCoCrAIYTa coating Grinding wheel
No. 60 SiC grinding wheel
Abrasive used
No. 120 corundum sand
12 Technical requirements of coating
12.1 Appearance
Part speed/(m/min)
60~150
Grinding wheel speed/(m/s)
Lubricant
Water mixture
Table 4 Liquid sandblasting process parameters of NiCoCrAIYTa coating Air pressure/MPa
Sandblasting distance/mm
80~-100
The sprayed coating should have a uniform appearance, and there should be no cracks, delamination, peeling or blistering on the coating, and no improper masking. 12.2 Thickness
The coating thickness shall meet the requirements of the design drawings.
12.3 Weight gain
Roughness Ra/μm
Time/s
For parts with weight gain requirements, the weight gain range should be determined by discussion between the supply and demand parties based on the test results. Since there is a certain correspondence between the weight gain value and the thickness distribution of the coating, the weight gain value can also be used as the basis for coating acceptance. 12.4 Bonding strength
The average bonding strength of the sprayed coating should be greater than 50MPa. 12.5 Cupping test
It is carried out on the test piece, and the coating without diffusion treatment should not delaminate. Capillary cracks or cracks in the coating near the test area are allowed. 12.6 Metallographic structure
The coating structure is uniform, the coating and the substrate should be well bonded, and there are no defects such as cracks and voids at the interface. Porosity <2%, the number of unmelted particles <2%, and the maximum particle diameter <10um. After diffusion treatment, there should be an obvious diffusion zone at the coating/substrate interface. The metallographic structure conforms to the typical structure shown in Figure 1.
Diffusion layer
Figure 1 Metallographic structure of the coating after diffusion treatment (X400) 164
12.7 Hardness
GB/T18681-2002
Microhardness of the coating: 530HVO.2~580HVO.2 in the sprayed state, ≥420HV0.2 after diffusion treatment. 12.8, Chemical composition of coating
The purpose is to test the correctness of the powder used, and the chemical composition of the coating material should be consistent with the chemical composition of the powder material. 12.9 Anti-oxidation/corrosion performance
The anti-oxidation/corrosion performance of the coating should meet the design requirements. 13 Coating quality inspection method
13.1 Appearance inspection
The coating surface can be observed by visual inspection or a magnifying glass of less than 10 times, and 100% inspection. Focus on checking the edge of the coating to see if there is any peeling or spray leakage.
13.2 Coating thickness inspection
13.2.1 Spray one test piece or test piece for each batch of parts before and after spraying. 13.2.2 Determine the location and direction of the dissection based on the size and shape of the test piece or test piece for inspection. 13.2.3 Perform a microscope inspection of the coating thickness according to GB/T6462. 13.3 Weight gain measurement
Weigh the parts after spraying and compare them with the original weight to calculate the weight gain of the workpiece, accurate to 1mg, and 100% inspection. 13.4 Coating bonding strength measurement
Before each batch of parts is formally sprayed, perform a bonding strength test on the test piece or test piece for inspection according to GB/T8642. 13.5 Cupping test method
Perform before spraying each batch of parts. Use a 100mm×70mm×1.3mm test piece, the test piece material is GH3030 or 1Cr18Ni9Ti. Spray the coating on one side of the test piece, the coating thickness is 50μm~100μm, and the minimum spraying area should be 45mmX45mm. During the test, use a 22mm steel ball indenter to press down from the uncoated side, and the indenter presses down to a depth of 5mm. After the cupping test, visually inspect the coating in the deformed area or use a magnifying glass of less than 10 times. 13.6 Metallographic Inspection
13.6.1 Spray one test piece or test piece for inspection before and after each batch of parts is sprayed. 13.6.2 Determine the anatomical location and direction of the test piece or test piece for inspection based on its size and shape. 13.6.3 Clamp (embed) the sample, and grind it lightly with the pre-grinding disc and sandpaper in turn. The grinding direction is about 45 degrees to the coating. Each time the sandpaper is changed, the sample is rotated 90%
13.6.4 Use coating etchant to display the coating microstructure. The etchant composition is: nitric acid: acetic acid: water: hydrofluoric acid = 33:33:33:1 (volume ratio) or nitric acid: hydrochloric acid: glycerol = 1:3:5 (volume ratio). The above reagents are all chemically pure, and the water is deionized water. Use it as soon as it is prepared. 13.6.5 Observe the coating structure, interface state, measure porosity, unmelted particle size and number. 13.7 Coating hardness
Carry out simultaneously with metallographic inspection. Measure according to GB/T9790. 13.8 Coating chemical composition test
Carry out on the test piece after each batch of parts is sprayed. Use X-ray fluorescence spectroscopy or electron probe analysis or scanning electron microscope energy error analysis to measure and confirm whether the powder used is accurate. 13.9 Anti-oxidation performance test of coating
The anti-oxidation performance test of coating is carried out in accordance with HB5258. 13.10 The high-temperature gas corrosion resistance test of coating is carried out on a gas corrosion tester. 1h is a cycle, in which heating in the tester for 55min and compressed air cooling outside the furnace for 5min. 165
GB/T18681—2002
Test temperature: 900℃±10℃.
13.10.2 Fuel flow rate: 0.2 L/h.
13-10.3 Oil-gas ratio: 1/45.
13.10.4Seawater concentration: 10-5, can be increased to 5×10-5 if necessary13.10.5Test time: 150h, can be increased to more than 200h if necessary. 13.10.6After the coating test, the corrosion products formed on the surface of the sample shall be removed according to GB/T16545. After the corrosion products are removed, it shall be ensured that no traces of corrosion products can be found by visual inspection or inspection with a ten-fold magnifying glass. Check the weight loss, appearance and metallographic structure of the coating before and after the magic corrosion, and record the test results.
Appendix A
(Informative Appendix)
References
GB/T18681—2002
The test method for the high temperature gas corrosion resistance of the coating refers to the enterprise standard of the Aviation Materials Research Institute of China Aviation Industry Corporation: Q/6S365-1983
3 High temperature gas corrosion test method.6 Metallographic structure
The coating structure is uniform, the coating and the substrate should be well combined, and there are no defects such as cracks and voids at the interface. Porosity <2%, number of unmelted particles <2%, maximum particle diameter <10um. After diffusion treatment, there should be an obvious diffusion zone at the coating/substrate interface. The metallographic structure conforms to the typical structure shown in Figure 1.
Diffusion layer
Figure 1 Metallographic structure of the coating after diffusion treatment (X400) 164
12.7 Hardness
GB/T18681-2002
Microhardness of the coating: 530HVO.2~580HVO.2 in the sprayed state, ≥420HV0.2 after diffusion treatment. 12.8, Chemical composition of the coating
The purpose is to test the correctness of the powder used. The chemical composition of the coating material should be consistent with the chemical composition of the powder material. 12.9 Anti-oxidation/corrosion performance
The anti-oxidation/corrosion performance of the coating shall meet the design requirements. 13 Coating quality inspection method
13.1 Appearance inspection
The coating surface can be observed visually or with a magnifying glass of less than 10 times, and 100% inspection is required. Focus on inspecting the edge of the coating to observe whether there is peeling or spray leakage.
13.2 Coating thickness inspection
13.2.1 Spray one test piece or test piece for each batch of parts before and after spraying. 13.2.2 According to the size and shape of the test piece or test piece for inspection, determine its anatomical location and direction. 13.2.3 Conduct a microscope inspection of the coating thickness according to GB/T6462. 13.3 Weight gain measurement
Weigh the parts after spraying and compare them with the original weight to calculate the weight gain of the workpiece, accurate to 1mg, and 100% inspection is required. 13.4 Coating bonding strength measurement
Before each batch of parts is formally sprayed, the test pieces or test pieces for inspection shall be tested for bonding strength according to GB/T8642. 13.5 Cupping test method
Before each batch of parts is sprayed. Use a 100mm×70mm×1.3mm test piece, and the test piece material is GH3030 or 1Cr18Ni9Ti. Spray the coating on one side of the test piece, the coating thickness is 50μm~100μm, and the minimum spraying area should be 45mmX45mm. During the test, use a 22mm steel ball indenter to press down from the uncoated side, and the indenter presses down to a depth of 5mm. After the cupping test, visually inspect the coating in the deformed area or use a magnifying glass of less than 10 times. 13.6 Metallographic inspection
13.6.1 Spray one test piece or test piece for inspection before and after each batch of parts is sprayed. 13.6.2 Determine the anatomical location and direction of the test piece or specimen according to its size and shape. 13.6.3 Clamp (mount) the specimen and grind it lightly with the pre-grinding disc and sandpaper in turn. The grinding direction is about 45 degrees to the coating. Rotate the specimen by 90% each time the sandpaper is changed. 13.6.4 Use coating etchant to display the microstructure of the coating. The etchant composition is: nitric acid: acetic acid: water: hydrofluoric acid = 33:33:33:1 (volume ratio) or nitric acid: hydrochloric acid: glycerol = 1:3:5 (volume ratio). The above reagents are all chemically pure, and the water is deionized water. Use as soon as it is prepared. 13.6.5 Observe the coating structure, interface state, measure porosity, unmelted particle size and number. 13.7 Coating hardness
Carry out simultaneously with metallographic inspection. Measure according to GB/T9790. 13.8 Coating chemical composition test
Carry out on the test piece after each batch of parts is sprayed. Use X-ray fluorescence spectroscopy or electron probe analysis or scanning electron microscope energy error analysis to measure and confirm whether the powder used is accurate. 13.9 Anti-oxidation performance test of coating
The anti-oxidation performance test of coating is carried out in accordance with HB5258. 13.10 The high-temperature gas corrosion resistance test of coating is carried out on a gas corrosion tester. 1h is a cycle, in which heating in the tester for 55min and compressed air cooling outside the furnace for 5min. 165
GB/T18681—2002
Test temperature: 900℃±10℃.
13.10.2 Fuel flow rate: 0.2 L/h.
13-10.3 Oil-gas ratio: 1/45.
13.10.4Seawater concentration: 10-5, can be increased to 5×10-5 if necessary13.10.5Test time: 150h, can be increased to more than 200h if necessary. 13.10.6After the coating test, the corrosion products formed on the surface of the sample shall be removed according to GB/T16545. After the corrosion products are removed, it shall be ensured that no traces of corrosion products can be found by visual inspection or inspection with a ten-fold magnifying glass. Check the weight loss, appearance and metallographic structure of the coating before and after the magic corrosion, and record the test results.
Appendix A
(Informative Appendix)
References
GB/T18681—2002
The test method for the high temperature gas corrosion resistance of the coating refers to the enterprise standard of the Aviation Materials Research Institute of China Aviation Industry Corporation: Q/6S365-1983
3 High temperature gas corrosion test method.6 Metallographic structure
The coating structure is uniform, the coating and the substrate should be well combined, and there are no defects such as cracks and voids at the interface. Porosity <2%, number of unmelted particles <2%, maximum particle diameter <10um. After diffusion treatment, there should be an obvious diffusion zone at the coating/substrate interface. The metallographic structure conforms to the typical structure shown in Figure 1.
Diffusion layer
Figure 1 Metallographic structure of the coating after diffusion treatment (X400) 164
12.7 Hardness
GB/T18681-2002
Microhardness of the coating: 530HVO.2~580HVO.2 in the sprayed state, ≥420HV0.2 after diffusion treatment. 12.8, Chemical composition of the coating
The purpose is to test the correctness of the powder used. The chemical composition of the coating material should be consistent with the chemical composition of the powder material. 12.9 Anti-oxidation/corrosion performance
The anti-oxidation/corrosion performance of the coating shall meet the design requirements. 13 Coating quality inspection method
13.1 Appearance inspection
The coating surface can be observed visually or with a magnifying glass of less than 10 times, and 100% inspection is required. Focus on inspecting the edge of the coating to observe whether there is peeling or spray leakage.
13.2 Coating thickness inspection
13.2.1 Spray one test piece or test piece for each batch of parts before and after spraying. 13.2.2 According to the size and shape of the test piece or test piece for inspection, determine its anatomical location and direction. 13.2.3 Conduct a microscope inspection of the coating thickness according to GB/T6462. 13.3 Weight gain measurement
Weigh the parts after spraying and compare them with the original weight to calculate the weight gain of the workpiece, accurate to 1mg, and 100% inspection is required. 13.4 Coating bonding strength measurement
Before each batch of parts is formally sprayed, the test pieces or test pieces for inspection shall be tested for bonding strength according to GB/T8642. 13.5 Cupping test method
Before each batch of parts is sprayed. Use a 100mm×70mm×1.3mm test piece, and the test piece material is GH3030 or 1Cr18Ni9Ti. Spray the coating on one side of the test piece, the coating thickness is 50μm~100μm, and the minimum spraying area should be 45mmX45mm. During the test, use a 22mm steel ball indenter to press down from the uncoated side, and the indenter presses down to a depth of 5mm. After the cupping test, visually inspect the coating in the deformed area or use a magnifying glass of less than 10 times. 13.6 Metallographic inspection
13.6.1 Spray one test piece or test piece for inspection before and after each batch of parts is sprayed. 13.6.2 Determine the anatomical location and direction of the test piece or specimen according to its size and shape. 13.6.3 Clamp (mount) the specimen and grind it lightly with the pre-grinding disc and sandpaper in turn. The grinding direction is about 45 degrees to the coating. Rotate the specimen by 90% each time the sandpaper is changed. 13.6.4 Use coating etchant to display the microstructure of the coating. The etchant composition is: nitric acid: acetic acid: water: hydrofluoric acid = 33:33:33:1 (volume ratio) or nitric acid: hydrochloric acid: glycerol = 1:3:5 (volume ratio). The above reagents are all chemically pure, and the water is deionized water. Use as soon as it is prepared. 13.6.5 Observe the coating structure, interface state, measure porosity, unmelted particle size and number. 13.7 Coating hardness
Carry out simultaneously with metallographic inspection. Measure according to GB/T9790. 13.8 Coating chemical composition test
Carry out on the test piece after each batch of parts is sprayed. Use X-ray fluorescence spectroscopy or electron probe analysis or scanning electron microscope energy error analysis to measure and confirm whether the powder used is accurate. 13.9 Anti-oxidation performance test of coating
The anti-oxidation performance test of coating is carried out in accordance with HB5258. 13.10 The high-temperature gas corrosion resistance test of coating is carried out on a gas corrosion tester. 1h is a cycle, in which heating in the tester for 55min and compressed air cooling outside the furnace for 5min. 165
GB/T18681—2002
Test temperature: 900℃±10℃.
13.10.2 Fuel flow rate: 0.2 L/h.
13-10.3 Oil-gas ratio: 1/45.
13.10.4Seawater concentration: 10-5, can be increased to 5×10-5 if necessary13.10.5Test time: 150h, can be increased to more than 200h if necessary. 13.10.6After the coating test, the corrosion products formed on the surface of the sample shall be removed according to GB/T16545. After the corrosion products are removed, it shall be ensured that no traces of corrosion products can be found by visual inspection or inspection with a ten-fold magnifying glass. Check the weight loss, appearance and metallographic structure of the coating before and after the magic corrosion, and record the test results.
Appendix A
(Informative Appendix)
References
GB/T18681—2002
The test method for the high temperature gas corrosion resistance of the coating refers to the enterprise standard of the Aviation Materials Research Institute of China Aviation Industry Corporation: Q/6S365-1983
3 High temperature gas corrosion test method.4Seawater concentration: 10-5, can be increased to 5×10-5 if necessary13.10.5Test time: 150h, can be increased to more than 200h if necessary. 13.10.6After the coating test, remove the corrosion products formed on the surface of the sample according to GB/T16545. After removing the corrosion products, it should be ensured that no trace of corrosion products can be found by visual inspection or inspection with a ten-fold magnifying glass. Check the weight loss, appearance and metallographic structure of the coating before and after the magic corrosion, and record the test results.
Appendix A
(Informative Appendix)
References
GB/T18681—2002
The test method for the high-temperature gas corrosion resistance of the coating refers to the enterprise standard of the Aviation Materials Research Institute of China Aviation Industry Corporation: Q/6S365-1983
3High-temperature gas corrosion test method.4Seawater concentration: 10-5, can be increased to 5×10-5 if necessary13.10.5Test time: 150h, can be increased to more than 200h if necessary. 13.10.6After the coating test, remove the corrosion products formed on the surface of the sample according to GB/T16545. After removing the corrosion products, it should be ensured that no trace of corrosion products can be found by visual inspection or inspection with a ten-fold magnifying glass. Check the weight loss, appearance and metallographic structure of the coating before and after the magic corrosion, and record the test results.
Appendix A
(Informative Appendix)
References
GB/T18681—2002
The test method for the high-temperature gas corrosion resistance of the coating refers to the enterprise standard of the Aviation Materials Research Institute of China Aviation Industry Corporation: Q/6S365-1983
3High-temperature gas corrosion test method.
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