IRON-BASED AMORPHOUS NANOCRYSTALLINE LASER CLADDING COMPOSITE COATING, PREPARATION METHOD AND TEST METHOD THEREOF

Abstract

The invention discloses an iron-based amorphous nanocrystalline laser cladding composite coating and preparation and test methods thereof; the composition of the cladding composite coating meets the molecular formula: FeaCobNicBdSiyNbe, wherein a, b, c, d, y, and e respectively represent the atomic percentage of the corresponding alloy element; a plus b plus c plus d plus y plus e equals 100; the preparation method is: weighing the raw materials and mixing to obtain the alloy powder, substrate pretreatment, tiling the alloy powder on the surface of the substrate, the laser beam is scanned vertically to perform laser cladding on the alloy powder. The composite has a certain amorphous content, high microhardness, excellent wear resistance, and outstanding fracture strength. The preparation process is simple, the raw materials do not contain rare earths or volatile elements, and the application prospect is broad.

Claims

1. An iron-based amorphous nanocrystalline laser cladding composite coating, wherein the composition of the cladding composite coating meets the molecular formula: FeaCobNicBdSiyNbe, where a, b, c, d, y, and e respectively represent the atomic percentage of the corresponding alloy element; a is greater than or equal to 32 and less than or equal to 44, b is greater than or equal to 10 and less than or equal to 15, c is greater than or equal to 10 and less than or equal to 15, d is greater than or equal to 18 and less than or equal to 20, y is greater than or equal to 4 and less than or equal to 23, e is greater than or equal to 4 and less than or equal to 5, and a plus b plus c plus d plus y plus e equals 100.

2. The iron-based amorphous nanocrystalline laser cladding composite coating according to claim 1, wherein the atomic percentage of Si element in the molecular formula is preferably that y is greater than or equal to 4.8 and less than or equal to 22.08, and a plus b plus c is greater than or equal to 55 and less than or equal to 72.

3. The iron-based amorphous nanocrystalline laser cladding composite coating according to claim 1, wherein the structure of the cladding composite coating is an amorphous nanocrystalline composite structure, and the maximum amorphous volume fraction is 12.4% to 40.9%, and the particle size of the nanocrystalline is 17 to 20 nm.

4. The iron-based amorphous nanocrystalline laser cladding composite coating according to claim 2, wherein the structure of the cladding composite coating is an amorphous nanocrystalline composite structure, and the maximum amorphous volume fraction is 12.4% to 40.9%, and the particle size of the nanocrystalline is 17 to 20 nm.

5. The iron-based amorphous nanocrystalline laser cladding composite coating according to claim 1, wherein the micro-Vickers hardness of the cladding composite coating is 720 to 1038 HV.sub.0.1; the wear resistance is more than 11 times that of the conventional 45# steel, and the breaking strength is 2160 to 2880 MPa.

6. The iron-based amorphous nanocrystalline laser cladding composite coating according to claim 2, wherein the micro-Vickers hardness of the cladding composite coating is 720 to 1038 HV.sub.0.1; the wear resistance is more than 11 times that of the conventional 45# steel, and the breaking strength is 2160 to 2880 MPa.

7. A preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating according to claims 1-6, wherein the preparation method comprises the following steps: step 1: weighing the raw materials according to the atomic percentage in the molecular formula FeaCobNicBdSiyNbe of the cladding composite coating: cobalt iron powder, nickel iron powder, boron iron powder, ferrosilicon powder, ferroniobium powder and pure iron powder, and mixing the raw materials uniformly to obtain the alloy powder; step 2: polishing the surface of the steel substrate to remove rust and grease to make the surface clean and flat; step 3: after removing the residual moisture from the alloy powder and the steel substrate, tiling the alloy powder on the surface of the steel substrate; step 4: adjusting the parameters of the laser cladding process so that the laser beam is scanned vertically; performing the laser cladding on the preset alloy powder to obtain the iron-based amorphous nanocrystalline laser cladding composite coating.

8. The preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating according to claim 7, wherein the raw materials in step 1 are: Fe is the pure iron powder with a content of greater than 99.9 wt %, Co is the cobalt iron powder with a content of greater than 99.9 wt %, Ni is the nickel iron powder with a content of greater than 99.9 wt %, B is the boron iron powder with a content of greater than 19.4 wt %, Si is the ferrosilicon powder with a content of greater than 75 wt %, and Nb is the ferroniobium powder with a content of greater than 70 wt %; the balance in the cobalt iron powder, nickel iron powder, boron iron powder, ferrosilicon powder, ferroniobium powder is Fe, and the particle size of each raw material powder is 100 to 150 m.

9. The preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating according to claim 7, wherein the method of mixing the raw materials in step 1 is to use a ball mill for ball milling and mixing; the ball milling speed is 100 to 120 r/min, and the ball milling time is 10 to 12 hrs; the method of removing the residual moisture from the alloy powder and the steel substrate in step 3 refers to drying the alloy powder in a drying box at a temperature of 80 to 100 C. for 4 to 5 hrs, and placing the steel substrate in the drying box to dry at a temperature of 80 to 100 C. for 30 to 40 mins.

10. The preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating according to claim 7, wherein in the method of tiling the alloy powder on the surface of the steel substrate in step 3, the thickness of the alloy powder tiled is 0.9 to 1 mm; in the method of adjusting the parameters of the laser cladding process in step 4, the specific parameters are a laser power of 2 to 2.5 kW and a laser scanning speed of 5 to 6 mm/s.

11. A test method of the iron-based amorphous nanocrystalline laser cladding composite coating according to claims 1-6, wherein the method is used to test the breaking strength of the cladding composite coating, comprising the following steps: 1) separating the iron-based amorphous nanocrystalline laser cladding composite coating from the iron-base, to obtain a sample of the amorphous nanocrystalline laser cladding composite coating; 2) placing the sample vertically on the compression table of a universal testing machine at room temperature, and setting the compression rate; 3) compressing the sample to obtain the stress-strain curve until the sample breaks.

12. The test method of the iron-based amorphous nanocrystalline laser cladding composite coating according to claim 11, wherein the sample of the amorphous nanocrystalline laser cladding composite is a rectangular parallelepiped with a length and a width of 0.5 to 1 mm and a height of 1 to 2 mm; the compression rate is 410.sup.4 s.sup.1 to 510.sup.4 s.sup.1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] FIG. 1 is a phase analysis diagram illustrating the iron-based amorphous nanocrystalline laser cladding composite coating ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.75-0.03xB.sub.0.2Si.sub.0.05+0.03x).sub.96Nb.sub.4 of the invention;

[0039] FIG. 2 is a hardness diagram illustrating the iron-based amorphous nanocrystalline laser cladding composite coating ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.75-0.03xB.sub.0.2Si.sub.0.05+0.03x).sub.96Nb.sub.4 of the invention;

[0040] FIG. 3 is a wear resistance diagram illustrating the iron-based amorphous nanocrystalline laser cladding composite coating ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.75-0.03xB.sub.0.2Si.sub.0.05+0.03x).sub.96Nb.sub.4 of the invention;

[0041] FIG. 4 is a breaking strength diagram illustrating the iron-based amorphous nanocrystalline laser cladding composite coating ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.75-0.03xB.sub.0.2Si.sub.0.05+0.03x).sub.96Nb.sub.4 of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0042] In order to further explain the content of the invention, the invention will be described in detail hereinafter with reference to the drawings and embodiments.

[0043] The invention is based on scientific research experience in the field of laser cladding. Through a large number of experiments, it has been found that the addition of Si element is beneficial to the precipitation of the hard phase of Fe.sub.3Si and increases the hardness of the cladding composite coating; however, excessive addition of Si element will deteriorate the wear resistance and cause abrasive wear during friction and wear. In the invention, a Fe-based alloy component ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.75B.sub.0.2Si.sub.0.05).sub.96Nb.sub.4 with high amorphous forming ability and high strength is selected, and the content of Si element is optimized on the basis.

[0044] Unless otherwise specified, % in the application document is a mass percentage. Unless otherwise specified, other materials and raw materials used in the present invention are conventional raw materials that can be purchased from the market. The equipment used is also conventional equipment in the art. The operations not mentioned in the invention are all conventional operations in the art.

Embodiment 1

[0045] An iron-based amorphous nanocrystalline laser cladding composite coating, wherein the composition of the cladding composite coating meets the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.75B.sub.0.2Si.sub.0.05).sub.96Nb.sub.4, which has high strength and high wear resistance; the structure is an amorphous nanocrystalline composite structure; the amorphous volume fraction is 21.4%, the particle size of the nanocrystalline is 17 nm, the micro-Vickers hardness is 720 HV.sub.0.1, the wear resistance is 11 times that of the conventional 45# steel, and the breaking strength is 2160 MPa.

[0046] A preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating, comprising the following steps:

[0047] 1. weighing the raw materials according to the atomic percentage in the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.75B.sub.0.2Si.sub.0.05).sub.96Nb.sub.4 of the cladding composite coating: pure iron powder (with a content of Fe greater than 99.9 wt %), cobalt iron powder (with a content of Co greater than 99.9 wt %), nickel iron powder (with a content of Ni greater than 99.9 wt %), boron iron powder (with a content of B of 19.4 wt %, the balance is Fe), ferrosilicon powder (with a content of Si of 75 wt %, the balance is Fe), and ferroniobium powder (with a content of Nb of 70 wt %, the balance is Fe), and the particle size of each raw material powder is 100 to 150 m; then placing the raw materials into a ball mill for ball milling and mixing; the ball milling speed is 120 r/min, and the ball milling time is 12 hrs; mixing the raw materials uniformly to obtain the alloy powder;

[0048] 2. selecting the national standard q235 low carbon steel with a size of 10 mm100 mm100 mm as the base material, polishing the surface with an angle grinder and sandpaper to remove rust, and cleaning the surface with acetone to remove grease to make the surface clean and flat;

[0049] 3. drying the alloy powder in a drying box at a temperature of 80 C. for 4 hrs, and placing the steel substrate in the drying box to dry at a temperature of 80 C. for 30 mins; then tiling the alloy powder on the surface of the steel substrate, and the thickness of the alloy powder tiled is 1 mm;

[0050] 4. adjusting the distance from the mirror surface of the 3 kW semiconductor laser to the surface of the substrate to a focusing distance of 310 to 320 mm; an infrared pre-scan is used to determine an area to be cladding;

[0051] 5. adjusting the parameters of the laser cladding process: setting a laser power of 2 to 2.5 kW, a laser scanning speed of 5 to 6 mm/s, and a spot size of 14.52.5 mm; the laser beam is scanned vertically; performing the laser cladding on the preset alloy powder to obtain the iron-based amorphous nanocrystalline laser cladding composite coating.

[0052] A test method of the iron-based amorphous nanocrystalline laser cladding composite coating, which is used to test the breaking strength of the cladding composite coating, comprising the following steps:

[0053] 1. removing the cladding composite coating and part of the substrate by wire cutting, then removing the substrate by sandpaper and polishing the cladding composite coating to the middle; preparing the middle of the cladding layer into a rectangular parallelepiped sample with a length of 0.5 mm, a width of 0.5 mm, and a height of 1 mm, and ensuring the opposite sides of the rectangular parallelepiped sample to be parallel;

[0054] 2. placing the sample vertically on the compression table of a universal testing machine at room temperature, and setting the compression rate as 510.sup.4 s.sup.1;

[0055] 3. compressing the sample to obtain the stress-strain curve until the sample breaks.

Embodiment 2

[0056] An iron-based amorphous nanocrystalline laser cladding composite coating, wherein the composition of the cladding composite coating meets the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.72B.sub.0.2Si.sub.0.08).sub.96Nb.sub.4, which has high strength and high wear resistance; the structure is an amorphous nanocrystalline composite structure; the amorphous volume fraction is 25.5%, the particle size of the nanocrystalline is 20 nm, the micro-Vickers hardness is 791 HV.sub.0.1, the wear resistance is 15 times that of the conventional 45# steel, and the breaking strength is 2428 MPa.

[0057] A preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating, comprising the following steps:

[0058] 1. weighing the raw materials according to the atomic percentage in the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.72B.sub.0.2Si.sub.0.08).sub.96Nb.sub.4 of the cladding composite coating: pure iron powder (with a content of Fe greater than 99.9 wt %), cobalt iron powder (with a content of Co greater than 99.9 wt %), nickel iron powder (with a content of Ni greater than 99.9 wt %), boron iron powder (with a content of B of 19.4 wt %, the balance is Fe), ferrosilicon powder (with a content of Si of 75 wt %, the balance is Fe), and ferroniobium powder (with a content of Nb of 70 wt %, the balance is Fe), and the particle size of each raw material powder is 100 to 150 m; then placing the raw materials into a ball mill for ball milling and mixing; the ball milling speed is 120 r/min, and the ball milling time is 12 hrs; mixing the raw materials uniformly to obtain the alloy powder;

[0059] 2. selecting the national standard q235 low carbon steel with a size of 10 mm100 mm100 mm as the base material, polishing the surface with an angle grinder and sandpaper to remove rust, and cleaning the surface with acetone to remove grease to make the surface clean and flat;

[0060] 3. drying the alloy powder in a drying box at a temperature of 80 C. for 4 hrs, and placing the steel substrate in the drying box to dry at a temperature of 80 C. for 30 mins; then tiling the alloy powder on the surface of the steel substrate, and the thickness of the alloy powder tiled is 1 mm;

[0061] 4. adjusting the distance from the mirror surface of the 3 kW semiconductor laser to the surface of the substrate to a focusing distance of 310 to 320 mm; an infrared pre-scan is used to determine an area to be cladding;

[0062] 5. adjusting the parameters of the laser cladding process: setting a laser power of 2 to 2.5 kW, a laser scanning speed of 5 to 6 mm/s, and a spot size of 14.52.5 mm; the laser beam is scanned vertically; performing the laser cladding on the preset alloy powder to obtain the iron-based amorphous nanocrystalline laser cladding composite coating.

[0063] A test method of the iron-based amorphous nanocrystalline laser cladding composite coating, which is used to test the breaking strength of the cladding composite coating, comprising the following steps:

[0064] 1. removing the cladding composite coating and part of the substrate by wire cutting, then removing the substrate by sandpaper and polishing the cladding composite coating to the middle; preparing the middle of the cladding layer into a rectangular parallelepiped sample with a length of 0.5 mm, a width of 0.5 mm, and a height of 1 mm, and ensuring the opposite sides of the rectangular parallelepiped sample to be parallel;

[0065] 2. placing the sample vertically on the compression table of a universal testing machine at room temperature, and setting the compression rate as 510.sup.4 s.sup.1;

[0066] 3. compressing the sample to obtain the stress-strain curve until the sample breaks.

Embodiment 3

[0067] An iron-based amorphous nanocrystalline laser cladding composite coating, wherein the composition of the cladding composite coating meets the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.69B.sub.0.2Si.sub.0.11).sub.96Nb.sub.4, which has high strength and high wear resistance; the structure is an amorphous nanocrystalline composite structure; the amorphous volume fraction is 41.9%, the particle size of the nanocrystalline is 17 nm, the micro-Vickers hardness is 918 HV.sub.0.1, the wear resistance is 19 times that of the conventional 45# steel, and the breaking strength is 2880 MPa.

[0068] A preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating, comprising the following steps:

[0069] 1. weighing the raw materials according to the atomic percentage in the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.69B.sub.0.2Si.sub.0.11).sub.96Nb.sub.4 of the cladding composite coating: pure iron powder (with a content of Fe greater than 99.9 wt %), cobalt iron powder (with a content of Co greater than 99.9 wt %), nickel iron powder (with a content of Ni greater than 99.9 wt %), boron iron powder (with a content of B of 19.4 wt %, the balance is Fe), ferrosilicon powder (with a content of Si of 75 wt %, the balance is Fe), and ferroniobium powder (with a content of Nb of 70 wt %, the balance is Fe), and the particle size of each raw material powder is 100 to 150 m; then placing the raw materials into a ball mill for ball milling and mixing; the ball milling speed is 120 r/min, and the ball milling time is 12 hrs; mixing the raw materials uniformly to obtain the alloy powder;

[0070] 2. selecting the national standard q235 low carbon steel with a size of 10 mm100 mm100 mm as the base material, polishing the surface with an angle grinder and sandpaper to remove rust, and cleaning the surface with acetone to remove grease to make the surface clean and flat;

[0071] 3. drying the alloy powder in a drying box at a temperature of 80 C. for 4 hrs, and placing the steel substrate in the drying box to dry at a temperature of 80 C. for 30 mins; then tiling the alloy powder on the surface of the steel substrate, and the thickness of the alloy powder tiled is 1 mm;

[0072] 4. adjusting the distance from the mirror surface of the 3 kW semiconductor laser to the surface of the substrate to a focusing distance of 310 to 320 mm; an infrared pre-scan is used to determine an area to be cladding;

[0073] 5. adjusting the parameters of the laser cladding process: setting a laser power of 2 to 2.5 kW, a laser scanning speed of 5 to 6 mm/s, and a spot size of 14.52.5 mm; the laser beam is scanned vertically; performing the laser cladding on the preset alloy powder to obtain the iron-based amorphous nanocrystalline laser cladding composite coating.

[0074] A test method of the iron-based amorphous nanocrystalline laser cladding composite coating, which is used to test the breaking strength of the cladding composite coating, comprising the following steps:

[0075] 1. removing the cladding composite coating and part of the substrate by wire cutting, then removing the substrate by sandpaper and polishing the cladding composite coating to the middle; preparing the middle of the cladding layer into a rectangular parallelepiped sample with a length of 0.5 mm, a width of 0.5 mm, and a height of 1 mm, and ensuring the opposite sides of the rectangular parallelepiped sample to be parallel;

[0076] 2. placing the sample vertically on the compression table of a universal testing machine at room temperature, and setting the compression rate as 510.sup.4 s.sup.1;

[0077] 3. compressing the sample to obtain the stress-strain curve until the sample breaks.

Embodiment 4

[0078] An iron-based amorphous nanocrystalline laser cladding composite coating, wherein the composition of the cladding composite coating meets the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.66B.sub.0.2Si.sub.0.14).sub.96Nb.sub.4, which has high strength and high wear resistance; the structure is an amorphous nanocrystalline composite structure; the amorphous volume fraction is 25.2%, the particle size of the nanocrystalline is 17 nm, the micro-Vickers hardness is 980 HV.sub.0.1, the wear resistance is 15 times that of the conventional 45# steel, and the breaking strength is 2596 MPa.

[0079] A preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating, comprising the following steps:

[0080] 1. weighing the raw materials according to the atomic percentage in the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.66B.sub.0.2Si.sub.0.14).sub.96Nb.sub.4 of the cladding composite coating: pure iron powder (with a content of Fe greater than 99.9 wt %), cobalt iron powder (with a content of Co greater than 99.9 wt %), nickel iron powder (with a content of Ni greater than 99.9 wt %), boron iron powder (with a content of B of 19.4 wt %, the balance is Fe), ferrosilicon powder (with a content of Si of 75 wt %, the balance is Fe), and ferroniobium powder (with a content of Nb of 70 wt %, the balance is Fe), and the particle size of each raw material powder is 100 to 150 m; then placing the raw materials into a ball mill for ball milling and mixing; the ball milling speed is 120 r/min, and the ball milling time is 12 hrs; mixing the raw materials uniformly to obtain the alloy powder;

[0081] 2. selecting the national standard q235 low carbon steel with a size of 10 mm100 mm100 mm as the base material, polishing the surface with an angle grinder and sandpaper to remove rust, and cleaning the surface with acetone to remove grease to make the surface clean and flat;

[0082] 3. drying the alloy powder in a drying box at a temperature of 80 C. for 4 hrs, and placing the steel substrate in the drying box to dry at a temperature of 80 C. for 30 mins; then tiling the alloy powder on the surface of the steel substrate, and the thickness of the alloy powder tiled is 1 mm;

[0083] 4. adjusting the distance from the mirror surface of the 3 kW semiconductor laser to the surface of the substrate to a focusing distance of 310 to 320 mm; an infrared pre-scan is used to determine an area to be cladding;

[0084] 5. adjusting the parameters of the laser cladding process: setting a laser power of 2 to 2.5 kW, a laser scanning speed of 5 to 6 mm/s, and a spot size of 14.52.5 mm; the laser beam is scanned vertically; performing the laser cladding on the preset alloy powder to obtain the iron-based amorphous nanocrystalline laser cladding composite coating.

[0085] A test method of the iron-based amorphous nanocrystalline laser cladding composite coating, which is used to test the breaking strength of the cladding composite coating, comprising the following steps:

[0086] 1. removing the cladding composite coating and part of the substrate by wire cutting, then removing the substrate by sandpaper and polishing the cladding composite coating to the middle; preparing the middle of the cladding layer into a rectangular parallelepiped sample with a length of 0.5 mm, a width of 0.5 mm, and a height of 1 mm, and ensuring the opposite sides of the rectangular parallelepiped sample to be parallel;

[0087] 2. placing the sample vertically on the compression table of a universal testing machine at room temperature, and setting the compression rate as 510.sup.4 s.sup.1;

[0088] 3. compressing the sample to obtain the stress-strain curve until the sample breaks.

Embodiment 5

[0089] An iron-based amorphous nanocrystalline laser cladding composite coating, wherein the composition of the cladding composite coating meets the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.63B.sub.0.2Si.sub.0.17).sub.96Nb.sub.4, which has high strength and high wear resistance; the structure is an amorphous nanocrystalline composite structure; the amorphous volume fraction is 18.5%, the particle size of the nanocrystalline is 18 nm, the micro-Vickers hardness is 1012 HV.sub.0.1, the wear resistance is 15 times that of the conventional 45# steel, and the breaking strength is 2354 MPa.

[0090] A preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating, comprising the following steps:

[0091] 1. weighing the raw materials according to the atomic percentage in the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.63B.sub.0.2Si.sub.0.17).sub.96Nb.sub.4 of the cladding composite coating: pure iron powder (with a content of Fe greater than 99.9 wt %), cobalt iron powder (with a content of Co greater than 99.9 wt %), nickel iron powder (with a content of Ni greater than 99.9 wt %), boron iron powder (with a content of B of 19.4 wt %, the balance is Fe), ferrosilicon powder (with a content of Si of 75 wt %, the balance is Fe), and ferroniobium powder (with a content of Nb of 70 wt %, the balance is Fe), and the particle size of each raw material powder is 100 to 150 m; then placing the raw materials into a ball mill for ball milling and mixing; the ball milling speed is 120 r/min, and the ball milling time is 12 hrs; mixing the raw materials uniformly to obtain the alloy powder;

[0092] 2. selecting the national standard q235 low carbon steel with a size of 10 mm100 mm100 mm as the base material, polishing the surface with an angle grinder and sandpaper to remove rust, and cleaning the surface with acetone to remove grease to make the surface clean and flat;

[0093] 3. drying the alloy powder in a drying box at a temperature of 80 C. for 4 hrs, and placing the steel substrate in the drying box to dry at a temperature of 80 C. for 30 mins; then tiling the alloy powder on the surface of the steel substrate, and the thickness of the alloy powder tiled is 1 mm;

[0094] 4. adjusting the distance from the mirror surface of the 3 kW semiconductor laser to the surface of the substrate to a focusing distance of 310 to 320 mm; an infrared pre-scan is used to determine an area to be cladding;

[0095] 5. adjusting the parameters of the laser cladding process: setting a laser power of 2 to 2.5 kW, a laser scanning speed of 5 to 6 mm/s, and a spot size of 14.52.5 mm; the laser beam is scanned vertically; performing the laser cladding on the preset alloy powder to obtain the iron-based amorphous nanocrystalline laser cladding composite coating.

[0096] A test method of the iron-based amorphous nanocrystalline laser cladding composite coating, which is used to test the breaking strength of the cladding composite coating, comprising the following steps:

[0097] 1. removing the cladding composite coating and part of the substrate by wire cutting, then removing the substrate by sandpaper and polishing the cladding composite coating to the middle; preparing the middle of the cladding layer into a rectangular parallelepiped sample with a length of 0.5 mm, a width of 0.5 mm, and a height of 1 mm, and ensuring the opposite sides of the rectangular parallelepiped sample to be parallel;

[0098] 2. placing the sample vertically on the compression table of a universal testing machine at room temperature, and setting the compression rate as 510.sup.4 s.sup.1;

[0099] 3. compressing the sample to obtain the stress-strain curve until the sample breaks.

Embodiment 6

[0100] An iron-based amorphous nanocrystalline laser cladding composite coating, wherein the composition of the cladding composite coating meets the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.6B.sub.0.2Si.sub.0.2).sub.96Nb.sub.4, which has high strength and high wear resistance; the structure is an amorphous nanocrystalline composite structure; the amorphous volume fraction is 14.5%, the particle size of the nanocrystalline is 18 nm, the micro-Vickers hardness is 1024 HV.sub.0.1, the wear resistance is 16 times that of the conventional 45# steel, and the breaking strength is 2410 MPa.

[0101] A preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating, comprising the following steps:

[0102] 1. weighing the raw materials according to the atomic percentage in the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.6B.sub.0.2Si.sub.0.2).sub.96Nb.sub.4 of the cladding composite coating: pure iron powder (with a content of Fe greater than 99.9 wt %), cobalt iron powder (with a content of Co greater than 99.9 wt %), nickel iron powder (with a content of Ni greater than 99.9 wt %), boron iron powder (with a content of B of 19.4 wt %, the balance is Fe), ferrosilicon powder (with a content of Si of 75 wt %, the balance is Fe), and ferroniobium powder (with a content of Nb of 70 wt %, the balance is Fe), and the particle size of each raw material powder is 100 to 150 m; then placing the raw materials into a ball mill for ball milling and mixing; the ball milling speed is 120 r/min, and the ball milling time is 12 hrs; mixing the raw materials uniformly to obtain the alloy powder;

[0103] 2. selecting the national standard q235 low carbon steel with a size of 10 mm100 mm100 mm as the base material, polishing the surface with an angle grinder and sandpaper to remove rust, and cleaning the surface with acetone to remove grease to make the surface clean and flat;

[0104] 3. drying the alloy powder in a drying box at a temperature of 80 C. for 4 hrs, and placing the steel substrate in the drying box to dry at a temperature of 80 C. for 30 mins; then tiling the alloy powder on the surface of the steel substrate, and the thickness of the alloy powder tiled is 1 mm;

[0105] 4. adjusting the distance from the mirror surface of the 3 kW semiconductor laser to the surface of the substrate to a focusing distance of 310 to 320 mm; an infrared pre-scan is used to determine an area to be cladding;

[0106] 5. adjusting the parameters of the laser cladding process: setting a laser power of 2 to 2.5 kW, a laser scanning speed of 5 to 6 mm/s, and a spot size of 14.52.5 mm; the laser beam is scanned vertically; performing the laser cladding on the preset alloy powder to obtain the iron-based amorphous nanocrystalline laser cladding composite coating.

[0107] A test method of the iron-based amorphous nanocrystalline laser cladding composite coating, which is used to test the breaking strength of the cladding composite coating, comprising the following steps:

[0108] 1. removing the cladding composite coating and part of the substrate by wire cutting, then removing the substrate by sandpaper and polishing the cladding composite coating to the middle; preparing the middle of the cladding layer into a rectangular parallelepiped sample with a length of 0.5 mm, a width of 0.5 mm, and a height of 1 mm, and ensuring the opposite sides of the rectangular parallelepiped sample to be parallel;

[0109] 2. placing the sample vertically on the compression table of a universal testing machine at room temperature, and setting the compression rate as 510.sup.4 s.sup.1;

[0110] 3. compressing the sample to obtain the stress-strain curve until the sample breaks.

Embodiment 7

[0111] An iron-based amorphous nanocrystalline laser cladding composite coating, wherein the composition of the cladding composite coating meets the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.57B.sub.0.2Si.sub.0.23).sub.96Nb.sub.4, which has high strength and high wear resistance; the structure is an amorphous nanocrystalline composite structure; the amorphous volume fraction is 12.4%, the particle size of the nanocrystalline is 18 nm, the micro-Vickers hardness is 1038 HV.sub.0.1, the wear resistance is 17 times that of the conventional 45# steel, and the breaking strength is 2171 MPa.

[0112] A preparation method of the iron-based amorphous nanocrystalline laser cladding composite coating, comprising the following steps:

[0113] 1. weighing the raw materials according to the atomic percentage in the molecular formula ((Fe.sub.0.6Co.sub.0.2Ni.sub.0.2).sub.0.57B.sub.0.2Si.sub.0.23).sub.96Nb.sub.4 of the cladding composite coating: pure iron powder (with a content of Fe greater than 99.9 wt %), cobalt iron powder (with a content of Co greater than 99.9 wt %), nickel iron powder (with a content of Ni greater than 99.9 wt %), boron iron powder (with a content of B of 19.4 wt %, the balance is Fe), ferrosilicon powder (with a content of Si of 75 wt %, the balance is Fe), and ferroniobium powder (with a content of Nb of 70 wt %, the balance is Fe), and the particle size of each raw material powder is 100 to 150 m; then placing the raw materials into a ball mill for ball milling and mixing; the ball milling speed is 120 r/min, and the ball milling time is 12 hrs; mixing the raw materials uniformly to obtain the alloy powder;

[0114] 2. selecting the national standard q235 low carbon steel with a size of 10 mm100 mm100 mm as the base material, polishing the surface with an angle grinder and sandpaper to remove rust, and cleaning the surface with acetone to remove grease to make the surface clean and flat;

[0115] 3. drying the alloy powder in a drying box at a temperature of 80 C. for 4 hrs, and placing the steel substrate in the drying box to dry at a temperature of 80 C. for 30 mins; then tiling the alloy powder on the surface of the steel substrate, and the thickness of the alloy powder tiled is 1 mm;

[0116] 4. adjusting the distance from the mirror surface of the 3 kW semiconductor laser to the surface of the substrate to a focusing distance of 310 to 320 mm; an infrared pre-scan is used to determine an area to be cladding;

[0117] 5. adjusting the parameters of the laser cladding process: setting a laser power of 2 to 2.5 kW, a laser scanning speed of 5 to 6 mm/s, and a spot size of 14.52.5 mm; the laser beam is scanned vertically; performing the laser cladding on the preset alloy powder to obtain the iron-based amorphous nanocrystalline laser cladding composite coating.

[0118] A test method of the iron-based amorphous nanocrystalline laser cladding composite coating, which is used to test the breaking strength of the cladding composite coating, comprising the following steps:

[0119] 1. removing the cladding composite coating and part of the substrate by wire cutting, then removing the substrate by sandpaper and polishing the cladding composite coating to the middle; preparing the middle of the cladding layer into a rectangular parallelepiped sample with a length of 0.5 mm, a width of 0.5 mm, and a height of 1 mm, and ensuring the opposite sides of the rectangular parallelepiped sample to be parallel;

[0120] 2. placing the sample vertically on the compression table of a universal testing machine at room temperature, and setting the compression rate as 510.sup.4 s.sup.1;

[0121] 3. compressing the sample to obtain the stress-strain curve until the sample breaks.

[0122] The property tests of the iron-based amorphous nanocrystalline laser cladding composite coatings of Embodiments 1 to 7 are performed, and the results are as follows:

[0123] The XRD pattern of the Fe-based cladding coating was measured using a D8Advance polycrystalline ray diffractometer (as shown in FIG. 2); it can be seen from FIG. 2 that with the increase of the content of Si element, the amorphous volume fraction of the cladding coating first increases and then decreases.

[0124] Jade software is used for simulation; the cladding coating prepared in Embodiment 3 has the highest amorphous volume fraction of 40.9%.

[0125] The Scherrer Formula can be used through XRD diffraction peak full width at half maximum to calculate the nanocrystalline particle size of the cladding coatings in Embodiments 1 to 7 from 17 to 20 nm (The Scherrer Formula is:

[00001]$D=\frac{K.Math..Math.}{B.Math..Math.\cos .Math..Math.};$

wherein D refers to the particle size, K refers to the Scherrer constant, and generally K is equal to 0.89, refers to the wavelength of X-rays (0.154056 nm), B refers to the full width at half maximum (Rad) of the diffraction peak of the test sample, and refers to the diffraction angle (Rad)).

TABLE-US-00001 TABLE 1 Full Width at Half Maximum of Diffraction Peaks and Nanocrystalline Particle Sizes in XRD Patterns of Cladding Coatings in Embodiments 1 to 7 Embodiment Full Width at Half Nanocrystalline Number Maximum () Particle Size (nm) Embodiment 1 0.514 17 Embodiment 2 0.431 20 Embodiment 3 0.506 17 Embodiment 4 0.492 17 Embodiment 5 0.488 18 Embodiment 6 0.472 18 Embodiment 7 0.485 18

[0126] The above Fe-based cladding coating is subjected to wire cutting, its cross-section is sanded and polished, and the cladding coating and the cladding coating-substrate interface are tested for hardness to obtain micro-Vickers hardness; FIG. 2 is the hardness distribution of the microhardness of the cladding coating from the surface of the cladding coating to the interface in Embodiments 1 to 7; it can be seen from the diagram that the micro-Vickers hardness of the cladding coating prepared in Embodiment 7 is the highest, reaching 1120 HV in the middle of the cladding coating, and the average micro-Vickers hardness is 1038 HV.

[0127] After the cladding coatings prepared in Embodiments 1 to 7 and the surface of 45# steel were polished with 1000-mesh sandpaper, the friction wear test was performed respectively with a load of 20 mN, friction distance of 4 mm, friction frequency of 5 Hz, a load of 10 mN, friction distance of 4 mm, friction frequency of 5 Hz, and a load of 10 mN, friction distance of 4 mm, friction frequency of 10 Hz, and a friction wear time of 30 mins, the results are shown in FIG. 3: the addition of a certain content of Si element improves the wear resistance of the cladding coating; the cladding coating prepared in Embodiment 3 has the best wear resistance, the wear volume is the lowest under three conditions of friction and wear (different loads and different friction frequencies), and the wear resistance is 19 times that of the conventional 45# steel.

[0128] The breaking strength of the cladding coatings prepared in Embodiments 1 to 7 is shown in FIG. 4; the addition of a certain content of Si element can improve the breaking strength of the cladding coating; the breaking strength of the cladding coating prepared in Embodiment 3 is up to 2880 MPa, and the yield strength of 235 MPa is greatly improved compared to q235 substrate, which is more than ten times that.

[0129] Although the invention has been described in detail with the general description and specific embodiments hereinabove, it is obvious to those skilled in the art that some modifications or improvements can be made based on the invention. Therefore, modifications or improvements made without departing from the spirit of the invention shall all fall within the protection scope of the invention.