Nb2O5-doped nickel-based brazing filler metal and brazed diamond thereof

Abstract

The invention discloses Nb2O5-doped nickel-based brazing filler metal and a brazed diamond thereof, and belongs to the technical field of welding. The brazing filler metal is obtained by mechanically ball-milling nickel-based brazing filler metal powder and Nb2O5 for 30 to 60 minutes, and comprises the following components: 6 to 8 weight percent of chromium (Cr), 4 to 5 weight percent of silicon (Si), 2.75 to 3.5 weight percent of boron (B), 2.5 to 3.5 weight percent of iron (Fe), 0 to 3 weight percent of Nb2O5 and the balance of nickel (Ni), the brazed diamond is obtained in the mode that Nb2O5-doped nickel-based brazing filler metal is placed in a tubular furnace protected by argon, the brazing temperature is lower than 1080 DEG C, the heat preservation time is shorter than 30 min, high-strength holding of the brazing filler metal on the diamond can be achieved through doping of Nb2O5, heat damage of the brazed diamond is effectively restrained, residual stress distribution is optimized, and the comprehensive performance of the brazing filler metal is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of welding, in particular to a nickel-based brazing filler metal doped with Nb2O5 and brazing diamond thereof. Technical Background

[0002] Diamond is known for its extremely high hardness, excellent wear resistance, corrosion resistance and low friction coefficient, and is therefore widely used in processing hard and brittle materials such as ceramics, cemented carbide and semiconductors. At present, the main preparation methods of diamond tools are sintering, electroplating and brazing. Among them, the advantage of brazing diamond tools is that it can form a strong chemical bond between diamond and brazing alloy, thereby significantly improving the interfacial bonding strength and improving the processing performance of the tool. In addition, commonly used brazing fillers mainly include copper-based, silver-based and nickel-based fillers. Among them, nickel-based fillers have become a hot topic in the field of diamond tool research in recent years due to their significant advantages such as high bonding strength, excellent wear resistance and long service life when brazing diamond tools. However, nickel-based fillers will form more brittle hard phases during high-temperature brazing, resulting in cracks at the brazed diamond bonding interface. At the same time, under the action of high brazing temperature and catalyst elements (such as Ni and Fe), diamond is susceptible to severe thermal damage. These factors will seriously affect the processing performance of diamond tools.

[0003] In view of the above-mentioned problems, the research and development of a brazing method that can not only alleviate the thermal damage caused by brazing diamond with Ni-based brazing filler metals and reduce residual stress at the bonding interface, but also further reduce costs has become a major research topic of concern to many scholars. Therefore, the present invention prepares a new nickel-based brazing filler metal by doping it with Nb2O5. This method optimizes the brazing filler metal structure, enhances the brazing filler metal / diamond interface bonding strength, and reduces thermal damage to the diamond, thereby improving the grinding performance of the brazed diamond. Summary of the Invention

[0004] The purpose of the present invention is to study the use of nickel-based brazing filler metal for brazing diamond tools by doping an appropriate amount of Nb2O5 in the filler metal. The main focus is on regulating the interface reaction, inhibiting the thermal damage of diamond, optimizing the residual stress distribution and improving the comprehensive performance of the filler metal by Nb2O5. A nickel-based brazing filler metal modified by doping with Nb2O5 and its brazing diamond are provided, which can effectively improve the processing performance of nickel-based brazing filler metal brazing diamond tools.

[0005] To achieve the above objectives, the present invention employs the following technical solutions: a nickel-based brazing filler metal doped with Nb2O5 and brazed diamonds thereof. The brazing filler metal is obtained by mechanically ball-milling the nickel-based brazing filler metal with Nb2O5 for 30 to 60 minutes and comprises 6 to 8 wt% chromium (Cr), 4 to 5 wt% silicon (Si), 2.75 to 3.5 wt% boron (B), 2.5 to 3.5 wt% iron (Fe), 0 to 3 wt% Nb2O5, and the remainder nickel (Ni). The brazed diamonds are obtained by brazing the nickel-based brazing filler metal doped with Nb2O5 in an argon-shielded tube furnace at a brazing temperature below 1080°C for a holding time of less than 30 minutes.

[0006] In a preferred embodiment, the ball mill has a rotation speed of 1000 r / min and a ball-to-material ratio of 10:1.

[0007] In a preferred embodiment, the mechanical ball milling time is 30 to 60 minutes.

[0008] In a preferred embodiment, the brazing temperature is 1030-1050°C.

[0009] In a preferred embodiment, the insulation time is 5 to 15 minutes.

[0010] In a preferred embodiment, the tubular furnace is filled with argon protective atmosphere.

[0011] In a preferred embodiment, multiple compounds such as Cr3C2 and Cr7C3 are generated on the surface of the brazed diamond, and the carbides on the surface of the brazed diamond are refined, thereby achieving high-strength grip of the brazing material on the diamond.

[0012] In a preferred embodiment, the thermal damage of the brazed diamond is effectively suppressed and the grinding performance is significantly improved.

[0013] The beneficial effects of the present invention are as follows: Nb atoms in the solder react with Ni atoms to form niobium-nickel compounds, consuming some of the nickel atoms, thereby weakening the catalytic effect of the catalyst element Ni on diamond graphitization. Simultaneously, O atoms in the solder react with B atoms in the solder to form low-hardness B2O3, consuming some of the B atoms and, to a certain extent, reducing the formation of hard and brittle phases such as Ni3B and CrB. This, in turn, helps reduce interfacial residual stress and prevents interfacial cracking. This achieves the dual modification effects of "thermal damage suppression" and "interface strengthening." BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The average microhardness, average friction coefficient and wear loss of the brazing layer of the embodiment of the present invention and comparative examples 1 and 2. Wherein, (a) is the microhardness of the brazing layer, and (b) is the average friction coefficient and wear loss of the brazing layer.

[0015] Figure 2 The morphologies of brazed diamonds obtained from the embodiment of the present invention and comparative examples 1 and 2 are shown. (a) shows diamond brazed with pure nickel-based brazing filler metal. (b) shows diamond brazed with nickel-based brazing filler metal doped with 1 wt% Nb. (c) shows diamond brazed with Ni-Cr brazing filler metal doped with 1 wt% Nb2O5.

[0016] Figure 3 The morphologies of brazed diamond carbides in the examples of the present invention and comparative examples 1 and 2 are shown. (a) is diamond brazed with pure nickel-based brazing filler metal, (b) is diamond brazed with nickel-based brazing filler metal doped with 1 wt% Nb, and (c) is diamond brazed with nickel-based brazing filler metal doped with 1 wt% Nb2O5.

[0017] Figure 4 The Raman spectra of brazed diamonds of the embodiment of the present invention and comparative examples 1 and 2 are shown. Among them, (a) is pure Ni-Cr brazing filler metal brazing diamond, (b) is nickel-based brazing filler metal brazing diamond doped with 1wt% Nb, (c) is nickel-based brazing filler metal brazing diamond doped with 1wt% Nb2O5, and (d) is the Raman spectra of diamond brazed with the three brazing filler metal systems. D :I G ratio;

[0018] Figure 5 The three-dimensional super-depth-of-field topography images after grinding experiments of brazed diamonds according to the present invention and comparative examples 1 and 2 are shown. (a) shows diamond brazed with pure nickel-based brazing filler metal, (b) shows diamond brazed with nickel-based brazing filler metal doped with 1 wt% Nb, and (c) shows diamond brazed with nickel-based brazing filler metal doped with 1 wt% Nb2O5. DETAILED DESCRIPTION

[0019] In order to better understand the technical solutions provided by the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0020] The specific operations for the preparation of nickel-based brazing filler metal doped with Nb2O5 and its brazing of diamond are as follows:

[0021] Example:

[0022] Step 1: Weigh 9.9 grams of nickel-based solder and 0.1 grams of Nb2O5 in a glove box, mix and mill them in a ball mill for 60 minutes at a speed of 1000 r / min and a ball-to-material ratio of 10:1; fully mix the two powders in the ball mill jar. The components include: 6-8wt% Cr, 4-5wt% Si, 2.75-3.5wt% B, 2.5-3.5wt% Fe, 1wt% Nb2O5, and the rest is Ni;

[0023] Step 2: Select 45 steel as the metal substrate for brazing diamonds. The size of 45 steel is 20mm×200mm×10mm. Before brazing, grind and polish the 45 steel substrate, and ultrasonically clean it with anhydrous ethanol for 10 minutes to remove impurities and oil stains on the surface. After cleaning, dry it in a drying oven.

[0024] Step 3: The selected diamond abrasive particle size is about 30 / 40 mesh. Select diamonds of good quality and ultrasonically clean the selected diamonds with anhydrous ethanol for 10 minutes to remove the oil on the surface. After cleaning, blow dry and set aside.

[0025] Step 4: Use the corresponding resin mold to evenly spread the prepared solder powder on the surface of the metal substrate with a thickness of about 0.5mm. Then evenly spread the diamond on the surface of the metal substrate and place the prepared brazing sample in the crucible.

[0026] Step 5: Finally, place the crucible into a tubular furnace for brazing. Perform high-temperature brazing under argon atmosphere protection with a brazing temperature of 1050°C, a heating rate of 10°C / min, and a holding time of 5 minutes. Before heating, continuously introduce argon into the furnace to exhaust any remaining air in the furnace. Remove the brazed sample after cooling to room temperature with the furnace.

[0027] Comparative Example 1:

[0028] This comparative example is basically the same as the embodiment, except that the solder in this comparative example is pure nickel-based solder, and its components include: 6-8wt% Cr, 4-5wt% Si, 2.75-3.5wt% B, 2.5-3.5wt% Fe, and the rest is Ni.

[0029] Comparative Example 2:

[0030] This comparative example is basically the same as the embodiment, except that the solder in this comparative example is a nickel-based solder doped with 1wt% Nb, and its components include: 6-8wt% Cr, 4-5wt% Si, 2.75-3.5wt% B, 2.5-3.5wt% Fe, 1wt% Nb, and the rest is Ni.

[0031] Figure 1 The average microhardness, average friction coefficient, and wear loss of the brazing layer of the embodiment of the present invention and comparative examples 1 and 2 are shown. (a) is the microhardness of the brazing layer, and (b) is the average friction coefficient and wear loss of the brazing layer. Comparison shows that doping with 1wt% Nb2O5 can further increase the hardness of the brazing layer of nickel-based brazing alloys, improve the material's wear resistance, and further enhance its mechanical properties.

[0032] Figure 2The morphology of the brazed diamond samples of the embodiment of the present invention and comparative examples 1 and 2 and the morphology of their surface carbides are shown. Among them, (a) is pure nickel-based brazing filler metal brazed diamond, (b) is nickel-based brazing filler metal brazed diamond doped with 1wt% Nb, and (c) is nickel-based brazing filler metal brazed diamond doped with 1wt% Nb2O5. By comparison, it was found that the surface of the diamond brazed with pure nickel-based brazing filler metal showed obvious thermal damage, and the diamond brazed with nickel-based brazing filler metal doped with 1wt% Nb had fine cracks at the junction with the interface, which would reduce the holding force of the matrix on the diamond and reduce the service life of the diamond tool. The diamond brazed with nickel-based brazing filler metal doped with 1wt% Nb2O5 had a better morphology, no obvious thermal damage on the diamond surface, and the cutting edge remained intact;

[0033] Figure 3 The following are morphologies of brazed diamond carbides according to the embodiment of the present invention and comparative examples 1 and 2. (a) is diamond brazed with pure nickel-based brazing filler metal, (b) is diamond brazed with nickel-based brazing filler metal doped with 1 wt% Nb, and (c) is diamond brazed with nickel-based brazing filler metal doped with 1 wt% Nb2O5. Comparison revealed that the addition of Nb2O5 effectively refined the carbides on the brazed diamond surface, increased the effective contact area between the diamond and the brazing filler metal layer, and improved the interfacial bonding strength of the brazed diamond to a certain extent.

[0034] Figure 4 The Raman spectra of brazed diamonds of the embodiment of the present invention and comparative examples 1 and 2 are shown. Among them, (a) is pure nickel-based brazing filler metal brazing diamond, (b) is nickel-based brazing filler metal brazing diamond doped with 1wt% Nb, (c) is nickel-based brazing filler metal brazing diamond doped with 1wt% Nb2O5, and (d) is the Raman spectra of diamond brazed with the three brazing filler metal systems. D :I G Ratio. Generally speaking, the Raman spectrum peak of diamond appears at 1332cm -1 Nearby, the amorphous carbon peak is at 1350cm -1 (D peak), graphite peak at 1580cm -1 (G peak), the intensity of the graphite peak and the amorphous carbon peak is low or the area ratio of the D peak to the G peak (I D :I G ) to evaluate the degree of graphitization of diamond, I D :I G The larger the ratio, the lower the degree of graphitization of diamond. By comparison, it is found that when doped with 1wt% Nb2O5, the I D :I G The value is the largest, indicating that Nb2O5 doping can reduce the degree of graphitization on the diamond surface;

[0035] Figure 5The following are three-dimensional super-depth-of-field morphologies of the brazed diamonds after grinding experiments in the embodiments of the present invention and comparative examples 1 and 2. Among them, (a) is pure nickel-based brazing filler metal brazed diamond, (b) is nickel-based brazing filler metal brazed diamond doped with 1wt% Nb, and (c) is nickel-based brazing filler metal brazed diamond doped with 1wt% Nb2O5. The brazed diamond samples were ground using a V600 high-precision CNC surface grinder. An Al2O5 grinding wheel with a diameter of 200mm and a thickness of 10mm was used for the grinding wheel. The grinding wheel rotated at 3000r / min, with a uniform feed of 10μm each time and an effective cutting depth of 1mm. A comparison revealed that the diamond sample brazed with nickel-based brazing filler metal doped with 1wt% Nb2O5 still maintained relatively intact edges and corners, significantly improving the diamond's grinding performance.

[0036] The above specific implementation methods are only examples of the technical solutions of the present invention, and the scope of protection of the present invention is not limited by them. Any technical solution based on the technical principle and core design of the present invention, which is realized through non-substantial adjustments such as equivalent replacement and structural deformation, or any technical solution that is directly transplanted and applied to other application scenarios without modification, shall fall within the scope of protection of the patent right of the present invention. In other words, any creative implementation behavior using the method concept and technical solution of the present invention shall fall within the protection boundary of the rights of the present invention.

Claims

1. A nickel-based brazing filler metal doped with Nb2O5, characterized in that: The solder is obtained by mechanical ball milling of nickel-based solder and Nb2O5, and its components include: 6-8wt% chromium (Cr), 4-5wt% silicon (Si), 2.75-3.5wt% boron (B), 2.5-3.5wt% iron (Fe), 0-3wt% Nb2O5, and the rest is nickel (Ni).

2. The nickel-based brazing filler metal doped with Nb2O5 according to claim 1, characterized in that: The ball mill has a rotation speed of 300 to 1000 r / min and a ball-to-material ratio of 2 to 10:

1.

3. The nickel-based brazing filler metal doped with Nb2O5 according to claim 1, characterized in that: The mechanical ball milling time is 30 to 60 minutes.

4. A nickel-based brazing filler metal doped with Nb2O5 for brazing diamond, characterized in that: The brazing temperature of the nickel-based brazing material Nb2O5 is lower than 1080°C in an argon-protected tube furnace and the holding time is less than 30 minutes.

5. The method for brazing diamond with a nickel-based brazing filler metal doped with Nb2O5 according to claim 4, wherein: The brazing temperature is 1010-1080°C.

6. The method for brazing diamond with a nickel-based brazing filler metal doped with Nb2O5 according to claim 4, wherein: The heat preservation time is 5 to 30 minutes.

7. The method for brazing diamond with a nickel-based brazing filler metal doped with Nb2O5 according to claim 4, wherein: The brazing diamond surface generates a plurality of compounds such as Cr3C2 and Cr7C3, and the carbides on the brazing diamond surface are refined, thereby achieving high-strength grip of the brazing material on the diamond.

8. The method for brazing diamond with a nickel-based brazing filler metal doped with Nb2O5 according to claim 4, wherein: The degree of graphitization of the brazed diamond is reduced, thereby effectively suppressing thermal damage to the diamond.

9. The method for brazing diamond with a nickel-based brazing filler metal doped with Nb2O5 according to claim 4, wherein: The brazed diamond sample still maintains a good and relatively complete cutting edge after grinding, showing excellent grinding performance.

Images