Injection-molded high-zinc-content copper-nickel-zinc alloy powder and sintering densification method

Abstract

The invention relates to the field of metal injection molding alloy manufacturing, in particular to injection molding high-zinc-content copper-nickel-zinc alloy powder and a sintering densification method.The method comprises the following steps that 1, powder is prepared, pure copper, pure nickel and pure zinc are molten, and copper-nickel-zinc alloy powder is prepared; 2, plating, wherein plating treatment is conducted on the surface of the copper-nickel-zinc alloy powder; 3, internal mixing is conducted, specifically, the mixed materials are put into an internal mixer with the set temperature, and copper-nickel-zinc feed is obtained; 4, injection molding is conducted, specifically, the copper-nickel-zinc feed is put into an injection molding machine to be subjected to injection molding, and an injection green body is obtained; 5, oxalic acid degreasing is conducted, specifically, the injection green body is subjected to catalytic degreasing, and a degreased blank is obtained; and 6, sintering is conducted, specifically, the degreased blank is put into a continuous furnace to be sintered, and a sintered part is obtained. According to the metal injection molding method adopted by the invention, parts with complex shapes can be produced on a large scale within a short time, and the production efficiency is greatly improved.

Description

Technical Field

[0001] The present invention relates to the field of manufacturing metal injection molding alloys, and particularly to an injection molding high-zinc-content copper-nickel-zinc alloy powder and a sintering densification method thereof. Background Art

[0002] The raw material copper-nickel-zinc alloy powder belongs to the copper alloy series materials, and can be classified into the category of "nickel silver" according to the content of nickel and zinc elements. Nickel silver is mainly used in the fields of shielding covers for the electronics industry, casings for resonators, camera parts, optical equipment, etched substrates, jewelry alloys, etc. due to its good workability, electrical conductivity, corrosion resistance, and magnetic shielding properties.

[0003] Taking nickel silver sheets as an example, the current preparation of nickel silver sheets on the market mainly includes process flows such as raw material selection and pretreatment, melting and casting, hot rolling, cold rolling and annealing, and surface treatment, which have problems such as complex processes, long process flows, difficulty in preparing parts with complex shapes, and high processing costs.

[0004] At the same time, the copper-nickel-zinc alloy powder contains a large amount of zinc element, and the boiling point of this element is extremely low, only 906 °C. During the high-temperature sintering densification process of the powder, it is extremely easy to cause the volatilization loss of the zinc element, resulting in a low zinc element content in the final product, not meeting the design composition requirements, and ultimately leading to a reduction in alloy performance. Summary of the Invention

[0005] Aiming at the problems existing in the prior art, the purpose of the present invention is to: use the metal injection molding process to prepare nickel silver process products, and provide a sintering densification method and alloy for injection molding high-zinc-content copper-nickel-zinc alloy powder that can form small and complex-shaped parts in large quantities in a short time, simplify the process flow, and reduce production costs.

[0006] To achieve the above purpose, the technical solution adopted by the present invention is: a sintering densification method for injection molding high-zinc-content copper-nickel-zinc alloy powder, comprising the following steps: Step 1: Powder preparation, melting pure copper, pure nickel and pure zinc by induction melting under atmospheric conditions, and then preparing copper-nickel-zinc alloy powder by gas atomization; Step 2: Coating, performing coating treatment on the surface of the copper-nickel-zinc alloy powder by electroless plating; Step 3: Kneading, adjusting the mass percentage of the copper-nickel-zinc alloy powder and the binder, performing uniform kneading, putting the kneaded material into a kneader with a set temperature, adjusting the rotation speed of the kneader, and obtaining copper-nickel-zinc feedstock after granulation; Step 4: Injection molding, adjusting the process parameters of the injection molding machine, putting the copper-nickel-zinc feedstock into the injection molding machine for injection molding to obtain an injection green body; Step 5: Oxalic acid degreasing. Using oxalic acid as a catalyst, adjust the degreasing parameters, and perform catalytic degreasing on the injection green body to obtain a degreased blank. Step 6: Sintering. Adjust the sintering parameters, put the degreased blank into a continuous furnace for sintering to obtain a sintered part.

[0007] The above-mentioned sintering densification method for injection-molded copper-nickel-zinc alloy powder with high zinc content. The step 1 includes: first melting copper and covering it with dry charcoal, raising the temperature to 1300 - 1350 °C, adding nickel blocks, keeping warm for 10 - 15 min to ensure full melting of nickel, cooling to 1100 - 1150 °C, adding zinc blocks wrapped with copper foil according to the proportion of zinc element content of 24 - 26 %, keeping warm for 10 - 15 min, and performing two high-temperature flame spraying for refining and degassing. When the zinc content measured on-site is 20 - 25 %, gas atomization is carried out to produce powder.

[0008] The above-mentioned sintering densification method for injection-molded copper-nickel-zinc alloy powder with high zinc content. During gas atomization to produce powder, the gas atomization parameters are as follows: adopting rapid solidification high-pressure gas atomization technology, the atomization medium is nitrogen, the spray apex angle is 35°, the diameter of the tundish nozzle is 6.2 mm, the melt flow rate is 300 - 400 g / s, the superheat temperature is 80 - 120 °C, the atomization nozzle adopts the free-fall type, the gas pressure is 3 - 7 MPa, and the particle size D50 of the atomized copper-nickel-zinc alloy powder is 14 - 18 μm.

[0009] The above-mentioned sintering densification method for injection-molded copper-nickel-zinc alloy powder with high zinc content. When performing the plating treatment in step 2, nickel is first plated and then copper is plated by electroless plating to form a core-shell structure with the copper-nickel-zinc alloy powder body as the core, an outer nickel layer of 0.4 - 0.6 μm and a copper layer of 0.6 - 1.2 μm. The composite powder particle size D50 is 15 - 19 μm, and its main component and content are as follows: Nickel: 18 - 22 %, zinc: 18 - 22 %, copper: the balance.

[0010] The above-mentioned sintering densification method for injection-molded copper-nickel-zinc alloy powder with high zinc content. In step 3, the binder includes the following components: Main binder: polyoxymethylene, accounting for 75.5 - 85.5 %, Skeleton binder: polypropylene, accounting for 10 - 17.5 %, The activator uses one or more of antioxidant B215, dispersant zinc stearate, and plasticizer dibutyl phthalate, accounting for 5 - 15 %.

[0011] For the above-mentioned sintering densification method of injection-molded copper-nickel-zinc alloy powder with high zinc content, in step 3, the weight percentages of the copper-nickel-zinc alloy powder and the binder are as follows: 87-90.3% of the copper-nickel-zinc alloy powder and 9.7-13% of the binder. The kneading temperature in the internal mixer is 170-190 °C, and the kneading time is 1-2 h.

[0012] For the above-mentioned sintering densification method of injection-molded copper-nickel-zinc alloy powder with high zinc content, in step 4, the process parameters include: injection temperature: 170-200 °C, injection pressure: 165-205 Mpa, mold temperature: 90-130 °C, injection speed: 12-65 mm / s.

[0013] For the above-mentioned sintering densification method of injection-molded copper-nickel-zinc alloy powder with high zinc content, in step 5, the debinding parameters include: oxalic acid feeding amount: 2-5 g / min; debinding temperature: 115-135 °C; debinding time: 6-10 h.

[0014] For the above-mentioned sintering densification method of injection-molded copper-nickel-zinc alloy powder with high zinc content, in step 6, the sintering parameters include: sintering temperature: 900-1000 °C; sintering holding time: 3-7 h; sintering atmosphere: pure hydrogen.

[0015] An injection-molded copper-nickel-zinc alloy powder with high zinc content is prepared by using the sintering densification method of injection-molded copper-nickel-zinc alloy powder with high zinc content as described in any one of the above. The components and their contents of the copper-nickel-zinc alloy are as follows: nickel: 20-25%, zinc: 13.5-14.5%, and the balance is copper.

[0016] The beneficial effects of the sintering densification method of injection-molded copper-nickel-zinc alloy powder with high zinc content in the present invention are as follows: Compared with the traditional rolling technology, the metal injection molding method adopted in the present invention can produce a large number of parts with complex shapes in a short time, and the production efficiency is greatly improved. In the operation process of the present invention, on the one hand, the content of zinc element is intentionally increased during the gas atomization powder making process, and on the other hand, copper is plated on the surface of the alloy powder first and then nickel is plated to form a relatively complete coating structure. A core-shell structure composite powder with a copper-nickel-zinc alloy powder as the core and a copper + nickel coating as the outer layer is prepared, and the effective control of the zinc content in the product is finally achieved by controlling the sintering temperature, and high-performance copper-nickel-zinc bulk materials are prepared. Brief Description of the Drawings

[0017] Figure 1 It is a process flow schematic diagram of the process method of the present invention. Detailed Embodiments

[0018] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be described below in combination with specific embodiments and the accompanying drawings.

[0019] As a new type of near-net shaping technology, the metal injection molding process ingeniously combines the advantages of traditional powder metallurgy process and plastic injection molding technology. It can form small-sized and complex-shaped parts in large quantities in a short time, with advantages such as short process flow, high material recycling rate, and low production cost.

[0020] Currently, stainless steel powder and titanium powder are two widely used materials in injection molding. They have something in common in the process. However, in specific applications, the similarities and differences between stainless steel and copper-nickel-zinc alloy in the injection molding process can be understood as follows: The injection molding of all materials can be divided into two main stages, namely injection and sintering. The requirement for injection is that the powder and additive materials have good fluidity after mixing, so as to facilitate the smooth filling of the cavity during the injection process, prepare complex-shaped components, and reduce defects. However, the additives used for each powder are different, which depends on the compatibility between the powder and the additive. For copper-nickel-zinc alloy, the additive adopted in the present invention is specially designed.

[0021] Example 1 This example provides a process for preparing copper-nickel-zinc alloy products by metal injection molding. The main process flow is gas atomization powder making - powder surface metal coating - internal mixer - injection molding - sintering, to prepare copper-nickel-zinc (Cu60Ni20Zn20) alloy products, and solve the problems of complex existing rolling forming process, difficult to form complex-shaped parts, and low zinc element concentration.

[0022] Regarding the difficulty of copper-nickel-zinc alloy injection molding, it mainly lies in the control of zinc content volatilization. This technical solution overcomes the large amount of zinc volatilization by means of nickel plating and copper plating combined with low-temperature sintering. As far as the current results are concerned, the zinc volatilization is within an acceptable range.

[0023] As Figure 1 shown, a method for sintering densification of high-zinc-content copper-nickel-zinc alloy powder by injection molding includes the following steps.

[0024] S1. Powder making: Melt pure copper, pure nickel, and pure zinc by induction melting under atmospheric conditions, and then prepare copper-nickel-zinc alloy powder by gas atomization.

[0025] Specifically, first melt copper and cover it with dry charcoal, raise the temperature to 1300 - 1350 °C, add nickel blocks, keep warm for 10 - 15 min to ensure full melting of nickel, cool down to 1100 - 1150 °C, add zinc blocks wrapped with copper foil according to the proportion of zinc element content of 24 - 26%, keep warm for 10 - 15 min, and carry out two high-temperature flame spraying for refining and degassing. When the zinc content measured on-site is 19 - 23%, carry out gas atomization powder making.

[0026] During gas atomization for powder production, the gas atomization parameters are as follows: the rapid solidification high-pressure gas atomization technology is adopted, the atomization medium is nitrogen, the injection apex angle is 35°, the diameter of the tundish nozzle is 6.2 mm, the melt flow rate is 300 - 400 g / s, the superheat temperature is 80 - 120 °C, the atomization nozzle adopts the free-fall type, the gas pressure is 3 - 7 MPa, the particle size D50 of the gas-atomized copper-nickel-zinc alloy powder is 14 - 18 μm, and the composition and content are as follows: Copper: 57 - 61%, Nickel: 17 - 21%, Zinc: 18 - 22%.

[0027] S2. Coating: The copper-nickel-zinc alloy powder is coated by electroless plating.

[0028] During the coating process, nickel is coated first and then copper by electroless plating, forming a core-shell structure with the copper-nickel-zinc alloy powder as the core, an outer nickel layer of 0.4 - 0.6 μm and a copper layer of 0.6 - 1.2 μm. The particle size D50 of the composite powder is 15 - 19 μm, and its main component composition and content are as follows: Copper: 58 - 62%, Nickel: 18 - 22%, Zinc: 18 - 22%.

[0029] S3. Kneading: Adjust the mass percentage of the copper-nickel-zinc alloy powder and the binder, conduct uniform kneading, put the kneaded material into a kneader with a set temperature, adjust the rotation speed of the kneader, and obtain the copper-nickel-zinc feedstock after granulation.

[0030] The weight percentage of the copper-nickel-zinc alloy powder to the binder is: copper-nickel-zinc alloy powder 87 - 90.3%, binder 9.7 - 13%.

[0031] The binder includes the following components: Main binder: copolymerized formaldehyde, accounting for 75.5 - 85.5%, Skeleton binder: polypropylene, accounting for 10 - 17.5%, Activator: one or more of antioxidant B215, dispersant zinc stearate and plasticizer dibutyl phthalate, accounting for 5 - 15%.

[0032] The kneading temperature in the kneader is 170 - 190 °C, and the kneading time is 1 - 2 h.

[0033] S4. Injection molding: Adjust the process parameters of the injection molding machine, put the copper-nickel-zinc feedstock into the injection molding machine for injection molding to obtain an injection green body.

[0034] The process parameters include: injection temperature: 170 - 200 °C, injection pressure: 165 - 205 Mpa, mold temperature: 90 - 130 °C, injection speed: 12 - 65 mm / s.

[0035] S5. Degreasing with oxalic acid: Using oxalic acid as a catalyst, adjusting the degreasing parameters, and catalytically degreasing the injection green body to obtain a degreased blank.

[0036] The degreasing parameters include: the amount of oxalic acid input: 2 - 5 g / min; degreasing temperature: 115 - 135 °C; degreasing time: 6 - 10 h.

[0037] S6. Sintering: Adjusting the sintering parameters, putting the degreased blank into a continuous furnace for sintering to obtain a sintered part.

[0038] The sintering parameters include: sintering temperature: 900 - 1000 °C; sintering holding time: 3 - 7 h; sintering atmosphere: pure hydrogen.

[0039] When applying the existing additives used in stainless steel injection molding to the copper - nickel - zinc alloy injection molding technology, the theoretical powder loading was determined to be 56% based on the tapped density and theoretical density of the copper - nickel - zinc alloy powder. To ensure that the binder can fully wrap the powder particles, combined with engineering practical experience, the powder loading was determined to be 54%, and the feed pellets were obtained after mixing and granulation.

[0040] In appearance, the surface of the pellets was rough. The flow rate of the feed was measured using a melt flow rate meter, and the feed could not flow. In the injection molding stage, the injection molding parameters needed to be adjusted to high injection pressure and high mold temperature to form a test injection sample, but there were many black streaks on the surface of the injection part, and slight cracks were found on the degreased part. To avoid defects such as poor injection molding and degreasing cracking caused by low feed fluidity as much as possible, the binder formula was adjusted, and a high - efficiency plasticizer dibutyl phthalate was added. The surface of the feed pellets obtained by internal mixer mixing was smooth, the feed fluidity was increased to 701.3 g / 10min, no obvious flow marks were seen on the surface of the injection part, the degreased part had no cracking, and the degreasing rate reached 97.6%.

[0041] Example 2 This example is a specific representation of Example 1, and the same parts as Example 1 will not be elaborated.

[0042] This example includes the following steps: S1. Weigh each component according to the mass percentage of copper - nickel - zinc alloy powder: binder = 90.3:9.7%, where the main binder is polyoxymethylene (POM), accounting for 85.5%; the skeleton binder is polypropylene (pp), accounting for 10%; the antioxidant is B215, accounting for 0.5%; the dispersant is zinc stearate, accounting for 4.0%.

[0043] S2. Heat the internal mixer to the set temperature of 170 °C. Add the copper-nickel-zinc alloy powder and stir slowly for preheating for 30 min. Then add the proportioned binder into the internal mixer to carry out internal mixing with the copper-nickel-zinc alloy powder. The internal mixer is heated to 190 °C, and the rotation speed of the internal mixer is 30 r / min. When it is kneaded into a dough-like state, reduce the rotation speed of the internal mixer. After granulation, copper-nickel-zinc feedstock with plump particles is obtained, and the total internal mixing duration is 2 h.

[0044] S3. Use a metal injection molding machine to inject the above feedstock into green compacts. The injection molding process parameters include: injection temperature: 180 - 195 °C, injection pressure: 160 - 170 Mpa, mold temperature: 120 °C, injection speed: 48 mm / s.

[0045] S4. Carry out oxalic acid debinding on the injection-molded green compacts. The debinding process includes: acid inlet amount: 5 g / min; debinding temperature: 125 - 130 °C; debinding time: 8 h.

[0046] S5. Put the debound compacts into a continuous furnace for sintering, introduce hydrogen, the sintering temperature is 985 °C, and keep the temperature for 4 h.

[0047] Test the copper-nickel-zinc alloy sample of this Example 1. The density of the sintered part is 8.539 g / cm 3 , the hardness is 104.5 HV, the tensile strength is 303.5 Mpa, the yield strength is 129.1 Mpa, and the elongation is 28.2%.

[0048] Example 3 This example is a specific representation of Example 1, and the same parts as Example 1 will not be elaborated again.

[0049] This example includes the following steps: S1. Weigh each component according to the mass percentage of copper-nickel-zinc alloy powder: binder = 89.0:11.0%. Among them, the main binder is polyoxymethylene (POM), accounting for 79.5%; the skeleton binder is polypropylene (pp), accounting for 15%; the antioxidant is B215, accounting for 0.5%; the plasticizer is dibutyl phthalate, accounting for 5.0%.

[0050] S2. Heat the internal mixer to the set temperature of 170 °C. Add the copper-nickel-zinc alloy powder and stir slowly for preheating for 30 min. Then add the proportioned binder into the internal mixer to carry out internal mixing with the copper-nickel-zinc alloy powder. The internal mixer is heated to 190 °C, and the rotation speed of the internal mixer is 30 r / min. When it is kneaded into a dough-like state, reduce the rotation speed of the internal mixer. After granulation, copper-nickel-zinc feedstock with plump particles is obtained, and the total internal mixing duration is 1.5 - 2 h.

[0051] S3. Inject the above-mentioned feedstock into a green compact using a metal injection molding machine. The injection molding process parameters include: injection temperature: 180 - 190 °C, injection pressure: 145 - 165 Mpa, mold temperature: 140 °C, injection speed: 65 mm / s.

[0052] S4. Perform oxalic acid debinding on the injection-molded green compact. The debinding process includes: acid feeding rate: 3.5 g / min; debinding temperature: 132 °C; debinding time: 6 h.

[0053] S5. Put the debound blank into a continuous furnace for sintering, introduce hydrogen, sintering temperature: 975 - 985 °C, heat preservation for 4 h.

[0054] Test the copper-nickel-zinc alloy sample of this Example 2. The density of the sintered part is 8.582 g / cm 3 , the hardness is 97.6 HV, the tensile strength is 323.6 Mpa, the yield strength is 133.95 Mpa, and the elongation is 26.5%.

[0055] Example 4 This example is a specific representation of Example 1, and the same parts as Example 1 will not be elaborated again.

[0056] This example includes the following steps: S1. Weigh each component according to the mass percentage of copper-nickel-zinc alloy powder: binder = 90.3:9.7%. Among them, the main binder is polyoxymethylene (POM), accounting for 80.5%; the skeleton binder is polypropylene (pp), accounting for 10%; the antioxidant is B215, accounting for 0.5%; the plasticizer is dibutyl phthalate, accounting for 5.0%; the dispersant is zinc stearate, accounting for 4.0%.

[0057] S2. Heat the internal mixer to the set temperature of 170 °C. After adding the copper-nickel-zinc alloy powder and slowly stirring for preheating for 30 min, add the proportioned binder into the internal mixer for internal mixing with the copper-nickel-zinc alloy powder. The internal mixer is heated to 190 °C, the rotation speed of the internal mixer is 30 r / min. When it is kneaded into a dough-like state, reduce the rotation speed of the internal mixer. After granulation, copper-nickel-zinc feedstock with plump particles is obtained, and the total internal mixing duration is 1.5 - 2 h.

[0058] S3. Inject the above-mentioned feedstock into a green compact using a metal injection molding machine. The injection molding process parameters include: injection temperature: 170 - 190 °C, injection pressure: 165 - 180 Mpa, mold temperature: 110 °C, injection speed: 40 mm / s.

[0059] S4. Subject the injection green compact to oxalic acid degreasing. The degreasing process includes: acid feed rate: 5 g / min; degreasing temperature: 125 - 135 °C; degreasing time: 10 h.

[0060] S5. Place the degreased blank into a continuous furnace for sintering, introduce hydrogen, sintering temperature 975 °C, holding time 4 h.

[0061] Test the copper-nickel-zinc alloy sample of this technical solution. The density of the sintered part is 8.593 g / cm 3 , hardness is 108.7 HV, tensile strength is 334.6 Mpa, yield strength is 164.3 Mpa, elongation is 30.7 %.

[0062] The effects of different parameters are shown in Table 1. Among them, serial numbers 1, 2, and 3 are comparative examples, and their sintering temperatures are all 990 °C to examine the effect of the coating. Serial numbers 4, 5, 6, 7, and 8 are examples, and the coating parameters are the same to examine the influence of the sintering temperature.

[0063] Table 1 Effects of different parameters .

[0064] The above examples are only to illustrate the inventive concept and features of the present invention. The purpose is to enable ordinary technicians in the field to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the essence of the content of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for sintering and densifying injection-molded high-zinc content copper-nickel-zinc alloy powder, characterized in that: The following steps are involved: Step 1: Powder preparation, using induction melting under atmospheric conditions to melt pure copper, pure nickel and pure zinc, and then preparing copper-nickel-zinc alloy powder by gas atomization; Step 2: Plating: plating the surface of the copper-nickel-zinc alloy powder by chemical plating; Step 3: Mixing, adjusting the mass percentage of the copper-nickel-zinc alloy powder and the binder, mixing evenly, placing the mixed materials into a mixer with a set temperature, adjusting the mixer speed, and obtaining the copper-nickel-zinc feed after granulation; Step 4: injection molding, adjusting the process parameters of the injection molding machine, placing the copper-nickel-zinc feed into the injection molding machine for injection molding, and obtaining an injection green body; Step 5: oxalic acid degreasing, using oxalic acid as a catalyst, adjusting degreasing parameters, and performing catalytic degreasing on the injection green body to obtain a degreased green body; Step 6: Sintering, adjusting sintering parameters, placing the debinded blank into a continuous furnace for sintering to obtain a sintered part.

2. The sintering densification method for injection molding high zinc content copper-nickel-zinc alloy powder according to claim 1, characterized in that: The step 1 comprises: firstly melting copper and covering it with dry charcoal, raising the temperature to 1300-1350°C, adding a nickel block, keeping the temperature for 10-15 minutes to ensure that the nickel is fully melted, cooling the temperature to 1100-1150°C, adding a zinc block wrapped in copper foil according to a ratio of 24-26% of the zinc content, keeping the temperature for 10-15 minutes, performing two high-temperature flame sprayings for refining and degassing, and performing gas atomization powder making when the zinc content is 20-25% as measured on site.

3. The sintering densification method for injection molding high zinc content copper-nickel-zinc alloy powder according to claim 2, characterized in that: During gas atomization powder making, the gas atomization parameters are: rapid solidification high-pressure gas atomization technology is adopted, the atomizing medium is nitrogen, the injection vertex angle is 35°, the diameter of the drain nozzle is 6.2 mm, the melt flow rate is 300~400 g / s, the overheating temperature is 80~120 ℃, the atomizing nozzle adopts free fall type, the gas pressure is 3~7 MPa, and the atomized copper-nickel-zinc alloy powder particle size D50 is 14~18 μm.

4. The sintering densification method for injection molding high zinc content copper-nickel-zinc alloy powder according to claim 3, characterized in that: When the plating treatment is performed in step 2, nickel is first plated and then copper is plated by chemical plating to form a core-shell structure with a copper-nickel-zinc alloy powder as the core and a 0.4-0.6 μm nickel layer and a 0.6-1.2 μm copper layer as the outer layer. The particle size D50 of the composite powder is 15-19 μm, and its main component components and contents are: Nickel: 18~22%, Zinc: 18~22%, Copper: balance.

5. The sintering densification method for injection molding high zinc content copper-nickel-zinc alloy powder according to claim 1, characterized in that: In step 3, the binder includes the following components: The main binder uses copolymer formaldehyde, accounting for 75.5~85.5%, the skeleton binder uses polypropylene, accounting for 10~17.5%, and the activator uses one or more of antioxidant B215, dispersant zinc stearate and plasticizer dibutyl phthalate, accounting for 5~15%.

6. The sintering densification method for injection molding high zinc content copper-nickel-zinc alloy powder according to claim 5, characterized in that: In step 3, the weight percentage of the copper-nickel-zinc alloy powder and the binder is: 87-90.3% of the copper-nickel-zinc alloy powder and 9.7-13% of the binder. The internal mixing temperature in the internal mixer is 170-190° C. and the internal mixing time is 1-2 h.

7. The sintering densification method for injection molding high zinc content copper-nickel-zinc alloy powder according to claim 1, characterized in that: In step 4, the process parameters include: injection temperature: 170~200°C, injection pressure: 165~205 MPa, mold temperature: 90~130°C, injection speed: 12~65 mm / s.

8. The sintering densification method for injection molding high zinc content copper-nickel-zinc alloy powder according to claim 1, characterized in that: In step 5, the degreasing parameters include: oxalic acid feeding amount: 2-5 g / min; degreasing temperature: 115-135°C; degreasing time: 6-10 h.

9. The sintering densification method for injection molding high zinc content copper-nickel-zinc alloy powder according to claim 1, characterized in that: In step 6, the sintering parameters include: sintering temperature: 900-1000°C; sintering holding time: 3-7 h; sintering atmosphere: pure hydrogen.

10. An injection-molded copper-nickel-zinc alloy powder with a high zinc content, characterized in that: The copper-nickel-zinc alloy is prepared by using the sintering densification method for injection-molded copper-nickel-zinc alloy powder with high zinc content as described in any one of claims 1 to 9, and the components of the copper-nickel-zinc alloy and the content of each component are: Nickel: 20~25%, Zinc: 13.5~14.5%, Copper: balance.

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