Search

CN-122012991-A - High-wear-resistance corrosion-resistant Zn-Mn-Cr-Mg zinc alloy and preparation method and application thereof

CN122012991ACN 122012991 ACN122012991 ACN 122012991ACN-122012991-A

Abstract

The invention provides a preparation method of a high-wear-resistance corrosion-resistance high-hardness zinc alloy with a component Zn-Mn-Cr-Mg, belonging to the field of zinc alloy and preparation and processing thereof. The zinc alloy comprises 2 at to 5 at percent of Mn, 0.01 at to 2 at percent of Mg and 0.01 at to 2 at percent of Cr, and consists of MnZn 13 、CrZn 17 , zn and Mg 2 Zn 11 or Mg dissolved in Zn, wherein the volume fraction of MnZn 13 phase is more than or equal to 55 percent, the volume fraction of CrZn 13 phase is more than or equal to 0.5 percent, and the content of Mg 2 Zn 11 and Mg dissolved in Zn matrix is very small. The alloy has finer and uniform structure through a rapid cooling means, has higher strength, the compressive yield strength is more than 400 MPa, the compressive strength is more than 600 MPa, and can reach the maximum compressive strain rate of more than 50 percent, can be rolled or extruded into a plate or bar, has higher hardness, wear resistance and corrosion resistance, and can be used for manufacturing bearings, gears, turbines, pneumatic and hydraulic accessories, agricultural machinery, automobile parts and the like.

Inventors

  • LI LICHEN
  • LIN WENJUN
  • JIANG WEN
  • LIU WEIPING
  • ZHU MINGMING
  • Zhan Yangfang
  • SHI ZHANGZHI

Assignees

  • 北京科技大学
  • 湖南株冶有色金属有限公司

Dates

Publication Date
20260512
Application Date
20260210

Claims (8)

  1. 1. A Zn-Mn series zinc alloy with high wear resistance and corrosion resistance and high hardness and high plasticity is characterized in that the zinc alloy consists of 4 metal elements, namely Zn element, mn element, cr element and Mg element, wherein the content of the elements is as follows, the content of the elements is 2-5% by atom percent, the content of the Cr is 0.01-2% by atom percent, the content of the Mg is 0.01-2% by atom percent, and the balance is Zn.
  2. 2. The method for producing a Zn-Mn-based zinc alloy according to claim 1, wherein the production of the zinc alloy is carried out according to the steps of: 1) Smelting, namely adding pure Zn, pure Mn, pure Cr and pure Mg into a crucible in a heating furnace in proportion, and preserving heat for 10 to 20 minutes at 600 to 700 ℃; 2) Cooling a copper bottom plate, namely, a casting mold is made of aluminum oxide or zirconium oxide with low heat conductivity coefficient, the height of the mold is 5 mm-20 mm, the bottom of the mold is a pure copper bottom plate with high heat conductivity coefficient, and before molten metal is poured into the mold, the pure copper bottom plate is placed into liquid nitrogen to be soaked for 1-10 minutes, so that the temperature of the pure copper bottom plate is cooled to below-20 ℃; 3) Pouring, namely pouring molten metal into the mould; 4) And (3) cooling the top and the bottom, namely immediately pressing a pure copper top plate with high heat conductivity on the molten metal after pouring the molten metal into a die, pouring liquid nitrogen on the pure copper top plate for cooling, enabling the liquid nitrogen to flow onto a pure copper bottom plate to continuously keep the temperature below 0 ℃, and cooling the molten metal to room temperature at a speed of more than 700K/min under the cooperative cooling of the copper bottom plate and the copper top plate to obtain the zinc alloy.
  3. 3. The preparation method of the aluminum alloy casting mold according to claim 2, wherein the casting mold is made of zirconia (2-3.5W/(m.K)) material with a heat conductivity coefficient lower than 5W/(m.K), the bottom of the mold is a pure copper bottom plate with a high heat conductivity coefficient, the pure copper bottom plate is always contacted with continuously circulating cooling water before molten metal is poured into the mold and in the process of cooling the molten metal, so that the temperature of the pure copper bottom plate is kept below 20 ℃, and the bottom water-cooled copper plate is forced to be cooled due to the fact that the mold is made of material with a low heat conductivity coefficient, and the heat flow direction is perpendicular to the bottom water-cooled copper plate, so that the effect of eliminating shrinkage cavity traditional solidification defects is achieved.
  4. 4. The zinc alloy produced by the method of claim 2, wherein when the Mg content is less than 0.5 at%, the structure of the zinc alloy is characterized by: 1) Consists of MnZn 13 、CrZn 17 , a Zn matrix phase and Mg dissolved in Zn, wherein the volume fraction of MnZn 13 is 55-65%, the volume fraction of CrZn 17 is 0.5-1%, and the rest is Zn matrix; 2) The size (expressed as equivalent diameter) of MnZn 13 phase is that the average size of MnZn 13 particles is 15 μm to 25 μm; 3) The MnZn 13 and CrZn 17 phases are uniformly distributed in the Zn matrix phase, which is continuous without large pieces of continuous MnZn 13 phase.
  5. 5. The zinc alloy produced by the method of claim 2, wherein when the Mg content is greater than 0.5 at%, the structure of the zinc alloy is characterized by: 1) Consists of MnZn 13 、CrZn 17 、Mg 2 Zn 11 , a Zn matrix phase and Mg dissolved in Zn, wherein the volume fraction of MnZn 13 is 55 to 65 percent, the volume fraction of CrZn 17 is 0.5 to 1 percent, the volume fraction of Mg 2 Zn 11 is 0 to 0.5 percent, and the rest is Zn matrix; 2) The size (expressed as equivalent diameter) of MnZn 13 phase is that the average size of MnZn 13 particles is 15 μm to 25 μm; 3) The MnZn 13 and CrZn 17 phases are uniformly distributed in the Zn matrix phase, which is continuous without large pieces of continuous MnZn 13 phase.
  6. 6. The alloy prepared by the method according to claim 2 is characterized in that the alloy has a special corrosion resistance mechanism that Zn matrix in the alloy is corroded preferentially in the soaking corrosion process, part of the Zn matrix is dissolved in the solution, znO is generated on the surface of the alloy in the other part of the Zn matrix, and a ZnO corrosion product layer is relatively loose in the zinc alloy, but an insoluble corrosion product Zn 5 (OH) 8 Cl 2 ·H 2 O is generated in the corrosion process due to the action of a small amount of Mg element in the alloy, and Cr 2 O 3 is formed by enrichment of Cr element on the surface of the alloy due to the dissolution of Zn, so that ZnO, zn 5 (OH) 8 Cl 2 ·H 2 O and Cr 2 O 3 form a compact corrosion product layer of the alloy together, and the corrosion of the alloy can be effectively prevented.
  7. 7. The alloy of claim 2, wherein the zinc alloy has the following properties: 1) The room temperature compression mechanical property is that the yield strength is 350 MPa to 550 MPa, the compressive strength is 600 MPa to 900 MPa, and the maximum compression strain rate is 15 to 55 percent; 2) The hardness of the material is at least 150 HV; 3) Performing a ring-block sliding wear test at a pressure of 120N, with a wear rate of 2.5 mg/h to 4.5 mg/h; 4) The corrosion rate was 0.14 g/(m 2 h) to 0.22 g/(m 2 h) for 48 hours in the neutral salt spray test at a temperature of 35 ℃ and ph=7.
  8. 8. Use of the zinc alloy produced by the method according to claims 2 to 5 for the production of bearings, gears, turbines, pneumatic and hydraulic fittings and agricultural and automotive parts.

Description

High-wear-resistance corrosion-resistant Zn-Mn-Cr-Mg zinc alloy and preparation method and application thereof Technical Field The invention belongs to the field of zinc alloy and preparation and processing thereof, and relates to a Zn-Mn-Cr-Mg zinc alloy with high wear resistance, corrosion resistance, high strength and high plasticity, a preparation method and application thereof. Technical Field The zinc-aluminum series alloy is the zinc alloy series which is most applied in industry at present, and is mainly used for replacing copper alloy, cast iron and aluminum alloy to manufacture bearings and the like. The zinc-aluminum alloy mainly comprises several series of ZA8, ZA12, ZA27, ZA35 and the like, wherein the ZA27 alloy has the best comprehensive mechanical property, the hardness is between 110 HV and 120 HV, the tensile strength is between 390 MPa and 440 MPa, and the elongation is 2 percent, which is disclosed in document 1. However, the hardness, plasticity, wear resistance and the like of the zinc-aluminum series alloy limit the further development and application of the zinc-aluminum series alloy, and the comprehensive mechanical properties of the zinc-aluminum series alloy are difficult to be greatly improved through decades of development, so that the change of the additive element Al in the Zn alloy and the improvement of the manufacturing process of the Zn alloy are another feasible scheme for improving the mechanical properties. At present, a great deal of researches are carried out on improving mechanical properties by adding Mn element into Zn alloy, in the researches, the Zn alloy is mainly used as medical degradable metal, the addition amount of Mn is generally below 1 wt percent, and the indexes of hardness, wear resistance, corrosion resistance and the like of the alloy are far less than the requirements of products such as industrial bearings, gears and the like, and the indexes are disclosed in documents 2 and 3. The hardness of medical degradable Zn-Mn series alloy reported in the current literature is generally lower than 100 HV. Prior art literature Literature 1：RITAPURE P P, YADAV R G, RASAL V T, et al. Comparative review and experimental validation of Tribological and Mechanical Properties of Zinc Aluminium Alloy (ZA27) and Aluminium Zinc Alloy (Al-25Zn). Journal of Alloys and Metallurgical Systems, 2024, 7:100099. Literature 2：SUN J, ZHANG X, SHI Z-Z, et al. Adjusting comprehensive properties of biodegradable Zn-Mn alloy through solution heat-treatment. Materials Today Communications, 2020, 23:101150. Literature 3：SHI Z-Z, YU J, JI Z-K, et al. Influence of solution heat treatment on microstructure and hardness of as-cast biodegradable Zn–Mn alloys. Journal of Materials Science, 2018, 54: 1728-1740. Disclosure of Invention The high-hardness zinc alloy comprises, by atom%, 2-5% of Mn, 0.01-2% of Cr, 0.01-2% of Mg and the balance Zn. A Zn-Mn series zinc alloy with high wear resistance and corrosion resistance and high hardness and high plasticity is characterized in that the zinc alloy consists of 4 metal elements, namely Zn element, mn element, cr element and Mg element, wherein the content of the elements is as follows, the content of the elements is 2-5% by atom percent, the content of the Cr is 0.01-2% by atom percent, the content of the Mg is 0.01-2% by atom percent, and the balance is Zn. The preparation method of the Zn-Mn zinc alloy comprises the following preparation steps: 1) Smelting, namely adding pure Zn, pure Mn, pure Cr and pure Mg into a crucible in a heating furnace in proportion, and preserving heat for 10 to 20 minutes at 600 to 700 ℃; 2) The casting mold is made of aluminum oxide or zirconium oxide with low heat conductivity coefficient, the height of the mold is 5 mm-20 mm, the bottom of the mold is a pure copper bottom plate with high heat conductivity coefficient, and before molten metal is poured into the mold, the pure copper bottom plate is placed into liquid nitrogen to be soaked for 1-10 minutes, so that the temperature of the pure copper bottom plate is cooled to below-20 ℃; 3) Pouring, namely pouring molten metal into the mould; 4) And (3) cooling the top and the bottom, namely immediately pressing a pure copper top plate with high heat conductivity on the molten metal after pouring the molten metal into a die, pouring liquid nitrogen on the pure copper top plate for cooling, enabling the liquid nitrogen to flow onto a pure copper bottom plate to continuously keep the temperature below 0 ℃, and cooling the molten metal to room temperature at a speed of more than 700K/min under the cooperative cooling of the copper bottom plate and the copper top plate to obtain the zinc alloy. The smelting process of the step (1) can be directly carried out in an air environment without depending on protective atmosphere or vacuum conditions, and when the traditional casting process is used for smelting in the air, the surface of molten metal can generate a thicker ox