Powder alloy for diesel rocker arm seat and method for manufacturing the same

Abstract

The application discloses a kind of powder alloy for preparing diesel rocker arm seat and a preparation method thereof, and belongs to the technical field of alloy material preparation, to solve the technical problems that the flowability and particle size uniformity of the powder alloy for preparing diesel rocker arm seat in the prior art need to be further improved;The present application uses iron-based main powder as the matrix, by introducing wetting auxiliary powder, titanium-based reinforcing powder and iron-molybdenum co-doped boron phosphorus microspheres to construct a multi-component premixed gold powder system, wherein the wetting auxiliary powder improves the interface adaptation and contact state between particles, the titanium-based reinforcing powder participates in the construction of the organizational framework and enhances the continuity of load transmission, and the iron-molybdenum co-doped boron phosphorus microspheres adjust the particle bonding area and pore evolution process, thereby synergistically improving the mixing stability, mold consistency and subsequent sintering organizational continuity of the premixed gold powder.

Description

Technical Field

[0001] This invention relates to the field of powder alloy preparation technology, specifically to a powder alloy for preparing a diesel rocker arm seat and its preparation method. Background Technology

[0002] Existing iron-based powder metallurgy materials are mostly based on iron-based main powder, combined with copper powder, graphite and alloying components such as nickel, molybdenum, phosphorus and boron to form premixed gold powder, which is then pressed and sintered to prepare structural parts. In order to balance formability and service requirements, existing technologies usually use pre-alloying, diffusion alloying or mechanical mixing to introduce different functional components. Some schemes also add hard reinforcing particles, intermetallic compound precursors or surface modified powders to adjust the microstructure formation, local bonding state and the overall performance of the final part during sintering.

[0003] However, in existing premixed gold powder systems, there are often significant differences in particle size distribution, particle morphology, bulk density, and surface properties among different components. In particular, when copper powder, graphite, fine active powder, and reinforcing particles are added simultaneously, inconsistent migration rhythms are more likely to occur during mixing, transfer, and molding. This may lead to local agglomeration, stratification, or unstable adhesion of fine powder, affecting the mixing uniformity and batch stability of the premixed gold powder, and further causing fluctuations in the filling state during molding, which is not conducive to the consistent formation of the subsequent compact structure.

[0004] Furthermore, in existing technologies, some of the added components are directly added to the iron-based system in the form of single-element powders, ordinary alloy powders, or hard particles with insufficient surface activity. During the subsequent sintering process, there is often a lack of good interfacial transition between these components and the iron-based main powder and copper-based phase. In particular, when multiple active elements and reinforcing components coexist, the particle bonding area is prone to local insufficient wetting, discontinuous connection, and concentrated pore residues. This leads to problems such as interfacial rupture, interruption of local load-bearing paths, and unbalanced pore evolution in the sintered structure, which limits the structural coordination of the iron-based premixed gold powder system.

[0005] To address this technical deficiency, a solution is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a powder alloy for preparing diesel rocker arm seats and its preparation method, which solves the technical problem that the flowability and particle size uniformity of the powder alloy for preparing diesel rocker arm seats need to be further improved in the prior art.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] A powder alloy for preparing a diesel rocker arm seat comprises the following raw materials in parts by weight: 472-483 parts alloy powder, 8-9 parts wetting auxiliary powder, 12-15 parts titanium-based reinforcing powder, 4-5 parts iron-molybdenum co-doped boron-phosphorus microspheres, and 2-3 parts zinc stearate. The alloy powder is obtained by mixing iron, copper, nickel, molybdenum, and graphite in a weight ratio of 250:4-5:2-3:1-2:2 and then milling the mixture through a 120-mesh sieve under nitrogen protection.

[0009] The titanium-based reinforced powder is prepared by the following method:

[0010] A1. Add deionized water to the reaction vessel and stir. Then add melamine, glucose and titanium-based precursor gel in sequence. After dispersing evenly, a slurry is obtained. The slurry is sent to the atomizing thermal reactor. Under a mixed atmosphere, the temperature of the atomizing thermal reactor is controlled at 880-930℃ and held for 12-15s. After post-processing, titanium-based reinforced intermediate powder is obtained.

[0011] A2. Heat-treat the titanium-based reinforced intermediate powder to obtain titanium-based reinforced powder.

[0012] Further, in step A1, the ratio of deionized water, melamine, glucose and titanium-based precursor gel is 50-60 mL: 3-4 g: 1-2 g: 10-12 g, wherein the mixing atmosphere is obtained by mixing ammonia and nitrogen in a volume ratio of 3-4: 6-7, and the post-treatment includes: collecting the powder and pulverizing it through a 200-300 mesh sieve to obtain titanium-based reinforced intermediate powder;

[0013] Further, in step A2, the heat treatment is as follows: the titanium-based reinforced intermediate powder is added to a tube furnace, heated to 1020-1060℃ under an argon atmosphere, held for 80-120 minutes, and then processed to obtain titanium-based reinforced powder; the post-processing includes: discharging the material after natural cooling, pulverizing it through a 275-325 mesh sieve, and obtaining titanium-based reinforced powder.

[0014] Furthermore, the preparation method of the titanium-based precursor gel is as follows: tetrabutyl titanate and anhydrous ethanol are added to a reaction vessel and stirred. After mixing evenly, acetylacetone is added and stirred evenly again. Then, the mixture is added, the reaction vessel is heated to 30-40℃, and stirred for 2-3 hours. The titanium-based precursor gel is obtained after post-treatment.

[0015] Furthermore, the ratio of tetrabutyl titanate, anhydrous ethanol, acetylacetone, and the mixture is 10-12g:28-32mL:2-3g:8mL. The mixture is obtained by mixing ferric nitrate nonahydrate, boric acid, deionized water, and anhydrous ethanol in a ratio of 6-7g:5-6g:6-7mL:15mL. The post-treatment includes: aging at 75-85℃ for 4-6 hours to obtain a gel material, vacuum drying the gel material at 65-75℃ for 6-10 hours, pulverizing it, and passing it through an 80-100 mesh sieve to obtain a titanium-based precursor gel.

[0016] Furthermore, the iron-molybdenum co-doped boron-phosphorus microspheres are prepared by the following method:

[0017] B1. Add hexachlorocyclotriphosphazene and acetonitrile to the reaction vessel and stir. After the mixture is evenly mixed, add the composite solution dropwise. The dropwise addition time is 30-50 min. During the dropwise addition, control the temperature at 0-10℃. After the dropwise addition is completed, raise the temperature to 25-35℃ and keep stirring for 3-6 h. After the reaction is completed, filter the filter cake and dry it to obtain phosphorus-nitrogen cross-linked microspheres.

[0018] B2. Add anhydrous ethanol and deionized water to a dispersion vessel and stir. Then add boric acid, ferric nitrate nonahydrate, ammonium molybdate tetrahydrate, and phosphorus-nitrogen cross-linked microspheres in sequence. After uniform dispersion, a precursor slurry is obtained. The precursor slurry is then fed into an atomizing thermal reactor. Under a composite atmosphere, the temperature of the atomizing thermal reactor is controlled at 740-790℃ and held for 10-18s. The powder is collected and pulverized through a 275-325 mesh sieve to obtain iron-molybdenum co-doped boron-phosphorus microspheres.

[0019] Furthermore, in step B1, the ratio of hexachlorocyclotriphosphazene, acetonitrile, and the composite solution is 16-20g:200mL:200mL, wherein the composite solution is obtained by mixing p-phenylenediamine, triethylamine, and acetonitrile in a ratio of 15-18g:27-32g:210mL.

[0020] Furthermore, in step B2, the ratio of anhydrous ethanol, deionized water, boric acid, ferric nitrate nonahydrate, ammonium molybdate tetrahydrate, and phosphorus-nitrogen cross-linked microspheres is 125mL:125mL:5-6g:3-4g:2-3g:20-25g, wherein the composite atmosphere is obtained by mixing ammonia and nitrogen in a volume ratio of 25-35:65-75.

[0021] Furthermore, the preparation method of the wetting auxiliary powder is as follows: deionized water is added to a reaction vessel and stirred, then nickel sulfate hexahydrate, stannous chloride dihydrate, sodium hypophosphite monohydrate and trisodium citrate dihydrate are added in sequence. After mixing evenly, 25-28 wt% ammonia water is added to adjust the pH of the reaction system to 8.6-9.0, then copper powder is added, the reaction vessel is heated to 75-80℃ and kept at that temperature while stirring for 50-70 min, and the wetting auxiliary powder is obtained after post-processing.

[0022] Furthermore, in the preparation of the wetting auxiliary powder, the ratio of deionized water, nickel sulfate hexahydrate, stannous chloride dihydrate, sodium hypophosphite monohydrate, trisodium citrate dihydrate, and copper powder is 100mL:3-4g:1g:3-4g:3g:10g, wherein the copper powder particle size is D. 50 =15-30μm, post-processing includes: after the reaction is complete, filter the cake and dry it, then pulverize it through a 180-220 mesh sieve to obtain wetting auxiliary powder.

[0023] This invention also discloses a method for preparing a powder alloy for diesel rocker arm seat, comprising the following steps: adding alloy powder to a stirred tank under argon protection and stirring, mixing evenly, adding wetting auxiliary powder, continuing mixing, then adding titanium-based reinforcing powder, iron-molybdenum co-doped boron-phosphorus microspheres and zinc stearate, controlling the temperature of the stirred tank at 25-45℃ during the mixing process, and mixing time at 60-120 min, after mixing is completed, grinding the composite powder through a 100-140 mesh sieve and sealing and packaging to obtain premixed gold powder.

[0024] The present invention has the following beneficial effects:

[0025] 1. In the composition of the premixed gold powder, the wetting auxiliary powder is not introduced as a simple additional filler, but is distributed between the iron-based alloy powder in the form of composite particles with surface-loaded Ni-P and a small amount of Sn components. This makes it easier for the copper, graphite and nickel-molybdenum components to maintain a relatively balanced contact relationship during mixing, sieving and transfer. On this basis, the titanium-based reinforcing powder is embedded in the main powder system in a finer particle state, which provides a certain constraint on local agglomeration. The iron-molybdenum co-doped boron-phosphorus microspheres supplement the particle size distribution and space filling relationship. Under the combined effect of the three, the dispersion state, particle migration rhythm and stacking consistency of the composite powder before and after molding are more coordinated. Correspondingly, the powder can exhibit a process adaptability state that matches the subsequent pressing and forming under the standard flowability and particle size evaluation system.

[0026] 2. When the titanium-based reinforcing powder prepared in this invention is placed in an iron-based sintering system, its effect is first manifested in the dispersed load-bearing positions in the sintering skeleton. This ensures that the reinforcing component does not remain as independent heterogeneous particles, but rather participates in the construction of the stress path together with the matrix structure. During the sintering stage, the interfacial transition conditions formed by the wetting auxiliary powder maintain a relatively continuous bonding state between the reinforcing particles and the iron-based structure, reducing the adverse effects of local interface abrupt changes on load transfer. At the same time, after the iron-molybdenum co-doped boron-phosphorus microspheres participate in the microstructure evolution, the microstructure coordination relationship in the local area of ​​the matrix becomes more coordinated. The resulting part exhibits a more stable overall response under external load, and there is also a good correspondence between the surface pressure contact area and the internal load-bearing area. Thus, the strength and hardness characterization can be based on a more consistent microstructure.

[0027] 3. After the introduction of iron-molybdenum co-doped boron-phosphorus microspheres into the composite powder system, their multi-element microsphere structure is more likely to enter the region where particle contact and tissue rearrangement are more active during sintering. This allows the formation, expansion, and connection of the sintering neck and surrounding tissues to maintain good continuity. During this process, the wetting auxiliary powder provides a more suitable premise for effective bonding between particles by regulating the initial interface contact state. The titanium-based reinforcing powder maintains the support and balance of the local structure as the skeleton gradually tightens, avoiding significant mismatch during the densification process. As a result, the pore morphology, distribution, and connectivity of the part are more regular after sintering, and the microstructure after steam treatment is more likely to maintain the aforementioned structural basis, thus forming a more natural correspondence between pore evaluation, surface state, and overall microstructure continuity. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a SEM image of the titanium-based reinforced powder prepared in Example 3 of the present invention;

[0030] Figure 2 This is a SEM image of the iron-molybdenum co-doped boron-phosphorus microspheres prepared in Example 6 of this invention;

[0031] Figure 3 This is a SEM image of the wetting aid powder prepared in Example 9 of the present invention. Detailed Implementation

[0032] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Example 1

[0034] This embodiment provides a method for preparing titanium-based reinforced powder, including the following steps:

[0035] Step I: Preparation of titanium-based precursor gel

[0036] Weigh out 6.0 g of ferric nitrate nonahydrate, 5.0 g of boric acid, 6.0 mL of deionized water, and 15.0 mL of anhydrous ethanol, and mix them to obtain a mixed solution;

[0037] Weigh out 10.0g of tetrabutyl titanate and 28.0mL of anhydrous ethanol and add them to the reaction vessel. Stir and mix well. Then add 2.0g of acetylacetone and continue stirring until well mixed. Then add 8.0mL of the mixture. Heat the reaction vessel to 30℃ and keep it at that temperature for 2h. Then heat it to 75℃ and age it for 4h to obtain a gel material. Dry the gel material under vacuum at 65℃ for 6h, pulverize it and pass it through an 80-mesh sieve to obtain a titanium-based precursor gel.

[0038] Step II: Preparation of titanium-based reinforced intermediate powder

[0039] Weigh out 50.0 mL of deionized water and add it to the reaction vessel. Stir, then add 3.0 g of melamine, 1.0 g of glucose and 10.0 g of titanium-based precursor gel in sequence. After dispersing evenly, a slurry is obtained. The slurry is sent to the atomizing thermal reactor. Under the mixed atmosphere of ammonia and nitrogen at a volume ratio of 3:6, the temperature of the atomizing thermal reactor is controlled at 880℃ and held for 12 s. The powder is collected and pulverized through a 200-mesh sieve to obtain titanium-based reinforced intermediate powder.

[0040] Step III: Preparation of titanium-based reinforced powder

[0041] Weigh 10.0g of titanium-based reinforced intermediate powder and add it to a tube furnace. Heat the furnace to 1020℃ under an argon atmosphere, hold for 80 minutes, and then discharge the powder after natural cooling. Grind the powder through a 275-mesh sieve to obtain titanium-based reinforced powder.

[0042] The reaction principle for preparing titanium-based reinforced powder is as follows:

[0043] Ferric nitrate nonahydrate and boric acid form iron- and boron-containing active components in a water-alcohol system. Tetrabutyl titanate undergoes restricted hydrolysis and condensation under the coordination regulation of acetylacetone, constructing an inorganic-organic precursor network with a Ti-O backbone and iron- and boron components dispersed within it. Melamine and glucose provide nitrogen- and carbon-containing reaction sources, respectively, in an atomized thermal field, and promote the removal, rearrangement, and solid-phase transformation of the precursor network in an ammonia / nitrogen atmosphere, resulting in the redistribution of titanium, iron, boron, carbon, and nitrogen elements within the particles. Subsequently, after heat treatment under argon conditions, the system further completes crystal phase integration, bonding structure adjustment, and component stabilization, forming titanium-based reinforced powder.

[0044] The mechanism of action of titanium-based reinforcing powder in premixed gold powder is as follows:

[0045] The titanium-based precursor gel, titanium-based reinforced intermediate powder and final titanium-based reinforced powder formed by this process correspond to the structural sources of three levels in the premixed gold powder system: the pre-distribution basis of components, the transition carrier of particle structure and the participating unit of the reinforcing skeleton.

[0046] Among them, the titanium-based precursor gel endows the components such as titanium, iron, and boron with a highly uniform initial spatial distribution, so that the subsequent reinforcing particles are not simply introduced from a single heterogeneous phase, but have a continuous source of components and relatively coordinated surface characteristics; the titanium-based reinforced intermediate powder further determines the particle size, dispersion state and contact compatibility of the reinforcing components with the iron-based main powder, so that it can participate in particle stacking and contact network construction in a relatively stable embedding mode in the premixed gold powder; the final titanium-based reinforced powder directly acts on the particle size distribution, flow and molding behavior of the premixed gold powder and the microstructure support state in the subsequent pressing and sintering, so that the reinforcing components can participate in the construction of local load-bearing paths and are not prone to abrupt interface breaks;

[0047] Meanwhile, the introduction of iron, boron, and carbon- and nitrogen-containing structural sources further improves the tissue affinity and interfacial transition ability between the reinforcing particles and the iron-based matrix. This allows the premixed gold powder to maintain a good foundation of coordination in terms of mixing uniformity, Hall flow rate, equivalent particle size characterization, and mold filling consistency. It also makes it more conducive to obtaining continuous tissue bonding regions, more balanced load transfer paths, and controlled pore structure evolution during the subsequent part formation process.

[0048] Example 2

[0049] This embodiment provides a method for preparing titanium-based reinforced powder, including the following steps:

[0050] Step I: Preparation of titanium-based precursor gel

[0051] Weigh out 7.0 g of ferric nitrate nonahydrate, 6.0 g of boric acid, 7.0 mL of deionized water and 15.0 mL of anhydrous ethanol and mix them to obtain a mixed solution;

[0052] Weigh out 12.0g of tetrabutyl titanate and 32.0mL of anhydrous ethanol and add them to the reaction vessel. Stir and mix well. Then add 3.0g of acetylacetone and continue stirring until well mixed. Then add 8.0mL of the mixture. Heat the reaction vessel to 40℃ and keep it at that temperature for 3h. Then heat it to 85℃ and age it for 6h to obtain a gel material. Dry the gel material under vacuum at 75℃ for 10h. After pulverizing, pass it through a 100-mesh sieve to obtain a titanium-based precursor gel.

[0053] Step II: Preparation of titanium-based reinforced intermediate powder

[0054] Weigh out 60.0 mL of deionized water and add it to the reaction vessel. Stir, then add 4.0 g of melamine, 2.0 g of glucose and 12.0 g of titanium-based precursor gel in sequence. After dispersing evenly, a slurry is obtained. The slurry is sent to the atomizing thermal reactor. Under the mixed atmosphere of ammonia and nitrogen at a volume ratio of 4:7, the temperature of the atomizing thermal reactor is controlled at 930℃ and held for 15 s. The powder is collected and pulverized through a 300-mesh sieve to obtain titanium-based reinforced intermediate powder.

[0055] Step III: Preparation of titanium-based reinforced powder

[0056] Weigh 12.0g of titanium-based reinforced intermediate powder and add it to a tube furnace. Heat the furnace to 1060℃ under an argon atmosphere, hold for 120min, and discharge the powder after natural cooling. Grind the powder through a 325-mesh sieve to obtain titanium-based reinforced powder.

[0057] Example 3

[0058] This embodiment provides a method for preparing titanium-based reinforced powder, including the following steps:

[0059] Step I: Preparation of titanium-based precursor gel

[0060] Weigh out 6.5g of ferric nitrate nonahydrate, 5.5g of boric acid, 6.5mL of deionized water and 15.0mL of anhydrous ethanol and mix them to obtain a mixed solution;

[0061] Weigh out 11.0 g of tetrabutyl titanate and 30.0 mL of anhydrous ethanol and add them to the reaction vessel. Stir and mix well. Then add 2.5 g of acetylacetone and continue stirring until well mixed. Then add 8.0 mL of the mixture. Heat the reaction vessel to 35 °C and keep it at that temperature for 2.5 h. Then heat it to 80 °C and age it for 5 h to obtain a gel material. Dry the gel material under vacuum at 70 °C for 8 h. After pulverizing, pass it through a 90-mesh sieve to obtain a titanium-based precursor gel.

[0062] Step II: Preparation of titanium-based reinforced intermediate powder

[0063] Weigh out 55.0 mL of deionized water and add it to the reaction vessel. Stir, then add 3.5 g of melamine, 1.5 g of glucose and 11.0 g of titanium-based precursor gel in sequence. After dispersing evenly, a slurry is obtained. The slurry is sent to the atomizing thermal reactor. Under the mixed atmosphere of ammonia and nitrogen at a volume ratio of 3.5:6.5, the temperature of the atomizing thermal reactor is controlled at 905℃ and held for 13.5 s. The powder is collected and pulverized through a 250-mesh sieve to obtain titanium-based reinforced intermediate powder.

[0064] Step III: Preparation of titanium-based reinforced powder

[0065] Weigh 11.0g of titanium-based reinforced intermediate powder and add it to a tube furnace. Heat the furnace to 1040℃ under an argon atmosphere, hold for 100min, and allow it to cool naturally before discharging. Grind the powder through a 300-mesh sieve to obtain titanium-based reinforced powder.

[0066] Example 4

[0067] This embodiment provides a method for preparing iron-molybdenum co-doped boron-phosphorus microspheres, including the following steps:

[0068] Step ①: Preparation of phosphorus-nitrogen cross-linked microspheres

[0069] Weigh out 15.0 g of p-phenylenediamine, 27.0 g of triethylamine and 210.0 mL of acetonitrile and mix them to obtain a composite solution;

[0070] Weigh 16.0 g of hexachlorocyclotriphosphazene and 200.0 mL of acetonitrile and add them to the reaction vessel and stir. After mixing evenly, add 200.0 mL of composite solution dropwise over 30 min. During the dropwise addition, control the temperature at 0 °C. After the dropwise addition is complete, raise the temperature to 25 °C and stir for 3 h. After the reaction is complete, filter the filter cake and dry it to obtain phosphorus-nitrogen cross-linked microspheres.

[0071] Step 2: Preparation of iron-molybdenum co-doped boron-phosphorus microspheres

[0072] Weigh out 125.0 mL of anhydrous ethanol and 125.0 mL of deionized water and add them to a dispersion vessel and stir. Then add 5.0 g of boric acid, 3.0 g of ferric nitrate nonahydrate, 2.0 g of ammonium molybdate tetrahydrate and 20.0 g of phosphorus-nitrogen cross-linked microspheres in sequence. After dispersing evenly, a precursor slurry is obtained. The precursor slurry is then fed into an atomizing thermal reactor. Under a composite atmosphere obtained by mixing ammonia and nitrogen in a volume ratio of 25:65, the temperature of the atomizing thermal reactor is controlled at 740℃ and held for 10 s. The powder is collected and pulverized through a 275-mesh sieve to obtain iron-molybdenum co-doped boron-phosphorus microspheres.

[0073] The reaction principle for preparing iron-molybdenum co-doped boron-phosphorus microspheres is as follows:

[0074] The amino group in the p-phenylenediamine molecule undergoes nucleophilic substitution of the P-Cl bond on the hexachlorocyclotriphosphazene ring. Triethylamine acts as an acid-binding agent to absorb the hydrogen chloride released during the reaction, thereby promoting the formation of a cross-linked network with PN bonds as the core between the phosphazene ring unit and the aromatic amine structure. During the solution nucleation and aggregation process, phosphorus-nitrogen cross-linked microspheres are generated. Subsequently, boric acid, ferric nitrate nonahydrate, and ammonium molybdate tetrahydrate are dispersed and loaded on the surface and inside of the cross-linked framework. Under the conditions of atomization thermal reaction, the phosphorus-nitrogen organic network undergoes thermal decomposition, condensation, and inorganic transformation. The iron, molybdenum, and boron components simultaneously undergo decomposition, coordination recombination, and solid-phase intercalation, while the phosphorus element is retained in the evolved framework structure, ultimately forming a microsphere system containing multiple elements such as iron, molybdenum, boron, and phosphorus.

[0075] The mechanism of action of iron-molybdenum co-doped boron-phosphorus microspheres in premixed gold powder is as follows:

[0076] The phosphorus-nitrogen cross-linked microspheres and iron-molybdenum co-doped boron-phosphorus microspheres formed by this process correspond to the structural origins of the multi-element synergistic support framework and the sintering contact zone adjustment unit, respectively, in the premixed gold powder system.

[0077] Among them, phosphorus-nitrogen cross-linked microspheres first endow phosphorus components with a relatively stable spherical carrier and a relatively balanced spatial distribution basis, so that the subsequent active elements are not locally enriched in the system in the form of free small molecules or disordered fine powders, but participate in the construction of composite powder as microsphere units with certain morphological integrity and dispersion stability. The further formed iron-molybdenum co-doped boron-phosphorus microspheres directly enter the contact network composed of iron-based main powder, copper-based components and graphite. Their spherical fine particles can not only embed into the gaps between the main particles and improve the particle size distribution and packing coordination, but also improve their tissue affinity with the iron-based main body and the continuity of the subsequent bearing path through the iron and molybdenum components.

[0078] Meanwhile, by involving boron and phosphorus components in the local transition and pore tightening rhythm regulation of the particle bonding region, these microspheres are no longer just additional fillers, but functional components with synergistic effects of interface connection, local tissue rearrangement and densification. Accordingly, the obtained premixed gold powder is more likely to maintain coordination in terms of mixing stability, Hall flow rate, molding consistency and equivalent particle size characterization, and is more conducive to the formation of continuous particle bonding regions, a more balanced tissue skeleton and a controlled pore structure evolution state during subsequent pressing and sintering.

[0079] Example 5

[0080] This embodiment provides a method for preparing iron-molybdenum co-doped boron-phosphorus microspheres, including the following steps:

[0081] Step ①: Preparation of phosphorus-nitrogen cross-linked microspheres

[0082] Weigh out 18.0 g of p-phenylenediamine, 32.0 g of triethylamine and 210.0 mL of acetonitrile and mix them to obtain a composite solution;

[0083] Weigh 20.0 g of hexachlorocyclotriphosphazene and 200.0 mL of acetonitrile and add them to the reaction vessel and stir. After mixing evenly, add 200.0 mL of composite solution dropwise over 50 min. During the dropwise addition, control the temperature at 10 °C. After the dropwise addition is complete, raise the temperature to 35 °C and stir for 6 h. After the reaction is complete, filter the filter cake and dry it to obtain phosphorus-nitrogen cross-linked microspheres.

[0084] Step 2: Preparation of iron-molybdenum co-doped boron-phosphorus microspheres

[0085] Weigh out 125.0 mL of anhydrous ethanol and 125.0 mL of deionized water and add them to a dispersion vessel and stir. Then add 6.0 g of boric acid, 4.0 g of ferric nitrate nonahydrate, 3.0 g of ammonium molybdate tetrahydrate and 25.0 g of phosphorus-nitrogen cross-linked microspheres in sequence. After uniform dispersion, a precursor slurry is obtained. The precursor slurry is then sent to an atomizing thermal reactor. Under a composite atmosphere obtained by mixing ammonia and nitrogen in a volume ratio of 35:75, the temperature of the atomizing thermal reactor is controlled at 790℃ and held for 18 s. The powder is collected and pulverized through a 325-mesh sieve to obtain iron-molybdenum co-doped boron-phosphorus microspheres.

[0086] Example 6

[0087] This embodiment provides a method for preparing iron-molybdenum co-doped boron-phosphorus microspheres, including the following steps:

[0088] Step ①: Preparation of phosphorus-nitrogen cross-linked microspheres

[0089] Weigh out 16.5g of p-phenylenediamine, 29.5g of triethylamine and 210.0mL of acetonitrile and mix them to obtain a composite solution;

[0090] Weigh 18.0 g of hexachlorocyclotriphosphazene and 200.0 mL of acetonitrile and add them to the reaction vessel and stir. After mixing evenly, add 200.0 mL of composite solution dropwise over 40 min. During the dropwise addition, control the temperature at 5 °C. After the dropwise addition is complete, raise the temperature to 30 °C and stir for 5 h. After the reaction is complete, filter the filter cake and dry it to obtain phosphorus-nitrogen cross-linked microspheres.

[0091] Step 2: Preparation of iron-molybdenum co-doped boron-phosphorus microspheres

[0092] Weigh out 125.0 mL of anhydrous ethanol and 125.0 mL of deionized water and add them to a dispersion vessel and stir. Then add 5.5 g of boric acid, 3.5 g of ferric nitrate nonahydrate, 2.5 g of ammonium molybdate tetrahydrate and 22.5 g of phosphorus-nitrogen cross-linked microspheres in sequence. After dispersing evenly, a precursor slurry is obtained. The precursor slurry is then fed into an atomizing thermal reactor. Under a composite atmosphere obtained by mixing ammonia and nitrogen in a volume ratio of 30:70, the temperature of the atomizing thermal reactor is controlled at 765℃ and held for 14 s. The powder is collected and pulverized through a 300-mesh sieve to obtain iron-molybdenum co-doped boron-phosphorus microspheres.

[0093] Example 7

[0094] This embodiment provides a method for preparing powder alloy for diesel rocker arm seats, including the following steps:

[0095] Step 1: Preparation of wetting auxiliary powder

[0096] Weigh 100.0 mL of deionized water and add it to the reaction vessel. Stir, then add 3.0 g of nickel sulfate hexahydrate, 1.0 g of stannous chloride dihydrate, 3.0 g of sodium hypophosphite monohydrate, and 3.0 g of trisodium citrate dihydrate in sequence. After mixing evenly, add 25 wt% ammonia water to adjust the pH of the reaction system to 8.6. Then add 10.0 g of copper powder with D50=15 μm. Heat the reaction vessel to 75℃ and keep it at that temperature while stirring for 50 min. After the reaction is complete, filter the cake and dry it. Then pulverize it through an 180-mesh sieve to obtain the wetting auxiliary powder.

[0097] The reaction principle for preparing wetting aid powder is as follows:

[0098] Nickel sulfate hexahydrate provides nickel ions in the aqueous phase. Trisodium citrate and ammonia work together to coordinate the metal ions and regulate the alkaline environment, allowing the nickel species to exist in a relatively stable complexed state. Sodium hypophosphite monohydrate, as a reducing phosphorus-containing component, promotes the reduction and deposition of nickel ions under heating conditions, and some phosphorus enters the deposition layer to form a nickel-phosphorus complex phase. Stannous ions in stannous chloride dihydrate participate in the interface redox and equilibrium regulation, which is conducive to the occurrence of initial deposition. Finally, when copper powder particles are used as the heterogeneous interface, the metal complexes in the system are adsorbed, reduced and continuously deposited on its surface, thus forming a surface coating layer containing nickel, phosphorus and a small amount of tin components on the outer layer of the particles.

[0099] The mechanism of action of wetting aid powder in premixed gold powder is as follows:

[0100] The wetting auxiliary powder obtained by this process can be regarded as an interface adjustment unit with surface transition properties in the premixed gold powder system. Its structure does not come from a single copper powder or a single nickel-based component, but is a composite particle formed by copper powder as the main particle and a composite coating layer containing nickel, phosphorus and a small amount of tin loaded on its outer layer.

[0101] When these particles enter a multi-component system consisting of iron-based main powder, titanium-based reinforcing powder, iron-molybdenum co-doped boron-phosphorus microspheres, and graphite, their main function is to mitigate the differences in surface properties between different particles, improve the interfacial compatibility and local wetting tendency during particle contact, and make it easier for fine active components to adhere, disperse, and embed into the contact network of the main powder, thereby reducing the possibility of local segregation, stratification, and contact imbalance during the mixing process. At the same time, the composite coating layer also enables these particles to preferentially participate in the transition construction of the particle bonding region during the subsequent pressing and sintering stages, promoting the formation of a relatively continuous connection zone between the iron-based main body and the copper-based and reinforcing phases, without the appearance of obvious abrupt interfacial fracture regions.

[0102] Accordingly, the wetting auxiliary powder not only supports the particle size distribution coordination, Hall flow rate, mold filling uniformity and mixing stability of the premixed gold powder, but also further affects the degree of connection of the internal structure of the subsequent parts, the local load transmission path and the pore tightening and distribution state, making the final structure more likely to present a more continuous bonding relationship and controlled pore evolution characteristics.

[0103] Step 2: Preparation of premixed gold powder

[0104] Iron, copper, nickel, molybdenum and graphite were mixed in a weight ratio of 250:4:2:1:2 and then milled through a 120-mesh sieve under nitrogen protection to obtain alloy powder.

[0105] By weight, 472 parts of alloy powder were weighed and added to a stirred tank under argon protection. After mixing evenly, 8 parts of wetting auxiliary powder were added and mixing continued. Then, 12 parts of titanium-based reinforcing powder prepared in Example 1, 4 parts of iron-molybdenum co-doped boron-phosphorus microspheres prepared in Example 4, and 2 parts of zinc stearate were added. During the mixing process, the temperature of the stirred tank was controlled at 25°C and the mixing time was 60 min. After the mixing was completed, the composite powder was ground through a 100-mesh sieve and sealed and packaged to obtain premixed gold powder.

[0106] The reaction principle for preparing wetting aid powder is as follows:

[0107] Iron, copper, nickel, molybdenum, and graphite first constitute a multi-component physical mixture system with iron-based powder as the main component. Each component is mainly distributed in an independent particle state. Copper, nickel, and molybdenum are introduced as metal components, and graphite exists as a carbon source. The wetting auxiliary powder is actually a composite particle with nickel, phosphorus, and a small amount of tin components loaded on its surface. When it comes into contact with the matrix powder, it forms a second phase material attached to the particle interface. The titanium-based reinforcing powder is an inorganic reinforcing particle containing elements such as Ti, Fe, B, C, and N. The iron-molybdenum co-doped boron-phosphorus microspheres are multi-component microsphere particles containing elements such as Fe, Mo, B, P, and N. The two are embedded in the iron-based mixed powder in the form of dispersed phases. Zinc stearate mainly exists on the particle surface in the form of organic small molecules coated or isolated. This makes the whole system appear as a composite powder aggregate composed of multiple metal phases, inorganic phases, and organic additives. Finally, premixed gold powder is prepared.

[0108] Example 8

[0109] This embodiment provides a method for preparing powder alloy for diesel rocker arm seats, including the following steps:

[0110] Step 1: Preparation of wetting auxiliary powder

[0111] Weigh 100.0 mL of deionized water and add it to the reaction vessel. Stir, then add 4.0 g of nickel sulfate hexahydrate, 1.0 g of stannous chloride dihydrate, 4.0 g of sodium hypophosphite monohydrate, and 3.0 g of trisodium citrate dihydrate in sequence. After mixing evenly, add 28 wt% ammonia water to adjust the pH of the reaction system to 9.0. Then add 10.0 g of copper powder with D50=30 μm. Heat the reaction vessel to 80℃ and keep it at that temperature while stirring for 70 min. After the reaction is complete, filter the cake and dry it. Then pulverize it through a 220 mesh sieve to obtain the wetting auxiliary powder.

[0112] Step 2: Preparation of premixed gold powder

[0113] Iron, copper, nickel, molybdenum and graphite were mixed in a weight ratio of 250:5:3:2:2 and then milled through a 120-mesh sieve under nitrogen protection to obtain alloy powder.

[0114] By weight, 483 parts of alloy powder were weighed and added to a stirred tank under argon protection. After mixing evenly, 9 parts of wetting auxiliary powder were added and mixing continued. Then, 15 parts of titanium-based reinforcing powder prepared in Example 2, 5 parts of iron-molybdenum co-doped boron-phosphorus microspheres prepared in Example 5, and 3 parts of zinc stearate were added. During the mixing process, the temperature of the stirred tank was controlled at 45°C and the mixing time was 120 min. After the mixing was completed, the composite powder was ground through a 140-mesh sieve and sealed and packaged to obtain premixed gold powder.

[0115] Example 9

[0116] This embodiment provides a method for preparing powder alloy for diesel rocker arm seats, including the following steps:

[0117] Step 1: Preparation of wetting auxiliary powder

[0118] Weigh 100.0 mL of deionized water and add it to the reaction vessel. Stir the mixture, then add 3.5 g of nickel sulfate hexahydrate, 1.0 g of stannous chloride dihydrate, 3.5 g of sodium hypophosphite monohydrate, and 3.0 g of trisodium citrate dihydrate in sequence. Mix well and then add 27 wt% ammonia water to adjust the pH of the reaction system to 8.8. Add 10.0 g of copper powder with D50 = 23 μm. Heat the reaction vessel to 78 °C and keep it at that temperature while stirring for 60 min. After the reaction is complete, filter the mixture, collect the filter cake, dry it, and then pulverize it through a 200-mesh sieve to obtain the wetting auxiliary powder.

[0119] Step 2: Preparation of premixed gold powder

[0120] Iron, copper, nickel, molybdenum and graphite were mixed in a weight ratio of 250:5:3:2:2 and then milled through a 120-mesh sieve under nitrogen protection to obtain alloy powder.

[0121] By weight, 478 parts of alloy powder were weighed and added to a stirred tank under argon protection. After mixing evenly, 9 parts of wetting auxiliary powder were added and mixing continued. Then, 14 parts of titanium-based reinforcing powder prepared in Example 3, 5 parts of iron-molybdenum co-doped boron-phosphorus microspheres prepared in Example 6, and 3 parts of zinc stearate were added. During the mixing process, the temperature of the stirred tank was controlled at 35°C and the mixing time was 90 minutes. After mixing, the composite powder was ground through a 120-mesh sieve and sealed and packaged to obtain premixed gold powder.

[0122] Comparative Example 1

[0123] The difference between this comparative example and Example 9 is that, in step two, copper powder of equal mass with D50=23μm is used to replace the wetting auxiliary powder in equal amounts.

[0124] Comparative Example 2

[0125] The difference between this comparative example and Example 9 is that, in the preparation process of the titanium-based reinforcing powder used in step two, step II is omitted, and in step III, the titanium-based precursor gel prepared in step I is used to replace the titanium-based reinforcing intermediate powder in an equal amount.

[0126] Comparative Example 3

[0127] The difference between this comparative example and Example 9 is that, in step 2, the addition of boric acid, ferric nitrate nonahydrate, and ammonium molybdate tetrahydrate to the iron-molybdenum co-doped boron-phosphorus microspheres was omitted in step ② of the preparation process.

[0128] Performance testing:

[0129] The premixed gold powders prepared in Examples 7-9 and Comparative Examples 1-3 were added to a mixer and mixed for 10 minutes, then passed through a 60-mesh sieve. The mixture was then added to a forming mold for pressing. The pressing method was bidirectional pressing, with a pressing pressure of 760 MPa and a holding pressure of 0.7 s. After demolding, a diesel rocker arm seat blank was obtained. The blank was then sent to a sintering furnace and heated under a N2 / H2 protective atmosphere with a volume ratio of 90:10. The temperature was first increased to 200°C at a rate of 10°C / min and held for 15 minutes, then increased to 400°C at a rate of 6°C / min. The temperature is increased to 50℃ and held for 20 minutes. The temperature is then increased to 760℃ at a rate of 5℃ / min and held for 20 minutes. The temperature is then increased to 1135℃ and held for 35 minutes to complete sintering. After sintering, the temperature is cooled to 650℃ at a rate of 1.8℃ / s and then further cooled to below 120℃ before being removed from the furnace. After being removed from the furnace, the sintered part is shaped under a pressure of 500MPa for 0.4s. After shaping, the part is placed in a steam treatment furnace and treated with steam at 540℃ for 90 minutes. After cooling to room temperature, the diesel rocker arm seat is obtained.

[0130] The flowability of the premixed gold powders prepared in Examples 7-9 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 1482-2022 "Standard Funnel Method (Hall Flow Meter) for Determination of Flowability of Metal Powders".

[0131] The Fisher particle size of the premixed gold powders prepared in Examples 7-9 and Comparative Examples 1-3 was tested according to the standard GB / T 3249-2022 "Determination of Fisher Particle Size of Metals and Their Compounds Powders".

[0132] The room temperature compressive strength of the diesel rocker arm seats prepared from the premixed gold powders in Examples 7-9 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 6525-2019 "Determination of room temperature compressive strength of sintered metallic materials".

[0133] The Rockwell hardness of the diesel rocker arm seats prepared from the premixed gold powders in Examples 7-9 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 230.1-2018 "Metallic materials - Rockwell hardness test - Part 1: Test method".

[0134] The porosity of diesel rocker arm seats obtained by processing the premixed gold powder prepared in Examples 7-9 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 5163-2006 "Determination of density, oil content and porosity of permeable sintered metal materials (excluding cemented carbide)".

[0135] See Table 1 for specific data;

[0136] Table 1 - Performance Test Data for Each Sample

[0137] Project Group Example 7 Example 8 Example 9 Comparative Example 1 Comparative Example 2 Comparative Example 3 Hall flow rate / s·50g 27.8 27.6 27.5 31.6 29.3 28.9 Fisher particle size / μm 36.4 36.3 36.2 39.1 37.6 37.0 Room temperature compressive strength / MPa 1520 1523 1525 1408 1386 1446 Rockwell hardness / HRC 32.1 32.1 32.2 29.8 29.3 30.7 Open area ratio / % 8.4 8.3 8.3 10.7 9.8 9.3

[0138] Data Analysis:

[0139] Comparative analysis of the data in Table 1 reveals that the premixed gold powder prepared in this invention has a Hall flow rate of 27.5 s·50 g and a Fisher particle size of 36.2 μm. Furthermore, the diesel rocker arm seat processed using this premixed gold powder exhibits a room temperature compressive strength of 1525 MPa, a Rockwell hardness of 32.2 HRC, and an open porosity of 8.3%. All these data are superior to the comparative example. This indicates that…

[0140] In Comparative Example 1, after deleting step one and replacing the original wetting auxiliary powder with ordinary copper powder in step two, the composite powder system no longer possesses the interfacial transition conditions established by surface loading. The original relatively coordinated contact relationship between particles is thus broken. As a result, the migration behavior of iron-based main powder, copper-based particles, graphite, and functional components during mixing and transport is more likely to differ, and the distribution balance in local areas is difficult to maintain. Consequently, the consistency of particle packing state before pressing and the internal structure of the pressed blank is affected. Further into the sintering stage, due to the lack of a stable connection foundation at the particle contact interface, the degree of local sintering bonding and the continuity of the structure tend to be insufficient. The pore morphology and its connectivity are not easily tightened synchronously, ultimately weakening the integrity of the internal structure of the part and the coordination between the surface state and the overall load-bearing state.

[0141] In Comparative Example 2, step II was removed, causing the titanium-based precursor gel obtained in step I to directly enter the subsequent high-temperature treatment without undergoing the atomization thermal reaction process. As a result, the refinement and reconstruction conditions formed by the reinforcing component during the intermediate conversion stage were lost. As a result, the titanium-based powder obtained could not maintain the configuration characteristics of the example in terms of particle morphology, surface state, and compatibility with the iron-based structure. After adding the premixed gold powder, its dispersion and embedding mode in the matrix and the subsequent force participation path also changed accordingly. After continuing to enter the sintering process, the uniformity of the transition of the structure around the reinforcing component decreased, and local areas were more prone to insufficient connection or discontinuous load transfer. This made it difficult to form a stable correspondence between the internal bearing path and the surface contact response. It was also not conducive to the synchronous adjustment of the pore structure and the tissue skeleton. Therefore, the overall composite performance of the sample decreased.

[0142] Although Comparative Example 3 retains the phosphorus-nitrogen cross-linked microspheres obtained in step ① and the subsequent heat treatment path, the microsphere system no longer possesses the original multi-element synergistic composition after the removal of the boron source, iron source and molybdenum source in step ②. Consequently, it loses the structural basis for synchronously adjusting the particle contact area during sintering. As a result, after the microsphere components enter the premixed gold powder, they can only participate in the system construction as relatively independent particles. It is difficult to maintain the original local rearrangement and connection effect during the microstructure evolution. As sintering densification continues to advance, the continuity and balance of the particle bonding area tend to weaken, and the phenomenon of uneven local microstructure is more likely to occur. It is also difficult to maintain a consistent rhythm between pore shrinkage and skeleton tightening. As a result, the internal pore structure, microstructure integrity and its correspondence with the surface state of the part are affected, and the composite performance decreases accordingly.

[0143] In conclusion, the technical solution of this application is not a simple superposition of components in the existing iron-based powder system, but rather a continuous configuration based on the powder contact state, the construction mode of the reinforcing phase, and the evolution path of the sintering structure. Among them, the wetting auxiliary powder first participates in the establishment of the initial interface of the composite powder, so that the multi-component particles have a relatively coordinated contact basis during the mixing, migration, and pre-pressing accumulation process; the titanium-based reinforcing powder enters the matrix after staged transformation, and forms an embedded relationship adapted to the iron-based structure in the subsequent sintering skeleton; the iron-molybdenum co-doped boron-phosphorus microspheres further intervene in the particle bonding region and the pore tightening process, so that the local structure rearrangement and the overall densification process are connected. After weakening the structural conditions of any of the above levels proportionally, the continuous relationship between powder dispersion, structure transition and pore evolution is difficult to maintain. Accordingly, the overall technical orientation embodied in the solution of this application is essentially based on the synergistic structural relationship of multiple components in the entire process of powder preparation, mixing and sintering.

[0144] The above description is merely an example and illustration of the structure of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the structure of the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

[0145] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0146] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A powder alloy for preparing a diesel rocker arm seat, characterized in that, The raw material composition includes the following parts by weight: 472-483 parts alloy powder, 8-9 parts wetting auxiliary powder, 12-15 parts titanium-based reinforcing powder, 4-5 parts iron-molybdenum co-doped boron-phosphorus microspheres and 2-3 parts zinc stearate. The alloy powder is obtained by mixing iron, copper, nickel, molybdenum and graphite in a weight ratio of 250:4-5:2-3:1-2:2 and then grinding it through a 120-mesh sieve under nitrogen protection. The titanium-based reinforced powder is prepared by the following method: A1. Add deionized water to the reaction vessel and stir. Then add melamine, glucose and titanium-based precursor gel in sequence. After dispersing evenly, a slurry is obtained. The slurry is sent to the atomizing thermal reactor. Under a mixed atmosphere, the temperature of the atomizing thermal reactor is controlled at 880-930℃ and held for 12-15s. After post-processing, titanium-based reinforced intermediate powder is obtained. A2. Heat-treat the titanium-based reinforced intermediate powder to obtain titanium-based reinforced powder.

2. The powder alloy for preparing a diesel rocker arm seat according to claim 1, characterized in that, In step A1, the ratio of deionized water, melamine, glucose and titanium-based precursor gel is 50-60 mL: 3-4 g: 1-2 g: 10-12 g, wherein the mixed atmosphere is obtained by mixing ammonia and nitrogen in a volume ratio of 3-4: 6-7.

3. The powder alloy for preparing a diesel rocker arm seat according to claim 1, characterized in that, In step A2, the heat treatment is as follows: titanium-based reinforced intermediate powder is added to a tube furnace, heated to 1020-1060℃ under an argon atmosphere, held for 80-120 min, and then post-treated to obtain titanium-based reinforced powder.

4. The powder alloy for preparing a diesel rocker arm seat according to claim 1, characterized in that, The preparation method of the titanium-based precursor gel is as follows: tetrabutyl titanate and anhydrous ethanol are added to a reaction vessel and stirred. After mixing evenly, acetylacetone is added and stirred evenly again. Then, the mixture is added, the reaction vessel is heated to 30-40℃, and stirred for 2-3 hours. The titanium-based precursor gel is obtained after post-treatment.

5. The powder alloy for preparing a diesel rocker arm seat according to claim 3, characterized in that, The ratio of tetrabutyl titanate, anhydrous ethanol, acetylacetone, and the mixture is 10-12g:28-32mL:2-3g:8mL. The mixture is obtained by mixing ferric nitrate nonahydrate, boric acid, deionized water, and anhydrous ethanol in a ratio of 6-7g:5-6g:6-7mL:15mL.

6. The powder alloy for preparing a diesel rocker arm seat according to claim 1, characterized in that, The iron-molybdenum co-doped boron-phosphorus microspheres were prepared by the following method: B1. Add hexachlorocyclotriphosphazene and acetonitrile to the reaction vessel and stir. After the mixture is evenly mixed, add the composite solution dropwise. The dropwise addition time is 30-50 min. During the dropwise addition, control the temperature at 0-10℃. After the dropwise addition is completed, raise the temperature to 25-35℃ and keep stirring for 3-6 h. After the reaction is completed, filter the filter cake and dry it to obtain phosphorus-nitrogen cross-linked microspheres. B2. Add anhydrous ethanol and deionized water to a dispersion vessel and stir. Then add boric acid, ferric nitrate nonahydrate, ammonium molybdate tetrahydrate, and phosphorus-nitrogen cross-linked microspheres in sequence. After uniform dispersion, a precursor slurry is obtained. The precursor slurry is then fed into an atomizing thermal reactor. Under a composite atmosphere, the temperature of the atomizing thermal reactor is controlled at 740-790℃ and held for 10-18s. The powder is collected and pulverized through a 275-325 mesh sieve to obtain iron-molybdenum co-doped boron-phosphorus microspheres.

7. The powder alloy for preparing a diesel rocker arm seat according to claim 6, characterized in that, In step B1, the ratio of hexachlorocyclotriphosphazene, acetonitrile, and the composite solution is 16-20g:200mL:200mL, wherein the composite solution is obtained by mixing p-phenylenediamine, triethylamine, and acetonitrile in a ratio of 15-18g:27-32g:210mL; In step B2, the ratio of anhydrous ethanol, deionized water, boric acid, ferric nitrate nonahydrate, ammonium molybdate tetrahydrate, and phosphorus-nitrogen cross-linked microspheres is 125mL:125mL:5-6g:3-4g:2-3g:20-25g, wherein the composite atmosphere is obtained by mixing ammonia and nitrogen in a volume ratio of 25-35:65-75.

8. The powder alloy for preparing a diesel rocker arm seat according to claim 1, characterized in that, The preparation method of the wetting auxiliary powder is as follows: Deionized water is added to a reaction vessel and stirred. Nickel sulfate hexahydrate, stannous chloride dihydrate, sodium hypophosphite monohydrate and trisodium citrate dihydrate are added in sequence. After mixing evenly, 25-28 wt% ammonia water is added to adjust the pH of the reaction system to 8.6-9.

0. Then copper powder is added. The reaction vessel is heated to 75-80℃ and kept at this temperature while stirring for 50-70 minutes. The wetting auxiliary powder is then obtained through post-processing.

9. The powder alloy for preparing a diesel rocker arm seat according to claim 8, characterized in that, In the preparation of the wetting auxiliary powder, the ratio of deionized water, nickel sulfate hexahydrate, stannous chloride dihydrate, sodium hypophosphite monohydrate, trisodium citrate dihydrate, and copper powder is 100mL:3-4g:1g:3-4g:3g:10g, wherein the copper powder particle size is D. 50 =15-30μm.

10. A method for preparing a powder alloy for a diesel rocker arm seat as described in any one of claims 1-9, characterized in that, The process includes the following steps: adding alloy powder to a stirred tank under argon protection and stirring until uniformly mixed, then adding wetting auxiliary powder and continuing mixing, followed by adding titanium-based reinforcing powder, iron-molybdenum co-doped boron-phosphorus microspheres and zinc stearate. During the mixing process, the temperature of the stirred tank is controlled at 25-45℃ and the mixing time is 60-120 minutes. After mixing, the composite powder is milled through a 100-140 mesh sieve and sealed in packaging to obtain premixed gold powder.

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