A stainless steel composite ceramic material protective plate and a preparation method thereof

Abstract

The application discloses a kind of stainless steel composite ceramic material's protective plate and its preparation method, belong to protective plate preparation technical field.The application is used to solve the technical problem that the fracture toughness and impact resistance of protective plate in prior art need to be further improved, specifically comprising the following steps: stainless steel powder, core-shell modified silicon carbide whisker and oleic acid modified zirconia are placed in a mixer, ethanol is added, mixed uniformly, after drying under reduced pressure, composite powder is obtained.The application first prepares core-shell modified silicon carbide whisker by chemical vapor deposition and pickling process, and surface grafting of nano zirconia is carried out using oleic acid, then the modified double-scale reinforcing phase and stainless steel powder are uniformly mixed by wet ball milling, and finally cold pressing and vacuum hot pressing sintering are carried out to construct the protective plate of stainless steel composite ceramic material with ternary synergistic effect, which significantly improves the fracture toughness and impact resistance of the protective plate.

Description

Technical Field

[0001] This invention relates to the field of protective plate preparation technology, specifically to a stainless steel composite ceramic material protective plate and its preparation method. Background Technology

[0002] With the increasing demands for lightweight and highly reliable protection in protective equipment, rail transit, special vehicles, and high-risk industrial scenarios, protective materials have gradually shifted from simply pursuing high hardness to a development direction that synergistically improves strength, fracture toughness, and impact resistance. Although existing protective materials have made some progress in terms of compressive strength and wear resistance, they still generally suffer from problems such as rapid crack initiation, short propagation paths, and sudden failure under conditions of high-speed impact, cyclic loading, and local stress concentration. In particular, brittle failure caused by insufficient fracture toughness has become a major bottleneck restricting its further engineering applications.

[0003] Currently, commonly used protective materials mainly include ceramic materials such as alumina, silicon carbide, and boron carbide, as well as high-strength steel, aluminum alloys, and metal-based ceramic composites. To improve their comprehensive performance, existing technologies typically employ methods such as rare earth oxide doping, gradient structure design, layered composite configuration control, and hot-pressing sintering parameter optimization to enhance the material's density, crack deflection capability, and impact energy dissipation level. However, these modification methods often focus on single-dimensional strengthening and still suffer from problems such as insufficient dispersion of reinforcing phases, unstable interfacial bonding, difficulty in matching strength and toughness, and difficulty in achieving both wear resistance and impact resistance. These issues make it difficult to meet the requirements of high-end protective materials for integrated multi-performance.

[0004] In the existing technology, there are significant differences between the metal matrix and the ceramic reinforcing phase of stainless steel-based composite protective plates in terms of elastic modulus, coefficient of thermal expansion and surface energy. This makes it easy for stress concentration to form at the interface and induce microcracks. In addition, ultrafine reinforcing particles are prone to agglomeration in the composite system, resulting in local unevenness and reduced load transfer efficiency. At the same time, although the high hardness reinforcing phase can improve wear resistance, if the interface is not properly controlled, it will often sacrifice fracture toughness and impact stability.

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

[0006] The purpose of this invention is to provide a protective plate made of stainless steel composite ceramic material and its preparation method, which solves the technical problem that the fracture toughness and impact resistance of the protective plate in the prior art need to be further improved.

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

[0008] A method for preparing a protective plate made of stainless steel composite ceramic material includes the following steps:

[0009] Step 1: Place stainless steel powder, core-shell modified silicon carbide whiskers and oleic acid modified zirconium oxide in a mixer, add ethanol, mix evenly, and then dry under reduced pressure to obtain composite powder.

[0010] Step 2: The composite powder is evenly loaded into the mold and cold-pressed at room temperature to obtain the green sheet of the protective board;

[0011] Step 3: Place the protective plate blank in a vacuum hot pressing sintering furnace, heat it to 1150-1250℃ in a vacuum environment at a heating rate of 5-10℃ / min, and apply an axial pressure of 20-35MPa at the same time. Hold it at the temperature and pressure for 1-2 hours. After cooling and demolding, the protective plate of stainless steel composite ceramic material is obtained.

[0012] Furthermore, in step one, the ratio of stainless steel powder, core-shell modified silicon carbide whiskers, oleic acid modified zirconium oxide, and ethanol is 75-85g:10-20g:2-5g:100-120mL, the vacuum drying temperature is 50-70℃, the drying time is 4-6h, and the stainless steel powder is spherical or near-spherical austenitic stainless steel powder with a D50 of 10-30μm.

[0013] Furthermore, in step two, the pressure for cold pressing is 50-100 MPa, and the holding time is 1-3 minutes.

[0014] Furthermore, the core-shell modified silicon carbide whiskers are prepared by the following steps:

[0015] A1. Place the crude silicon carbide whisker product and hydrofluoric acid aqueous solution in a single-necked bottle, ultrasonically wash for 15-30 min, and then post-process to obtain acid-washed silicon carbide whiskers.

[0016] A2. Pickled silicon carbide whiskers, titanium powder, sodium chloride, potassium chloride and ethanol are placed in a reaction vessel and stirred evenly. The reaction vessel is heated to 50-60℃ and the ethanol is removed by vacuum distillation to obtain molten salt blend.

[0017] A3. Place the molten salt blend in a crucible in a tube furnace, purge it with argon gas for protection, heat it to 1300-1400℃ at a heating rate of 3-5℃ / min, hold it at that temperature for 20-24h, and then process it to obtain core-shell modified silicon carbide whiskers.

[0018] Further, in step A1, the ratio of the crude silicon carbide whisker product to the hydrofluoric acid aqueous solution is 1g:10mL, and the concentration of the hydrofluoric acid aqueous solution is 35-40wt%. The post-processing steps include: after acid washing, filtration, washing the filter cake with deionized water until neutral, transferring it to an oven at a temperature of 50-60℃, and drying it to constant weight to obtain acid-washed silicon carbide whiskers.

[0019] Furthermore, in step A2, the ratio of the amount of acid-washed silicon carbide whiskers, titanium powder, sodium chloride, potassium chloride and ethanol is 2-4g:0.2-0.4g:3-5g:3-5g:15-30mL.

[0020] Furthermore, in step A3, the post-processing step includes: after the reaction is completed and the reaction system is cooled to room temperature, the product is taken out and washed 2-4 times with deionized water, transferred to a vacuum drying oven at a temperature of 50-60℃, and vacuum dried for 10-12 hours to obtain core-shell modified silicon carbide whiskers.

[0021] Furthermore, the crude silicon carbide whisker product is prepared by the following steps:

[0022] B1. Place silicon dioxide, carbon black, ferric nitrate, sodium fluoride and ethanol in a ball mill, add grinding balls, wet mill for 0.5-1 h, and dry to obtain precursor mixture;

[0023] B2. Place the precursor mixture in a crucible in a tube furnace, purge it with argon gas for protection, heat it to 1400-1550℃ at a heating rate of 5-10℃ / min, hold it at that temperature for 20-24h, and after cooling, obtain the crude product of silicon carbide whiskers.

[0024] Furthermore, in step B1, the ratio of silicon dioxide, carbon black, ferric nitrate, sodium fluoride, and ethanol is 4-6g:2.4-4.8g:0.1-0.3g:0.05-0.10g:20-40mL. The grinding balls are obtained by uniformly mixing zirconium oxide balls with diameters of 10mm, 5mm, and 3mm at a mass ratio of 2:4:4, and the ball-to-material ratio for wet grinding is 10:1.

[0025] Furthermore, the preparation method of the oleic acid modified zirconium oxide is as follows: nano zirconium oxide and ethanol are placed in a reaction vessel, stirred and dispersed for 15-30 min, oleic acid is added, the reaction vessel is heated to 60-80℃, and the reaction is maintained for 4-6 h. After post-treatment, oleic acid modified zirconium oxide is obtained.

[0026] Furthermore, the ratio of nano-zirconia, ethanol, and oleic acid is 2-4g:40-60mL:0.2-0.6g. The post-processing steps include: after the reaction is completed, the reaction system is cooled to room temperature, filtered, the filter cake is washed with ethanol 2-4 times, transferred to a vacuum drying oven at 50-60℃, vacuum dried for 10-12h, and ground through a 200-mesh sieve to obtain oleic acid modified zirconia.

[0027] The present invention also proposes a protective plate made of stainless steel composite ceramic material, wherein the protective plate made of stainless steel composite ceramic material is prepared by the preparation method of the protective plate made of stainless steel composite ceramic material described above.

[0028] The present invention has the following beneficial effects:

[0029] 1. The protective plate of stainless steel composite ceramic material prepared by the present invention introduces core-shell modified silicon carbide whiskers and oleic acid modified nano-zirconia to construct a heterogeneous reinforcement network. The titanium-based coating layer inhibits high-temperature side reactions and improves wettability, forming high-strength metallurgical bonds. The active carbon phase from the in-situ pyrolysis of oleic acid further assists stress transfer, realizing modulus matching and smooth stress transition between the stainless steel powder matrix and the reinforcing phase, significantly reducing micro-stress concentration, and making the protective plate system have both high hardness and structural stability.

[0030] 2. The protective plate of stainless steel composite ceramic material prepared by the present invention has a multi-level energy dissipation mechanism. When subjected to impact, the core-shell whiskers rely on the strengthening interface to induce crack deflection and pull-out energy dissipation. Simultaneously, nano-zirconia undergoes martensitic phase transformation. The volume expansion of the phase transformation generates a compressive stress zone at the crack tip to close the crack, thereby realizing stress redistribution under dynamic load and significantly improving the fracture toughness and impact resistance of the plate.

[0031] 3. The protective plate of stainless steel composite ceramic material prepared by the present invention achieves a strong and tough integrated isotropic structure through the complementary intrinsic properties between the components. Oleic acid modification gives zirconium oxide excellent dispersion stability and avoids stress defects formed by the agglomeration of ultrafine particles. Meanwhile, the core-shell modified whiskers act as a spatial skeleton support. This microscopic topological network jointly constructed by one-dimensional whiskers and zero-dimensional nanoparticles not only strengthens the deformation resistance of the matrix through the interface synergistic effect, but also gives the protective plate excellent wear resistance on a macroscopic level. 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] The austenitic stainless steel powder used in this invention was purchased from Hebei Tengshuang Metal Materials Co., Ltd., and its elemental composition is Cr: 16-18%, Ni: 10-14%, Mo: 2-3%, Mn≤2.0%, C≤0.03%, Si≤1.0%.

[0034] The titanium powder used in this invention was purchased from Pengxia Furnace Lining Material Processing Plant in Lingshou County, with a density of 4.5 g / cm³. 3 The D50 is 10-30 μm, and the specific surface area is 0.1-1.5 m². 2 / g;

[0035] The silica used in this invention was purchased from Guangzhou Xinxi Metallurgical Chemical Co., Ltd., and its density is 2.2 g / cm³. 3 The particle size is 5-10 μm, and the preferred specific surface area is 210-240 m². 2 / g;

[0036] The carbon black used in this invention was purchased from Shandong Guohua Chemical Co., Ltd., and its density is 1.8-2.1 g / cm³. 3 The particle size is 10-80 nm, and the specific surface area is 30-300 m². 2 / g;

[0037] The nano-zirconia used in this invention was purchased from Pingxiang Baitian New Materials Co., Ltd., with a D50 of 0.3-50 μm and a specific surface area of ​​3-150 m². 2 / g.

[0038] Example 1

[0039] This embodiment provides a method for preparing oleic acid-modified zirconium oxide, including the following steps:

[0040] Weigh 20g of nano-zirconia and 400mL of ethanol and place them in a reaction vessel. Stir and disperse for 15min. Add 2g of oleic acid. Heat the reaction vessel to 60℃ and keep it at that temperature for 4h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, wash the filter cake twice with ethanol, transfer it to a vacuum drying oven at 50℃, vacuum dry for 10h, grind it through a 200-mesh sieve, and obtain oleic acid modified zirconia.

[0041] High temperature induces the carboxyl groups at the end of oleic acid molecules to coordinate and undergo dehydration esterification reactions with the free hydroxyl groups on the surface of nano-zirconia, forming stable chemical bonds. Through this interfacial reaction, oleic acid molecules are grafted onto the surface of zirconia particles, and their nonpolar hydrocarbon chains extend outward to construct an organic monomolecular coating layer, ultimately obtaining surface-organically grafted modified nano-zirconia.

[0042] Oleic acid is grafted onto nano-zirconia through high-temperature esterification. Spatial hindrance is used to suppress agglomeration and achieve homogeneous dispersion. During sintering, the organic layer is pyrolyzed in situ into an active carbon phase, which mediates the construction of continuous metallurgical bonding between core-shell modified silicon carbide whiskers and stainless steel powder. This stimulates the energy consumption of zirconia phase transformation and whisker pull-out, optimizes stress transmission, and significantly improves the fracture toughness and wear resistance of the plate.

[0043] Example 2

[0044] This embodiment provides a method for preparing oleic acid-modified zirconium oxide, including the following steps:

[0045] Weigh 30g of nano-zirconia and 500mL of ethanol and place them in a reaction vessel. Stir and disperse for 22min. Add 4g of oleic acid. Heat the reaction vessel to 70℃ and keep it at that temperature for 5h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, wash the filter cake three times with ethanol, transfer it to a vacuum drying oven at 55℃, vacuum dry for 11h, grind it through a 200-mesh sieve, and obtain oleic acid modified zirconia.

[0046] Example 3

[0047] This embodiment provides a method for preparing oleic acid-modified zirconium oxide, including the following steps:

[0048] Weigh 40g of nano-zirconia and 600mL of ethanol and place them in a reaction vessel. Stir and disperse for 30min. Add 6g of oleic acid. Heat the reaction vessel to 80℃ and keep it at that temperature for 6h. After the reaction is complete, wait for the reaction system to cool to room temperature, filter, wash the filter cake 4 times with ethanol, transfer it to a vacuum drying oven at 60℃, vacuum dry for 12h, grind it through a 200-mesh sieve, and obtain oleic acid modified zirconia.

[0049] Example 4

[0050] This embodiment provides a method for preparing crude silicon carbide whiskers, comprising the following steps:

[0051] Step ①: Preparation of precursor mixture

[0052] Zirconia balls with diameters of 10 mm, 5 mm, and 3 mm were mixed evenly at a mass ratio of 2:4:4 to obtain grinding balls for later use.

[0053] Weigh out 40g of silicon dioxide, 24g of carbon black, 1g of ferric nitrate, 0.5g of sodium fluoride and 200mL of ethanol and place them in a ball mill. Add grinding balls at a ball-to-material ratio of 10:1, wet mill for 0.5h, transfer to a vacuum drying oven at 60℃, and dry to constant weight to obtain the precursor mixture.

[0054] Step 2: Preparation of crude silicon carbide whiskers

[0055] The precursor mixture was placed in a crucible in a tube furnace and protected with argon gas. It was heated to 1400°C at a heating rate of 5°C / min and held for 20 hours. After cooling, the crude silicon carbide whisker product was obtained.

[0056] Through multi-stage wet milling, silica, carbon black, ferric nitrate, and sodium fluoride are homogeneously mixed and dispersed at the microscale. In a high-temperature argon atmosphere, the system undergoes a carbothermic reduction reaction, in which ferric nitrate decomposes and melts to form iron-based liquid droplets to provide catalytic sites. Sodium fluoride is vaporized and assists the solid silicon source in converting into highly active volatile silicon phase gas. The gaseous silicon source and carbon source continuously dissolve on the surface of the metal catalytic droplets and reach supersaturation. Subsequently, based on the gas-liquid-solid mechanism, they continuously precipitate along specific crystal planes to generate coarse silicon carbide whiskers.

[0057] Carbothermic reduction reaction induces silicon carbide to grow in a preferred orientation by precisely controlling the supersaturation of silicon and carbon components, generating whisker reinforcements with high aspect ratio. The whisker phase constructed in situ in this process has excellent mechanical properties. When introduced into the stainless steel composite system as a skeleton, it can effectively play the functions of crack deflection and load transfer. By optimizing the stress distribution gradient inside the composite material, the fracture toughness of the protective plate is significantly improved.

[0058] Example 5

[0059] This embodiment provides a method for preparing crude silicon carbide whiskers, comprising the following steps:

[0060] Step ①: Preparation of precursor mixture

[0061] Zirconia balls with diameters of 10 mm, 5 mm, and 3 mm were mixed evenly at a mass ratio of 2:4:4 to obtain grinding balls for later use.

[0062] Weigh out 50g of silicon dioxide, 36g of carbon black, 2g of ferric nitrate, 0.75g of sodium fluoride and 300mL of ethanol and place them in a ball mill. Add grinding balls at a ball-to-material ratio of 10:1, wet mill for 1 hour, transfer to a vacuum drying oven at 65℃, and dry to constant weight to obtain the precursor mixture.

[0063] Step 2: Preparation of crude silicon carbide whiskers

[0064] The precursor mixture was placed in a crucible in a tube furnace, protected by argon gas, heated to 1500℃ at a heating rate of 7℃ / min, held for 22h, and then cooled to obtain crude silicon carbide whiskers.

[0065] Example 6

[0066] This embodiment provides a method for preparing crude silicon carbide whiskers, comprising the following steps:

[0067] Step ①: Preparation of precursor mixture

[0068] Zirconia balls with diameters of 10 mm, 5 mm, and 3 mm were mixed evenly at a mass ratio of 2:4:4 to obtain grinding balls for later use.

[0069] Weigh out 60g of silicon dioxide, 48g of carbon black, 3g of ferric nitrate, 1g of sodium fluoride and 400mL of ethanol and place them in a ball mill. Add grinding balls at a ball-to-material ratio of 10:1, wet mill for 1 hour, transfer to a vacuum drying oven at 70℃ and dry to constant weight to obtain the precursor mixture.

[0070] Step 2: Preparation of crude silicon carbide whiskers

[0071] The precursor mixture was placed in a crucible in a tube furnace and protected with argon gas. It was heated to 1550°C at a heating rate of 10°C / min and held for 24 hours. After cooling, the crude silicon carbide whisker product was obtained.

[0072] Example 7

[0073] This embodiment provides a method for preparing core-shell modified silicon carbide whiskers, including the following steps:

[0074] Step (1): Preparation of acid-washed silicon carbide whiskers

[0075] Weigh 10g of the crude silicon carbide whisker product prepared in Example 4 and 100mL of 35wt% hydrofluoric acid aqueous solution into a single-necked bottle, ultrasonically wash for 15min, filter after washing, wash the filter cake with deionized water until neutral, transfer it to an oven at 50℃ and dry to constant weight to obtain acid-washed silicon carbide whiskers.

[0076] Step 2: Preparation of molten salt blend

[0077] Weigh out 20g of acid-washed silicon carbide whiskers, 2g of titanium powder, 30g of sodium chloride, 30g of potassium chloride, and 150mL of ethanol and place them in a reaction vessel. Stir well and heat the reaction vessel to 50℃. Remove the ethanol by vacuum distillation to obtain the molten salt blend.

[0078] Step (3): Preparation of core-shell modified silicon carbide whiskers

[0079] The molten salt blend was placed in a crucible in a tube furnace and protected with argon gas. It was heated to 1300℃ at a heating rate of 3℃ / min and held at that temperature for 20h. After the reaction was completed, the reaction system was cooled to room temperature. The product was taken out and washed twice with deionized water. It was then transferred to a vacuum drying oven at 50℃ and vacuum dried for 10h to obtain core-shell modified silicon carbide whiskers.

[0080] The whiskers were purified and their surface activated by selectively dissolving the residual free silica in the crude silicon carbide whisker product with hydrofluoric acid. Then, sodium chloride and potassium chloride were introduced as eutectic reaction media. After homogenization and solvent removal of titanium powder in the liquid phase, a low-viscosity high-temperature molten salt liquid phase mass transfer system was constructed in a high-temperature argon environment. The melting of the eutectic salt promoted the transformation of solid titanium powder into highly active titanium species and accelerated its diffusion and migration to the surface of silicon carbide whiskers in the liquid phase. The titanium species that reached the surface underwent an in-situ high-temperature interfacial solid-liquid reaction with the silicon carbide matrix to generate a stable titanium-based compound coating layer, constructing a homogeneous core-shell structure, and obtaining core-shell modified silicon carbide whiskers.

[0081] Hydrofluoric acid rinsing removes residual impurities and exposes surface active sites. Molten salt medium reduces microscopic mass transfer resistance, driving in-situ reaction between titanium and silicon carbide to construct a titanium-based coating layer. This core-shell structure suppresses interfacial side reactions between whiskers and the stainless steel matrix during high-temperature sintering, regulates the wetting behavior of the ceramic reinforcing phase and the metal system to mediate metallurgical bonding, and constructs a continuous interfacial stress transfer network, significantly improving the fracture toughness of the protective plate.

[0082] Example 8

[0083] This embodiment provides a method for preparing core-shell modified silicon carbide whiskers, including the following steps:

[0084] Step (1): Preparation of acid-washed silicon carbide whiskers

[0085] Weigh 10g of the crude silicon carbide whisker product prepared in Example 5 and 100mL of 37.5wt% hydrofluoric acid aqueous solution into a single-necked bottle, ultrasonically wash for 22min, filter after washing, wash the filter cake with deionized water until neutral, transfer it to an oven at 55℃ and dry to constant weight to obtain acid-washed silicon carbide whiskers.

[0086] Step 2: Preparation of molten salt blend

[0087] Weigh out 30g of acid-washed silicon carbide whiskers, 3g of titanium powder, 40g of sodium chloride, 40g of potassium chloride, and 220mL of ethanol and place them in a reaction vessel. Stir well and heat the reaction vessel to 55℃. Remove the ethanol by vacuum distillation to obtain the molten salt blend.

[0088] Step (3): Preparation of core-shell modified silicon carbide whiskers

[0089] The molten salt blend was placed in a crucible in a tube furnace and protected with argon gas. It was heated to 1350℃ at a heating rate of 4℃ / min and held at that temperature for 22h. After the reaction was completed, the reaction system was cooled to room temperature. The product was taken out and washed three times with deionized water. It was then transferred to a vacuum drying oven at 55℃ and vacuum dried for 11h to obtain core-shell modified silicon carbide whiskers.

[0090] Example 9

[0091] This embodiment provides a method for preparing core-shell modified silicon carbide whiskers, including the following steps:

[0092] Step (1): Preparation of acid-washed silicon carbide whiskers

[0093] Weigh 10g of the crude silicon carbide whisker product prepared in Example 6 and 100mL of 40wt% hydrofluoric acid aqueous solution into a single-necked bottle, ultrasonically wash for 30min, filter after washing, wash the filter cake with deionized water until neutral, transfer it to an oven at 60℃ and dry to constant weight to obtain acid-washed silicon carbide whiskers.

[0094] Step 2: Preparation of molten salt blend

[0095] Weigh out 40g of acid-washed silicon carbide whiskers, 4g of titanium powder, 50g of sodium chloride, 50g of potassium chloride, and 30mL of ethanol and place them in a reaction vessel. Stir well and heat the reaction vessel to 60℃. Remove the ethanol by vacuum distillation to obtain the molten salt blend.

[0096] Step (3): Preparation of core-shell modified silicon carbide whiskers

[0097] The molten salt blend was placed in a crucible in a tube furnace and protected with argon gas. It was heated to 1400℃ at a heating rate of 5℃ / min and held at that temperature for 24 hours. After the reaction was completed, the reaction system was cooled to room temperature. The product was taken out and washed four times with deionized water. It was then transferred to a vacuum drying oven at 60℃ and vacuum dried for 12 hours to obtain core-shell modified silicon carbide whiskers.

[0098] Example 10

[0099] This embodiment provides a method for preparing a protective plate made of stainless steel composite ceramic material, including the following steps:

[0100] Step I: Preparation of composite powder

[0101] Weigh out 750g of stainless steel powder, 100g of core-shell modified silicon carbide whiskers prepared in Example 7, and 20g of oleic acid modified zirconium oxide prepared in Example 1, place them in a mixer, add 1000mL of ethanol, mix evenly, and dry under reduced pressure at 50℃ for 4h to obtain composite powder.

[0102] Step II: Preparation of protective sheet blanks

[0103] The composite powder is uniformly loaded into the mold and cold-pressed at 50MPa for 1 minute at room temperature to obtain the green blank of the protective plate.

[0104] Step III: Preparation of protective plates made of stainless steel composite ceramic material

[0105] The protective plate blank is placed in a vacuum hot pressing sintering furnace and heated to 1150°C at a heating rate of 5°C / min under vacuum. At the same time, an axial pressure of 20MPa is applied and the plate is held at the temperature and pressure for 1 hour. After cooling and demolding, the protective plate of stainless steel composite ceramic material is obtained.

[0106] By using liquid-phase assisted blending and vacuum distillation, a macroscopically homogeneous distribution of core-shell modified silicon carbide whiskers, oleic acid modified nano-zirconia, and stainless steel powder is achieved. Based on cold pressing, vacuum hot pressing sintering is used to induce thermal diffusion and capillary action between the phases. At high temperature, the stainless steel powder undergoes surface diffusion and interfacial migration to achieve particle densification. At the same time, the core-shell layer mediates micro-wetting and metallurgical bonding at the interface. Under axial pressure, the internal pores of the material close, ultimately forming a protective plate of stainless steel composite ceramic material with stainless steel powder as the continuous matrix and core-shell modified silicon carbide whiskers and oleic acid modified zirconia as the reinforcing phases.

[0107] Wet milling and blending ensures the isotropic distribution of heterogeneous reinforcing phases, and the core-shell modified layer mediates the evolution of interfacial wettability, establishing a high-strength metallurgical bonding interface and effectively blocking the brittle transformation between phases. This system utilizes the bridging and deflection effect of whiskers and the phase transformation toughening mechanism of nano-zirconia to construct an energy dissipation network at the microscale, thereby improving the interfacial bonding strength and toughness of the plate.

[0108] Example 11

[0109] This embodiment provides a method for preparing a protective plate made of stainless steel composite ceramic material, including the following steps:

[0110] Step I: Preparation of composite powder

[0111] Weigh out 800g of stainless steel powder, 150g of core-shell modified silicon carbide whiskers prepared in Example 8, and 35g of oleic acid modified zirconium oxide prepared in Example 2, place them in a mixer, add 1100mL of ethanol, mix evenly, and dry under reduced pressure at 60℃ for 5h to obtain composite powder.

[0112] Step II: Preparation of protective sheet blanks

[0113] The composite powder is uniformly loaded into the mold and cold-pressed at 75MPa for 2 minutes at room temperature to obtain the green blank of the protective board.

[0114] Step III: Preparation of protective plates made of stainless steel composite ceramic material

[0115] The protective plate blank is placed in a vacuum hot pressing sintering furnace and heated to 1200℃ at a heating rate of 7℃ / min under vacuum. At the same time, an axial pressure of 30MPa is applied and the plate is held at the temperature and pressure for 1.5h. After cooling and demolding, the protective plate of stainless steel composite ceramic material is obtained.

[0116] Example 12

[0117] This embodiment provides a method for preparing a protective plate made of stainless steel composite ceramic material, including the following steps:

[0118] Step I: Preparation of composite powder

[0119] Weigh out 850g of stainless steel powder, 200g of core-shell modified silicon carbide whiskers prepared in Example 9, and 50g of oleic acid modified zirconium oxide prepared in Example 3, place them in a mixer, add 1200mL of ethanol, mix evenly, and dry under reduced pressure at 70℃ for 6h to obtain composite powder.

[0120] Step II: Preparation of protective sheet blanks

[0121] The composite powder is uniformly loaded into the mold and cold-pressed at 100MPa for 3 minutes at room temperature to obtain the green blank of the protective plate.

[0122] Step III: Preparation of protective plates made of stainless steel composite ceramic material

[0123] The protective plate blank is placed in a vacuum hot pressing sintering furnace and heated to 1250°C at a heating rate of 10°C / min under vacuum. At the same time, an axial pressure of 35MPa is applied and the plate is held at the temperature and pressure for 2 hours. After cooling and demolding, the protective plate of stainless steel composite ceramic material is obtained.

[0124] Comparative Example 1

[0125] The difference between this comparative example and Example 12 is that, in step (2) when preparing the molten salt blend, an equal amount of crude silicon carbide whisker product is used to replace the acid-washed silicon carbide whiskers.

[0126] Comparative Example 2

[0127] The difference between this comparative example and Example 12 is that, in step I, nano-zirconia is used in an equal amount to replace oleic acid-modified zirconia when preparing the composite powder.

[0128] Comparative Example 3

[0129] The difference between this comparative example and Example 12 is that oleic acid-modified zirconium oxide was omitted in step I when preparing the composite powder.

[0130] Performance testing:

[0131] The three-point bending strength of the protective plates prepared in Examples 10-12 and Comparative Examples 1-3 at room temperature was tested in accordance with the standard GB / T 6569-2006 "Test Method for Bending Strength of Fine Ceramics".

[0132] The Vickers hardness of the protective plates prepared in Examples 10-12 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 4340.1-2024 "Metallic materials - Vickers hardness test - Part 1: Test method".

[0133] The fracture toughness values ​​of the protective plates prepared in Examples 10-12 and Comparative Examples 1-3 were tested in accordance with the standard GB / T 23806-2025 "Test Method for Fracture Toughness of Fine Ceramics - Single-sided Precracked Beam (SEPB) Method".

[0134] The volumetric wear of the protective plates prepared in Examples 10-12 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 12444-2006 "Test Methods for Wear of Metallic Materials - Ring-Block Sliding Wear Test".

[0135] The impact strength of the protective plates prepared in Examples 10-12 and Comparative Examples 1-3 was tested in accordance with the standard GB / T 38494-2020 "Test Method for Impact Resistance of Ceramic Products".

[0136] See Table 1 for specific data.

[0137] Table 1 - Performance Test Data for Each Sample

[0138] Project Group Example 10 Example 11 Example 12 Comparative Example 1 Comparative Example 2 Comparative Example 3 Three-point bending strength / N 695 712 705 536 582 505 Vickers hardness / HV 639 658 647 512 546 490 <![CDATA[Volume wear / mm 3 > 0.36 0.28 0.39 0.65 0.53 0.78 Fracture toughness value / N 457 468 461 322 354 296 <![CDATA[Impact strength / (J / cm 2 )]]> 24.1 24.5 23.8 14.2 16.5 12.8

[0139] Data Analysis:

[0140] Analysis of the data in the table above shows that the protective plate made of stainless steel composite ceramic material prepared in this invention has a three-point bending strength of 712 N, a Vickers hardness of 658 HV, and a volumetric wear of 0.28 mm. 3 It has a fracture toughness of 468 N and an impact strength of 24.5 J / cm. 2 All data points are better than the comparative data.

[0141] The present invention first prepares core-shell modified silicon carbide whiskers through chemical vapor deposition and acid washing process, and then uses oleic acid to graft nano-zirconia onto the surface. Subsequently, the modified dual-scale reinforcing phase and stainless steel powder are homogenized by wet ball milling. Finally, the protective plate of stainless steel composite ceramic material with ternary synergistic effect is constructed by cold pressing and vacuum hot pressing sintering, which significantly improves the fracture toughness and impact resistance of the protective plate.

[0142] 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.

[0143] 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.

[0144] 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 method for preparing a protective plate made of stainless steel composite ceramic material, characterized in that, Includes the following steps: Step 1: Place stainless steel powder, core-shell modified silicon carbide whiskers and oleic acid modified zirconium oxide in a mixer, add ethanol, mix evenly, and then dry under reduced pressure to obtain composite powder. Step 2: The composite powder is evenly loaded into the mold and cold-pressed at room temperature to obtain the green sheet of the protective board; Step 3: Place the protective plate blank in a vacuum hot pressing sintering furnace, heat it to 1150-1250℃ in a vacuum environment at a heating rate of 5-10℃ / min, and apply an axial pressure of 20-35MPa at the same time. Hold it at the temperature and pressure for 1-2 hours. After cooling and demolding, the protective plate of stainless steel composite ceramic material is obtained.

2. The method for preparing a protective plate of stainless steel composite ceramic material according to claim 1, characterized in that, In step one, the ratio of stainless steel powder, core-shell modified silicon carbide whiskers, oleic acid modified zirconium oxide, and ethanol is 75-85g:10-20g:2-5g:100-120mL. The vacuum drying temperature is 50-70℃, and the drying time is 4-6h. The stainless steel powder is spherical or near-spherical austenitic stainless steel powder with a D50 of 10-30μm.

3. The method for preparing a protective plate of stainless steel composite ceramic material according to claim 1, characterized in that, In step two, the pressure for cold pressing is 50-100 MPa, and the holding time is 1-3 min.

4. The method for preparing a protective plate of stainless steel composite ceramic material according to claim 1, characterized in that, The core-shell modified silicon carbide whiskers are prepared by the following steps: A1. Place the crude silicon carbide whisker product and hydrofluoric acid aqueous solution in a single-necked bottle, ultrasonically wash for 15-30 min, and then post-process to obtain acid-washed silicon carbide whiskers. A2. Pickled silicon carbide whiskers, titanium powder, sodium chloride, potassium chloride and ethanol are placed in a reaction vessel and stirred evenly. The reaction vessel is heated to 50-60℃ and the ethanol is removed by vacuum distillation to obtain molten salt blend. A3. Place the molten salt blend in a crucible in a tube furnace, purge it with argon gas for protection, heat it to 1300-1400℃ at a heating rate of 3-5℃ / min, hold it at that temperature for 20-24h, and then process it to obtain core-shell modified silicon carbide whiskers.

5. The method for preparing a protective plate of stainless steel composite ceramic material according to claim 4, characterized in that, In step A1, the ratio of the crude silicon carbide whisker product to the hydrofluoric acid aqueous solution is 1g:10mL, and the concentration of the hydrofluoric acid aqueous solution is 35-40wt%; in step A2, the ratio of the acid-washed silicon carbide whisker, titanium powder, sodium chloride, potassium chloride, and ethanol is 2-4g:0.2-0.4g:3-5g:3-5g:15-30mL.

6. The method for preparing a protective plate of stainless steel composite ceramic material according to claim 4, characterized in that, The crude silicon carbide whisker product is prepared by the following steps: B1. Place silicon dioxide, carbon black, ferric nitrate, sodium fluoride and ethanol in a ball mill, add grinding balls, wet mill for 0.5-1 h, and dry to obtain precursor mixture; B2. Place the precursor mixture in a crucible in a tube furnace, purge it with argon gas for protection, heat it to 1400-1550℃ at a heating rate of 5-10℃ / min, hold it at that temperature for 20-24h, and after cooling, obtain the crude product of silicon carbide whiskers.

7. The method for preparing a protective plate of stainless steel composite ceramic material according to claim 6, characterized in that, In step B1, the ratio of silica, carbon black, ferric nitrate, sodium fluoride, and ethanol is 4-6g:2.4-4.8g:0.1-0.3g:0.05-0.10g:20-40mL. The grinding balls are obtained by uniformly mixing zirconium oxide balls with diameters of 10mm, 5mm, and 3mm in a mass ratio of 2:4:

4. The ball-to-material ratio for wet grinding is 10:

1.

8. The method for preparing a protective plate of stainless steel composite ceramic material according to claim 1, characterized in that, The preparation method of the oleic acid modified zirconium oxide is as follows: nano zirconium oxide and ethanol are placed in a reaction vessel, stirred and dispersed for 15-30 min, oleic acid is added, the reaction vessel is heated to 60-80℃, and the reaction is kept at this temperature for 4-6 h. After post-treatment, oleic acid modified zirconium oxide is obtained.

9. The method for preparing a protective plate of stainless steel composite ceramic material according to claim 8, characterized in that, The ratio of nano-zirconia, ethanol, and oleic acid is 2-4g:40-60mL:0.2-0.6g.

10. A protective plate made of stainless steel composite ceramic material, characterized in that, The protective plate made of stainless steel composite ceramic material is prepared by the method for preparing a protective plate made of stainless steel composite ceramic material as described in any one of claims 1-9.