阅读说明：本技术 一种整体氧化锆陶瓷切削刀具材料及其制备方法 (Integral zirconia ceramic cutting tool material and preparation method thereof ) 是由 颜炳姜 李伟秋 于 2020-11-25 设计创作，主要内容包括：本发明属于陶瓷切削刀具技术领域,公开了一种整体氧化锆陶瓷切削刀具材料及其制备方法。该整体氧化锆陶瓷切削刀具材料是将80～90wt％氧化锆粉,1～2.5wt％硬脂酸,6～10wt％石蜡,0.5～2.5wt％邻苯二甲酸二丁酯,2.5～5wt％高密度聚乙烯在160～180℃混炼,螺杆挤出造粒,注射成型,萃取脱脂,750～850℃排胶,1380～1500℃烧结制得。本发明的氧化锆陶瓷的厚壁刀具材料的方法具有可大批量生产,生产效率高,产品良率高的优异特点。本发明的整体刀具材料晶粒细小均匀耐磨性好,以其制造的刀具可用于高速加工高强度石墨,有色金属或改性塑料等零件。(The invention belongs to the technical field of ceramic cutting tools, and discloses an integral zirconia ceramic cutting tool material and a preparation method thereof. The integral zirconia ceramic cutting tool material is prepared by mixing 80-90 wt% of zirconia powder, 1-2.5 wt% of stearic acid, 6-10 wt% of paraffin, 0.5-2.5 wt% of dibutyl phthalate and 2.5-5 wt% of high-density polyethylene at 160-180 ℃, extruding and granulating by a screw, performing injection molding, performing extraction and degreasing, discharging glue at 750-850 ℃, and sintering at 1380-1500 ℃. The method for preparing the zirconia ceramic thick-wall cutter material has the excellent characteristics of mass production, high production efficiency and high product yield. The whole cutter material has fine and uniform crystal grains and good wear resistance, and the cutter manufactured by the material can be used for processing parts such as high-strength graphite, nonferrous metals or modified plastics and the like at high speed.)

1. An integral zirconia ceramic cutting tool material is characterized in that zirconia ceramic is prepared by mixing 80-90 wt% of zirconia powder, 1-2.5 wt% of stearic acid, 6-10 wt% of paraffin, 0.5-2.5 wt% of dibutyl phthalate and 2.5-5 wt% of high-density polyethylene at 160-180 ℃ to prepare a mixed material; extruding and granulating the mixed material at a temperature of 90-130 ℃ by a screw, and performing injection molding on the prepared granulated material at a temperature of 150-170 ℃ to obtain an injection blank; extracting and degreasing the injection blank at 25-50 ℃ by using an extracting agent, then discharging the prepared degreased blank in air at 750-850 ℃, and sintering the prepared discharged blank in air at 1380-1500 ℃.

2. The monolithic zirconia ceramic cutting tool material of claim 1, wherein the zirconia powder is yttrium stabilized zirconia having a purity of 95% or greater and a particle size of less than 0.5 μm; the purity of the stearic acid, the paraffin, the dibutyl phthalate and the high-density polyethylene is more than 98 percent.

3. The monolithic zirconia ceramic cutting tool material of claim 1, wherein the mixing time is 5 to 12 hours.

4. The monolithic zirconia ceramic cutting tool material of claim 1, wherein the screw extrusion granulation speed is 6-15 rpm, and the granulation speed is 110-115 rpm.

5. The monolithic zirconia ceramic cutting tool material according to claim 1, wherein the mold temperature in the injection molding is 60 to 100 ℃, the injection pressure is 500 to 900bar, the injection speed is 50 to 80mm/s, the pressure holding pressure is 600 to 800bar, and the pressure holding time is 5 to 10 s.

6. The monolithic zirconia ceramic cutting tool material of claim 1, wherein the time for the extraction degreasing is 8-24 hours; the extracting agent is n-octane or n-butane, and the concentration of the extracting agent is 50-99%.

7. The monolithic zirconia ceramic cutting tool material of claim 1, wherein the binder removal process is: heating to 160-180 ℃ at a speed of 15-17 ℃/h, and preserving heat for 1.5-2.5 h; heating to 200-220 ℃ at a speed of 4-5 ℃/h, and preserving heat for 7-9 h; heating to 245-255 ℃ at a speed of 18-22 ℃/h; heating to 445-455 ℃ at a speed of 10-11 ℃/h, and preserving heat for 1.5-2.5 h; heating to 780-850 ℃ at a speed of 100-130 ℃/h, and preserving heat for 0.5-2 h; and then cooling to the normal temperature at the speed of 60-80 ℃/h.

8. The monolithic zirconia ceramic cutting tool material of claim 1, wherein the sintering process is: heating to 480-530 ℃ at a speed of 400-500 ℃/h; heating to 1050-1150 ℃ at a speed of 280-320 ℃/h; heating to 1380-1500 ℃ at the speed of 180-210 ℃/h, and preserving heat for 0.5-4 h; then cooling to 550-650 ℃ at 300-350 ℃/h; then cooling to room temperature at a rate of 50-60 ℃/h.

9. The monolithic zirconia ceramic cutting tool material of claim 1, wherein the monolithic zirconia ceramic cutting tool material has a strength of 800 to 1500MPa, a hardness of 1300 to 1450HV, and a toughness of 4 to 12 MPa-m^{1 /2}。

10. The method for preparing a monolithic zirconia ceramic cutting tool material according to any one of claims 1 to 9, comprising the specific steps of:

s1, mixing zirconium oxide powder, stearic acid, paraffin, dibutyl phthalate and high-density polyethylene at 160-180 ℃ to prepare a mixed material;

s2, pouring the mixed materials into a screw extrusion granulator for granulation at 90-130 ℃, and discharging after granulation to prepare granules;

s3, pouring the granulated material into a ceramic injection machine, setting the injection temperature to be 150-170 ℃, the mold temperature to be 60-100 ℃, the injection pressure to be 500-900 bar, the injection speed to be 50-80 mm/s, the pressure maintaining pressure to be 600-800 bar and the pressure maintaining time to be 5-10 s, and preparing an injection blank after injection molding;

s4, degreasing the injection blank in an extracting agent at the temperature of 25-50 ℃, and taking out the injection blank after degreasing for 8-24 hours to obtain a degreased blank;

s5, placing the degreased blank into a rubber discharging furnace, and discharging rubber at the temperature of 750-850 ℃ in an air atmosphere to obtain a rubber discharging blank;

s6, placing the binder removal blank into a sintering furnace, and sintering at 1380-1500 ℃ in air to obtain the integral zirconia ceramic cutting tool material.

Technical Field

The invention belongs to the technical field of ceramic cutting tools, and particularly relates to an integral zirconia ceramic cutting tool material and a preparation method thereof.

Background

Cutting is the most basic technique in the field of machining, and is the most important manufacturing means for precision parts. With the development of new materials and new technologies, cutting machining is developing towards high speed, high efficiency and high precision, and the cutter technology is a key technology for high speed, high efficiency and precision machining. In recent years, with the development of the electronics industry, there is an increasing demand for non-ferrous materials, such as high-strength graphite, electrode copper alloy, novel aluminum alloy, multifunctional plastics, and the like. In the face of machining of these materials, it is difficult for conventional tool materials such as high-speed steel, cemented carbide, etc. to satisfy machining speed and machining accuracy. Therefore, it is necessary to develop new tool materials and processing techniques to improve the processing efficiency, improve the quality of the processed surface and reduce the cost.

The zirconia ceramic as a structural ceramic has excellent strength and toughness and higher hardness, and has wide application prospect when used as a precision forming cutter. Zirconia can obtain a precise structure through sharpening, has good cutting edge integrity, and can obtain better processing quality than the traditional cutter when used as a processing cutter made of materials such as nonferrous metal, plastics, graphite and the like. The traditional zirconia material has high strength and toughness and is widely applied to precision mechanical parts, but the traditional zirconia material has low hardness and is difficult to meet the requirements of cutting tools. On the other hand, the traditional dry pressing, casting and other forming technologies are difficult to meet the requirement of efficient forming of the whole cutter. The zirconia injection molding technology is an effective means for efficiently producing ceramic parts in batches, but the existing zirconia injection molding can only meet the molding requirement of thin-wall parts and is difficult to meet the molding requirement of large-diameter integral cutters with complex shapes. The problems of injection cracking, degreasing and binder removal cracking, sintering cracking, chipping and the like are often caused when the injection molding is carried out by using the traditional thin-wall molding formula. Meanwhile, in order to cope with the low density of the traditional injection green body, densification is often realized by high-temperature pressure sintering means such as hot isostatic pressing, and the cost is high. Therefore, the development of a thick-wall injection formula, the improvement of the green density and the reduction of the sintering difficulty are also problems to be solved for preparing the integral zirconia cutter.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention provides a monolithic zirconia ceramic cutting tool material which has the excellent characteristics of high hardness, easy sintering and compactness and high product yield.

The invention also aims to provide a preparation method of the integral zirconia ceramic cutting tool material. The method can be operated in batch, and has high production efficiency and high product yield. The method comprises the steps of mixing raw materials, extruding and granulating by a screw, injection molding, extracting and degreasing, discharging glue at high temperature, and sintering at high temperature to prepare the integral zirconia ceramic cutting tool material.

The purpose of the invention is realized by the following technical scheme:

an integral zirconia ceramic cutting tool material is prepared by mixing 80-90 wt% of zirconia powder, 1-2.5 wt% of stearic acid, 6-10 wt% of paraffin, 0.5-2.5 wt% of dibutyl phthalate and 2.5-5 wt% of high-density polyethylene at 160-180 ℃ to prepare a mixed material; extruding and granulating the mixed material at a temperature of 90-130 ℃ by a screw, and performing injection molding on the prepared granulated material at a temperature of 150-170 ℃ to obtain an injection blank; extracting and degreasing the injection blank at 25-50 ℃ by using an extracting agent, then discharging the prepared degreased blank in air at 750-850 ℃, and sintering the prepared discharged blank in air at 1380-1500 ℃.

Preferably, the zirconia powder is yttrium-stabilized zirconia, the purity of the yttrium-stabilized zirconia is more than 95%, and the particle size of the yttrium-stabilized zirconia is less than 0.5 micrometer; the purity of the stearic acid, the paraffin, the dibutyl phthalate and the high-density polyethylene is more than 98 percent.

Preferably, the mixing time is 5-12 h.

Preferably, the rotation speed of the screw extrusion granulation is 6-15 revolutions per minute, and the granulation rotation speed is 110-115 revolutions per minute.

Preferably, the temperature of the injection molding die is 60-100 ℃, the injection pressure is 500-900 bar, the injection speed is 50-80 mm/s, the pressure maintaining pressure is 600-800 bar, and the pressure maintaining time is 5-10 s.

Preferably, the time for extracting and degreasing is 8-24 h; the extracting agent is n-octane or n-butane, and the concentration of the extracting agent is 50-99%.

Preferably, the process of rubber discharge comprises the following steps: heating to 160-180 ℃ at a speed of 15-17 ℃/h, and preserving heat for 1.5-2 h; heating to 200-220 ℃ at a speed of 4-5 ℃/h, and preserving heat for 7-9 h; heating to 245-255 ℃ at a speed of 18-22 ℃/h; heating to 445-455 ℃ at a speed of 10-11 ℃/h, and preserving heat for 1.5-2 h; heating to 780-850 ℃ at a speed of 100-130 ℃/h, and preserving heat for 0.5-2 h; and then cooling to the normal temperature at the speed of 60-80 ℃/h.

Preferably, the sintering process is as follows: heating to 480-530 ℃ at a speed of 400-500 ℃/h; heating to 1050-1150 ℃ at a speed of 280-320 ℃/h; heating to 1380-1500 ℃ at the speed of 180-210 ℃/h, and preserving heat for 0.5-4 h; then cooling to 550-650 ℃ at 300-350 ℃/h; then cooling to room temperature at a rate of 50-60 ℃/h.

Preferably, the strength of the integral zirconia ceramic cutting tool material is 800-1500 MPa, the hardness is 1300-1450 HV, and the toughness is 4-12 MPa-m^1/2。

The preparation method of the integral zirconia ceramic cutting tool material comprises the following specific steps:

s1, mixing zirconium oxide powder, stearic acid, paraffin, dibutyl phthalate and high-density polyethylene at 160-180 ℃ to prepare a mixed material;

s2, pouring the mixed materials into a screw extrusion granulator for granulation at 90-130 ℃, and discharging after granulation to prepare granules;

s3, pouring the granulated material into a ceramic injection machine, setting the injection temperature to be 150-170 ℃, the mold temperature to be 60-100 ℃, the injection pressure to be 500-900 bar, the injection speed to be 50-80 mm/s, the pressure maintaining pressure to be 600-800 bar and the pressure maintaining time to be 5-10 s, and preparing an injection blank after injection molding;

s4, degreasing the injection blank in an extracting agent at the temperature of 25-50 ℃, and taking out the injection blank after degreasing for 8-24 hours to obtain a degreased blank;

s5, placing the degreased blank into a rubber discharging furnace, and discharging rubber at the temperature of 750-850 ℃ in an air atmosphere to obtain a rubber discharging blank;

s6, placing the binder removal blank into a sintering furnace, and sintering at 1380-1500 ℃ in air to obtain the integral zirconia ceramic cutting tool material.

The injection raw material formula and the injection process are a complete technical scheme, and the obtained zirconia ceramic material is subjected to targeted formula and technical optimization to be applied as an integral cutting tool. The high-content zirconia powder in the formula can allow the injection to adopt high injection pressure, the solid content density of an injection blank is high, the stress generated in the binder removal sintering process is small, and even if the thick-wall integral cutter part has high blank strength after binder removal, the linear shrinkage can be stably realized without cracking after sintering. Aiming at the injection material with high solid content, the binder component is optimized pertinently, and the injection material has the characteristics of good high-temperature stability, good high-temperature fluidity, easy degreasing and glue discharging and the like. Aiming at the requirements of the integral cutter on mechanical properties, yttrium stabilized zirconia powder with high theoretical hardness is adopted, and a second-phase hard phase is not generated, so that stable and controllable injection is realized, and sintering and densification are easy to realize.

Compared with the prior art, the invention has the following beneficial effects:

1. the integral zirconia ceramic cutting tool material has fine, uniform and good wear resistance, and the tool manufactured by the material can be used for processing parts such as high-strength graphite, novel nonferrous metal, novel modified plastic and the like at high speed, has high hardness, and is easy to sinter and compact.

2. The formula and the process can be used for preparing large-size thick-wall cutter components with complex shapes.

3. The method prepares the integral zirconia ceramic cutting tool material by mixing raw materials, extruding and granulating by a screw, injection molding, extracting and degreasing, discharging glue at high temperature and sintering at high temperature.

Drawings

FIG. 1 is a photograph of a solid blank of the monolithic zirconia ceramic cutting tool material prepared in example 1.

FIG. 2 is a micrograph of the monolithic zirconia ceramic cutting tool material prepared in example 1.

Detailed Description

The following examples are presented to further illustrate the present invention and should not be construed as limiting the invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Example 1

1. Mixing 87.25 wt% of zirconia powder (3 mol% of yttrium-stabilized zirconia, the purity is 98%, and the particle size is 0.2 micron), 1.42 wt% of stearic acid, 7.06 wt% of paraffin, 1.03 wt% of dibutyl phthalate, and 3.24 wt% of high-density polyethylene, wherein the specific mixing operation is as follows:

(1) firstly, pouring zirconium oxide powder and stearic acid into a mixing roll simultaneously, setting the temperature of the mixing roll at 170 ℃, carrying out banburying and positive rotation for 1h, and setting the rotating speed at 20 r/min;

(2) adding half of paraffin and half of high-density polyethylene, mixing for 1h, and rotating for 5 min;

(3) adding the other half of paraffin and the other half of high-density polyethylene, mixing for 1 hour in a forward rotation manner, adding all weighed dibutyl phthalate into the mixed material, mixing for 2 hours in a forward rotation manner, and rotating for 5 minutes in a reverse direction;

(4) then mixing forward rotation for 2h and reverse rotation for 5min, mixing forward rotation for 2h, and reverse rotation for 5min to stop mixing;

(5) turning off heating, cooling, and then turning off and discharging to obtain a mixed material;

2. and (3) pouring the just-mixed material into a screw extrusion granulator for granulation, wherein the temperature is 112 ℃, the screw rotating speed is 10 revolutions per minute, the granulating rotating speed is 112 revolutions per minute, and granulating and discharging to obtain the granulated material.

3. Pouring the granulated material into a ceramic injection machine, setting the injection temperature to be 165 ℃, the mold temperature to be 80 ℃, the injection pressure to be 700bar, the injection speed to be 55mm/s, the pressure maintaining pressure to be 750bar and the pressure maintaining time to be 10s, and obtaining an injection blank after injection molding;

4. degreasing the injection blank in normal octane with the concentration of 90% and the temperature of 30 ℃, and taking out the injection blank after degreasing for 24 hours to obtain a degreased blank;

5. putting the degreased blank into a glue discharging furnace, and discharging glue under the air atmosphere, wherein the specific process comprises the following steps: heating to 170 ℃ at the speed of 17 ℃/h, and keeping the temperature for 2 h; heating to 210 ℃ at the speed of 4 ℃/h, and keeping the temperature for 8 h; then heating to 250 ℃ at the speed of 20 ℃/hour; then heating to 450 ℃ at the speed of 10 ℃/hour, and preserving the heat for 2 hours; heating to 750 deg.c at 110 deg.c/hr and maintaining for 0.5 hr; then cooling to normal temperature at 70 ℃/h; taking out to obtain a discharged rubber blank;

6. putting the rubber discharge blank into a sintering furnace, and heating to 500 ℃ in air at a speed of 500 ℃/hour; then heating to 1100 ℃ at 300 ℃/h; then raising the temperature to 1450 ℃ at the speed of 200 ℃/hour, and preserving the temperature for 0.5 hour; then cooling to 600 ℃ at 300 ℃/hour; then cooling to room temperature at the rate of 50 ℃/hour; and taking out to obtain the integral zirconia ceramic cutting tool material.

The bulk zirconia ceramic cutting tool material obtained in this example had a strength of 1100MPa, a hardness of 1420HV, and a toughness of 5.3MPa · m^1/2。

FIG. 1 is a photograph of a solid blank of the monolithic zirconia ceramic cutting tool material prepared in example 1. As can be seen from FIG. 1, the prepared large-size monolithic zirconia ceramic cutting tool material has no spots and cracks, and the overall appearance is uniform and smooth. FIG. 2 is a micrograph of the monolithic zirconia ceramic cutting tool material prepared in example 1. As can be seen from FIG. 2, the crystal grains are fine and uniform without pores and impurities. The integral zirconia ceramic cutting tool material obtained by the invention has complete, stable and reliable surface, simultaneously meets the requirement of the tool on fine grain and high hardness, and fine grains can meet the requirement of sharpening a fine cutting edge structure, so that a processed workpiece can obtain excellent surface finish.

Example 2

The difference from example 1 is that: the zirconia powder is 2 mol% yttrium-stabilized zirconia, and the integral zirconia ceramic cutting tool material is prepared.

The bulk zirconia ceramic cutting tool material obtained in this example had a strength of 1300MPa, a hardness of 1350HV, and a toughness of 8.4MPa m^1/2。

Example 3

The difference from example 1 is that: the raw material mixture ratio of the embodiment is 80.35 wt% of zirconia powder, 2.41 wt% of stearic acid, 8.45 wt% of paraffin, 1.90 wt% of dibutyl phthalate, and 3.64 wt% of high density polyethylene; the injection process comprises the following steps: the injection temperature is 155 ℃, the mold temperature is 62 ℃, the injection pressure is 550bar, the injection speed is 75mm/s, the pressure maintaining pressure is 700bar, and the pressure maintaining time is 6s, so that the integral zirconia ceramic cutting tool material is prepared.

The bulk zirconia ceramic cutting tool material obtained in this example had a strength of 1070MPa, a hardness of 1390HV, and a toughness of 5.8MPa m^1/2。

Example 4

The difference from example 1 is that: the raw material mixture ratio of the embodiment is 89.95 wt% of zirconia powder, 1.01 wt% of stearic acid, 6.02 wt% of paraffin, 0.50 wt% of dibutyl phthalate, and 2.52 wt% of high density polyethylene; the injection process comprises the following steps: the injection temperature is 170 ℃, the mold temperature is 100 ℃, the injection pressure is 850bar, the injection speed is 55mm/s, the pressure maintaining pressure is 750bar, and the pressure maintaining time is 10s, so that the integral zirconia ceramic cutting tool material is prepared.

The bulk zirconia ceramic cutting tool material obtained in this example had a strength of 1090MPa, a hardness of 1440HV, and a toughness of 4.6MPa · m^1/2。

Example 5

The difference from example 1 is that: the sintering process of the embodiment is to heat up to 500 ℃ at 500 ℃/h; then the temperature is raised to 1150 ℃ at 320 ℃/hour; then heating to 1380 ℃ at the speed of 210 ℃/hour, and preserving the heat for 2 hours; then cooling to 650 ℃ at 300 ℃/h; and then cooling to room temperature at the rate of 50 ℃/hour to prepare the integral zirconia ceramic cutting tool material.

The bulk zirconia ceramic cutting tool material obtained in this example had a strength of 950MPa, a hardness of 1450HV, and a toughness of 4.4MPa · m^1/2。

Example 6

The difference from example 1 is that: the zirconia powder of this example was 2 mol% yttrium stabilized zirconia; the sintering process is that the temperature is increased to 480 ℃ at 400 ℃/hour; then heating to 1050 ℃ at 280 ℃/h; then heating to 1500 ℃ at the speed of 180 ℃/hour, and preserving the heat for 4 hours; then cooling to 600 ℃ at 300 ℃/hour; and then cooling to room temperature at the rate of 50 ℃/hour to prepare the integral zirconia ceramic cutting tool material.

The bulk zirconia ceramic cutting tool material obtained in this example had a strength of 1450MPa, a hardness of 1310HV, and a toughness of 11.4MPa m^1/2。

The integral zirconia ceramic cutting tool material prepared by the invention has the strength of 800-1500 MPa, the hardness of 1300-1450 HV and the toughness of 4-12 MPa.m^1/2. The integral zirconia ceramic cutting tool material has complete surface, is stable and reliable, simultaneously meets the requirement of the tool on fine grains and high hardness, and fine grains can meet the requirement of sharpening a fine cutting edge structure, so that a processed workpiece can obtain excellent surface finish.

The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents thereof, and all such changes, modifications, substitutions, combinations and simplifications are intended to be included in the scope of the present invention.