JPH06335865A - Zirconia projecting member - Google Patents

Abstract

(57) [Summary] [Structure] Substantially the whole amount is under a sieve with an opening of 2.36 mm, the average density is 95% or more, the average crystal grain size is 1.0 μm or less, and the average. A zirconia shot material made of a partially stabilized zirconia sintered body having a Vickers hardness of 1000 kgf / mm ² or more. [Effect] Despite excellent striking force, polishing, and scouring force, the surface roughness and strain of the material to be treated are small, and it is excellent in wear resistance, mechanical strength, hardness, etc. Is easy. Conventionally, the metal surface of the base is scratched,
It is possible to remove the old ceramic sprayed coating, which was difficult to remove if the strain is not increased, and to perform shot blasting such as surface priming without generating rust.

Description

Detailed Description of the Invention

[0001]

The present invention relates to shot peening,
The present invention relates to an artificial shot material used for shot blasting and the like.

[0002]

2. Description of the Related Art Shot peening for preventing stress corrosion cracking of steel materials, imparting wear resistance to mirror surfaces of various metals and alloys, and providing decorative effects on the surface of the treated material as an alternative to buffing; Rust, old coatings, lining coatings, thermal spray coatings, plating coatings, etc., or after finishing welding such as lathing after welding, deburring after molding of resin products, etc. Artificial shot material used for shot blasting etc. for imparting irregular asperity of, irregular particles such as fused alumina, silicon oxide, steel grit, cast iron grit, steel shot, glass beads, alumina Spherical particles such as balls are known.

In recent years, for imparting abrasion resistance to the mirror surface of various alloys and for imparting a decorative effect on the mirror surface as an alternative to buffing,
Shot peening and the like using a shot material having a small particle size other than metals such as glass, zircon, and alumina are performed.

[0004]

The characteristics of a shot material having a small particle size used for shot peening and shot blasting are that, like the shot material having a large particle size, it has a large specific gravity.
It is said that it is preferable that it has high mechanical strength and is hard to be crushed by the impact of projection.

In recent years, in order to meet the increasing complexity of the shape of the material to be treated and the demand for surface characteristics such as surface smoothness, dimensional accuracy, reflectance and gloss, a projection material of 3 mm or less,
In particular, when the required accuracy is high, a projection material of 0.3 mm or less has been required. Fused alumina and silicon oxide are used for shot blasting to remove rust and burrs because they have better machinability than metal shot materials.
In particular, silicon oxide is a needle-shaped crystal, so it is easily broken and difficult to reuse. When the surface of the material to be treated such as stainless steel or aluminum alloy is treated with steel grit or cast iron grit, the projection material bites into the surface or causes an inlaid phenomenon, which causes rust from this part or rust on the projection material itself. To do. Glass beads form a thin and glossy matte surface on the surface of the material to be treated, and have an excellent hitting effect, but the smaller the diameter of the beads, the more easily they are charged with static electricity, and the beads adhere to the inside of the device and also mechanically. Since the strength is weak, the blast material itself will be crushed by one shot and cannot be reused.

[0006] Zircon and alumina blast material have a better impact action than glass beads, but their toughness is low, so they are not excellent in mechanical strength so that they can be used many times, and their specific gravity is small, so they are projected. When the material diameter becomes small, the projection material adheres to the inside of the apparatus due to static electricity, or the projection powder worn by the projection or the crushed scraps make it impossible to project the material under a certain condition.

According to the present invention, these problems have been solved, the blast material itself does not rust even when used in a wet state, and the surface of the material to be treated after blasting is smoother than that of the glass beads.
It has a higher specific gravity than zircon or alumina blasting material, is less likely to adhere to the inside of the blasting equipment due to static electricity, and is excellent in striking action and removal action such as polishing and scouring. It has mechanical strength, does not break, and does not rust on the material to be treated, so post-processing such as acid cleaning of the material to be treated is unnecessary, and it has high wear resistance and can be treated even after repeated use. An object of the present invention is to provide a blast material capable of maintaining a constant blast condition and processing on the blast material.

[0008]

DISCLOSURE OF THE INVENTION In the present invention, substantially the whole amount is under a sieve having an opening of 2.36 mm, and the average vs. theoretical density is 9
5% or more, the average crystal grain size is 1.0 μm or less, and the average Vickers hardness is 1000 kgf / mm.
^The gist is a zirconia-based shot material composed of at least ^two partially stabilized zirconia-based sintered bodies.

In the present specification, the "average crystal grain size" relating to the sintered body is read by subjecting the sample to thermal etching and image-analyzing the size of each crystal grain observed by a scanning electron microscope. The diameter of a circle with the same area as the area.

"Vickers hardness" means JIS R 1
Measured by the Vickers hardness test method for fine ceramics specified in 610, that is, using a Vickers hardness tester or a micro Vickers hardness tester, using a diamond quadrangular pyramid indenter with a facing angle of 136 degrees A value is calculated by the following formula from the surface area of the dent obtained from the diagonal length of the dent and the test load by making a dent on the mirror-polished flat surface of the sample under the test load of. The test load is 50 gf to 10 depending on the size of the sample.
It is selected from the range of kgf and the load time is 10 seconds.

Vickers hardness (kgf / mm ² ) = 1.
8544P / SP: Test load (kgf) S: Surface area of depression (mm ² ) The "crush strength" of the spherical projectile material is determined by the following method.

The particle size of the spherical shot material (d below) is 0.2 m
Those larger than m are based on the compression strength test method of fine ceramics specified in JIS R1608,
Thickness 10m heat-treated to Rockwell hardness HRC60 ± 3 of a strength evaluation tester specified in IS B 7733.
Set between steels with a cross head speed of 0.
A load is applied at 5 mm / min, and the load when the sample is broken is measured. The particle size of the spherical shot material (d below) is 0.
2 mm or less, using the compression test mode of the strength evaluation tester that employs the micro-compression displacement measurement method, a constant increase rate due to electromagnetic force on the sample fixed between the upper pressurizing indenter and the lower pressurizing plate. The load at which the sample breaks is measured by measuring the load, but if the sample does not break even when a load of up to 500 gf is applied, the load when the sample is deformed by 10% is measured. And the following formula (Hiramatsu, Oka, Kiyama; Japan Mining Magazine,
81.10.24 (1965)) is used to calculate the crush strength.

Crushing strength (kgf / mm ² ) = 2.8 P / πd ² P: Measured value of the above load (kgf) d: Maximum dimension of the projected cross section seen from above when the sample is placed on a horizontal surface And the average of the minimum dimension (mm) The "diameter" of the spherical shot material is the height of the sample placed on the zirconia plate, that is, the state parallel to the surface of the zirconia plate during the measurement of the impact strength described below. The plane is lowered from above the sample while keeping it, and the distance between the zirconia plate and the plane when the plane comes into contact with the sample.

"Impact strength" means the value obtained as follows. That is, the elastic modulus of 2.1 × 10 ⁴ k
Place a spherical shot material on a gf / mm ² zirconia plate, drop a weight of 120 g on it, and raise the drop height to measure the height at which the shot material is broken. Ask for.

Impact strength (kgf / mm ² ) = 0.12 ×
h / V (volume: V) h: height at which the above-mentioned shot material is destroyed (mm) V: height of the shot material of the sample placed on the above-mentioned zirconia plate, that is, parallel to the zirconia plate A flat surface of the sample is dropped from above the sample, and the volume of the sphere whose diameter is the distance between the zirconia plate and the flat surface when the flat surface comes into contact with the sample (mm ³ ). “Degree” means the one obtained by the following formula.

Sphericity = (4π × area of projected cross section) / (peripheral length) ² Hereinafter, details of the present invention will be described.

(A) Grain size The grain size of the zirconia shot material is such that substantially all of the grain size is under a sieve having a mesh opening of 2.36 mm, that is, a sieve having a mesh opening of 2.36 mm (for example, Substantially all the material must pass the standard mesh screen nominal size 2.36) specified in JIS Z8801.

The larger the grains are, the higher the hitting action is. However, if the grains are too large, the surface of the material to be treated is roughened by shot peening, so that the material to be treated is subjected to electrolytic polishing treatment or the like to smooth the surface. This is because in shot blasting, the number of particles of the shot material projected per unit time decreases, and it becomes impossible to completely remove the scale and the sprayed coating. On the other hand, the smaller the particle size, the more complicated the shape of the material to be treated in recent years and the higher sophistication of the requirements relating to surface characteristics such as surface smoothness, dimensional accuracy, reflectance, and gloss can be met. In blasting, if the blast material is too small, it may be difficult to classify the rust or metal powder removed from the material to be treated by the blast and the blast material, so it is more preferable that substantially the entire amount is 0.02 mm. Of the size above the sieve and below the sieve with an opening of 2 mm.

The effect of the projection on the material to be processed depends on the conditions such as the projection speed, the projection distance and the projection angle. Therefore, depending on the shape and material of the material to be processed and the above projection conditions, the classifier It is necessary to adjust the particle size and distribution of the shot material by using a sieve.

(B) Density The average versus theoretical density of the zirconia shot material must be 95% or more.

If the average vs. theoretical density is less than 95%, the abrasion resistance and mechanical strength are poor, the particles are crushed when they are projected on the surface of the material to be treated, or they are worn when repeatedly projected, and due to static electricity during projection. This is because the shot material that has been worn or crushed adheres to the inside of the device. Average to theoretical density is 9
It is even better if it is 7% or more. The density of the sintered body is JIS
It can be measured by the method for measuring the specific gravity of an artificial abrasive specified in R 6125.

There are irregularly shaped grit and spherical shots as the shape of the shot material. However, since the shot has a great effect of hitting the surface, the reaction force causes strain in the crystal grains when the material to be treated is a metal. It is easy to occur. The degree of this distortion increases as the density of the sintered compact of the shot material increases. The zirconia shot material has a sintered body density of about 6, which is considerably larger than 2.5 of glass and 3.8 of alumina, and is close to that of steel 7, so that the degree of strain increases. Therefore, it is necessary to adjust the shape of the projection material, the projection pressure, the distance, the angle, and the nozzle diameter so that the arc height value suitable for the material of the material to be processed is obtained by using the almen strip and the gauge.

(C) Average crystal grain size The average crystal grain size of the zirconia crystals of the zirconia shot material must be 1.0 μm or less.

The average grain size of the zirconia shot material is 1.
When it exceeds 0 μm, when the projection is performed under a high pressure, the stress easily transforms the tetragonal crystal structure into a monoclinic crystal, which increases the consumption of the projection material and the surface texture of the material to be treated. Is not preferable because it worsens. More preferably, the average crystal grain size is 0.7 μm or less. However, the lower limit of the average crystal grain size of the normally obtained zirconia sintered body is about 0.2 μm when the average versus theoretical density is 95% or more.

(D) Vickers hardness The average Vickers hardness of the zirconia shot material is 1000.
Must be at least kgf / mm ² , especially 1100
The range of up to 1500 kgf / mm ² is preferable.

Average Vickers hardness is 1000 kgf / m
When it is less than m ² , the processing speed of the material to be treated becomes slow, and the consumption and damage rate of the shot material increase, which is not preferable. Further, if it exceeds 1500 kgf / mm ² , the consumption rate of the material to be processed increases depending on the material of the material to be processed, which is not preferable.

(E) Crushing strength The average crushing strength of the zirconia shot material is 40 kgf / m.
It is preferably m ² or more.

When the average crush strength is 40 kgf / mm ² or more, the abrasion resistance and mechanical strength of the shot material are high,
This is because when it is projected onto the surface of the material to be treated, it is less likely to be crushed and is less likely to be worn even when repeatedly projected.

(F) Tetragonal Zirconia Amount in Zirconia Crystal Component The zirconia-based shot material preferably contains at least 70 mol% of tetragonal zirconia in the zirconia crystal component.

This is because a zirconia-based sintered body having a tetragonal zirconia content of 70 mol% or more in the zirconia crystal component has particularly high toughness and strength. Satisfies this condition, and
5 mol% of monoclinic zirconia in the zirconia crystal phase
And less than 30 mol% of cubic zirconia is even better.

The amount of each crystal phase in the zirconia crystal component is
The cross-section of the sintered body is mirror-finished with a diamond grindstone having a particle size of 1 to 5 μm, and the area intensity is obtained from the diffraction peak of each crystal phase on the surface by the X-ray diffraction method, and it can be obtained by applying the following formula.

M (monoclinic zirconia mol%) = [{I
_{m (111)} + I _{m (11-1)} } / {I _{m (111)} + I _{m (11-1)} + I
_{c + t (111)} }] × 100 C (cubic zirconia mol%) = [I _{c + t (111)} / {I
_{m (111)} + I _{m (11-1)} + I _{c + t (111)} }] × [I _{c (400)} /
{I _{c (400)} + It ₍₄₀₀₎ + It ₍₀₀₄₎ }] × 100 T (tetragonal zirconia mol%) = 100−MC where the subscript m is monoclinic zirconia and c is cubic. Crystalline zirconia, t is tetragonal zirconia, and c + t is both cubic zirconia and tetragonal zirconia. Also, each face index is shown in parentheses and the subscripts I are attached.
Represents the area intensity at each surface index of each crystal phase.

Component (g) As a stabilizer for the zirconia-based sintered body, MgO, Ca
Although rare earth oxides such as O, Y ₂ O ₃ and CeO ₂ are often used, in order to have the tetragonal zirconia content in the zirconia crystal component to be 70 mol% or more, for example, Y ₂ O ₃
Then, the molar ratio of Y ₂ O ₃ / ZrO ₂ is 1.5 / 98.
It is preferably in the range of 5 to 4.0 / 96.0.
If it is less than 1.5 / 98.5, the amount of monoclinic zirconia increases and the amount of tetragonal zirconia decreases, so that a high-strength shot material cannot be obtained due to the transition, while 4.0 / 96.0 If it exceeds, tetragonal zirconia is reduced and cubic zirconia is mainly contained, so that the crystal grain size is increased, the toughness is lowered, and the strength is lowered. In addition, ZrO ₂ and Y ₂ O ₃
Besides, Al ₂ O ₃ , TiO ₂ , SiO ₂ , MgO, Ca
O, rare earth oxides and the like may coexist. Among these, those having a lower melting point than zirconia, such as Al ₂ O ₃ , TiO ₂ , and SiO ₂ , lower the sintering temperature of zirconia due to its lower melting point, and also reduce MgO, CaO, Ce.
O _{2 and the} like form a solid solution in the zirconia crystal phase to lower the sintering temperature, which is advantageous in the production of shot materials. These are Zr
It is preferably used within the range of 0.05 to 30 wt% with respect to the total of O ₂ and Y ₂ O ₃ . Its content is 30wt
%, The toughness becomes low and the original properties of zirconia are deteriorated, resulting in crushing at the time of projection and increased wear.

(H) Impact Strength The average impact strength of zirconia shot material is 7 × D ^−0.95 k.
gf / mm ² or more (D is the average diameter (mm) of the shot material)
Is preferred). When such a condition is satisfied, cracks in the shot material are reduced and the amount of wear is reduced. If the impact strength is less than this, the abrasion resistance and mechanical strength are low, and when the impact strength is projected onto the surface of the material to be treated, the material is likely to be crushed and is repeatedly worn, and thus is easily worn. If the impact strength satisfies this value, the above-mentioned average crush strength of 40 kgf / mm ² or more is satisfied.

(I) Roundness When the shot material is spherical, the average roundness is preferably 0.9 or more.

The shape of the shot material of the present invention is not limited, but when the uniformity of the projected amount and the uniformity of the movement of the shot material pose a problem, it is desirable that the shape is close to a true sphere. By setting the average sphericity to 0.9 or more, it becomes easy to make the projection amount constant, the surface roughness and distortion of the material to be processed can be reduced, and the decorativeness can be made excellent. The shot material used for shot blasting does not need to be spherical unless there is a requirement for the shot amount, and may be a grit-like material having an irregular pointed shape as in the conventional one.

The zirconia-based shot material of the present invention is prepared by the electrofusion method,
Zirconia powder obtained by hydrolysis method, neutralization coprecipitation method, hydrolysis-neutralization method, hydrothermal oxidation method, thermal decomposition method, alkoxide method, etc. Granulation method is selected from rolling granulation method, extrusion granulation method, compression granulation method, stirring granulation method, liquid phase granulation method, etc. according to the distribution etc .; or the zirconia powder Can be used as a slurry, and a spherical molded body obtained by granulating by a granulation drying method such as a spray granulation method can be manufactured by firing at 1300 to 1600 ° C.

Further, the crush strength of the sintered body can be further improved by subjecting the zirconia-based shot material obtained by primary sintering to hot isostatic pressing (HIP). Also,
If the shape is spherical, improve the crush strength and impact strength of the sintered body by polishing the surface by barrel polishing after sintering so that there are no defects or cracks exceeding 10 μm on the surface and in the vicinity thereof. Can be made.

[0039]

INDUSTRIAL APPLICABILITY As described above, the zirconia-based shot material of the present invention is excellent in striking force, polishing, and scouring power, but has a small surface roughness and distortion on the surface of the material to be treated and is resistant to wear. ,
Since it has excellent mechanical strength and hardness, it can be easily recovered and reused.

By using this zirconia-based shot material,
It is possible to perform shot blasting, such as surface priming, without removing old ceramic sprayed coatings that were difficult to remove unless the metal surface of the underlying metal is conventionally damaged or strain is not increased, or rust is generated.

In addition to the surface treatment for imparting wear resistance to the mirror surface of the alloy, a shot for the purpose of decorative effect on the mirror surface or resin surface of stainless steel or aluminum alloy products as an alternative to buffing. Peening processing is now possible.

If this zirconia-based shot material is used, fine processing can be performed, and the complicated shape of the material to be processed, surface roughness accuracy of the finished surface, dimensional accuracy, external surface characteristics such as reflectance and gloss, etc. Can meet strict requirements regarding.

The projection material in the present invention is an automobile part such as a front axle beam, a wheel cap, a leaf spring, a crankshaft, a piston ring, a rocker arm, a camshaft, a gear part, a cylinder, a steering ring knuckle, a coil spring, and a connecting rod. Engine parts of various vehicles, aircraft parts such as turbine blades of jet engines and their engine parts, ship parts such as screws and their engine parts, reactors of chemical or petrochemical plants, mechanical equipment such as presses, indexing table ,Center,
Machine tool tools such as chucks, medical parts such as scalpels, tweezers, and injection needles, artificial bone materials such as stems, dental materials such as teeth and roots, fatigue and stress corrosion of metal such as various stainless steels and welding surfaces, and grain boundaries Besides being used as shot peening for the purpose of extending the limit of damage due to corrosion; Western dishes, spoons, forks, knives, pots, kettles,
Household or commercial kitchen utensils such as frying pans, industrial or consumer knives such as stainless steel knives, cutters and cutters, system kitchens, sinks, kitchen equipment,
Household equipment such as vanity, storeroom, garage, gate,
House materials such as fences, decorative plates, wall hangings, indoor and outdoor decorations such as nameplates, home appliances such as TVs, videos, refrigerators, washing machines and dryers, word processors, office automation equipment such as personal computers, air conditioners, Air conditioning equipment such as stoves, lighters, smoking equipment such as ashtrays, optical machines such as cameras and microscopes, golf equipment, camping equipment, bicycles, motorbikes, automobiles, yachts, motor boats, suitcases and other living and leisure goods, Watch, gold, silverware,
Jewelry such as rings, necklaces, winning cups, shields, medals, badges, inner surface of lighting hoods, metal, resin,
Applying a satin finish to the surface of glass, wood, stone, ceramics, etc. to improve the product value and design, or to save labor during the finishing process and post-treatment process; various machined parts and extrusions.
Deburring and surface cleaning of metals, resins, ferrites, ceramics, etc. molded by casting, injection molding, etc .; Adhesion of adhesives, paints, glazes, thermal spray materials, and roughening of the surface to improve the adhesive effect; Brazing surface Impurities, cured film after electrical discharge machining,
After quenching steel materials, removal of welding burrs, rust, old sprayed coatings, plating, coating films, enamel, etc .; internal surface cleaning of internal pressure containers such as various cylinders; various molds, mold parts, automobile parts, various vehicle parts, etc. It can be used for polishing and cleaning when finishing machine parts, or for blast cleaning before repair.

[0044]

EXAMPLES The present invention will be described in detail below with reference to examples and comparative examples.

The present invention is not limited to these examples.

Examples 1 to 6 and Comparative Examples 1 to 4 Using zirconium oxychloride aqueous solution having a concentration of 50 g / l to which yttria was added so as to have a ZrO ₂ / Y ₂ O ₃ conversion molar ratio shown in Tables 1 and 2, was used as a raw material. By the hydrolysis method, zirconia powder having the characteristics shown in Table 1 was obtained. This powder is dry pulverized to obtain granulated core particles of about 0.1 mm with a stirring granulator, which are further grown with a stirring granulator, and the size of which is expected to shrink due to firing is opened 2 .8
The particle size distribution was adjusted with a sieve of 3 to 0.020 mm to obtain molded spheres, which were fired under the conditions shown in Tables 3 and 4 to obtain zirconia-based sintered bodies. In Examples 3 and 4 and Comparative Example 4, HIP treatment was further performed at a pressure of 150 MPa and a temperature of 1500 ° C. for 1 hour. The sintered body obtained as described above was subjected to shot peening and shot blast tests by using a sieve having an opening of 2.36 mm and removing the portion above the sieve.

Examples 7 to 9 and Comparative Example 5 As the zirconia-based powder, the zirconia-based powder obtained in Example 1 and the like was added to high-purity alumina powder having an average particle size of 0.3 to 0.5 μm (AKP-manufactured by Sumitomo Chemical Co., Ltd.). 30) in a ratio shown in Tables 1 and 2, pulverized and mixed by using a vibrating ball mill, dried, and then pulverized by dry pulverization, and the zirconia powder obtained is used. A sintered body was obtained, and in Examples 8 and 9, Example 3 was further prepared.
HIP treatment was performed under the same conditions as described above, and the shot peening and shot blast tests were performed.

Example 10 In the granulation, about 0.1 mm core particles obtained by an agitation granulator were grown by a spherical sizing machine, and the size of the granules, which is expected to shrink due to firing, opens from 2.83 to. Example 1 except that a molded sphere is obtained by adjusting the particle size distribution with a 0.020 mm sieve.
6 and Comparative Examples 1 to 4 were carried out under the conditions shown in the columns.

Examples 11 to 13 and Comparative Example 6 As the granules to be subjected to calcination, the zirconia powder obtained in Example 1 or the like was used as a zirconia slurry and granulated and dried by a spray dryer. Example 1 except firing and HIP under the same conditions as in Example 3
6 and Comparative Examples 1 to 4 were carried out under the conditions shown in the columns.

Examples 14 to 15 As the granules to be subjected to calcination, the alumina-containing zirconia powder obtained under the same conditions as in Example 7 was used as a zirconia slurry, which was granulated and dried by a spray dryer. Then, except that the air bubbles in the above-mentioned slurry were removed by an antifoaming agent and subjected to granulation drying, the conditions were as shown in the columns of Examples 1 to 6 and Comparative Examples 1 to 4.

Examples 16 to 22 and Comparative Examples 7 to 12 The components shown in Tables 1 and 2 were added to the zirconia-based powders obtained in Example 1 and the like in the proportions shown therein, and wet milled for 8 hours with an attrition mill. Then, it is dried to obtain a zirconia-based powder, a granulation core particle of about 0.1 mm is obtained by a stirring granulator, and further grown by a rolling granulator to a size in which shrinkage due to firing is expected. To obtain granules, which are fired under the conditions shown in Tables 3 and 4 to obtain a zirconia-based sintered body,
The surface was glossed by barrel polishing, and the projection material was finished until no large defects were found on the surface by observing with a microscope at a magnification of 50 times. The shot material thus obtained was subjected to impact strength measurement and shot peening and shot blast tests.

Comparative Examples 13 and 14 Alumina spheres (aluminite A balls manufactured by Naigai Ceramics Co., Ltd. Sintered body density 3.8 g / cm ³ , average particle size 1.9 m)
m) (Comparative Example 13) and glass beads (UB-810L manufactured by Union Corp., average particle size 145 μm) (Comparative Example 14).
For, shot peening and shot blasting tests were performed.

In the former case, spheres that are damaged by repeated projections are generated, and it is recognized that the density of the sintered body is low, but the depth of deformation of the surface of the object to be processed was small and its surface roughness was large. In the latter case, the beads were damaged to such an extent that they could not be used repeatedly by one shot.

In each of the above examples, the characteristics of the zirconia powder for producing the shot material are shown in Tables 1 and 2, the firing conditions are shown in Tables 3 and 4, the characteristics of the shot material are shown in Tables 5 to 8, and the shot material is used. The results of the shot peening and shot blasting tests are shown in Tables 9 and 10.

The particle size distribution of the obtained shot material (sintered body under the sieve of 2.36 mm aperture) is 2.36.
00, 1.70, 1.40, 1.18, 1.00, 0.
850, 0.710, 0.600, 0.500, 0.4
25, 0.355, 0.300, 0.250, 0.21
2, 0.200, 0.180, 0.150, 0.12
5, 0.100, 0.090, 0.075, 0.06
3, 0.053, 0.045, 0.038, 0.025
And 0.020 (both in mm) were sequentially stacked on the pan in order from the one with the smallest opening, and measured by shaking with a low tap tester for 5 minutes.
Of the sieves containing the sieved samples, the mesh size of the uppermost sieve is the upper limit of the particle size distribution,
The mesh size of the lowermost sieve was set as the lower limit of the particle size distribution.

The shot peening test was conducted by using a direct pressure type nozzle type utilizing compressed air with a gauge pressure of 4 kgf / cm ² , and using SUS316 having a thickness of 5 mm as the material to be treated, a single projection time was 120 minutes. The treatment was repeated 3 times. The damage rate is 0.020 mesh on the saucer.
mm sieve, and a sieve having an opening corresponding to approximately 1/3 of the average value of the above-mentioned upper and lower limits of the particle size distribution of the projection material before projection, further laid thereon, and 100 g of projection material after projection from above , And shake with a low tap tester for 5 minutes to screen,
The weight of the obtained product was applied to the following formula to calculate.

Damage rate (wt%) = {A / (100−B)} × 100 A: amount of sample in sieve with 0.020 mm mesh (g) B: amount of sample in saucer (g) ) Further, the depth and the surface roughness of the surface deformation amount after the shot peening of the surface of the material to be treated (Ra: center line average roughness).
Was measured.

The shot blast test is performed by blasting carbon steel (SS41 50 mm × 50 mm × 5 m).
m) partially stabilized zirconia powder (Tosoh TZ-3
Y.

Y ₂ O ₃ 3 mol%) with a film thickness of 200 μ
A test piece was obtained by plasma spraying to m. That is, zirconia-based projection material was blast-treated with a compressed air having a gauge pressure of 5 kgf / cm ² from a nozzle having a diameter of 6 mm on the test piece for 10 minutes under the conditions of a projection distance of 30 cm and a projection angle of 60 °, and the sprayed surface of the test piece The blasting condition was observed, and the damage rate of the shot material was obtained as in the shot peening test.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Table 3]

[0063]

[Table 4]

[0064]

[Table 5]

[0065]

[Table 6]

[0066]

[Table 7]

[0067]

[Table 8]

[0068]

[Table 9]

[0069]

[Table 10]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (31) Priority claim number Japanese Patent Application No. 4-293197 (32) Priority date Hei 4 (1992) October 30 (33) Country of priority claim Japan (JP) (31) Priority Claim number Japanese patent application No. 5-75639 (32) Priority date 5 (1993) April 1 (33) Priority claiming country Japan (JP) (72) Inventor Riji Ogai 5-3 Nijigaoka, Hikari City, Yamaguchi Prefecture No. 24 (72) Toshio Kawanami, 153 Kitanoda, Sakai-shi, Osaka-1 -1 (72) Koji Ohnishi, 445, Keana-cho, Sakai-shi, Osaka-20

Claims (8)

[Claims] 1. Substantially the whole amount is under a sieve having an opening of 2.36 mm, the average density is 95% or more, the average crystal grain size is 1.0 μm or less, and the average Vickers hardness is A zirconia-based shot material comprising a partially stabilized zirconia-based sintered body having a weight of 1000 kgf / mm ² or more. 2. The partially stabilized zirconia-based sintered body is spherical and has an average crush strength of 40 kgf / mm ² or more and an average sphericity of 0.9 or more. Zirconia shot material. 3. The zirconia-based material according to claim 1 or 2, wherein substantially the whole amount of the partially stabilized zirconia-based sintered body is on a sieve having an opening of 0.02 mm and under a sieve having an opening of 2 mm. Projectile material. 4. The zirconia shot material according to claim 1, wherein the partially stabilized zirconia sintered body has an average pair theoretical density of 97% or more. 5. A partially stabilized zirconia-based sintered body is ZrO ₂
And Y ₂ O ₃ and the ZrO ₂ / Y ₂ O ₃ molar ratio is 9
The zirconia-based shot material according to any one of claims 1 to 4, which is 8.5 / 1.5 to 96/4. 6. The zirconia shot material according to claim 1, wherein the amount of tetragonal zirconia in the zirconia crystal component of the partially stabilized zirconia sintered body is 70 mol% or more. 7. The amount of tetragonal zirconia in the zirconia crystal component of the partially stabilized zirconia sintered body is 70 mol% or more, and Al ₂ O ₃ , TiO ₂ , SiO ₂ , MgO,
At least one of CaO and rare earth oxide is ZrO
The zirconia shot material according to claim 5, comprising 0.05 to 30 wt% with respect to the total of ₂ and Y ₂ O ₃ . 8. The partially stabilized zirconia-based sintered body is spherical, and the average impact strength of the zirconia-based sintered body is 7 × D ^−0.95 kgf / mm ² or more, the average diameter of which is represented by D mm. The zirconia shot material according to claim 6 or 7.