JPS59227726A - Grinding material of alumina-zirconia-titania system - Google Patents

Abstract

PURPOSE:The titled grinding material applicable to heavy grinding fields, having improved grinding performances, obtained by adding ZrO2, TiO2 and Y2O3 or a mineral of rare earth element containing or Y2O3 as a melting additional matter to Al2O3, melting them, cooling them rapidly. CONSTITUTION:In a grinding material of Al2O3-ZrO2-TiO2 system obtained by adding ZrO2 and TiO2 to Al2O3, melting them, cooling them rapidly, preferably 0.05-7wt% Y2O3 or a mineral of rare earth element containing Y2O3 as another melting additional matter based on the total amounts of Al2O3, ZrO2, and TiO2 is added to them, so that grinding performances are improved and this grinding material is applicable to especially light grinding among heavy grinding, and applicable well to Ti alloy. The addition of Y2O3 or the mineral of rare earth element containing Y2O3 in the range crystallizes tetragonal system crystal of ZrO2 in about 70-100% remaining ratio, precipitation ratio of alpha-Al2O3 of initial crystal is suppressed to <= about 5%, and grinding performances can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to improvements in the grinding performance of alumina-zirconia-titania based abrasives.

In general, alumina-zirconia based abrasive grains are abrasive grains that have been rapidly gaining popularity in recent years for use in snacking ε steel materials such as special steels and stainless steels. That is, the main reason for this is that it has superior grinding performance such as wear resistance and anti-fracture properties compared to alumina-based abrasive grains, and exhibits excellent grinding power under high pressure. The invention disclosed in Publication No. 48-35594 was able to provide an alumina-zirconia-titania-based abrasive material having even better grinding performance.

In other words, when zirconia is added to alumina, 5 to 30 wt% of titanium oxide is further added to the zirconia, melted, and rapidly cooled. Focusing on the inherent transition phenomenon of zirconia, high-temperature square products are produced. Approximately 25 to 30% of the crystals remained at room temperature, thereby contributing to improvements in grinding performance such as wear resistance and crush resistance.

By the way, in recent years, grinding methods have been gradually changing, and the field of heavy grinding has been subdivided, and in particular, the shift from heavy grinding to light grinding is becoming more prominent as technology advances. Applications to new fields of abrasive materials, such as grinding titanium alloys, are also increasing. Under these circumstances, abrasives that are well suited for these fields are required today, and in this case, the required grinding performance is even higher than that of the alumina-zirconia-titania-based abrasives. There are some things that have to be made even more severe, and the current situation is that a satisfactory abrasive has not yet been obtained.

However, in order to be adapted to the above uses, it is necessary to provide an abrasive material made of alumina-zirconia eutectic with a relatively large amount of zirconia, such as the zirconia FF140% type. In the case of alumina-zirconia-titania system by addition of titania mentioned above, the residual rate of high-temperature type tetragonal crystals is still extremely low even in the 11 material, the addition effect is poor, and the addition effect is poor. Crystal size is max 20μ
However, since α-AI203, which is a first product, precipitates at a rate of about 10 to 15%, there was a problem in that it was not possible to obtain a predetermined eutectic mixture.

Therefore, the purpose of this invention is to make it possible to use it particularly well for light grinding even in heavy grinding, and furthermore, to make it particularly suitable for use with titanium alloys. Dramatically increase the rate and increase the α of the first product.
-The aim is to provide an alumina-zirconia-titania-based abrasive material that reduces the precipitation rate of AI203 and thereby further improves grinding performance. Furthermore, the abrasive material contains yttrium oxide or a rare earth mineral containing yttrium oxide as another additive, so to speak, as an alumina-zirconia-titania-yttria-based abrasive material.

That is, in addition to titania, yttrium oxide or a rare earth mineral containing yttrium oxide is added as an additive, and the abrasive material is melted and rapidly cooled to obtain an abrasive material that satisfactorily and satisfactorily achieves the above objectives. In particular, the addition of yttrium oxide or a rare earth mineral containing yttrium oxide m h<, within the range of more than 0.05 wt% to 7 wt% with respect to the total amount of alumina, zirconia and titania; 70-10 crystals
It was possible to crystallize with a residual rate of 0%, and moreover, within the same range, the precipitation rate of primary α-AI203 could be suppressed to 5 wt% or less.

Furthermore, even if the additive amount is 7wt% or more or 0.05wt% or less, the residual rate of zirconia tetragonal crystals shows a relatively large value compared to conventional crystals, and the primary crystal α-120
Although there is a tendency to slightly suppress the precipitation rate of 3, adding 7wt% or more leads to the precipitation of cubic crystals, which is undesirable from the viewpoint of improving grinding performance, and adding 0.05wt% or less does not have a significant effect. More than .05wt% and 7wt
%, most preferably 1 to 5 wt%.

Furthermore, even for grinding H containing a relatively small amount of zirconia (2), for example, a 25% type alumina-zirconia cocrystal, the above-mentioned alumina with a relatively large amount of zirconia
Similar to abrasive materials made of zirconia eutectic, the residual rate of tetragonal zirconia is extremely high, so there is little change in volume due to zirconia transition, and the remaining tetragonal zirconia retains sufficient internal energy. As a result, improvements in properties such as good crush resistance were observed.

Next, embodiments of the present invention will be explained.

The yttrium oxide and the rare earth mineral containing yttrium oxide used in the examples of the present invention had the analytical values shown in Table 1.

Table 1 Example 1 The composition was calculated so that the zirconia in the abrasive grains was 40%, and Bayer method alumina (99.6% Al 203) was used.
50 kg, Zirconia (96% Zr02) 32.6
kgk: Zirconia 2 to 2 weight percent
．． Titanium oxide (95% Ti 02 ) corresponding to 5% 0
．． 8 kq and further yttrium oxide (99,
9% Y203) to 0.05.0% of the total amount of the previous three types.
1.0.5.1.2.5.5.10 wt% was added, melted in an electric furnace at 95V300kW, and then rapidly solidified to obtain molten castings with various addition amounts.

For comparison, the addition period of yttrium oxide was 0 wt%.
A molten cast product was also cast under the same conditions.

The analytical values of these castings are shown in Table 2.

(See next page) Table 2 Next, the obtained casting was repeatedly crushed using an impeller breaker and a roll crusher V-.
The grains were collected using grain scoops #24 and #60 specified in I5R-6001.

Table 3 shows the ratio of zirconia crystal forms determined by X-ray diffraction for particle size #24.

(See next page) Table 3 As is clear from the results of X-ray diffraction, when yttrium oxide is added, the abrasive grains are 1 no. It was observed that the crystals tended to increase dramatically, especially in the case of 1-
It was observed that 100% of tetragonal crystals were crystallized when the amount added was 5 wt%. Furthermore, when the amount added was 0.05 wt%, although there was a tendency for the crystallization of tetragonal crystals to increase, there was not much difference from the conventional method, and when the amount exceeded 10 wt%, precipitation of cubic crystals was observed.

On the other hand, the same particle size #24, for example, the conventional one (sample number @1) and the indium oxide 1 to lium addition ff1
When the precipitation state of primary α-AI203 was observed using a total refraction microscope for 0.5wt% (sample number 3), it was found that Fig. 1 (A>(13) and Fig. 2<A) ( B)
The results shown were obtained. In both cases, the magnification is X100
FIG. 1 (A>(B) is an enlarged photograph of sample number 1 and its schematic diagram, and FIG. 2 (A) and (B) are enlarged photographs of sample number 3 and its schematic diagram.

In both figures, 1 is an alumina-zirconia eutectic;
2 is the primary crystal of α-AI203.

As is clear from Figures 1 and 2, the precipitation of the initial product of α-AI203 was suppressed by 11i+1 in the case of the one to which yttrium oxide was added, indicating that 1g of the specified eutectic mixture was added. Admitted.

Furthermore, it has been confirmed that a similar tendency exists even with the addition of yttrium oxide, but the amount added is 0.
At 05 wt%, the precipitation of α-Atz 03 is about 10% rough, and considering that the conventional one is about 10 to 15%, there is a slight tendency toward this, but there is not a huge difference. Ta.

Next, a grinding performance test was conducted on Kurumaro #60.

In other words, an ω1 friction belt was prepared and subjected to a grinding test, and the results are shown in Table 4.

In addition, for grinding test 1~, the belt size used is 100x
2500mlto, the material to be ground is 5US-304, the belt speed is 150m/min, and the pressure is 5! + for 1
Grinding was performed for 0 minutes, and Table 4 compares the cumulative amount of grinding obtained by the grinding.

Also, the numbers in parentheses do not indicate the comparison when the conventional one (sample number 1) is set at 100.

Curve <8> in Table 1I and FIG. 3 is a graph plotting the cumulative grinding amount values in Table 4.

As is clear from Table 4 and FIG. 3 above, it was found that the eutectic abrasive grains to which yttrium oxide was added exhibited extremely superior grinding power compared to the conventional abrasive grains to which yttrium oxide was not added.

Incidentally, this result roughly corresponds to the ratio of zirconia tetragonal crystals shown in Table 3, and the addition ff10
．． When it is 0.5 wt%, there is not much difference from the conventional one, but when it exceeds 1 Qwt%, there is a tendency for it to be lower than the conventional one due to the precipitation of cubic crystals.

However, the addition of yttrium oxide significantly increases the tendency of the grinding force as a whole, and considering that this test result was a comparison of only 10 minutes of grinding time, it is difficult to understand in actual use. can contribute to extremely improved grinding performance.

Example 2 The composition was calculated so that zirconia in the abrasive grains was 40%, and Bayer method alumina<99.6%△1zoi)5
0kq, zirconia (96% Zr 02 ) 32.6
kn, 2.5% in medium weight percentage for zirconia
Titanium oxide (95% Ti 02 ) equivalent to 0.8
k! 1,2 and 5.5 wt% of the total amount of the first three ink were added to the rare earth minerals containing yttrium oxide (analyzed values shown in Table 1), and heated in an electric furnace. It was melted at 95v1300kw and then rapidly solidified to obtain molten castings with various addition amounts.

The analytical values of these #ri products are shown in Table 5. Similarly to Example 1, J3 sample number 1 is a conventional sample without addition of yttrium oxide.

(Hereinafter on the next page) Table 5 1" Y20a Other rare earths Next, the obtained casting was repeatedly crushed using an impeller breaker and a roll crusher, and J
[Collected with particle size #24 and #60 specified in 5R-6001, respectively.

Table 6 shows the conversion rate of zirconia crystal form by X-ray diffraction for particle size #24.

(See next page) Table 6: As is clear from the results of X-ray diffraction, the addition of rare earth minerals containing yttrium oxide is the same as the addition of yttrium oxide (alumina zirconia ditania without addition) It was observed that the crystals of the square grain tended to increase significantly compared to the Nagi grain (sample number '1), and the crystal size of the square grain was 2.5 to 5
It was observed that 100% of tetragonal crystals were crystallized in the wt% added fil.

Next, a grinding performance test was conducted on the particle size #60.

The test conditions are the same as in Example 1. The results of b are shown in Table 7.

Curve (b) in Table 7 and FIG. 3 is a graph plotting the cumulative grinding amount values shown in Table 7.

As is clear from Table 7 or Figure 3 above, similar to the case of Example 1 with the addition of yttrium oxide, the eutectic abrasive grains to which rare earth minerals containing yttrium oxide are added exhibit excellent grinding power. This was recognized.

Example 3゜The blending t1m was carried out so that the zirconia in the abrasive grains was 40%, and Bayer method alumina 50kq, zirconia 32
．． IJLm percent for zirconia in 6kg is 5
．． Analysis values of castings for a mixture of 15 wt % titanium oxide 1.7.4.9 kn and 0.5 wt % yttrium oxide added to the previous three mixtures, X-rays for particle size #24 Cumulative fa for zirconia crystal form ratio and particle size #60 by diffraction 1III
rjll fA was measured.

The results are shown in Tables 8, 9 and 10, respectively.

For comparison, the results for the case where yttrium oxide was not added for the case where titanium oxide was added in an amount of 2.5 wt% and the case where yttrium oxide was not added for each case containing ditania are also shown.

゛ Also, the test methods are both Example 1 and Example 1+! l
It is the same as 2.

(See next page) Table 8 Table 9 Table 10 As is clear from the above table, the residual rate of tetragonal Zr 02 shows an increasing tendency as the amount of titanium oxide added increases; A significant tendency for increase was observed with the addition of yttrium oxide.

Correspondingly, a tendency for the grinding force to increase is recognized from the numerical results of cumulative grinding days.

Example 4: The composition was calculated so that the zirconia in the abrasive grains was 25% and 32%, and Bayer method alumina (99.6% A
lzO3>50kq and 24.5kq, zirconia<
96%7rO2) 16.6k<+ and 11.51u+
Then, the zirconia was replaced with 4, and the distance between the vehicles was O12,
5, 5, 10, 15, 20, 30, 40% titanium oxide (95% Ti 02 ) was added, and the abrasive grains were mixed with zirconia at 25%,
Bayer method alumina (99,6%Δ1zox >50
k(+, ; Zirconia <96% Zr 02 ) 16.6
kg, O15 in weight per tip for zirconia
, 10, 15, 20, 30, 40% titanium oxide (95
%TtO2) and further added yttrium oxide.
f! ! 0.5wt% added to the total amount of each substance was melted and rapidly solidified by arc heat using an electric furnace, and then sized according to a general abrasive grain production method, and JI
The abrasive grains were S#12.

A fracture resistance measurement test was conducted on these materials, ie, zirconia 25% type and 32% type without yttrium oxide, and zirconia 25% type with yttrium oxide added. Single grain crushing strength was used to measure crush resistance. 1 This method uses a sample of 1680~2
The particles are sized to 000 microns and made into small samples by the reduction method.
100 pieces were randomly sampled from among them, and the compressive strength 1& of each piece was measured using a 2-ton Amsler compressor, and the average value was taken as the single-grain crushing strength.1. :.

The single grain crushing strength of these abrasive grains is shown in Table 11, and the relationship between the 131 grain crushing strength and Ti 02 /Zr 02 is shown in FIG.

As is clear from Table 4 of tff11, TiO2/Zr02 is 10 to 20% by weight in any type of J3.
The wax value is shown within the range of % and decreases when it reaches /lo%, but especially for those with yttrium oxide added, the wax value is even lower when compared to the 32% type as well as the 25% Zr02 type. It was recognized that it exhibited excellent crush resistance.

As described above, the present invention provides an alumina-zirconia-titania-based abrasive material in which zirconia and titania are added to alumina, melted, and then quenched by one cycle.

Furthermore, by containing yttrium 11 oxide or rare earth minerals containing yttrium oxide as other melt additives, up to 100% of the tetragonal zirconia crystals remain in the abrasive grains, and the amount of zirconia is relatively large. This is an abrasive material made of an alumina-zirconia eutectic in which the precipitation of 1203 in primary α- crystals is suppressed to 5% or less, thereby providing an abrasive material with significantly improved grinding performance.

Therefore, it can be used especially for light grinding in (1) grinding, and also for titanium alloys as it has an exceptionally good EIII performance.

Furthermore, even in the case of an abrasive material containing an alumina-zirconia eutectic with a relatively small amount of zirconia, its properties such as crush resistance can be further improved when compared with conventional materials.

[Brief explanation of the drawing]

Figure 1 (A>(B) is an enlarged photograph and schematic diagram of a conventional alumina-zirconia eutectic mixture (sample number @ 1) without the addition of yttrium oxide, and Figure 2 (A><8) is an enlarged photograph of the conventional alumina-zirconia eutectic mixture (sample number @ 1). An example of an alumina-zirconia eutectic mixture with addition of yttrium oxide
An enlarged photograph of sample number 3) and a similar view of sample number 4. Figure 3 shows the addition of yttrium oxide, etc. in the same example and other examples, such as abrasives containing yttrium oxide and abrasives containing rare earth minerals containing yttrium oxide. Figure 4 is a diagram showing the relationship between the amount of titanium oxide added and the single grain crushing strength in an abrasive material with a relatively small amount of zirconia. Figure 2 (A) Figure 3 Y20JgL<KYa05 'dr41p earth order*LQs
t>4. ho amount (wy>[α)-・-Y2O5a>:*
n. (b) -...Y2Dsk* is also 44:r, -1'fJu'
4j; aoh, h.

Claims (3)

[Claims] (1) An alumina-zirconia-titania-based abrasive material made by adding and melting zirconia and titania to alumina and rapidly cooling the alumina-zirconia-based abrasive material, which further contains yttrium oxide or a rare earth mineral containing yttrium oxide as another molten additive. Thousand archtania type abrasive material. (2) The alumina-zirconia-titania-based abrasive material according to claim 1, in which the amount of yttrium oxide added exceeds 0.05 Vt% and reaches 7 wt% based on the total amount of alumina, zirconia, and titania. (3) The amount of rare earth minerals including yttrium oxide added is
0.0 for the total amount of alumina, zirconia and titania
The alumina-zirconia-titania-based abrasive material according to claim 1, which has a content of more than 5 wt% and up to 7 wt%.