JPS6041019B2 - Alumina-based sintered ceramic with high strength - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an alumina-based sintered ceramic having high strength.

In general, alumina-based Akatsuki ceramics (hereinafter referred to as AI203-based ceramics) containing aluminum oxide (hereinafter referred to as AI203) as a main component have high hardness and have excellent wear resistance, corrosion resistance, and electrical insulation properties. Because of its excellent properties, it has been widely used in the production of cutting tools, corrosion-resistant parts such as various nozzles, and insulating substrates.

However, this AI203 series ceramic has poor sardine properties, so it only exhibits a low transverse rupture strength of about 30 to 50 k9/m, and therefore, although it has great potential in the field of use, it is not practical. It was only used in fields where tensile stress or impact force was not applied much. Therefore, research has been conducted to improve the toughness and strength of this AI203-based brazed ceramic, and as a result, an AI203-TIC-based competitive ceramic containing titanium carbide (hereinafter referred to as TIC) has been proposed.

Indeed, this AI203-TIC fired ceramic is
Because it has a high transverse rupture strength of 60 to 90k9/copy,
For example, it became possible to use it in applications where impact forces are applied, such as cutting edges for milling, which brought about a turning point in the field of application.

However, when this AI203-TIC-based cryoceramic is manufactured, if normal setting is carried out in a vacuum or non-oxidizing atmosphere, AI203 and TIC react to generate CO gas, which inhibits the progress of scaling. Therefore, production by hot pressing is indispensable because of the difficulty of manufacturing. Therefore, in order to turn the adjoining material after hot pressing into a final product, cutting and polishing processes are required, resulting in low productivity and The shapes of products that can be manufactured are not only limited to simple ones, but also have problems such as having so-called anisotropy, in which mechanical properties differ between the pressing direction and the direction perpendicular to the pressing direction.

For these reasons, recently, in order to solve the above-mentioned manufacturing and characteristic problems of the AI203-TIC type Akatsuki ceramic, it has been developed using hot isostatic pressing (hereinafter referred to as NIP). It is being manufactured using a method using

This method was devised primarily for the purpose of removing cavities that exist in powder metallurgy products such as ultra-hard alloys. Theoretical density ratio (ratio of measured density to theoretical density) manufactured by Shintsu sintering in an atmosphere 93-95%
Preliminary bodies with a high density of about 400℃
This is a method for producing HIP-treated products under conditions of a pressure of approximately 1,500 atmospheres. When carrying out this method, it is necessary to use a pre-sintered body with the above-mentioned high density in which no lotus holes remain inside, while this method is applied to a pre-sintered body that does not have such a high density. When applying this, it is necessary to form various non-permeable coating layers on the surface of the pre-dawn compact.
In this case, the above-mentioned non-air permeable coating layer forming step and HI
This increases the cost because it involves new steps such as the coating layer removal step after the P treatment. In addition, while the AI2Q-TIC sintered ceramic manufactured by the hot pressing method as described above exhibits a high transverse rupture strength of 60 to 90k9/cm, the AI20 manufactured by applying the HIP method described above
3-TIC type bran ceramic has a transverse rupture strength of only about 50 to 60k9/iso, and with this level of toughness, if it is used as a cutting edge for milling, for example, it will break due to lack of impact resistance. This resulted in problems such as: Therefore, from the above-mentioned viewpoints, the present inventors have developed a method that utilizes mP, which has extremely high productivity, to produce a non-porous coating layer without the need to form it on the surface of a preliminary bran aggregate, and In order to obtain a Yama 203 series domed ceramic that has good retaining properties that can be used as a pre-sintered body depending on the application, and also has high strength and excellent impact resistance,
In particular, as a result of research focusing on the AI203-TIC-based precipitated ceramic, which has high strength but also has anisotropy, which could only be manufactured using the hot press method with low productivity, we found that {a' relative AI203-TIN (and/or TICN) containing either or both of titanium carbonitride (hereinafter referred to as TICN) and TIN, which has a high ratio of titanium nitride (hereinafter referred to as TIN) to TIC (hereinafter referred to as AI203) -A group consisting of oxides of calcium oxide (hereinafter referred to as Ca○), yttrium oxide (hereinafter referred to as Y203), and rare element oxides (hereinafter collectively referred to as metals) When one or more of the following (referred to as oxides) is added and contained, the density is improved, and the theoretical density ratio required for HIP treatment by Shintsu sintering is 93~
A product with a high density of about 95% or more can be obtained.

'b} Yama 203 - When Mo and Ni are added to the TIC type brazed ceramic, the competitive bondability is improved and the strength is also improved. [c} When vanadium carbide (hereinafter referred to as VC) is added to the N203-TIN-based cemented ceramic containing Mo and Ni, the strength is further improved.

{d' High strength mountain 20 containing Mo, Ni, and V
When aluminum nitride (hereinafter referred to as "N") is added to 3-TIN-based sintered ceramic, the impact resistance is further improved.

We have obtained the knowledge shown in the 'a--rigid term' above.

Therefore, this invention has been made based on the above findings, and in terms of volume %, one or two of TIN and TICN: 2 to 15%, Mo: 0.1 to 3%, Ni: 0 .5 to 3%, metal oxide consisting of one or more of Ca○, Y203, and oxides of rare earth elements: 0.1 to 2%
, VC: 0.1 to 3%, and if necessary, NN: 0.1 to 3%, and N203 and unavoidable impurities: the remainder. H
It is characterized by the AI203 series Kyoketsu ceramic, which has high strength and excellent impact resistance that can be applied with IP treatment.

Next, the reason for limiting the component composition range as described above in the ceramic of the present invention will be explained.

'a} TIN and/or TICN These components have the effect of suppressing the grain growth of AI203 and improving the strength of the ceramic, but if their content is less than 2%, the desired effect cannot be obtained. On the other hand, 1
If the content exceeds 5%, the groove competitiveness deteriorates and it becomes impossible to manufacture the desired pre-sintered twill body, so the content was set at 2 to 15%.

In addition, when containing TICN or TICN + TIN, if the relative ratio of TIC to TIN exceeds 50% by weight, N
203 and TIC begin to react, resulting in CO
Since gas is generated and it becomes difficult to stably obtain a pre-sintered body with the high density required for HIP treatment, it is necessary to make the content ratio of Tin at least equal to TIC, or Or it needs to be more than TIC. 'b' The MoMo component, when coexisting with Ni, has the effect of uniformly dispersing Ni in the core material and improving the strength of the ceramic, as well as improving the strength of the ceramic. If the content is less than 3%, the desired effect cannot be obtained, while if the content exceeds 3%, the branability will deteriorate.
%. {c} Ni As a metal component, Ni component contributes to improving the rutting property of ceramic, which is a brittle body, and this sardine property improving effect is mutually improved when it coexists with Mo, but if its content is less than 0.5% In this case, the desired quality improvement effect cannot be secured, and on the other hand, in 3
If the content exceeds 0.5%, the wettability with AI203, the main component, will deteriorate, and this will lead to a decrease in competitiveness, so the content was set at 0.5 to 3%. .

[d- Metal oxides These components react with AI2Q to form a low-melting glass phase or spinel phase, and have the equivalent effect of improving the crystalline structure, but if the content is 0.1%, If the desired effect is not obtained in the above action, and on the other hand, if the content exceeds 2%,
Since the formation of the glass phase or spinel phase becomes too large and causes a decrease in strength, its content is reduced to 0.
．． It was set at 1 to 2%.

[e'VC The VC component has the effect of significantly improving the strength of ceramic when coexisting with Mo, Ni, and Ni, but if its content is less than 0.1%, the desired effect cannot be obtained. On the other hand, if the content exceeds 3%, competitiveness will decrease, so the content should be adjusted to 0.1 to 3%.
%.

'f'NN This component has the effect of particularly improving impact resistance, so it is an ingredient that is added as necessary when used for applications such as milling cutting edges that require impact resistance. However, if the content is less than 0.1%, the desired effect of improving impact resistance cannot be secured, so it is necessary to contain more than 0.1%, but if the content exceeds 3%, Since NN decomposes during sintering and the density of the preliminary sintered body decreases due to the influence of the decomposed gas generated as a result, its content was determined to be 0.1 to 3%.

The ceramic of this invention is produced by heating a green compact formed from a mixed powder of a predetermined composition according to a normal powder metallurgy method to remove plasticizers such as paraffin, and then in a neutral inert gas atmosphere, preferably in vacuum, at a temperature of about 1450 to 170030 for 30 minutes to 2
A pre-scorched silk body is produced by holding the pre-sintered silk body for about an hour. In this case, the conditions for setting the pre-sintered silk body are adjusted so that the density of the pre-sintered silk body is 93 to 95% or more of the theoretical density ratio, and depending on the application, it can be used in this state. In particular, when used for applications requiring strength and impact resistance, the pre-fired body is heated at a temperature of 1300 to 1500.
0○, holding time 1~2 hours, inert gas pressure 1000~
It is manufactured by performing HIP treatment under conditions of about 200 mm of hydrophobic pressure, and in order to ensure particularly high strength, it is preferable to select and adjust the manufacturing conditions so that the average grain size in the ceramic is 3 mm or less. Next, the ceramic of the present invention will be explained using examples and comparing with comparative examples.

As raw material powder, both commercially available average grains: 0.4rm
Q-AI203 powder with the same 1.5 mm, TIN powder with the same 1.3 mm, TICN (TIC/TIN=4/6
, weight ratio) powder, Mo powder of 1.3 mm, Nj powder of 2 m, Ca0 powder of 0.5 m, Y2Q powder of 0.1 m, Y2Q powder of 0.5 rm. 203 powder, Ce2Q powder of 0.3 m, N et al. 03 powder of 0.3 m, 1
．． Prepare 41 m of VC powder and 1.1 m of AIN powder, mix these raw powders with the composition shown in Table 1, add methyl alcohol as a solvent, and place in a ball mill. After mixing for 3 days, paraffin accounting for 1% by weight of the mixed powder was added as a plasticizer, and after drying, a green compact was formed from the mixed powder by press molding. was heated in a vacuum to a temperature of 500 CO to remove paraffin, and then sintered in a vacuum and held at a temperature of 1550 q0 for 1 hour. Atmospheric pressure to medium, temperature: 145
Comparative brazed ceramics 1 to 1 of the present invention, which have substantially the same final component composition as the blended composition by performing HIP treatment under the condition of holding at 0.000° C. for 1 hour.
IQ and conventionally set ceramics were produced respectively.

In addition, Comparative Competitive Ceramics 1 to 10 all have compositions in which the content of any one of the constituent components (marked with * in Table 1) is outside the scope of this invention. be.

The theoretical density ratio, Rockwell hardness (A scale),
And when transverse rupture strength was measured for the purpose of evaluating strength,
The results are shown in Table 2.

From the results shown in Table 2, the Kyowei Ceramic 1 of the present invention
No. 15 all have extremely high density, hardness, and strength, but as seen in Hisame Yakiniku Silk Ceramics No. 1 to No. 10, even the content of any one of the constituent components is not sufficient to meet the requirements of the present invention. If it deviates from this range, at least one of the above characteristics will become inferior, and it is clear that a sintered ceramic having all of these characteristics cannot be obtained. It can be seen that this material also has superior strength compared to the conventional Akatsuki Silk Ceramic.

Next, regarding the fired silk ceramics 1 to 1 of the present invention and the conventional solidified ceramics, workpiece material: SNCM-8 (hardness: 8270), chip shape: SNGN432, cutting speed:
Steel continuous high-speed cutting test under the conditions of 40 blood/min, depth of cut: 2 sides, feed: 0.2 sides/rev, cutting time: Shin, and work material: FC.
25 (hardness: HB180), work material dimensions: width 12 bars x
Length: 35 mm, tool shape: double negative type cutter (diameter: 16 mm), only 1 tip used, cutting speed: 5
5 h/min, Depth of cut: 2 sides, Feed per tooth: 0.2 ribs/tooth, Cutting form: Cutting with the cutter center aligned with the center line in the width direction of the workpiece.

A high-speed cutting test was conducted with a cast iron milling machine under the following conditions. In the former cutting test, the average flank wear width of the tip was measured, and in the latter cutting test, the number of passes until the tip chipped was measured.

These results are shown in Table 2. From the results shown in Table 2, the adjacent striped ceramic of the present invention showed excellent cutting performance in all cutting tests, especially when milling cast iron (intermittent).
In high-speed cutting tests, it is clear that the cutting performance is much superior to that of conventional Akatsukijima ceramics.

As mentioned above, the anti-scratch ceramic of the present invention has extremely high strength and impact resistance, and can be manufactured by applying HIP treatment with excellent productivity without the need for forming an air-impermeable coating layer. Therefore, it has industrially useful properties such as excellent mass production and economic efficiency.

Claims (1)

[Claims] 1 One or two of titanium carbonitride and titanium nitride: 2 to 15%, Mo: 0.1 to 3%, Ni: 0.5 to 3%, calcium oxide, yttrium oxide, and rare earths. One or more oxides of elements: 0.1 to 2%,
An alumina-based sintered ceramic having high strength, characterized in that it contains vanadium carbide: 0.1 to 3%, and the remainder is aluminum oxide and unavoidable impurities (volume %). 2 One or two of titanium carbonitride and titanium nitride
Seeds: 2 to 15%, Mo: 0.1 to 3%, Ni: 0.5 to 3%, one or more of calcium oxide, yttrium oxide, and rare earth element oxides: 0.1 to 2%,
Contains vanadium carbide: 0.1 to 3%, further contains aluminum nitride: 0.1 to 3%, and has a composition (volume %) with the remainder consisting of aluminum oxide and unavoidable impurities. Alumina-based sintered ceramic with high strength.