JPS6340787A - Antiabrasive ceramic tool material - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a ceramic tool material with excellent wear resistance, particularly a tool material capable of cutting steel, cast iron, high nickel, aluminum, titanium, etc. at high speed.

<Prior art> Silicon nitride ceramics, whose main component is silicon nitride (S'sNa), have excellent properties such as strength, oxidation resistance, abrasion resistance, thermal shock resistance, and corrosion resistance, so they are used as cutting tool materials. It is attracting attention as being preferable as such.

However, Si and N alone lack quality stability and homogeneity compared to metals, and higher toughness is desired from the viewpoint of improved reliability and high properties.

Therefore, JP-A-59-30770, JP-A-59-5
No. 4680, JP-A No. 60-246268, Si
Attempts have been made to use C whiskers as a reinforcing material to create a composite material, but as a cutting tool material, although the chipping resistance can be improved, the wear resistance is insufficient, so it is particularly difficult to use for high-speed cutting of heat-resistant steel, etc. The reality is that it has not been put to practical use as a material for tools.

<Problems to be Solved by the Invention> In view of the above-mentioned actual situation, the present invention improves fracture resistance by modifying the surface layer of a Si-, N-based ceramic material that has excellent high-temperature properties and toughness. The objective is to create a cutting tool material that has both wear resistance and wear resistance.

Means for solving the problem of melting point> The present invention was made as a result of various studies to achieve the above object, and the outline thereof is as follows.

5 to 40 layers of Si'C whiskers, 1 to 1 layer of sintering aid
50 TL! 11%, the remainder consists of Si, N, or 1
No. 4-9. An average film thickness of 0.1 to 5μ is applied to the surface of the Si3N4-based ceramic sintered body.
The first invention is a ceramic tool material provided with a dense AI, 03 coating layer, and before applying the AI, O, coating layer, AIN or ju
The average film thickness including the intermediate layer is 0 when the intermediate I/sound is set consisting of ON.
．． The second invention is a ceramic tool material provided with a dense Al, O, coating layer of 1 to 5 μm thick.

First, let's talk about Si, N, and ceramic sintered bodies.
5isN is the matrix material, and the sintering aid is 1~
50 weights and 1 inch are added, but this range is complex.

If the density is less than 1-fold ffi, it will not be possible to obtain the desired density, and if it is more than 50% by weight, the high-temperature properties will deteriorate due to the glass phase. This is because it is not preferable as a cutting tool material whose tip becomes hot. Moreover, the addition of such a sintering aid is particularly effective when employing the pressureless sintering method.

Typical examples of sintering aids added here are Mg and Al.

One or more metal oxides selected from the group of Y, Zr and lanthanides.

In addition, SiC whiskers have a weight of 5 to 40, but 5
If the amount is less than 40% by weight, no improvement in the toughness of the ceramic material will be seen, while if it exceeds 40% by weight, the sinterability will decrease, and both will be easily chipped during cutting and have poor fracture resistance. The range is preferably 10 to 30% by weight, and more preferably 10 to 30% by weight.
The most preferable range is 15 to 25 FFI.

The general definition of a whisker is that the cross-sectional area is 8 x 10”1
n2 + food 1ヲ→Although it is a single crystal with an average diameter of 10 times or more compared to the average diameter of the cross section, the whiskers used in the present invention have an average diameter of 0.2 to 1 μm and an average length of 5～
A 50μ fake one is preferable in order to obtain a dense body with high toughness.

degree can be set to a preferable value.

The present invention relates to a cutting tool material in which a coating layer of Al, O, is provided on the surface of such a Si, N, base ceramic material. The first invention is provided directly on the surface of the material, and the second invention is provided via an intermediate layer made of AIN or AI ON.

However, in both cases, the company is 0. chemical vapor deposition method (c
vn). This CVD method includes, for example, 1. a Si, N4-based ceramic material is heated to Oa°C to 1,100°C, and a mixed gas of AICM, , Go, , H, and optionally CO is introduced into the reaction vessel to facilitate the heating. can be done. The treatment temperature is selected between 900°C and 1,500°C depending on the conditions, but if the temperature is too high, Al, O
, the particle size tends to become coarser and the density tends to be lost.
It is desirable to process at a relatively low temperature for a long time.

Al! The thickness of O1 coating layer is 0.1-5 μym
It is preferable because it exhibits the wear resistance of Al and Os and does not cause thermal cranking even if an excessively rapid temperature gradient occurs in the surface layer during cutting. If the thickness of the Al, O, coating layer is less than Q,13n1, the effect will be insufficient, and if it is thicker than 5μ, it will easily peel off due to thermal shock.

Also, the thermal expansion coefficients of Ksi3N4 and Al, O are 3.2 x 10-7'' (3 for the former, 7.8 x 1 for the latter).
Since it is greatly different from 0''/''C, peeling may occur in this coating layer depending on the cutting conditions.

In the second invention, in order to prevent this phenomenon, 1Si,
A person IN or A is placed on the base material made of N4-based ceramic material.
By providing a thin layer of 10N as an intermediate layer, it is possible to relieve the thermal stress caused by the difference in thermal expansion coefficient between the base material and the Al, O, coating layer, and to provide a stronger Al, Os coating layer. .

In this case, the thickness of the above-mentioned intermediate layer is preferably 3 μm or less from the viewpoint of relaxing thermal stress, and A1.
O. It is preferable to set the thickness of the coating layer to 0.1 to 5 μm from the viewpoint of wear resistance and peeling resistance during cutting. If the thickness of the intermediate layer and the n, o, and layers including the intermediate layer are larger than these, cracks will easily form between the sintered body and the coating layer due to thermal shock, which will cause the cutting edge to break during cutting. .

When the coating layer is formed by the CVD method, it is provided by the following precipitation reaction.

1) 2A'lfJ, + 5CO, + 3H, →A
l, O, + icl + 3CO2) 2AIC1
, + N, + 5H, → 2A1N + 6HC15)
2AIC1, +2CO, +3H, +N, →2AIO
The N+6HC1+2CO coating layer may be a single coating consisting only of Am and O, but it can be formed using the reaction formulas 2) and 3) described above.
Multiple coating layers can be obtained by providing one or more layers of AIN or ANON by the precipitation reaction shown by K, and then providing layers of Al, O, by the precipitation reaction shown by reaction formula 1).

In addition to the above-mentioned CVD, the coating layer of the present invention can be formed by P
It is also possible to use methods such as VD (physical vapor deposition) and sputtering.

<Example> Prototype test 1 SiC whiskers (Toka whiskers manufactured by Tokai Carbon Co., Ltd.) and sintering aids were uniformly dispersed in SL, N, and powder with an average particle size of 0.6P at the ratio shown in the attached table (Table 1). After mixing, a temperature of 1,700°C to 1,800°C was obtained in the graphite mold.

Next, this sintered body is 5NGN 433 y-Yanfa-0
, 051
lCl, 12 volume ffi, Co, 2s volume and H8
A mixed gas of 65 volumes MkS was flowed into the reaction vessel.

In addition, the reaction vessel is heated to 20 to 30 Torr by a vacuum pump.
The film thickness of Am, O, and coating was controlled by changing the reaction time.

Using the samples obtained in this way and the samples before coating, cutting tests were conducted on a high nickel alloy (Inconel 718), which is known to be an extremely difficult-to-cut material, under the following conditions. was measured.

The cutting conditions are as follows.

Cutting speed 200 ra/min Cut 1.5n Feed speed: 0.15M/rev.

Cutting time 10 min The results are shown in Table 1.

According to this, Si of the composition according to the present invention (first invention)
0.1 to 5 Al on the surface of the 3N4 ceramic material,
0. Ceramic tool materials with a coating layer do not cause chips even when cutting high nickel alloys, which are difficult-to-cut materials, and are recognized to have excellent wear resistance.Comparative examples have almost no chips or chipping. It has been proven that this method causes a large amount of wear and is not practical.

Prototype Example 2 In the same manner as Prototype Example 1, Si, N4 powder, SiC Quiscar of 20 heavy economic conditions, Al of 20 heavy ffi%, O, -Z
rO.

The sintered body was sintered by adding (1:4) of sintering aid.
Processed to NGN 432 and placed in cvn reaction vessel 105
After heating to 0 °C, AlCl, , bird, N, ,
A mixed gas of Co was continuously changed and flowed into the reaction vessel.

A when forming a mixed intermediate layer of AlN-Al0N
1C1-518 volume 3N4 gas 12 volume H, gas 7O volume AI, O, were formed on the outer layer.

When forming the A'IN intermediate layer, a mixed gas of 18 volumes of AlC, 12 volumes of AlC, 12 volumes of H gas, and 70 volumes of H gases was flowed.

When forming an Al0N intermediate layer, a mixed gas containing 12 volumes of AlCl, 7 volumes of N gas, 16 volumes of Go gas, 16 volumes of gas, and 65 volumes of gas was flowed.

By varying the contact time of these mixed gases on the surface of the sintered body, chips with different thicknesses of the intermediate layer and the outer layer were obtained. Next, this chip was subjected to a milling test under the following cutting conditions.

Cutting conditions: Rigid material FCD 55 Cutting speed: 200 m/min Feed: 0.5 m/tooth depth of cut: 1.5 layers Impact count: s, o o.

The results are shown in Table 2. According to this, AIN and Al0
It has been found that the second invention in which an intermediate layer of N 2 is provided has an increased impact resistance and a longer cutting life than those without this.

<Effects of the Invention> According to the first invention, SL composited with SiG whiskers
Utilizing the excellent toughness of the 3N4 ceramic sintered body, we provide a tool material with improved chipping resistance and wear resistance necessary for cutting tools by applying A-0 and K coatings. Yes, and according to the second invention, AI
, O, When installing a coating, AIN
Or by providing the A'lON layer as an intermediate layer,
It is possible to provide a cutting tool with improved impact resistance and significantly extended cutting life compared to the one according to the first invention.

Claims (2)

[Claims] (1) The average film thickness is 0.1 to 5 μm on the surface of a Si_3N_4 ceramic sintered body consisting of 5 to 40% by weight of SiC whiskers, 1 to 30% by weight of sintering aid, and the balance of Si_3N_4. Wear-resistant ceramic tool material provided with a dense Al_2O_3 coating layer of (2) AlN or AlON with a thickness of 3 μm or less is coated on the surface of a Si_3N_4-based ceramic sintered body consisting of 5 to 40% by weight of SiC whiskers, 1 to 30% by weight of the sintering aid, and the balance of Si_3N_4. A dense Al layer with an average thickness of 0.1 to 5 μm including the intermediate layer is formed through the intermediate layer.
Wear-resistant ceramic tool material provided with _2O_3 coating layer