JPS63185876A - Ceramic tool material - Google Patents

Abstract

(57) [Summary] 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 is applicable to ceramic tool materials that require exceptional fracture resistance and wear resistance, especially for rough machining and high-speed cutting of duct ties/L' cast iron, etc. Suitable for use in cefmic tool materials.

``Conventional technology'' Conventional high-speed cutting tool materials include A, which has excellent wear resistance.
Although Os and AhOs-Tic materials are generally known, their thermal shock resistance and mechanical shock resistance are insufficient, so they are not suitable for cutting where the cutting edge is constantly subject to thermal shock or mechanical shock. is not fully satisfactory.

Therefore, S i s Na and the general formula S 1m-zAlzo
β-sialon, represented by zNs-z, has attracted attention as a tool material because of its high thermal shock resistance and mechanical strength, and its high toughness is used as a material for high-speed cutting tools such as castings.

However, these tools still have insufficient wear resistance for cutting ductile μ cast iron and steel, so the applicant has developed a sintered tool mainly made of SiS N4 or β-sialon to improve this. Tic, TiN on the surface of the body
Alternatively, a ceramic tool for high-speed cutting provided with a T1CN coating layer (Japanese Patent Application Laid-open No. 108204/1983) was proposed. On the other hand, these tools have the problem of not only having insufficient wear resistance but also being prone to chipping and cracking during use, so recently composite materials reinforced with ceramic fibers (including whiskers) have been developed. For example, β-
A sialon-based cefmix consisting of sialon and a predetermined amount of SIC whiskers and a guffy phase (%
No. 462,689) has been proposed, and the applicant himself has previously added 5 to 40% by weight of r SiC whiskers, Zr0z 5
We proposed a "high-toughness ceramic tool material" (Japanese Patent Application No. 191585/1985) characterized in that it is composed of ~25% by weight and the balance is β-sialon group Cefmix.

"Problems to be Solved by the Invention" The present invention improves the Cefmic tool for high-speed cutting described in JP-A-60-108204 and the high-toughness ceramic tool material disclosed in Japanese Patent Application No. 191-585-1985, and improves both of them. The objective is to provide a tool material that has both excellent cutting properties.

The high-toughness ceramic tool material is used as a base, and a coating layer having a thickness of 0.8 to 10 μm and having a layer of Tic, TIN, or T1CN as the outermost layer is provided on the surface of the base.

"action" The operation of the present invention will be explained first from the substrate side.

Composition formula of β-sialon group Cefmix 5i6-zAl
The preferred binary value for zOzNs-z is O<z≦1, but the reason is that when z>1, the mechanical strength and toughness decrease, and the necessary mechanical properties as a cutting tool cannot be satisfied. This is because it disappears.

Next, referring to the composition of the tool material of the present invention, the reason why the amount of SIC whiskers in the present invention is set to S~≠Y% by weight is that if it is less than 3% by weight, the reinforcing effect by the whiskers is small. This makes it difficult to obtain a fracture toughness value, and if the weight exceeds 1A, it is difficult to uniformly disperse the whiskers in the matrix, resulting in a decrease in sinterability, strength, and toughness. This is because anything outside the range is undesirable as it will cause defects during cutting.

The reason why the Zr compound is adjusted to 8 to 20% by weight in terms of Zr is that if it is less than 8% by weight, the toughness improvement effect is insufficient;
This is because if it exceeds 0.02 it%, the hardness, thermal conductivity, and toughness of the sintered body will decrease, and the wear resistance and chipping resistance will be inferior, which is not preferable. Here, as the Zr compound, for example, Z
r0z (monoclinic, tetragonal, cubic or their coexistence)
Examples include, but are not limited to, compounds whose X-ray diffraction results match fairly well with ZrO of ASTM Card-1'b20-684.

The reason for this is that the Zr compound can be added as a compound such as Zr0z + ZrN, but regardless of the addition form, Zr dissolves in the -H glass phase during sintering and forms a bond between the glass phase and SI.
By improving the wettability of both C whiskers at the interface and enabling a stronger bond, the toughness is improved by acting to fully demonstrate the original characteristics of SiC whiskers. However, after sintering, a part remains in the glass phase and most of it precipitates from the glass phase, and can take on different compound forms depending on the compounding composition. That is, even if the compositional formula or crystal system of the compound is different, since the action of Zr during sintering is the same, all of them result in a sintered body having the same high strength and toughness.

Next, the reason why the amount of the glass phase containing Zr l St I Al t 01 N and unavoidable impurities or one or more of Y, Mg, Ca, and rare earth elements is 1 to 25% by weight is that less than 1% by weight is a matrix. If β-SiAlON is not sintered sufficiently, and conversely exceeds 2.5% weight, it will deteriorate its toughness and high-temperature strength, and as a cutting tool material, it is prone to breakage at the tip of the cutting edge during cutting. This is not desirable.

The sintered body of the present invention may contain a trace amount of 5bNzO+ depending on the purity of the 5isN4 powder used as a starting material and the ratio of the composition.
5hONxt Y! 03 ・5isNat8Y!
03 ・5AbOs +10Y20s ・9StOx
・5isNn, YSiChN, 4YsOs・
5LOx'Si3N4 HMg5INt 9Mgl5i
In some cases, compounds such as 04 are produced and present in the sintered body, but there is no particular problem with their presence as long as the properties are not adversely affected.

Although there is no particular limitation regarding SIC whiskers,
The average diameter is 0.2 to 1 μm, the average length is 5 to 100 μm, and the aspect ratio is 5 to 500. AI + Ca *
Mg + Ni b Fe + Mn * Co +
In order to obtain a high-toughness sintered body, it is preferable to use whisker-like crystals having a cationic impurity such as Cr and a Stow content of 1.0 weight or less and having few constrictions, branches, and surface defects.

The functions related to the structure of the base body described above are essentially the same as those exhibited by the invention "High Toughness Ceramic Tool Material" filed on August 18, 1986.

Next, the outermost layer made of Tic, TIN, or T ICN increases the surface hardness of the substrate, while reducing the substrate and the S in the substrate.
This prevents the reaction between the IC whisker and the rigid material, which in turn has the effect of improving wear resistance. Therefore, the intermediate layer made of one or more of Alums and AlON interposed between the base and the outermost layer not only increases the adhesion between the outermost layer and the base, but also has the effect of buffering the difference in thermal expansion between the two. .

However, if the thickness of the intermediate layer exceeds 5 .mu.m, grain growth becomes intense and the layer becomes brittle and easily peels off, so the thickness was limited to 5 .mu.m or less. In addition, regardless of the presence or absence of this intermediate layer, if the total thickness of the outermost layer and the intermediate layer is less than 0.8 μm, the wear resistance will be poor, and if the thickness exceeds 10 μm, grain growth will be intense, making it brittle and easy to peel off. Therefore, the total thickness should be 0.8 to 10μ.
m.

Both the outermost layer and the intermediate layer are formed by a well-known physical vapor deposition method, chemical vapor deposition method, or the like (for example, the CVD method described in JP-A-60-108204).

"Example" Example 1 5tsNa powder with an α rate of 90% and an average particle size of 0.6 μm, α-A 1 z Os powder with an average particle size of 1 μm, SiC whiskers (5C-9 manufactured by ARCO Chemical), and an average particle size of 0
．． 8 μm monoclinic Zr (h powder) was blended in the proportions shown in Table 1, uniformly dispersed and mixed in ethanol, and dried.
After passing through the mesh sieve, in a graphite mold, the temperature shown in Table 1,
A dense sintered body was obtained by hot pressing under the conditions of a pressure of 200Kt/d and a holding time of 60 minutes, and then this sintered body was heated to 5N
The substrate was manufactured by polishing into a chip shape of GN482. The base composition was confirmed by X-ray diffraction, chemical analysis, and carbon quantification, and it was confirmed that Zr0z and SiC whiskers remained almost the same as the composition.

The binary values of Sialon were determined by X-ray diffraction and from the lattice constant of Sialon.

This substrate was loaded into a stainless steel reaction container, heated to 1050°C together with the container, and TiCl4°CH4,
H! , N! By flowing a gas such as into a reaction vessel to perform a chemical vapor deposition reaction on the surface of the substrate, Cefmic tool materials 1 to I'h2 having the coating layer shown in Table 1 can be prepared.
0 was manufactured. The thickness of the coating layer was controlled by changing the contact time between the substrate surface and the reaction gas.

Table 1 shows the results of cutting Ductai μ cast iron (FCD55) under the following conditions using ceramic tool materials Arashi 1 to -20 and measuring the amount of chipping and wear after cutting.

Cutting conditions: Cutting speed: 850 m/min Feed rate: 0.5 m/rev Depth of cut: 2 m Cutting time: 15 minutes From the results in Table 1, the comparison Cefmic tool material caused breakage and chipping and was not suitable for practical use. On the other hand, it was found that the ceramic tool material of the present invention exhibits excellent cutting performance with no occurrence of chipping or the like, less wear and tear.

Example 2 The raw material powder and SiC whiskers used in Example 1, Y2O2, MgO, CaO and D)' with an average particle size of 2 μm or less
zOs was blended in the proportions shown in Table 2, uniformly dispersed and mixed in ethanol/L', dried, passed through a 60 mesh sieve, and placed in a graphite oven at 1750'' C1 pressure 2004/d.

A dense sintered body was obtained by hot pressing under conditions of a holding time of 60 minutes, and then this sintered body was polished into a 5NGN432 chip shape to produce a base body. This substrate was loaded into a stainless steel reaction container, and 1
AlCl5 + Hz + while heated to 060°C
Mixed gas of Nz and C(h and TiC1a, C
H4, H2 and N! By sequentially flowing a mixed gas into a reaction vessel to cause a chemical vapor deposition reaction on the surface of the substrate, ceramic tool materials having a coating layer shown in Table 2 can be prepared.
1 to 86 were manufactured. The thickness of the coating layer was controlled by changing the contact time between the substrate surface and the reaction gas.

Duct tie μ using ceramic tool material-21~seat 85
Cast iron (FCD55) was milled under the following conditions, the number of impacts until the cutting edge broke was measured, and the average value of the results for each 10 points is shown in Table 2.

Cutting conditions Cutting speed 200m1m1n Feed rate 0.8m/tooth depth of cut
1.5 ml From the results in Table 2, it was found that the ceramic tool material of the present invention having an intermediate layer of A 120s or Al0N has an increased number of impacts and a longer cutting life compared to those without an intermediate layer. .

Example 8 In the blended composition of Example 2, ZrO! The composition of the sintered base material obtained by sintering the base powder prepared in the same manner as in Example 2 except for using ZrN in the proportions shown in Table 8 was fixed by X-ray diffraction. In addition, strength and toughness were measured as mechanical properties, and the results are shown in Table 8.
From this result, regardless of the type of Zr compound added, the Zr compound added after sintering has Zr0z depending on the composition.
It was found that Zr compounds, which are thought to be oxynitrides of ZrO and Zr, were present in the sintered body. Also, Zr0z
It has been found that even if it exists as a monoclinic crystal, a tetragonal crystal, a cubic crystal, or a coexistence thereof depending on the composition, all of them result in a sintered body having the same high strength and high toughness.

Example 4 Example 2 except that β-sialon powder synthesized to approximately Z = O, a was used as the starting material in addition to 5ixNi.
In the same manner as above, the base powder obtained by blending in the proportions shown in Table 4 was molded into a size of 20 x 7 m at a molding pressure of 0.5 ton/
After press forming in step d, the primary sintered body was sintered in a nitrogen gas atmosphere of 1 atm at 1,750°C for 2 hours to obtain a primary sintered body. The product was re-sintered for 2 hours in a vacuum chamber to obtain a H& dense secondary sintered body. After processing the sintered body thus obtained in the same manner as in Example 2, Cefmic tool materials Nn48 to N152 having the coating layers shown in Table 4 were manufactured. A cutting test was conducted using ceramic tool materials N148 to N52 under the following cutting conditions, and the defects and wear amount after cutting were measured.

Cutting conditions: Rigid material: FCD 55 Cutting speed: 850m1min Cutting depth: 2 Feed speed: 0.5 w/rev Cutting time
15 minutes These results prove that within the scope of the present invention, the tool material with a coating layer applied to the surface of the sintered body has excellent cutting performance with excellent chipping resistance and wear resistance. .

"Effects of the invention" A ceramic tool material with excellent fracture resistance and wear resistance.

Patent applicant: Nippon Tokushu Togyo Co., Ltd. 1. - Representative Tei Suzuki - ( ゛ - Procedural amendment vM (voluntary) Commissioner of the Patent Office Kuro 1) Akio Tono 1, Indication of the case 1985 Patent Application No. 299766 2, Name of the invention Ceramic tool material 8, Amendment Relationship with the case of a person who does will be corrected as shown in the attached sheet.

that's all

Claims (3)

[Claims] (1) A sintered body consisting of 5 to 45% by weight of SiC whiskers, 3 to 20% by weight of Zr compound converted to Zr, and the balance β-sialon ceramics is used as a base, and the surface of the base is coated with TiC, TiN, or TiCN. A ceramic tool material characterized in that it is provided with a coating layer having a thickness of 0.8 to 10 μm and having the outermost layer as the outermost layer. (2) β-sialon-based ceramics are prefabricated Si_6
＿−＿zAl_zO_zN_6＿−＿z(However, 0<Z
≦1), 1 to 25% by weight of Zr, Si, Al, O, N, and a glass phase containing unavoidable impurities or one or more of Y, Mg, Ca, and rare earth elements. A ceramic tool material according to claim 1, characterized in that: (3) Al_2O_3 and AlO between the substrate and the outermost layer
The ceramic tool material according to claim 1, further comprising an intermediate layer having a thickness of 5 μm or less and comprising one or more kinds of N.