JPS6055595B2 - Manufacturing method of surface-coated superhard alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing superhard metal products for cutting and wear-resistant parts having a thin coating layer with excellent wear resistance.

Conventionally, in order to improve the wear resistance of cemented carbide products,
The surface to be used can be coated with a single layer or multiple layers of various carbides, nitrides, and carbonitrides of group metals such as titanium carbide and titanium nitride, and/or aluminum oxide and zirconium oxide. This is well known, and coated cemented carbide products have been widely put into practical use as throw-away tips for cutting.

The most widely used coating material is titanium carbide, which has better oxidation resistance, lubricity, and
It has excellent physical properties as a cutting tool in terms of affinity with iron and hardness. However, although titanium carbide-coated cemented carbide exhibits excellent performance in terms of flank wear resistance, it does not have sufficient wear resistance on the rake face, which shortens its lifespan. It was hot.

Zirconium carbide and hafnium carbide, which are homologous to titanium carbide, also have excellent physical properties as cutting tools, but the wear resistance on the rake face is not sufficient.

In addition, although carbides of these group metals exhibit excellent performance as coating materials, they lack compatibility with the superhard alloy that is the base material, and in particular, they lack compatibility with the bonding metal, ie, CO. ．． The wettability with Ni, etc. is not good, and as a result, the adhesion strength at the boundary between the base material and the hard layer is not sufficient, making it difficult to perform cutting with large mechanical impact such as interrupted cutting and uneven thickness cutting, and welding. In the case of cutting work materials that are prone to bending, the hard layer has the disadvantage of being easy to peel off. As a result of intensive research to eliminate these drawbacks, the inventor of the present invention found that
The hard layer is made of carbonate nitride (0
xycarb0nitride) improves oxidation resistance and improves rake face wear resistance, which had been a drawback, and also increases affinity with the base material, so it has better affinity with the base material and has better wettability with the bonding metal. Easy, MOLTa. ．． N
b,. The present invention was completed by successfully obtaining a coating layer with satisfactory performance by dissolving W as a solid solution and coating it with aluminum oxide having excellent wear resistance.

That is, the present invention provides Ti. ．．
Zr,. One or more halides of Hf and MO. Ta. Nb. ．． One or more halides of W, hydrogen and carbon monoxide or carbon dioxide and hydrocarbon and nitrogen or ammonia, 8
The general formula (MxAy
)(CpNqOr)2 where M is Ti. ．． Zr,. One or more types of Hf, A is MO, Ta, . Nb. ．． One or more types of W, C,
．． NlO represents carbon, nitrogen, and oxygen, respectively, X, and y represent the metal component ratio, and P. ．． q,. r is each C. ．． The atomic ratio of NlO is expressed by the ratio of the non-metallic component to the metallic component, and these satisfy the following conditions. The gist of the present invention is a method for producing a surface-coated superhard alloy, which is characterized by coating an alloy and coating the coated superhard alloy with aluminum oxide.

Although the details of the above reactions are unknown, it is believed that basically various reactions shown by the following reaction formulas occur in the furnace.

As an example, the case of w as a metal solid-dissolved in Ti as a metal group will be shown below.

X,. The ratio of y can be arbitrarily changed within the range of 0.1≦x≦0.95 depending on the amount of halide used in the reactions (1) and (2).

TiXWy(CpN,Or) mainly consists of (3) and (4)
), (5), and (6).
By controlling the CO partial pressure, CH4 partial pressure, and N2 partial pressure in the furnace, any P. q. The composition of r can be obtained.

In addition, carbon diffuses from the base superhard alloy, (7)
The reaction shown in the formula occurs, and as a result, the carbon concentration in the hard layer near the boundary between the base material and the hard layer increases. Utilizing this phenomenon, the carbon concentration in the hard layer can be changed continuously, and similarly, the nitrogen and oxygen concentrations can also be changed continuously by controlling the atmospheric gas. Similarly, the concentration of the metal compositions X, , and y in the hard layer can be continuously changed by controlling the atmospheric gas. In particular, for the purpose of dissolving metals in the hard layer, the concentration can be high near the boundary with the base material in the hard layer, and the concentration can be decreased toward the surface. Furthermore, these hard layers contain oxygen in the coating layer, so they have good affinity with oxides, and are especially suitable for cutting tools such as aluminum oxide (MO), which has excellent wear resistance.
When coated on top of the A,)(CpN9O,)2 film, it has excellent adhesion and the abrasion resistance of the two layers combine to provide excellent abrasion resistance.

Conventionally, as a method of coating the surface of a coated superhard alloy with an oxide layer, for example, a base coated with titanium carbonitride is fired at high temperature to diffuse W and CO into the coating layer, and then oxidized from the surface. A method of coating with aluminum oxide has been proposed.

However, in this method, a gradient occurs in the oxygen concentration of the coating layer, which impairs the homogeneity. Also, at that oxidation temperature, oxides are more stable in terms of free energy, so T1 oxides, W oxides, and CO oxides are prioritized as products, and carbonate nitrides are difficult to form. It is also mixed with various oxides and does not form a continuous homogeneous layer like the product of the present invention. For this reason, the bonding mechanism with the surface oxide becomes complicated, and together with the diffusion of WlCO, this results in a decrease in the hardness and plastic deformation resistance of titanium carbonitride at high temperatures, and this effect remains even after coating with aluminum oxide. Therefore, it is difficult to expect an improvement in the final cutting performance of the multilayer coated tip, which is determined by the performance of each layer. In contrast, in the present invention, (MOAy) (C, NqO,
) 2 is simultaneously formed, and aluminum oxide is coated on top of the aluminum oxide, each layer is strongly laminated while maintaining uniformity, and the excellent performance of each layer can be comprehensively exhibited.

Compared to conventional coated carbide layers, the superhard alloy with a hard coating layer manufactured by the above method has the following advantages: First, it has good wear resistance on both the flank and rake faces during cutting. It is to show. This is partly due to the superior oxidation resistance due to the presence of oxygen in the lower layer, but it is also thought to be due to the addition of effects such as improved toughness and increased high-temperature hardness due to the solid solution metal. Furthermore, the oxidation resistance of the upper layer of aluminum oxide and the reaction resistance with the work material are added, and it exhibits extremely excellent wear resistance. The second point is that it has excellent chipping resistance during interrupted cutting. This is thought to be due to the solid solution metal increasing the affinity with the base material and improving the adhesion strength. Generally, when a hard layer contains oxygen, the wettability with metal tends to deteriorate, so a solid solution metal is absolutely necessary. General formula MxAy(C,
In the composition of NqO, )2 (the meaning of each symbol in the formula is as described above), the metal composition is 0.1≦x≦0.950.0
It is necessary to set the range of 5≦y≦0.90, and if the solid solution metal is less than 5 at%, the effect of the solid solution will be small, and if it exceeds 90 at%, the effect of the group metal will be reduced, which is not preferable.

In addition, the oxygen content is 0.05≦r≦0.90, and 5at
If it is less than 90at%, the effect on oxidation resistance is small, and if it is less than 90at%
If it exceeds this value, the toughness of the oxide will decrease, which is undesirable. The ratio of metals and nonmetals is 0.8≦z≦1.0, and 0
．． 8T. If it exceeds 1.0, there will be many lattice defects, and if it exceeds 1.0, there will be a lot of free carbon, which are both undesirable as they lead to a decrease in hardness and strength. In the case of a double layer, the thickness of the layer is 0.5 to 20p for the lower layer MxAy(CpNqO,)2.
1 upper layer A]203 is preferably in the range of 0.5 to 5μ.

If the thickness is less than these, the effect of wear resistance will be small, and if it is more than this, the toughness will decrease, which is not preferable.

This will be explained below using examples.

Example 1 Super hard alloy P-30 (JIS) grade (WC80%,
COIO%, TiC8%, TaC2%, all weight%
) was heated to 1000°C in a reaction vessel made of a heat-resistant alloy, and 42% by volume of TiCl, 6l% by volume of WCl, C
A reaction gas mixed in the proportions of Ol volume %, N 22 mass %, and H 2 residue was fed at a flow rate of 10 e1 min and reacted for 2 hours.

After the reaction, the residual gas was removed, and the reaction gas mixed in the proportions of % AlCl3, % CO2, and residual H2 was added to 10'1 m
The reaction was carried out for 2 hours by feeding at a flow rate of in. After the reaction, the remaining gas was removed and the chip surface was taken out after cooling and had an average of 5
μ's titanium and tungsten oxycarbonitride and 2
μ, coated with Al2O3. The composition ratio of titanium and tungsten was determined by analysis using an X-ray microanalyzer.
．． 7WO. 3, C, . N. ．． The component ratio of O was determined by mechanical analysis. lONO. 65OO. It was 25. The composition of the titanium/tungsten oxycarbonitride thus obtained was TlO. 7WO. 3 (CO.
lNO. 65OO. 25). Example 2 A substrate was coated in the same manner as in Example 1 under the following conditions.

Reaction temperature: 1000C Gas flow rate: 10eImin Reaction time: 2 hours Thereafter, Al2O3 was coated under the same conditions as in Example 1.

The lower coating layer has a thickness of 5.5p, and as a result of X-ray microanalyzer and Auger analysis, the composition is TlO 65M.
The upper layer, which was 00-35 (CO.3N0.500.2), was Al2O32P. Example 3 A substrate was coated in the same manner as in Example 1 under the following conditions.

Reaction temperature: 1050℃ Gas flow rate: 10'1min Reaction time: 2 hours Thereafter, Al2O3 was coated under the same conditions as in Example 1.

However, the reaction time was 1 hour. The obtained lower coating layer has a thickness of 6p and a component ratio of ZrO. 8TaO. 2 (CO・
The upper coating layer was 1μ of Al2O3.

Example 4 A substrate was coated in the same manner as in Example 1 under the following conditions.

Reaction time: 1050 examples C gas flow rate: 10e1min Reaction time: 2 hours Thereafter, Al2O3 was coated under the same conditions as in Example 3.

The coating thickness of the lower layer is 6μ, and the component ratio is HfO/9Nb.
0-1 (CO-4N0・400・2) and the upper layer Al2O
No. 3 had a thickness of 1 μm. Example 5 A substrate was coated in the same manner as in Example 1 under the following conditions.

However, the gas concentrations of TiCl4 and WCl6 were changed as the reaction time progressed. TiCl,O. Melt amount % (reaction start) → 2 volume % (near the end of reaction) WCl6
2% by volume (start of reaction) →0. Melt amount%
(Near the end of the reaction) COO. Solubility %N2l5〃 Reaction temperature: 100CfC Gas flow rate: 10e1min Reaction time: 2 hours Thereafter, Al2O3 was coated under the same conditions as in Example 1.

The thickness of the lower coating layer is 5p, and its components are TlO. , WO4 (CO.l, NO.6O.
．． In 2), the surface of the coating layer is TlO. 9WO. l(Cu, 5N04500.2) and the thickness of the upper layer Al2O3 is 2
It was μ. Example 6 Substrate 7 was coated in the same manner as in Example 1 under the following conditions.

However, the amount of CO and the amount of N2 were continuously changed during the reaction. Ti
CI, 2% by volume WCl6l% by volume COI. Melt amount % (reaction start) →01 volume % (near the end of reaction) N
22% by volume (start of reaction) → 1% by volume
(Near the end of the reaction) Reaction temperature: 10000C Gas flow rate: 1
0eImin Gate reaction time: 2 hours After the reaction, Al2O3 was coated under the same conditions as in Example 1.

The thickness of the lower coating layer is 5p, and its components are TlO・7W0・3 (CO・7N0・200・1) near the boundary with the base metal.
So, the area near the surface is TlO. 7WO. 3 (CO.lNO.7
O. ．． 2) It was hot. The Al2O3 in the upper layer was heated at 2p.

Example 7 A cutting test was conducted on the coated superhard alloy cutting tips obtained in Examples 1 to 6.

P-3 used as a substrate in Examples 1 to 6 as a comparative example
DEI1 hard alloy, and TiC. Coated cemented carbide, each coated with 6μ of TIN, was simultaneously cut. The composition of the coating layer of each sample whose description is omitted in the following cutting examples is summarized as follows.

Comparative Example 1P30 Comparative Example 2 TiC Comparative Example 3 TiN Example 1 T10/7W0-3 (CO-1N0/Can 00/25)
+Al2O3 cutting example 1 Cast iron continuous cutting (JIS) FC-2
Cutting speed v=200m, 1 to 5s Purinel hardness HBl8
min1 feed f=0.2 ugly 1rev1 cut t=1.5
Ugly life comparison (rake face wear 200p or flank face wear 0.
The life limit was set at 4wm.

Cutting example 2 Carbon steel cutting (JIS) S3OCl Purinel hardness HB2
lO,v=180mImin. ．． f=0.2m
vlt=1.5mm Life comparison (same as cutting example 1) Cutting example 3 Interrupted cutting of alloy steel square material (JIS) SNCM-8 (dimension 1
50×300×800m square timber), v=150m1min
Under the condition that 1t=1.5, the feed is further increased by 0.2 each.
5th term 1reV10.35? 'RevlO. 45wlIr
The time until cutting edge breakage was compared with EV.

As described above, the product of the present invention showed good results in both wear resistance and chipping resistance.

Claims (1)

[Claims] 1. On the surface of the superhard alloy, 1 of Ti, Zr, and Hf
species or two or more halides and Mo, Ta, N
b, one or more halides of W, hydrogen, carbon monoxide or carbon dioxide, hydrocarbon and nitrogen or ammonia are reacted at 800 to 1200°C to form a compound of the general formula (M_xA_y) (C_pN_q
O_r)_zHere, M is one or two of Ti, Zr, and Hf.
A represents one or more of Mo, Ta, Nb, and W; C, N, and O represent carbon, nitrogen, and oxygen, respectively;
y is the metal component ratio, and p, q, and r are C, N, and O, respectively.
z indicates the ratio of nonmetallic components to metallic components, and these are x+y=1, 0.1≦x≦0.95 0.05≦y≦0.90 p+q+r=1, p・q・The ultra-hard metal carbonate nitride layer is formed with a uniform oxygen concentration within the layer, which satisfies the following conditions: r>0 0.05≦r≦0.90 0.8≦z≦1.0 A method for producing a surface-coated superhard alloy, which comprises coating an alloy and coating aluminum oxide thereon.