JPH02120213A - Silicon nitride block - Google Patents

Abstract

PURPOSE:To provide the title noncrystalline block containing TiN separated in a grain form, suitable for coating materials, bearing materials, etc., through a vapor separation process under specified conditions. CONSTITUTION:Using a blowing tube 4, a combination of an inner and outer tubes 8, 9, a nitrogen-depositing source gas (e.g., NH3), a silicon-depositing source gas (e.g., SiCl4) and a titanium-depositing source gas (e.g., TiCl4) are blown onto a heated substrate 2, respectively. In this case, the nitrogen- depositing source gas flux is surrounded by a mixed gas of the silicon-depositing source gas and titanium-depositing source gas, and a vapor phase decomposition reaction is induced on or near the substrate 2 to effect deposition on the substrate 2 of the objective noncrystalline silicon nitride block containing TiN separated in a grain form. This block can suitably used for coating materials to coat the surface of e.g., bites, dies, bearings, and tool materials such as carbide bites.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a silicon nitride block produced by a chemical vapor deposition method.

(Problem B to be Solved by the Prior Art and the Invention) Conventionally, a method of manufacturing silicon nitride by a chemical vapor deposition method is known. In this case, the raw material gas used in the above method is a silicon deposition source gas that contains silicon and is deposited in a vapor phase, such as 5iCj! n.

SiH2, 5iBrn+ 51g4, etc., and a nitrogen deposition source gas that contains nitrogen and precipitates in the vapor phase, for example, MHz
, NtHa, etc. are used, and when the above two types of gases are reacted under reduced pressure and at high temperature, silicon nitride is precipitated. At this time, if a carbon plate is present, silicon nitride is formed into a plate shape on top of it. It is known that amorphous or crystalline silicon nitride blocks can be obtained by deposition.

It is also known that in addition to silicon nitride lumps, amorphous silicon nitride powder can be produced by changing the precipitation conditions.

By the way, regarding silicon nitride containing Ti, US Pat. No. 4,145,224 discloses that a powder body can be obtained using a chemical vapor deposition method.

That is, according to the same publication, amorphous silicon nitride powder containing TiN can be obtained by introducing SiCj! Crystalline silicon nitride powder requires a heat treatment temperature of 1500 to 1600°C for crystallization, whereas amorphous silicon nitride powder containing TiN requires a heat treatment temperature of 1500 to 1600°C.
Heat treatment at a lower temperature of 400'C in N2 for 2 hours results in 60% crystallization, which consists of 97% by weight of alpha silicon nitride and 3% by weight of beta silicon nitride. Note that the Ti content is preferably 1.5 to 5% by weight, but 0.5% by weight.
It is described that amorphous silicon nitride is crystallized at 1400°C even when Ti is contained in an amount of 0.01% by weight.

Furthermore, according to the above-mentioned US patent publication, Ti is precipitated and generated.
It is described that silicon nitride containing .

The present invention includes granular TiN, which has not been previously known,
The object of the present invention is to provide a silicon nitride block that is substantially amorphous.

(Means for solving problems) Next, the present invention will be explained in detail.

The present invention relates to a substantially amorphous silicon nitride block containing granular TiN.

As mentioned above, silicon nitride powders that are mainly amorphous and contain Ti are known, and silicon nitride powders that are mainly crystalline and contain Ti are known.
Although sintered bodies of silicon nitride powder containing i are also known,
A substantially amorphous silicon nitride block containing granularly precipitated TiN as in the present invention has not been known.

This is because, according to U.S. Pat. No. 4,145,224, an amorphous silicon nitride powder containing Ti is obtained, whereas when this powder is molded and fired, crystalline nitride containing Ti is obtained. Although it is disclosed that a silicon sintered compact can be obtained, the present invention differs from that of the above-mentioned publication in that it is amorphous and is not a powder sintered compact.

The lumps of the present invention are manufactured by a manufacturing method using vapor phase precipitation, which will be described later. By controlling the manufacturing conditions, silicon nitride consisting only of an amorphous substance and containing Ti (silicon nitride is hereinafter abbreviated as Si3N4) can be produced. S containing Ti that is substantially amorphous and contains a small amount of α-type crystals.
There can be two types of i3N4 aggregates, but of course, both of these two types of aggregates are completely unknown in the past.

Next, the structure, properties, and properties of the Ti-containing Si3N of the present invention and the aggregate will be explained.

As mentioned above, the aggregate of the present invention refers to an amorphous substance, and refers to one that is entirely or mostly amorphous, including cases in which a small amount of α-type crystals, for example, about 10% by weight or less, is mixed. . Further, Ti is contained in the form of TiN, and its content is within the range of 5 to 30% by weight based on the total amount of TiN, and the amount can be controlled by manufacturing conditions as described below.

The state of the contained TiN can be easily confirmed using a transmission electron microscope, and the results show that TiN is dispersed and precipitated in the amorphous matrix as fine grains of several tens of diameters.

The density of the agglomerates of the present invention varies depending on manufacturing conditions, but
．． It is within the range of 24 to 3.35 g/cm'. By the way, for example, the theoretical density of α-type SiJ is 3.18 g/cm3,
Since the density of β-type Si3N4 is 3.19 g/am3 and that of TiN is 5.43 g/cm', the density increases as the TiN content increases.

The hardness of the lump of the present invention at room temperature (load: 100 g) is within the range of 1900 to 2 gQQkg/mm'', and as will be described later (this hardness varies depending on the temperature at which the lump is manufactured). The mass of the present invention can be satisfactorily used as a cutting tool.

The Ti-containing 5tJ4 mass of the present invention is pure Si3N
.

0 For example, as shown in Figure 1, the electrical conductivity of an amorphous Si mountain ( ) containing Ti at 300°C is higher than that of α-type St, N4, which does not contain Ti at the same temperature.
It is seven orders of magnitude higher than that of (2), and is characterized by a small temperature coefficient of electrical conductivity.

Since it has the above-mentioned electrical conductivity and a unique temperature coefficient of electrical conductivity, it is expected that it will be applied as an electrical material utilizing these properties.

Next, the manufacturing method of the present invention will be explained with reference to FIG.

According to the present invention, a nitrogen deposition source gas, a silicon deposition source gas, and a titanium deposition source gas are each sprayed onto a substrate 2 heated within a temperature range of 500 to 1900° C. using a combination tube 4, and at this time, the substrate 2 is heated to a temperature range of 500 to 1900° C. The nitrogen deposition gas flux blown onto the substrate 2 is surrounded by a mixed gas of a silicon deposition source gas and a titanium deposition source gas, and a gas phase decomposition reaction of both gases is caused on or near the substrate 2. 5ilN4 containing Ti
5t3N containing the produced Ti can be deposited as a lump on the substrate.

Note that it is advantageous that at least the tip end and the base of the combination tube are both placed in a closed container where the atmosphere and pressure can be adjusted.

As a silicon deposition source compound which is one of the starting materials for producing Si+Na containing Ti in the present invention, silicon halides (
sicz4.5tF4. SiBr4.5i14+ 5
izC1h+Si, Br, Si, 1. , 5iBrC
l 3.5iBr3Cl, 5iBr, Cl +5i
ICj! z), hydride (SiH4+5i4H+o+S
i: +Hs, 5iJb), hydrogen halide (Sill
Cl 3.5iHBr3, 5iHF++ 5iHIs)
Any one or two or more selected from these can be used, preferably 5iHn which is gaseous at room temperature, or 5iHCfi+5iC which has a high vapor pressure at room temperature.
jl! 4 can be used advantageously. Also, as a nitrogen deposition source compound, a hydrogen compound of nitrogen (HN3゜NH: +
, NzH4), ammonium halide (NH, Cl
.

NH4F, NH4HF2. Any one type or two or more types selected from NH41) can be used,
NH3 and N2114 are relatively inexpensive and easily available, so they can be preferably used. In addition, titanium halide (TrCf) is used as a titanium deposition source compound.
41TiBr4+ TiF4+ Ti14) can be used. TiCl4 is relatively inexpensive and easily available, so it can be preferably used.

The temperature of the substrate from which Si and N containing Ti are obtained from the silicon deposition source compound, titanium deposition source compound, and nitrogen deposition source compound is 50
Within the range of 0 to 1900°C, but 1000 to 160
It is preferred to use a temperature range of 0°C.

In order to convey one or two of the nitrogen deposition source compound, silicon deposition source compound, and titanium deposition source compound, Nz
, Ar, l(e+ Hz). One or more of the following can be used as a carrier gas. Of these, N2 can also be a source material for nitrogen deposition, and N2 can be used for silicon and titanium deposition. May participate in reactions during gas phase decomposition of source compounds.

The carrier gas is used to control the total gas pressure in the container containing the substrate, to control the mixing ratio of the vapors of the silicon, titanium, and nitrogen deposition source materials, to control the gas flux shape in the container, and/or N, H, 5iJ4 containing Ti can be generated without using a carrier gas.

Next, a method for producing Si3N containing Ti will be described in the case where 5iC14+ TiCj2a and NH3 are used as raw materials and 2 is used as a carrier gas.

Said 5iCj! 4. TiCl2. and N11. are respectively introduced into the container using, for example, the combination tube 4 as shown in the second example, but N113 passes through the inner tube 8 of the combination tube 4, and 5iCj! A mixed gas of 4 and T1Cf4 is introduced through the outer tube 9, and the surrounding flux of NH3 is 5iCj! a and Ti(I
Both gases are sprayed onto the substrate 2 in the container while surrounding it with a mixed gas of No. 14. At this time, carrier gas N2 is blown through the outer tube 9 and 5iC14 and TiCj! It is advantageous to premix with a.

The flow rate of N2 is preferably within the range of 100 to 7000 cc/min (100 (1 to 4000 cc/min is most appropriate).
Good within the range of 0cc/akin<, 50~500c/
The most appropriate range is within the win range.

TiCj! , the flow rate (vapor B) is 0.1 to 100 c
It is good within the range of c/1lIin, 1 to 50cc/lll
A range of 1n is most appropriate. The flow rate of NH3 is 50~
Good within the range of 500 cc/min (80 to 400 c
The most suitable range is c/lll1n.

The total gas pressure in the container housing the substrate 2 is 1 to 760 mm
Hg is preferably within the range, and 5 to 100 mmHg is optimal.

Note that even if the gas pressure is 1 atm or more, the 5i containing Ti of the present invention
J4 can be manufactured.

(Example) Next, the relationship between the manufacturing conditions and the manufactured lumps will be explained.

Table 1 is a table showing an example of the influence of the manufacturing temperature on the crystal state of Si3N< when producing the Si, N, and agglomerates of the present invention containing Ti and the Si3N4 agglomerates not containing Ti. Here, as manufacturing conditions other than the manufacturing temperature, if Ti is included, the gas pressure in the container is 30+r+mHg, 5iC
ffi4 flow rate to 136 cc/min (steam state)
, T1Cf4 flow rate is 18cc/min (steam-like!
, the NHz flow rate was 120cc/min.

The N2 flow rate is 2720 cc/win, and if Ti is not included, the gas pressure in the container is 30 KHg, 5iC1a.
Flow rate 136cc/win (steam state), NH3
Flow rate: 120 cc/min, N2 flow rate: 2720 cc
/lll1n.

Table 1 As is clear from Table 1, when Ti is included, the temperature at which α-type crystals are formed is 300°C compared to when Ti is not included.
It can be seen that β-type crystals, which have traditionally been difficult to produce by chemical vapor deposition, can be easily formed as the temperature decreases.

In the present invention, the TiN content in the agglomerates is 28% by weight when the manufacturing temperature is 1100°C, as shown in FIG. .2% by weight.

As shown in FIG. 4, the density of Si3N containing Ti of the present invention is 3 at a manufacturing temperature of 1100°C.
3 at a manufacturing temperature of 1500°C from 33 g/cm3
, to 24 g/cm', which decreases with increasing production temperature, but these density values are similar to those of TiN (theoretical density:
5.43 g/cm3), the logical density of α type 5iJ4 is 3.18 g/cm3, and the logical density of β type 5isNa is 3.
．． 19 g/cm”.

Next, the relationship between the manufacturing temperature and the micro-Vickers hardness when manufacturing the mass of the present invention will be explained with reference to FIG. When the manufacturing temperature is up to 1300°C, the higher the temperature, the higher the hardness, but when it exceeds 1300°C, the hardness decreases.

Next, the Ti-containing Si3N4 lump of the present invention and T
FIG. 6 shows a comparison of the effects of the manufacturing temperature and the gas pressure in the container on the crystalline state of Si, N, and lumps that do not contain i. According to the same figure, in the Si3N containing Ti of the present invention, in the lumps, A is made of amorphous, B is mainly made of amorphous and a small amount of α-type crystals, D is mainly made of α-type crystals, It can be seen that both of the materials E mainly consisting of β-type crystals can be produced at a lower temperature than the St 3N4 lumps that do not contain Ti.

Next, the present invention will be explained using more specific examples.

Back plate construction Using the device shown in Fig. 7, a plate-shaped substrate 2 made of artificial graphite is sandwiched between copper electrodes 3, and the inside of the furnace is heated to 10 mmH in advance.
The pressure was reduced to 1.5 g, and the substrate was heated to 500° C. or higher by applying electricity to the substrate to degas the substrate. Then the base was heated to 1100
It was kept warm at °C. Add 120 cc of ammonia gas to this
Hydrogen gas (flow rate 1360 cc/ml) was flowed out from the inner tube at 20 °C (flow rate 1360 cc/ml) and simultaneously passed through silicon tetrachloride (vapor pressure 76 mm Hg) at 0 °C and titanium tetrachloride (vapor pressure 10 mm Hg) at 20 °C. ) The mixed gas of hydrogen gas (flow rate: 1360 cc/ml) was allowed to flow out from the outer tube.

The flow rate of silicon tetrachloride gas under these conditions is 136 c/m
In, the flow rate of titanium tetrachloride gas was 18 cc/win. The pressure inside the container at that time was 30 mmHg. After flowing gas for 8 hours, the electric current was turned off, the mixture was cooled, and the substrate 2 inside was taken out, and a plate-like black Si3N4 containing Ti with a thickness of 0.7 mm was obtained on the surface of the substrate 2. As a result of X-ray analysis, it was found that Ti present in this 5isN4 plate existed as TiN, and transmission electron microscopy revealed that Ti was uniformly dispersed in the amorphous material with a particle shape of approximately 30 mm in diameter.
N crystals were confirmed. Other properties of this Ti-containing 5isNa were measured and found to be as follows. Crystal structure: amorphous, density 3.33 g/cm', containing TiN (100 g).

Using the same equipment as in Example 1 and performing the same operations, T
Si3N containing i was produced. First, set the substrate temperature to 120
The temperature was maintained at 0°C, and ammonia gas was flowed out from the inner tube at a rate of 120 cc/min, and at the same time, hydrogen gas (flow rate 1360 cc/Iwin) was passed through silicon tetrachloride (vapor pressure 76 mmHg) at 0°C. ) and hydrogen gas (flow rate: 1,360 cc/ml) passed through titanium tetrachloride (vapor pressure: 10 mmh) at 20° C., and then flowed out from the outer tube.

The pressure inside the container at that time was 30 mm lg.

After flowing gas for 8 hours, the electric current was turned off, the mixture was cooled, and the substrate 2 inside was taken out, and a black 5iJn containing Ti with a thickness of 0.8 mm was obtained on the surface of the substrate 2. As a result of X-ray analysis, it was found that the Ti present in this Si3N4 plate existed as TiN, and transmission electron microscopy confirmed TiN crystals uniformly dispersed in the amorphous material with a particle shape of approximately 30 mm in diameter. It was done. Other properties of this Ti-containing 5isN4 were as follows. Crystal structure: It was amorphous, but the presence of some α-type was confirmed on the substrate side. Density 3.27
g/cm3, TiN content 11% by weight, room temperature hardness:
2600kg/kaku2 (load 100g), DC electrical conductivity 3X10-'Ω-'cm-' (700°C).

Table 2 shows a summary of various factors and their ranges for producing the Ti-containing Si, N, and agglomerates of the present invention.

Utilizing the excellent properties shown in Table 2 and above, the Ti-containing Si2N4 of the present invention can be used in the following fields.

1. As a coating material (a) By coating the surface of tools such as bits, dies, drills, cutters, etc., it extends the tool life and facilitates the management of automatic machining systems.

(b) Prevent wear and high-temperature seizure by coating the surfaces of mechanical parts that require wear resistance, such as bearings, gears, and rotating shafts.

(c) By coating the surfaces of various materials such as metals, compounds, ceramics, graphite, etc., they are provided with highly hard surfaces and further improve mechanical properties at high temperatures (engine parts, turbine parts, etc.).

(d) By coating the surface of a substrate made of arbitrary material,
Conductivity is also imparted to a base made of an insulating material.

(e) Prevent the generation of static electricity by coating the surface of the insulator.

2. As a block material (f) It is useful as a tool material for carbide bits, carbide dies, etc.

(g) Used for hard physical and chemical instruments that require high hardness.

(H) It is useful for bearings, rotating shafts, bearings, and sealing materials that require high hardness and need to maintain that hardness at high temperatures.

(S) Can be used as a structural material used at high temperatures, such as engine parts and turbine parts.

(n) It can be used in heating elements that are lightweight and require high temperatures, such as thermal recording pens.

(Le) Can be used as a recorder for electrostatic printing equipment.

(wo) Used as a high-temperature filament.

(W) Used as a heating element for high temperatures.

[Brief explanation of drawings]

Figure 1 is a diagram comparing the relationship between the DC electrical conductivity and temperature of Si3N4 containing Ti and 5isNa not containing Ti according to the present invention, Figure 2 is a perspective view of the spray pipe according to the present invention, and Figure 3 is a A diagram showing the relationship between the TiN content and manufacturing temperature in Si3N4 containing Ti according to the present invention, Figure 4 is a diagram showing the relationship between the density and manufacturing temperature of Si3N4 containing Ti according to the present invention, and Figure 5 is a diagram showing the relationship between the manufacturing temperature in Si3N4 containing Ti according to the present invention. Figure 6 is a diagram showing the influence of manufacturing temperature and gas pressure in the container on the crystalline state of 5iJn. 1 is a fragmentary cross-sectional view showing an example of a manufacturing apparatus for Si3N containing Ti. 1...Container 2...Base...Gripping rod...Vacuum gauge placement port...Discharge port...Outer tube

Claims (1)

[Claims] 1. A substantially amorphous silicon nitride block containing TiN precipitated in granular form.