JPS6089543A - Erosion resistant metal-ceramics composite material - Google Patents

Abstract

PURPOSE:To obtain a metal-ceramics composite material showing superior erosion resistance when used as a material for a high temp. apparatus by adding a specified amount of ceramics having a specified particle size to a metallic base material. CONSTITUTION:A metallic base material having about 0.5-50mum particle size such as Fe, Ni or Ni-Cr powder is blended with 5-80vol% one or more kinds of ceramics having <=10mum average particle size to obtain a metal-ceramics composite material. One or more kinds of compounds selected among oxides such as Al2O3 and Y2O3, carbides such as NbC and SiC, and nitrides such as Si3N4 and TaN are used as the ceramics. When the composite material is used, damage due to erosion at high temp. can be surely prevented in a high temp. apparatus such as an energy apparatus utilizing coal.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal-ceramic composite material having excellent erosion resistance when used in high-temperature equipment.

High-temperature generators such as thermal power boilers have traditionally used oil as their main source, but in recent years, pulverized coal-fired boilers,
The use of coal, such as coal-fired boilers such as fluidized bed boilers, is being rediscovered.

However, the device design is based on the design concept when using petroleum. For example, coal-fired boilers and cab boilers are manufactured using the same material composition as oil-fired boilers, but unlike oil-fired boilers, coal-fired boilers differ from oil-fired boilers in that ash of the same shape falls out as clinker inside the boiler. The boiler tubes that make up the coal-fired boiler are subject to severe erosion damage at high temperatures due to the boiler tubes that form the coal-fired boiler.

However, the only ways to prevent such erosion are, for example, in coal-fired boilers, by lowering the flow velocity and installing protectors and pan-full plates. Ta. However, even if the flow velocity is limited as a design measure, it may result in uneven flow areas where the flow velocity is higher than expected, and the installed protectors and baffle plates themselves may suffer erosion damage and wear out. There are problems such as Furthermore, there are few studies on erosion at high temperatures, and its behavior is not clear. Therefore, there is currently little demand for appropriate erosion-resistant materials, partly because little countermeasures have been taken regarding materials.

By the way, erosion is a phenomenon that occurs when solid particles collide with an object with kinetic energy, so in a short-term sense, it can be prevented by increasing the hardness of the object being collided, just like normal wear phenomena. However, in reality, it is not that simple. For example, if we compare the erosion characteristics of soft ductile materials such as metals and hard but brittle materials such as ceramics, we find that Slight differences in conditions can lead to completely different results, such as ductile materials causing greater erosion when the collision angle is small, but brittle materials causing greater erosion when the collision angle is large. However, the erosion phenomenon under actual operation, where various conditions such as the collision angle and collision speed are different, is different from normal wear phenomena, and there are various problems that have not been solved. It is. Furthermore, erosion at high temperatures is accompanied by even more complex phenomena and behavior.

The present inventor has realized that it is possible to reduce the flow rate restriction in the device, which had conventionally been necessary to prevent erosion, to improve the thermal efficiency of the device, to downsize the device, and to achieve both erosion resistance and corrosion resistance. It can be used in many environments where erosion resistance is required more than ever before, and it can be applied to environments where erosion resistance is required more than ever before. As a result of extensive research in order to obtain an erosion-resistant material that can be applied to highly eroded parts and further extend the life of the equipment, we have discovered that the erosion-resistant properties of metal materials vary depending on the material. Recognizing that it is difficult to completely prevent erosion damage, by incorporating ceramics into the metal base material, we also recognize that the diameter and content of ceramic particles are important as well as the hardness of the ceramic particles. That is, the present invention was made based on the recognition that the object can be achieved by containing a specific amount of ceramics of a specific size in a metal base material. That is, the present invention preferably has a powder particle size of 0.5
A metal base material of ~50 μm is coated with at least one type of ceramic having an average diameter of 10 μm or less at a volume ratio of 5 to 8.
This is an erosion-resistant metal/ceramic composite material containing 0%.

The metal base material used in the present invention is not particularly limited as long as it can withstand the operating temperature and atmosphere, but for high temperature applications, P'es Ns and CO, or Cr based on these may be used.

It is preferable to mix AL Sis Mo or the like in an appropriate amount.

In addition, examples of ceramics used include Tio
,,Al2O3,5i02,Y2O3,The,,Zr
02 (containing stabilized zirconia), such as Tics 5iCs W2Cz
B4C% TaCXNbC, Cr2Cs, Cr, C,
, Cr, Co, MO2C, etc. and carbide-based ceramics such as graphite carbon (fiber), and for example TiN, TaNXSi3N, BN%
Nitride ceramics such as Cr2N%CrN are used, and at least one kind or two or more kinds of ceramics selected from these are used in an appropriate combination.

However, the hardness of the added ceramics is higher than that of ordinary wide-area materials, but for the purpose of erosion resistance, the particle size and content are more important than the particle hardness. As a result of a high temperature erosion test, the average diameter of the dispersed particles needs to be 10 μm or less, and the content rate needs to be 5 to 80% by volume.

That is, when the average diameter is 10 μm or more and the volume fraction is 5
If the volume fraction is less than 80%, the properties of the metal base material will be exposed to the surface and the erosion resistance will not improve, and if the volume fraction is more than 80%, the toughness and ductility will deteriorate and the material cannot be used as a member. . In addition, in the case of string-like ceramics such as carbon fibers, the average diameter is considered to be the average cylindrical cross section, and when it is different from a true sphere, it is considered to be the diameter of a sphere that has the same volume as 1.

Next, as a method for manufacturing the composite material of the present invention, for example,
A method of turning metal parts into powder and making them into compacts after powder metallurgy, ■
A method in which ceramics are suspended in a plating bath and then dispersed and precipitated on a plating film; ■ A method in which ceramic powder is applied to a metal base material and then the metal elements are diffused and penetrated from the surface; ■ A method in which oxides, carbides, and nitrides are There are methods in which a metal base material containing the elements to be formed is subjected to treatments such as internal oxidation, carburizing, and nitriding to form a post-mixture layer on the surface layer.
There is no problem with any method depending on the shape of the part, purpose, etc. Therefore, as a product form, the entire product may be made of composite material, or only the required surface may be made of composite material.

In the present invention, the metal base material contains at least one type of ceramic with an average diameter of 10 μm or less in a volume ratio of 5 to 80%, so it has excellent durability even when used under harsh conditions at high temperatures. It was possible to obtain a composite material with erosion properties, and by using this composite material, it is possible to significantly extend the life of the equipment, or to reduce the flow rate restriction within the equipment, thereby improving equipment thermal efficiency. This can make it possible to downsize the device. The material of the present invention is recognized to have excellent effects such as being able to obtain excellent erosion resistance and corrosion resistance not only in a high temperature environment but also in a low temperature environment.

Next, examples of the present invention will be described.

Examples 1 to 21 As a metal base material, Fe%NiNNi-20C
r, NiNi-5O, C01AI, Si, etc.-added alloys, and other alloy powders, all of which are high purity powders as raw material powders, for example ~Fll+, 99.3%
, the balance contains Mn% 02, etc., and Ni has 9
9.7% and the rest is C011? 'Including 6th grade,
Paddy rice with a grain size of 1 to 10 μm was used, and ceramic powders such as A la Os, Y203, Tio, and Zr were used.
O2, NbCz S I CN Cr23 Ca,'r
ict WCX%C%B4 CN S 131'J4,
TaN and BN were mixed at a blending ratio that sharpened the average dispersion diameter and the parting ratio as shown in Table 2, and
Using the IP method (hot compression molding method), a composite material was prepared under molding conditions of temperature: 1150° C. and pressure: 900 Kd10A, and a high temperature erosion test was conducted under the conditions shown in Table 1. The results are shown as erosion thickness reduction rate, which is calculated by measuring the maximum thickness reduction depth that occurred on the test piece using a surface roughness meter for up to 10 hours.
It was calculated by converting it into the rate of thinning (μ: m/h). Based on these results, Comparative Examples 1 to 9 Comparative samples were prepared in the same manner as in the examples, and erosion tests were conducted under the conditions shown in Table 1 in the same manner as in the examples. The results are shown in Table 3.

As shown in Table 3 above, according to the present invention, it is possible to reliably prevent high-temperature erosion damage in high-temperature equipment such as coal-based energy equipment, improve the thermal efficiency of the high-temperature equipment, and dramatically extend the service life of the high-temperature equipment. This brings about extremely useful effects on labor production, such as making it possible to

Patent applicant: Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] 1) An erosion-resistant metal-ceramic composite material comprising a metal base material containing 5 to 80% by volume of at least one type of ceramic having an average diameter of 10 μm or less.