UA63469C2 - Diamond-hard-alloy plate - Google Patents

Abstract

Invention concerns the branch of obtaining the composite materials, namely, diamond-hard-alloy plates. Diamond- hard-alloy plate contains diamond layer and hard-alloy plate. Diamond layer and hard-alloy plate additionally contain chromium diboride. The present invention ensures the formation of homogeneous structure with durable body of hard-alloy plate and diamond layer and, as consequence, the reduction of brittleness, the increase of heat resistance, strength and wear resistance of material. Furthermore, the operation of producing of interlayer is excluded, which considerably simplifies the process of their obtaining.

Description

The invention relates to the field of production of composite materials, namely diamond-hard alloy plates and can be used in the sintering of layer-by-layer non-separable connections hard alloy substrate - diamond polycrystal under conditions of high pressure and temperature for the manufacture of mainly destructive elements of drill bits and cutters.

The closest technical essence to the invention is the diamond-hard alloy plate described in the method of obtaining a combined sintered insert | see US patent Me4403015, IPC B22E3/14, publ. 06.09.831|, containing a diamond layer and a carbide plate, between which there is an intermediate layer containing diamonds.

The method of its production consists in the fact that a solid sintered compact containing diamond or B. VM in the amount of more than 20 vol. 95, are connected to the hard alloy substrate with the help of an intermediate layer less than 2 mm thick. This intermediate layer contains such an amount of V. vm, which ensures a rigid adhesion of a solid sintered press with a hard alloy substrate, but no more than 7095 vol. The other part of this layer consists of a mixture of carbides, nitrides, carbonitrides, or borides of transition metals of Mendeleev's periodic table 4a, 5a, ba, a mixture of these compounds or their solid solutions. To improve the sintering of the intermediate layer, it contains AI and/or 51i in an amount of more than 0.wt. 905.

The disadvantage of the diamond-hard alloy plate obtained according to the prototype is fragility, low heat resistance and weak chemical connection of the intermediate layer with the hard alloy plate and the diamond layer. Carbides, nitrides, carbonitrides of transition metals of Mendeleev's periodic table 4a, 5a, ba, or their mixtures, regardless of their relative resistance to heating, are brittle and inert to chemical bonds. When AI and 5i particles are introduced at high temperature, brittle intermetallic compounds and layers are formed, which reduce the mechanical properties and wear resistance of the sintered material. During sintering, the plates are heated to a temperature of 1200-17007C, and after their rapid cooling, temperature stresses commensurate with the modulus of strength and even exceed it occur, which leads to the appearance of microcracks and cracks in the intermediate and diamond layers, which leads to the degradation of the operational properties of the plate.

The basis of the invention is the task of improving the diamond-hard alloy plate, in which, due to the introduction of chromium diboride into the charge of the hard alloy plate and the diamond layer and the proposed ratio of components, the formation of a homogeneous structure with a strong frame of the hard alloy plate and the diamond layer and the chemical bond between them is ensured reduction of fragility, and, as a consequence of creating such a structure - increase of heat resistance, strength and wear resistance of the material. In addition, the operation of the intermediate layer is excluded, which greatly simplifies the process of obtaining them.

The specified task is solved due to the fact that in the diamond-hard alloy plate containing a diamond layer and a hard alloy plate, according to the invention, the diamond layer and the hard alloy plate contain chromium diboride with the following ratio of components, wt. 90: diamond layer: diamonds -90...97 chromium diboride -0.5...10 carbide plate: hard melt -90...99.5 chromium diboride -0.5...10

It is optimal when the diamond layer additionally contains a metal binder, such as at least one metal from the following series: cobalt, nickel, iron, molybdenum, titanium, zirconium, and the diamond layer and the carbide plate contain tungsten diboride (U/2В5 ) in the amount of 0.1...5wt.9o.

The cause-and-effect relationship between the set of features that is claimed and the technical results achieved during its implementation is as follows.

Thanks to the introduction of active refractory compounds of chromium diboride (StVg) into the charge for the hard alloy plate and the diamond layer, not only the valence, but also the internal electrons of the additional a-level of the chromium and tungsten atoms are generalized, which is manifested in a very strong hexagonal structure. A layer of chromium atoms is placed on a hexagonal close-packed lattice, alternating with layers of boron atoms, forming a hexagonal two-dimensional grid. These circumstances make it possible for SgiVo and M/2B5 atoms to form strong chemical bonds both in their own crystals and in compounds with other elements. In addition, due to their chemical activities, SgVo atoms form active nuclei with other atoms of the system and cause their three-dimensional growth over the entire sintering interval, which contributes to the diffusion and self-diffusion of elements and the transfer of mass and heat, and, as a result, the thermal stress decreases. As a result of such effects, a structural-phase transformation of all components occurs, which contributes to the formation of a fine-grained structure with a strong frame and physical and mechanical properties of a diamond-hard alloy plate.

We built a phenomenological model of the sintering process of diamond-containing composite materials for polydisperse systems. The module is based on the proposition that the sintering shrinkage rate and the chemical reaction rate are proportional to the product of the generalized rate constant of the process, in which the activation energy depends on temperature and pressure, and a model function that satisfies the condition of the physical dependence of mass transfer mechanisms during sintering on the system parameters, and the best thus approximates the experimental results. The obtained equations make it possible to calculate the activation energy of the system and the kinetic parameters of mass transfer (mechanism of mass transfer due to diffusion and nucleation of new phases) under the given conditions of temperature and pressure.

When tungsten diboride (M/285) is added to these layers, the modulus of elasticity, resistance and shear are additionally increased, which significantly affects the strength, wear resistance and reliability of the diamond-hard alloy plate.

The limits of the content of StB2 and UU2B5 in the charge were determined based on the condition of the main task - increasing the heat resistance, strength and wear resistance of the material.

The upper limits of the content of SIVg2 and UUM2B5 were limited to the sintering conditions under which the temperature and pressure did not exceed the values of 1700"C and 8.0 GPa, respectively. Under these conditions, from the obtained kinetic equations, the minimum values of the activation energy of the sintering system were determined for which the kinetic parameter t, which characterizes mass transfer due to diffusion, and the kinetic parameter, which characterizes the nucleation of new phases and its growth rate n, approached the values of 1/3 and 4, respectively, at the compaction stage. Those quantitative values

SiB" and M2B5, in which the activation energy acquires the smallest values at t-1/3, and n-4 are essential for the formation of the best physical and mechanical properties and structure of the sintered material.

The invention is illustrated by drawings, where Fig. 1 shows the equipment of the high-pressure cell before sintering, Fig. 2 shows the general view of the diamond-hard alloy plate after sintering.

Example 1

To equip the high-pressure cell (Fig. 1), a container made of lithographic stone 1, a heat-insulating disk 2, pressed from pyrophyllite, heating elements - disks З and a tubular heater 4, made of graphite, hard alloy plate 5, sintered from VKA alloy, were taken charge of which 1.O0 mass was introduced. 95 StgV" and 1.0O0mas. 95 М/2В5, diamond layer 6, consisting before sintering of a mixture of ASM 60/40 diamond powder with particle sizes of 40...60 μm (94 mass. 95), Co powder (4 mass. 95), StV»2 powder (1 .5 wt. 95) and powder M/2B5 (0.5 wt. oo) with particle sizes of 5...10 μm, electrically insulating disk 7 pressed from graphite-like boron nitride, electric current conductors - molybdenum disk 8 and iron cylinder 9, sleeve 10 from lithographic stone. The equipment was carried out according to the scheme shown in Fig.1. Sintering was carried out in a toroid-type high-pressure apparatus according to the following scheme and modes: for three minutes, the pressure was increased to 8 GPa at a constant speed of 44.4 MPa/s, and in parallel, heating was carried out to 17007 °C at a constant speed of 9.4 °C/b. At a temperature of 17007C and a constant pressure of 8 GPa, sintering was carried out for two minutes. Next, within 3...5x8v. the pressure was reduced to atmospheric and simultaneously cooled to 80"C due to forced convection. Samples of diamond-hard alloy plates with a diameter of 15 mm and a height of 4 mm were obtained. After sintering, the material samples were mechanically processed to a state suitable for studying the structure and physical and mechanical properties. The diamond-hard alloy plate (Fig. 2) consists of a hard alloy plate 5 and a diamond layer b, which was formed as a result of sintering the system under conditions of high pressure and temperature. On a scanning electron microscope (SEM) 85-340, equipped with a digital image processing system and an energy analyzer X-ray spectra of "I IPK-860", a qualitative analysis of phase distribution was performed based on digital images in the characteristic radiation of elements of characteristic phases. The conducted studies showed that the diamond layer contains 94 wt. 95 diamonds, 4.2 wt. 95 cobalt, 1 4 wt. 95 chromium diboride , 0.4 wt. 90 of tungsten boride (M/2B5), while the final composition of the samples was differs from the initial charge, which confirms the presence of heterogeneous diffusion processes that occurred during sintering. As a result of the introduction of chromium diboride and tungsten boride (M/2B5), solid solutions and new active phases were formed, their three-dimensional growth occurred over the entire sintering interval, which stimulated diffusion processes, made it possible to evenly distribute all elements of the system throughout the volume of the material, create self-diffusion and strong adhesion of the diamond layer to the carbide plate. At the same time, micropores and microcracks are completely absent on the surface of the "diamond layer-hard alloy plate" interface.

To determine the temperature stresses, a mathematical model of the thermoelastic state of the diamond-hard alloy plate was considered, which occur in a two-layer heterogeneous plate under conditions of high pressure and temperature. The module takes into account the features of sintering and cooling due to forced convection and radiation of an absolutely black body. When cooling a plate, the heat flow from its surface is not a linear function of the temperature difference between this surface and the environment that surrounds it. Here it is taken into account that the plate is bounded by an absolutely black body with an absolute temperature To, loses the amount of heat that is assigned to a unit of its surface per unit of time according to the law: o-vvigita) where b . Stefan-Boltzmann constant;

E is the relative emissivity of the surface (degree of blackness).

For tungsten carbides, it is 0.7; chromium diboride and tungsten boride - 0.9; for a mixture of diamond and cobalt powders - 0.93.

Thus, the temperature stresses in the diamond-hard alloy plate were determined with great accuracy, which due to active diffusion (covalent bond between the diamond layer and the hard alloy plate), the absence of inert carbides, carbonitrides, etc., high thermal conductivity and heat transfer in conditions sintering is significantly reduced and does not exceed the physical and mechanical properties of the material. After that, their wear resistance was determined by the value of the specific consumption of the working edge of the plate after grinding quartz sandstone with them on the friction path of 1000M.

See examples 1-6. The table, which is given for those cases that relate to the declared signs. Examples 7-10 - beyond the declared features. Example 11 - reproduction of a diamond-hard alloy plate according to the prototype. The change in the composition of the ATP layers was achieved by performing a separate charge for each material sample.

As can be seen from the table, thanks to the proposed invention, the temperature stresses are reduced by 30GPa, the thermal conductivity coefficients of the diamond layer and the carbide plate are increased by 250 and 5W/m, respectively. K) and resistance against abrasive irrigation increased up to one and a half times compared to the prototype.

Diamond carbide plates can be used as rock-breaking inserts in drill bits, cutters for cutting metal plates, wood, etc.

The operation of a diamond drill bit using the indicated plate does not differ from the operation using the well-known drill bits with which drill bits were equipped, except for the reduction of the cost of soldering in the manufacture of bits and the use of cheap solders and the expansion of drilling opportunities due to the high temperature resistance, wear resistance and strength of the proposed plate. Diamond carbide plates are soldered to the outer surface of the bit body, which rotates at a constant speed, and the drilling speed depends on the type of rock.

Table

The object of production where Sumarne | What happens in Diboride Hard Diboride temper. |Hyploprovid Wear resistance) Notes

IF the song was sung by avn

ATPpZhidnobi | 94 | 15 2409; - | | HER 1051 98 | 1 | 1 | 108 | 400 | 00020 of the invention/ 2 90 | 10 | 6 20/10 /-1-І- ІІ - | 90 | 10 | - | 188 | from 00 | 0o0ozo | shrs(eE (3 97 | 05 |1й0| 1 - /-Й1-1- 1011 9957 | 03 | - | 89 | 420 | 00020

Shen En 3 EE: 5955 05 | - І- І - /-І1-І-І- | with | 1 | 1 | 88 | what | 024

(6 90 | lo | - |- HER - 1-1 -11-1- 1 99551 051 | for | zgo | pog | shrkfe:

Separation "Iv v| 1 11111717 e| z | 21 zha | syu | soma

Cracks in 99.7 1.3 95 Z 2 490 diamond layer (а; 89 | 9 | 1/1 7 - 71-1-- 1 - | 88 | 12 | - | 410 | 238 | 000399 ой вв | лю | 2, - ІІ /-І-І-1 | 99571031 - | 46 | go | 0omo

ATP for x post 1 | 111111 | yuyu || I | with | 7) The diamond layer of the diamond-hard alloy plate according to the prototype additionally contains 5 wt. 95 cobalt. .

FDI pi R p 2 o

Ina

WHERE

THEIR postnnkpk certain shanii our and

WITH

Figi

Fig. 2

Claims (1)

The device for protecting gas and electric stoves from contamination contains a flexible plate made of heat-resistant material with a perforation on its surface for the introduction of technological elements of the plates, and is distinguished by the fact that at least one more plate of heat-resistant material is inserted into it, and the size of the plates they are chosen from the condition that the surface area of the individual plates is less than the surface area of the plate table, and the total area of the plates exceeds the table surface area. Plates are made of aluminum foil or other flexible, non-toxic and heat-resistant materials with a high reflective capacity. To expand the consumer assortment and ease of use, plates can be supplied with perforations in the form of notches and holes. After cooking, the contamination of the plate is removed. The surface of the stove remains perfectly clean. As a result of the implementation of the claimed device, convenience and comfort are increased and the sanitary and hygienic conditions for cooking food on stovetops are improved. In addition, the care and maintenance of the stove is significantly simplified. Thanks to the properties of the foil plates, heat rays are reflected, the efficiency of the stove increases significantly, cooking time is reduced, and gas and electrical energy are saved. In addition, plates can be used as carriers of advertising information, which is applied by pressing, sticking, applying non-toxic dyes.