SE444674B - TOOL COMPONENT OF DIAMOND OR CUBIC BORN NITRID AND PROCEDURE FOR ITS MANUFACTURING - Google Patents

Description

78Ûí87ï2 ~ 8 2 The invention relates to a tool component containing at least about 70% by volume of particles of diamond or cubic boron nitride, which characterized in that it comprises: (a) self-bonding particles of diamond or cubic boron nitride, such as constitutes about 70 to 95% by volume of the component, and (b) a network of communicating or interconnected, empty pores, which are distributed throughout the component and are delimited by and between about 0, GS and 3% by volume of a metal phase, which consist of sintering aids for the abrasive particle mass in question, and is selected from (1) a catalytically active metal in mental form selected from the group consisting of metals belonging to it periodic table group VIII, Cr, Mn, Ta, (2) a mixture of alloy metals of the catalytically active metal or de catalytically active metals and non-catalytically active metal or non-catalytically active metals, (3) an alloy of at least two of the catalytically active metals, (4) an alloy of one or more catalytically active metals and one or more more non-catalytically active metals, preferably for mantle, and (5) cobalt, cobalt alloy or aluminum alloy and an alloying metal selected from the group consisting of Ni, Mn, Fe, V and Cr, preferably for cubic boron nitride, the pores comprising takes between about 5 and 30 volume percent of the component.

It has been found that the removal of substantially all of the of the infiltrated material gives an abrasive particle press body, which shows a significantly improved resistance to chemical deterioration or destruction at high temperature.

According to one embodiment, a composite compact is constituted according to the invention essentially of a layer of self-bonding abrasive tiklar and a substrate layer (preferably of cemented carbide, cemented carbide) bonded to the layer of abrasive particles.

The attached drawing figure shows a photomicrograph of a part of a ground surface of a diamond compact made according to the invention.

Figure 1 shows a diamond press body, but the figure also forms an illustration of alternative embodiments of the invention, according to which the abrasive particles consist of cubic boron nitride (CBN).

The compact comprises diamond particles 11, which constitute 7801872-8 3 between 70 and 95% by volume of the compact. (The term particle was used in the present context to denote an individual crystallite or a fragment thereof) -V Interfaces 13 exempli- the self-bond or diamond-to-diamond bond between adjacent particles ll. The same diamond crystals ll, shown in the ground surface of the compact in the figure, is in it third dimension or direction bound to adjacent diameters mantle crystals (not visible in the figure). A metallic phase of sintering aid (not shown in the figure) is infiltrated essentially uniform throughout the compact and is assumed to be encapsulated in enclosed areas, formed by adjacent diamond- particles. This phase comprises between about 0.05 and 3%, calculated on the volume of the compact. A network of communicating, empty pores 15 are distributed throughout the compact and are bounded by diamond particles. ll and the metal phase (not shown). The pores 15 form between about 5 and 30 volume percent of the component.

According to one embodiment, the compression body consists only of self-bonded particles. According to a second embodiment, the press body pen bonded to a substrate (not shown), which preferably consists of cobalt-bonded tungsten carbide.

Acceptable particle size range for diamond particles ll is between 1 and 1000 pm. For CBN, this is the acceptable size range between l and 300 μm.

The invention also comprises a process for the preparation of of a tool component with improved high temperature resistance with the following steps: (a) Introduction into a reaction cell or charge unit of a mass of abrasive particles, which are diamond or CBN, as well as a mass of material, which is effective as a sintering aid for the abrasive particulate mass in question, (b) the cell and its contents were simultaneously exposed to influence of a temperature in the range 1200 - 2000 ° C and pressures in excess of 40 kilobars, (c) the heat supply to the cell is interrupted, (d) the pressure applied to the cell is removed, (e) removing an abrasive body from the cell. as forth- 7801872-8 4, set out in steps (a) to (d) and which consists of the articles in self-bonded form with a metal phase comprising the sintering aid infiltrated throughout the abrasive the body, and (f) substantially the entire amount of the metal phase infiltrated in the body, is removed so that this phase constitutes between about 0.05 and about 3 volume percent of the component.

The term "simultaneously" in step (b) above refers to p that high pressure and high temperature are brought into effect at the same time fy but does not require the times of initiation or termination 1 of the effect of high pressure and high temperature coincide (also if in many cases they do so).

The term "sintering aid" is used in accordance with the invention to denote material which is a catalyst for diamond as defined below, and / or a material, which promotes sintering of CBN as indicated below. The mechanism (catalytic or other type), with which the sintering aid promotes self-binding of CBN, is not known._ Preferred embodiments of steps (a) to (e) in the above specified method for manufacturing a tool component of Å diamond particles are described in more detail in U.S. Pat documents 3,745,623 and 3,609,818, which are intended to constitute a part of the present description.

In general, as stated in these patents, diamond compacts are made by a at high pressure and high temperature completed process, whereby hot, compressed diamond particles are infiltrated with a catalytic material through axial or radial sweep-through of the material through the diamond particles. During the sweeping, catalyzing is obtained sintering of the diamond particles, resulting in extensive diamond f -to-diamond-binding. As disclosed in U.S. Pat. 2,947,609 and 2,947,610, both of which are intended to constitute a part of the present description, the catalytically active one is selected the material from the group consisting of (1) a catalytic metal in elemental form selected from the group consisting of metals group VIII, Cr, Mn, Ta, (2) mixtures of alloy metals of the catalytically active metal or metals and non-catalytic metal or non-catalytic metals, (3) an alloy of at least 1 two of the catalytic metals and (4) an alloy of the catalytic the lytic metal or the catalytic metals and a non- -catalytic metal or non-catalytic metals. Cobalt i elemental form or alloy form is preferred. This material forms a metal phase in the abrasive body which is formed at high pressure and high temperature as indicated in step (e) above.

Preferred embodiments of steps (a) to (e) thereof the above method of manufacturing tool components of particles of cubic boron nitride are described in more detail in U.S. Pat. perhaps U.S. Pat. No. 3,767,371, which is intended to be a part of the present description. As described in and in connection with Example 1 In this patent specification, cubic compacts are prepared boron nitride with a process carried out at high pressure and high temperature cess, in which particles of cubic boron nitride are infiltrated with a molten sintering aid material (cobalt metal) by axial sweeping the material through the particles of cubic boron nitride.

During the sweeping, sintering of the particles of cubic boron nitride room and provides extensive bonding of cubic boron nitride to cubic boron nitride. Other materials active such as sintering Cubic Nitride Aids are disclosed in U.S. Pat. document 3,743,489, spelled 3, rea e to zo, een consists of lege- rings of aluminum and an alloy metal selected from the group consisting of nickel, cobalt, manganese, iron, vanadium and chromium. Cobalt and cobalt alloys are preferred. The sintering aid forms the the pine phase indicated in step (e) above.

In the practical implementation of an embodiment of the steps (a) to (e) according to U.S. Pat. Nos. 3,745,623, 3,767,371 and 3,743,489, a composite compact is produced by in situ bonding of an abrasive particle layer (diamond or cubic boron) nitride) to a cemented carbide substrate (sintered carbide). Mate- material for the preparation of the carbide substrate (either of a carbide forming powder or of a preformed body) is the preferred one the source of the sintering aid. In this context can be referred to U.S. Patent No. 3,745,623, column 5, line 58 to column 6, row 8 and column 8, row 57 to column 9, row 9 regarding examples of details regarding the material.

Another embodiment of the invention relates to the manufacture of a compression body consisting essentially of self-bonding abrasive 7sø1s72-s 6 tiklar. According to this embodiment, steps (a) to (Q) are performed in the manner described above with the exception of the arrangement of the material for formation is preferably omitted of * the cemented carbide substrate for the abrasive particle layer either such as carbide forming powder or in the preformed state. When adding To this end, the sintering aid is added separately, e.g. as shown and described in U.S. Pat 3,609,818. Of course, a base of cemented carbide or other material is brazed to the compact after the removal of the metal the phase (step f) for the production of a tool blank or tool insert.

According to the invention it has been found that the metal phase can removed from the compact by acid treatment, extraction with liquid zinc, electrolytic depletion or similar methods and leaves a compact of essentially 100% abrasive particles in self-bound form. -The compression body thus contains essentially no residual metal phase capable of catalyzing conversion of the abrasive particle bonds and / or expand and thereby break the particle bonds, which are the two mechanisms that assumed to cause thermal destruction or deterioration of the former known compacts at high temperature. :It has shown that compacts made according to the invention can withstand impact of temperatures up to 1200 - 300 ° C without significant thermal deterioration or destruction.

Example 1

A plurality of disc-shaped diamond compacts were made by that l) a layer with a thickness of 1.4 mm of fine diameters was applied mantle particles, which were nominally less than 8 μm, and one sintered tungsten carbide with a thickness of 3.2 mm and a diameter of 8.8 mm (13 weight percent Co, 87 weight percent WC) in a zirconium container unit with thickness 0.05 mm, 2) stacked a number of these units in one device for high pressure and high temperature according to figure 1 in a vessels according to U.S. Pat. No. 3,745,623, 3) increased the pressure to about 65 kb and about 140 ° C for 15 minutes, 4) long-_ and lowered the temperature first and then the pressure, S) removed the specimens from the device for high pressure and high temperature and ground the specimens to obtain diamond compacts with a thickness of 0.5 mm bonded to the layer of cobalt-bonded tungsten 73131872-8 7 carbide with a thickness of 2.7 mm. was removed by surface grinding.

As shown in Table I, half of the samples were leached in hot concentrated acid solutions for removing the metal phase and any other soluble non-diamond material. Two different methods was used to remove the infiltrated material. For one first group, designated Samples A-1 and A-4, used only nitric acid-hydrofluoric acid 1: 1 for treatment of sample Å-3 and A-4. For a second group, designated samples B-1 to B-4, were replaced nitric acid-hydrofluoric acid with hot 3: 1 concentrated hydrochloric acid-hydrochloric acid nitric acid (king water) for the treatment of samples B-3 and B-4. The found that the removal rate increased markedly with use The carbide layer in each compact of » Samples A-3 and A ~ 4 acid-treated Samples B-3 and B-4 of the latter acid solution. was placed for a period of time between 8 and 12 days. were treated between 3 and 6 days. In both methods obtained below the acid treatment does not change the dimension of the samples and nor was any splitting or splitting of the diamond observed.

All weight loss can therefore be attributed to the removal of metal phases. the infiltrant, as diamond is not dissolved by these acids.

The amount of metal phase that was infiltrated into these compacts was calculated to be about 8.1% by volume or 19.8% by weight, based on density measurements of the compact before leaching and of diamond and metal used as a starting material for the production of After leaching, about 0.5% by volume or The removal of up the press body. 0.2% by weight of the infiltrated metal. to 90% by weight (sample B-4) of the infiltrated material also indicates that most of the metal phase is localized to the continuous or continuous network of pores. electron microscopic examination (SEM + examination) of a fracture surface of a leached sample shows that the network of pores extends throughout the diamond layer. It turns out that the holes are distributed within the entire layer and most have a diameter less than 1 μm.

This indicates that the acid has penetrated the entire diamond layer and removed the metal phase is substantially uniform throughout the diamond layer.

The transverse breaking limit and Young's modulus of elasticity (E) were measured also for the diamond layers as indicated in Table I. The operations were carried out on a three-point beam loading device.

The device comprises two steel rollers mounted on a base with 7so1sv2-sp 8 a third steel roll centered above with its axis parallel to the other two rollers. The test rods were centered over the lower ones the rollers and were loaded until crime occurred. the pieces were measured in parallel with the elongation stress with use of resistance strain gauges connected to a resistance strain gauge indicator. Samples A-1 to A-4 were prepared for strength testing and finishing with a diamond grinding wheel (l77 to 250 um diamond particles). Samples B-1 to B-4 were prepared for strength test by surface finishing with a patching machine using 15 μm diamond abrasives to provide a more surface defect-free surface than that obtained on test pieces A-1 to A-4 by grinding. It is assumed that the better polished surfaces of them test pieces that were surface treated with fine diamond give higher strength. values due to the more perfect surface conditions This The elongation of the test was reached, i.e. fewer number of stress concentrating defects. is assumed to explain the lower cross-breaking limit values that were measured for the leached specimens (A-3, A-4, B-3, B-4).

Table I.

Removal of infiltration- Transverse- Elasticity- material limit 2 module (E) _ Sample (weight loss%) (kp / mm) (x 103 kp / mmz) A-1 O lll - A-2 O 10 - A-3 l6, l 73 - A-4 l6.2 87 »- B-l O 129 89 B-z o _ 143 i 92 B-3 - 17.0 88 78 B-4 17.9 81 80 In contrast to the transverse fracture test results, it was affected not the E measurements (Table I) of the porosity, since E is a measure on the internal strength and rigidity of a material and not includes microcracking. The average change of the E-value amounted to only about 12% lower when the metal phase filter the rant was removed from the specimens. This difference in for the porosity of the leached specimens, because s: OO CD :so GI) * J RÖ ß Q? ß) _M-c E "I Youngs module momentary distance to outer fiber moments of inertia and M-C do not change, but I decrease as the effective area HÖZEÛ H N II II reduced in proportion to the porosity. If therefore spherical cavities and random distribution is assumed, E =% -% ï: šï is obtained, where x = the proportion of pores (the pore fraction), whereby the value of E becomes greater than the measured. Mean 79 x 103 kp / mmz for E for samples B-3 and B-4 (leached) is corrected to 85 x 103 kp / mm 2 or about 5% lower than the average value 90 x 103 kp / mmz The removal of the metal phase infiltrant therefore has a lot small impact on E and shows the strength of the diamond layer almost exclusively due to the diamond-to-diamond bond.

The E-value 90 x 103 kp / mmz is about 10% lower than the average league value 100 x 103 2 the constant values for single crystal of diamond.

Example 2.

A press body was produced in a manner that was identical as in Example 1 for samples A-1 to A-4 with except that a 1: 1 mixture of diamonds particles with a size of 149 to 177 μm and 105 to 125 μm was used instead of the particles with a size of 8 μm. The compaction body was calculated before leaching to contain 89.1 percent diamond (96.5 volume percent) and 11.9 weight percent metal phase (4.5% by volume). After leaching, a decrease of 11.5% was obtained total weight of the compact, which means that about 0.15 percent of the metal phase (0.06% by volume) remained in the press for E for samples B-1 and B-2. kp / mm, which can be calculated from the the body.

Example 3. _ Four diamond compacts were prepared on it in Example 1 specified way. The carbide was ground from each compact. From two of the compacts, the metal phase infiltrant was removed by acid leaching in hot acid mixture 1HF: 1HNO 3 and 3HCl: 1HNO 3. Every specimens were then mounted with epoxy on a round tungsten carbide substrate measuring 0.89 cm. This composite body was mounted in a tool holder in a lathe and turning test for sub- search of the abrasion resistance was then carried out. »7801872-8 i io » the piece consisted of quartz sand-filled rubber rod, which is commercially available under the Ebonite Black Diamond brand. The test conditions var: Surface speed 107 - 168 surface meters / minute (in a heat treatment group was the maximum intervaløßá'ytmeter / minute), cutting depth 0.76 mm, transverse feed 0.13 mm / revolution and test time 60 minutes.

After the test, the specimens were heat-treated in a stirring tube in a flowing manner dry argon atmosphere. The heat treatment temperature was 700 ° C to 1300 ° C with exposure at 100 ° C intervals. Exposure time was l0 minutes at each temperature. After each treatment, the specimens were examined for signs of deterioration during electron microscope and then mounted for abrasion testing with except for the heat treatments at 100 ° C, 100 ° C and 130,000.

Both the top and bottom edges were used as cutting edges before grinding. IN The results of the abrasion test are summarized in Table II.

The specimens showed relatively similar properties throughout the test. There was a tendency for a decrease of the abrasion resistance from the untreated condition to the first heat treatment at 700 ° C. The unpainted samples, samples 3 and 4, did not change until catastrophic thermal disturbance occurred between 800 ° C and 9009C. The heat treatment had proved to be independent of abrasion resistance until the diamond the phase could no longer contain the entrapped metal phase and cracking occurred. This behavior also indicates the presence of two distinct phases: The bound diamond phase, which exerts it cutting effect in the test, as well as the metal phase, which is a stood from the sintering process. The leached specimens, the specimens 1 and 2, the heat treatment withstood very well, even to 1200 ° C.

The tendency at 1200 ° C seems to be a tendency for a slight deterioration of the specimen that may indicate incipient thermal conversion surface. 7801872-8 ll Table II. värme_ Lakad Unlakad treatment Sample- Sample- Sample- Sample- (° C) piece 1 piece 2 piece 3 piece 4 Untreated 150-200 120-150 150 100-120 700 150 120 120 100 800 p _ 120 100 _ 120 100 900 120 i 100 _ A Raaieiia cracks IOOO, ~ - ~ _ 1100 - - - i - 1200 86-100 100-120 ~ i i ä 1300 '- - - 1 - The test results in Table II indicate the time per unit of press body wear in 25.4 mm x 100. Tool wear was determined by measuring the width of the flat surface (flat) on the press body, which was caused by the contact with the workpiece. Vär- these are meaningful only for comparison of the relative uses properties of the lacquered and unpainted specimens.

The leached Ptov pieces show on average higher test values than the unpainted specimens. This may be due to thermal disturbance or deterioration of the unpainted press pieces during cutting the machining tests with the test pieces. Thus the same destruction mechanism may occur during the wear test as in the heat treatments. If so, when will the tool tip is heated to a high temperature in contact with the workpiece the cobalt phase to expand more than the diamond phase and crack the edge at the tip within the first few particle layers. The damaged tip is thereby weakened and inferior use properties are obtained. The however, the leached specimens are thermally stable to higher working temperature and does not deteriorate thermally on contact with the bite piece.

Scanning electron microscopic examination showed that they were unpainted the specimens showed many different properties when compared with the leached specimens. The metal phase began to be extruded or penetrate from the surface between 700 and 8DO ° C when examined with magnification ZOOOX. When the temperature was raised to 900 ° C it burst the specimens radially from the rounded cutting edge to the center of 7801872-8 12 the test piece. The onion specimens did not show this property but were relatively unchanged at 1300 ° C. The diamond layers are pure at 120,000, but at 1300 ° C shows photographs with ZOX round and uneven images and photographs with The degree of failure of the iO00X shows an etched surface with many exposed crises taller. This is probably due to thermal deterioration or deterioration disturbance of the surface but may also be the result of less oxygen 'ions in the argon atmosphere in the tube furnace.

Example 4.

Two diamond compacts (Samples IV-1 and IV-2) were prepared in the manner set forth in Example 1, except that the carbide was not sanded, An epoxy plastic (Epon 826 with nodic methyl- anhydride and benzyldimethylamine curing agent) were poured around the paragraph IV-1 and cured. The surface of the diamond layer was exposed through sanding the entire amount of plastic on the surface of the layer. The test piece IV-1 was then introduced into boiling 3HCl: 1HNO 3 for 37.15 hours time. After removal from the acid, the plastic was removed from the carbide. layer and examined visually. Signs of a slight reaction between the acid and the unexposed surface was observed. The surface of the carbide however, the layer did not appear to be significantly damaged by the acid.

The surface of the diamond layer was then examined with scanning electron microscopy. scoop (up to ZOOOX magnification). ^ The surface of the diamond layer had a appearance similar to the surfaces of the diamond layer of the lacquered samples. the pieces according to Example 1. The test piece IV-1 was then examined with energy-distributing X-ray analysis for comparison of the intensities for the components in the metal phase with corresponding values for one! compact of the same type not leached. The results of scanning microscopic examination and X-ray analysis showed that the acid penetrated the diamond layer and removed a significant proportion of the metal phase.

Samples IV-1 and IV-2 were then subjected to turning testing for testing the abrasion resistance in the manner specified given in Example 3 above. Abrasion test results (calculated in the manner set forth in Example 3) were 120 - 150 for specimen IV-1 (lacquered) and 100 - 120 for specimen IV-2 (unlacquered).

These test results show the superiority of the leachate the compact corresponds to the results obtained according to Example 3 and thus confirms that the removal of the metal phase in the field of the cutting edge improves the use properties of the diamond press body.

Claims (12)

7so1a72-s 13 PÄTENTKRAV Tool component containing at least about 70% by volume of particles of diamond or cubic boron nitride, characterized in that it comprises: V ia) self-bonded particles of diamond or cubic boron nitride, which constitute about 70 to 95 volume -% of the component, and (b) a network of communicating or interconnected, empty pores, which are distributed throughout the component and bounded by the particles and between about 0.05 and 3% by volume of a metal phase. which consists of sintering aids for the abrasive particulate mass in question, and is selected from (1) a catalytically active metal in elemental form selected from the group comprising metals belonging to the periodic table group VIII, Cr, Mn, Ta, (2) metals of the catalytically active metal or metals and non-catalytically active metals or non-catalytically active metals, (3) an alloy of at least two of the catalytically active metals, (4) an alloy of one or more catalytically active metals and one or more non-catalytically active metals, preferably for diamond, and (5) carbon, cobalt alloy or aluminum alloy and an alloy metal selected from the group consisting of Ni, Mn, Fe, V and Cr, preferably for cubic boron nitride, the pores comprising between about 5 and 30% by volume of the component. 2. A component according to claim 1, characterized in that the diamond particles have a size varying between about 1 and 1000 microns. 3. A component according to claim 1 or 2, characterized in that the particles of cubic boron nitride have a size of Tellan 1 and 300 μm. A Component according to one of Claims 1 to 3, characterized in that the component has a transverse breaking limit of at least about 35 kp / mm 2. 7801872-8 14 Component according to one of Claims 1 to 4, characterized in that the component has a value for Young's modulus of at least about 50,000 kp / mm 2. IN Component according to any one of claims 1 to 5, characterized in that the component further comprises a cemented carbide substrate (binder-bound carbide) which is bonded to the self-bonded particles. A process for producing a tool component containing particles of diamond or cubic boron nitride, wherein 0 (a) in a reaction cell is introduced into a mass of abrasive particles, which are diamond or cubic boron nitride, and a mass of sintering aids for the abrasive particles, (b) simultaneously exposing the cell and its contents to a temperature of 1200-200000 and a pressure exceeding 40 kilobars, (c) interrupting the supply of heat to the cell, (d) removing from the cell an abrasive body which prepared by steps (a) to (c), wherein the body comprises the particles in self-bonded form with the sintering aid infiltrated among all the particles, characterized in that the sintering aid consists of (1) a catalytically active metal in elemental form selected from the group consisting of metals belonging to group VIII, Cr, Mn, Ta, (2) a mixture of alloyable metals of the catalytically active metal or metals and one or more non-catalytically active metals, (3) an alloy of at least two of the catalytically active metals and (4) an alloy of the catalytically active metal, (5) one or more non-catalytically active metals, preferably for diamond and (6) Co, alloys of Co or alloys of Al and an alloy metal selected from the group consisting of Ni, Mn, Fe, V and Å Cr, preferably for cubic boron nitride, and that substantially all of the sintering aid which is incorporated is removed. . filtered in the body, so that the amount of infiltrated sintering aid amounts to between about 0.05 and about 3% by volume of the component. 8. A method according to claim 7, characterized in that the metal is removed from the body by immersing the body in an acid. 9. A process according to claim 8, characterized in that the acid consists of king water, nitric acid, hydrochloric acid or hydrofluoric acid. 10. A method according to claim 7, characterized in that the metal is removed from the body by extraction with liquid zinc. ll. Method according to claim 7, characterized in that the metal is removed by electrolytic depletion. 12. A process according to any one of claims 7-11, characterized in that the amount of particles of diamond or cubic boron nitride is adjusted so that they constitute 70-95% by volume of the body.