Hard alloy anvil used for compounding diamond compound sheet and preparation method thereof

Abstract

The invention provides a hard alloy anvil, which is higher in compression strength, higher in bending strength and fine and uniform in structure, and is used for compounding a diamond compound sheet. The weight percent of bonding phase cobalt is 6%-9%; Cr or Ta carbide is taken as an additive of which the weight percent is 2.0%-8.5% of the bonding phase; the rest is WC (Wolfram Carbide); and in the hard alloy anvil, an average grain size of the WC is 0.8-1.2 microns and the maximum grain size of the WC is less than or equal to 10 microns. A preparation method for the hard alloy anvil comprises the following steps in sequence: carrying out classified screening on WC raw material powder; after pre-grinding the additive, grinding the additive together with the WC raw material powder, the bonding phase and a molding agent, thereby acquiring a wet ground mixture; and performing spray drying, cold isostatic pressing and integrally de-waxing low-pressure sintering on the wet ground mixture, thereby acquiring the hard alloy anvil. The preparation method has the advantages that process flow is short, batch control is stable, production cost is low and service life of the hard alloy anvil is greatly prolonged.

Description

technical field [0001] The invention relates to a cemented carbide anvil used in the artificial diamond industry, in particular to a cemented carbide anvil used for synthesizing diamond composite sheets. Background technique [0002] The cemented carbide anvil is the key component and consumable material of the ultra-high pressure device for the synthesis of artificial diamond, cubic boron nitride and its sintered body by the static pressure ultra-high pressure method. Once synthesized, the top hammer needs to go through procedures such as boosting, temperature rising, pressure keeping, heat preservation, cooling, depressurization (pressure relief), etc. The time is generally 20 to 40 minutes. During the synthesis process, the top surface of the top hammer bears about 5.5Gpa Ultra-high pressure and high temperature of hundreds of degrees (combined temperature is about 1500 ℃), the whole anvil is subjected to low-cycle fatigue stress of compressive stress, tensile stress, she...

AI Technical Summary

Problems solved by technology

[0010] ①. Although it is added to tungsten oxide in the form of metal salt, this form of inhibitor is most uniformly dispersed, but the production cost is high, and the accuracy of the added amount is not easy to control;

[0011] ②. Subsequent use of traditional wet abrasive + mixing granulation with SBP forming agent, pressing, dewaxing, low-pressure sintering process, the production process is long, and the short-term mixing of forming agent and wet abrasive has uneven penetration and uneven material particles. It leads to uneven carbon content and uneven density of the anvil;

[0012] ③. Due to the fine particle size of the submicron mixture, stratification and cracks are prone to occur during pressing; the sintering activity is high, the sintering temperature is low and the range is narrow;

[0013] ④. Since the SBP molding agent cannot be removed and collected in the integrated dewaxing and sintering furnace, it can only be dewaxed at low temperature in the dewaxing furnace first, and then sintered at low pressure. Type dewaxing and oxygen increase in the sintering process lead to unstable carbon control, especially for large-sized anvils, the loss of carbon on the surface is large after long-term removal, and the oxygen increase in the process increases the carbon gradient of the anvil, thus affecting Top hammer quality, reduced service life

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