CN1775701A - Die core with superhard coating - Google Patents

Abstract

The invention relates to a mould kernel applying super-hard coating, comprising a mould kernel substrate and a coating, where the coating adheres to the surface of the mould kernel substrate and comprises a coating substrate crystalloid-free SiCN material and nano craystallized SiCN particles scattered in the coating substrate.

Description

Die core with superhard coating

【Technical field】

The invention relates to a mold core with a superhard coating, in particular to a mold core with a superhard coating with high hardness and easy mold release.

【Background technique】

Mold cores are widely used in the molding process, especially in the manufacture of optical glass products, such as aspheric glass lenses, ball lenses, prisms, etc. Direct Press-molding technology can be used to directly produce optical glass products without grinding, polishing, etc. Subsequent processing steps can greatly improve production efficiency and output, and the product quality is good. However, the direct compression molding method has very high requirements on the chemical stability, thermal shock resistance, mechanical strength, and surface smoothness of the mold core. Therefore, the development of compression molding technology mainly depends on the progress of mold core material and mold core manufacturing technology. There are generally the following requirements for mold cores for compression molding:

(1) At high temperature, it has good rigidity, mechanical impact resistance and sufficient hardness;

(2) Under the thermal shock of repeated and rapid heating and cooling, the mold core does not produce cracks and deformation;

(3) There is no chemical reaction between the molding surface of the mold core and the optical glass at high temperature, and it does not adhere to the glass;

(4) high temperature oxidation does not occur;

(5) Good processing performance, easy to process into profiles with high precision and high surface finish;

(6) Low cost.

Most of the traditional mold cores use stainless steel or heat-resistant alloys as the mold core material. Such mold cores are prone to high-temperature oxidation. Under the action of repeated thermal shocks, the grains will grow, so that the surface of the mold core becomes rough and the glass is bonded.

In order to solve the above problems, non-metallic and superhard alloys are used in mold cores. According to reports, silicon carbide (SiC), silicon nitride (Si ₃ N ₄ ), titanium carbide (TiC), tungsten carbide (WC) and tungsten carbide-cobalt alloys have been used to make mold cores. However, the hardness of the above-mentioned various carbide ceramics is very high, and it is difficult to process them into the required shape, especially the high-precision aspherical shape. In addition to being difficult to process, superhard alloys may also undergo high-temperature oxidation after a period of use.

Therefore, it is a new development direction to use carbide or superhard alloy as the base of the mold core and form a composite structure mold core with other material coatings or coatings on the surface. US Patent No. 4,685,948 discloses a composite structure mold core for direct molding optical glass products. It uses high-strength superhard alloys, carbide ceramics or cermets as the base of the mold core, and forms an iridium (Ir) film layer on the molding surface of the mold core, or iridium (Ir) and platinum (Pt), rhenium (Re ), osmium (Os), rhodium (Rh) or ruthenium (Ru) alloy film layer, or ruthenium (Ru) film layer, or ruthenium (Ru) and platinum (Pt), rhenium (Re), osmium (Os), Rhodium (Rh) alloy thin film layer.

However, the above-mentioned precious metals or their alloy resources are scarce and expensive, which increases the cost of the mold core; moreover, carbide or cermet is used as the base of the mold core, which is formed by sintering, and cobalt (Co), nickel ( Metal elements such as Ni) or molybdenum (Mo) are used as additives, so that after the mold core is used for a long time, these elements will diffuse to the outer surface of the mold core through the above-mentioned precious metal layer, thereby reacting with the glass formed by molding, affecting the precision of the mold core And the quality of molded glass products, and even affect the service life of injection mold cores and molding molds.

In view of this, it is necessary to provide a mold core with high hardness and easy demoulding superhard coating.

【Content of invention】

The object of the present invention is to provide a mold core with a superhard coating film with high hardness and easy mold release.

The technical solution of the present invention to solve the technical problem is to provide a mold core applied with a superhard coating, which includes a mold core base and a coating film. The coating film is attached to the surface layer of the mold core base, and the coating film is composed of the amorphous silicon carbon nitrogen material of the coating film base material and the nano-scale crystalline silicon carbon nitrogen particles dispersed in the coating film base material.

Compared with the prior art, the beneficial effect of the mold core with superhard coating in the present invention is that the nanoparticles dispersed in the coating substrate have superhard properties, which help to increase the surface mechanical properties of the mold core, and can be used At this time, the nanoparticles will be squeezed to the side due to the external force, but the coating substrate next to it is soft because of its hardness, so it can withstand the extrusion without damaging the mold. At the same time, most of the nanoparticles are covalently bonded, which has strong oxidation resistance and can also prevent the mold from being damaged at high temperatures. In addition, the carbon atoms of the amorphous silicon carbon nitrogen material that make up the coating substrate contain a large number of sp ² bonds, making it have good self-lubricating properties, so molded glass products are easy to release.

【Description of drawings】

Fig. 1 is a schematic diagram of the structure of a mold core applying a superhard coating in the present invention.

【Detailed ways】

Please refer to FIG. 1 , which is a schematic diagram of the core structure of the mold applying the superhard coating in the present invention. The mold core 10 includes a mold core base 11 with a smooth plane and a coating film 12 covering the smooth plane. The core base 11 can be manufactured by sintering the following ceramics, cermets or superhard alloys as main materials: SiC, Si, Si ₃ N ₄ , ZrO ₂ , Al ₂ O ₃ , TiN, TiO ₂ , TiC, B4C , WC, W or WC-Co. The coating film 12 is composed of a coating film substrate 13 and nanoparticles 14 , and the nanoparticles 14 are dispersed in the coating film substrate 13 . The coating substrate 13 is an amorphous-Silicon Carbon Nitride material (a-SiCN for short), and the nanoparticles 14 are nano-scale crystalline Silicon Carbon Nitride particles (nano crystalline-Silicon Carbon Nitride).

The a-SiCN carbon atoms that make up the coating substrate 13 contain a large number of sp ² bonds, making it have good self-lubricating properties, so molded glass products are easy to demould; When in use, it can protect the mold core from being damaged by strong mechanical force.

The nanoparticles 14 (nanoscale crystalline silicon carbon nitrogen particles) dispersed in the coating substrate 13 help to increase the surface mechanical properties of the mold core 10 due to their superhard properties. The effect will be squeezed to the side, but the coating substrate 13 next to it is soft because of its hardness, so it can withstand the squeeze without damaging the mold.

At the same time, most of the nanoparticles 14 are covalently bonded, have strong oxidation resistance, and can also prevent the mold from being damaged under high temperature.

In the mold core 10, the mold core base 11 is prepared by sintering or other processing methods, and the coating film 12 can be deposited by plasma chemical vapor deposition (CVD), such as microwave plasma chemical vapor deposition ( micro wave plasma chemical vapor deposition (MW CVD for short); it can also be deposited on the surface of the mold core base 11 by sputtering, which can increase the service life of the mold core and facilitate demoulding.

The superhard coating film of the present invention can not only be used for mold cores of smooth flat optical glass products, but also can be applied to mold cores of other molded products with different shapes and different purposes.

Claims (6)

1. die of using superhard plated film, it comprises a die core substrate and a plated film, it is characterized in that: this plated film does not have crystalloid silicon-carbon nitrogen material by coating material and is dispersed in nano crystals silicon-carbon nitrogen granulometric composition in this coating material.

2. the die of the superhard plated film of application as claimed in claim 1 is characterized in that: this plated film adopts the plasma chemical vapor deposition process deposition to form.

3. the die of the superhard plated film of application as claimed in claim 1 is characterized in that: this plated film adopts microwave plasma chemical CVD (Chemical Vapor Deposition) method deposition to form.

4. the die of the superhard plated film of application as claimed in claim 1 is characterized in that: this plated film adopts the jet-plating method deposition to form.

5. the die of the superhard plated film of application as claimed in claim 1 is characterized in that: this die core substrate is by sintering or the preparation of other method.

6. the die of the superhard plated film of application as claimed in claim 1 is characterized in that: this die core substrate is by SiC, Si, Si ₃N ₄, ZrO ₂, Al ₂O ₃, TiN, TiO ₂, TiC, B ₄Pottery, sintering metal or superhard alloys such as C, WC, W or WC-Co make.

Images