JP2011006272A - Ceramics for decorative part and decorative part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic for decorative parts which has a silver color tone, which imparts a sense of luxury, a feeling of aesthetic satisfaction and spiritual comfort, which has excellent mechanical characteristics such as hardness and toughness and which shows little color difference.SOLUTION: The ceramic for decorative parts comprising a titanium carbide-sintered compact includes 5 mass% or more and 25 mass% or less of cobalt, 1 mass% or more and 10 mass% or less of chromium and 2 mass% or more and 10 mass% or less of niobium. Chromium and niobium are dissolved with cobalt to form a solid solution. In the ceramic for decorative parts, sintering property is enhanced by improving the wettability of a bonded phase and titanium carbide, and thus particle shedding and chipping during working of the ceramic hardly occur.

Description

  The present invention relates to a ceramic for decorative parts that produces a beautiful silver color and a decorative part using the same.

  2. Description of the Related Art Conventionally, silver and its alloys, or various metals plated with silver are used for ceramics for decorative parts and decorative parts that exhibit a silver color in terms of color tone and corrosion resistance.

  However, since silver, its alloys, or silver-plated metallic materials all have low hardness, there is a problem that the surface is scratched or deformed due to contact with a hard substance. Recently, in order to solve such problems, various ceramics for decorative parts have been proposed.

  For example, in Patent Document 1, 70 to 95% of a hard phase composed of titanium carbonitride and 4a, 5a, and 6a group carbides, nitrides, and carbonitrides, 5 to 30% of a binder phase composed of an iron group metal, and a bond Disclosed is a super-hard alloy composed of 4%, 5a, and 6a group elements 1 to 5% (more than weight percent) and inevitable impurities dispersed and dissolved in the phase. Even if cracks occur, chipping occurs like the cemented carbide P type, but it has excellent chipping resistance that does not cause defects.

In Patent Document 2, one or more of tungsten carbide, tantalum carbide, and titanium carbide are used as a main component, and one or two of Ni and Co are included in 5 to 30%, Cr and In a cemented carbide containing 1 or 2 or more of Cr carbides in terms of Cr in an amount of 2 to 15% (more than weight%), one or two of Ni and Co are the main components. When the peak intensity of the (111) plane in the X-ray diffraction of the bonded phase is I (111) and the peak intensity of the (200) plane is I (200), the following formula I _A = I (111) / I ( 200)
_A decorative cemented carbide having an IA value of 5.0 or more is disclosed. According to this, the mechanical strength is high, “cloudy” after heat treatment and non-uniform pattern after ion plating treatment are not seen, and it has better thermal corrosion resistance than before, especially for watches, necklaces and other decorations It has an excellent effect.

  Patent Document 3 discloses a titanium carbide-based cermet alloy composed of a hard phase mainly composed of titanium carbide and a binder phase mainly composed of one or two of Co and Ni, and includes Ti and Mo in the binder phase. A titanium carbide-based cermet alloy whose content satisfies the conditions 0.85 ≦ Mo (wt.%) / Ti (wt.%), 6 wt.% ≦ Ti + Mo is disclosed. According to this, it is possible to obtain a TiC-based cermet alloy that has a hardness equivalent to that of a TiCN-based cermet alloy and has significantly improved toughness, and that there is no problem of generation of pores due to denitrification during vacuum sintering. Is.

  Further, Patent Document 4 is a silver-colored sintered alloy having titanium carbide as a dispersed particle phase and chromium, molybdenum, nickel as a binder phase, and 58.1 to 90% by weight of the titanium converted into carbides in the total amount. 1 to 15% by weight of chromium in terms of carbide in the total amount, 3 to 32% by weight of molybdenum in terms of carbide in the total amount, 1 to 20% by weight of nickel in the total amount, and ANSI / ASTM B276- The silver-colored sintered alloy having a porosity of A-2 class or higher as defined in 54, and this silver-colored sintered alloy contains one or more of W, Nb, and Co, and W is a carbide in the total amount. 1% by weight or less in terms of conversion, Nb being 1.7% by weight or less in terms of carbide in the total amount, and Co being 1% by weight or less in the total amount are disclosed. According to this, a silver mirror surface that exhibits excellent strength and hardness without any hindrance in decorative applications and wear-resistant applications, and has excellent corrosion resistance and depth appears. By maintaining the wear resistance, it is awarded as a decorative member such as a wall material, watch case, brooch, memorial medal, button, bracelet, ring, pendant, fishing gear, and wear resistant member.

JP-A-7-173568 JP-A-5-287432 JP-A-6-172914 Japanese Patent No. 3321873

  However, since the composition of the superhard alloy described in Patent Document 1 is shown in a very wide range, it may be a material having a color tone other than silver. Furthermore, since the composition shown in the examples is only when the hard phase is TiCN and WC and the binder phase is Co and Ni, it becomes a blackish tone due to the influence of WC exhibiting black, and has a beautiful silver color. There was a problem that it was not a color tone.

  Further, in the cemented carbide described in Patent Document 2, since the color tone is adjusted by the ion plating process, when the surface is worn, there is a problem that color unevenness occurs between the original color tone of the material, and titanium carbide. Since only one example of the main component is shown, there is a problem that the range of the composition of ceramics having a beautiful silver color tone is unclear.

  In addition, in the titanium carbide-based cermet alloy described in Patent Document 3, the composition shown in the example has a hard phase composed of TiC and WC, and thus has a blackish tone due to the influence of WC that exhibits a black color. There was a problem that it was not a ceramic having a color tone.

  Furthermore, the silver-colored sintered alloy described in Patent Document 4 has an excellent strength and hardness without any hindrance for decorative and wear-resistant applications, and has a deep and deep silver mirror surface with excellent corrosion resistance. A silver sintered alloy that can be used for fishing gear with better wear resistance due to the recent large-scale fishing boom in the ocean, although it has the effect of maintaining decoration effect and wear resistance for a long time. There was a problem of being sought.

  The present invention has been devised to solve the above-mentioned problems, and has a silvery color tone, which provides high-quality feeling, aesthetic satisfaction and mental comfort, and has excellent corrosion resistance and ceramics for decorative parts. It is an object of the present invention to provide a fishing line guide decorative part, a watch decorative part, a mobile phone decorative part, and a daily life decorative part.

  The ceramic for decorative parts of the present invention is a ceramic for decorative parts made of a titanium carbide sintered body, wherein cobalt is 5 mass% to 25 mass%, chromium is 1 mass% to 10 mass%, and niobium is 2 mass%. The chromium and niobium are contained in a solid solution with cobalt in a content of not less than 10% by mass and not more than 10% by mass.

  Moreover, the ceramic for decorative parts of the present invention is characterized by containing molybdenum in a content of 35% by mass or less with respect to cobalt.

  The ceramic for decorative parts of the present invention contains zirconia in a content of 9% by mass to 30% by mass, and the total of zirconia, cobalt, chromium, niobium and molybdenum is less than 50% by mass. Is.

  The fishing line guiding decorative part of the present invention is characterized by comprising the decorative part ceramics of the present invention having any one of the above-described configurations.

  Moreover, the decorative part for timepieces of the present invention is characterized by comprising the ceramics for decorative parts of the present invention having any one of the above-described configurations.

  In addition, a decorative part for a mobile phone of the present invention is characterized by comprising the ceramic for decorative parts of the present invention having any one of the above-described configurations.

  Moreover, the decorative part for daily goods of the present invention is characterized by comprising the ceramic for decorative parts of the present invention having any one of the above-described configurations.

  According to the ceramic for decorative parts of the present invention, it is a ceramic for decorative parts made of a titanium carbide sintered body, wherein cobalt is 5 mass% to 25 mass%, chromium is 1 mass% to 10 mass%, niobium Since the chromium and niobium are in solid solution with cobalt, the wettability between the binder phase and titanium carbide is improved and the sinterability is improved. It is possible to prevent the occurrence of grain removal and chipping during the processing of ceramics.

  Furthermore, when the ceramic for decorative parts of the present invention contains molybdenum in a content of 35% by mass or less with respect to cobalt, it works to lower the firing temperature and suppress the grain growth of the crystal grains. Since chipping hardly occurs, a decorative member having a beautiful surface can be formed.

  Furthermore, the ceramic for decorative parts of the present invention is the ceramic for decorative parts of the present invention, which contains zirconia in a content of 9% by mass to 30% by mass, and the total of zirconia, cobalt, chromium, niobium and molybdenum is 50% by mass. Since zirconia suppresses oxidation and wear of titanium carbide because it is less than 50%, a stable and favorable silver sintered body that can be used for a long period of time is provided, even when used for sliding parts. it can.

  Further, according to the decorative component for fishing line guide of the present invention, when made of the ceramic for decorative component of the present invention, it is possible to obtain mental comfort through vision such as high-class feeling and aesthetic satisfaction. In addition, when used for a fishing line guide ring that guides the fishing line, even if it is rubbed against fine sand adhered to the fishing line, it has high hardness, so the surface is not easily scratched and the silver color tone is maintained. However, it can withstand long-term use.

  Further, according to the decorative part for a watch of the present invention, when it is made of the ceramic for decorative parts of the present invention, it is possible to obtain mental comfort through vision such as luxury and aesthetic satisfaction. Can also be suitably used for a required timepiece.

  Further, according to the decorative part for mobile phone of the present invention, when it is made of the ceramic for decorative part of the present invention, it is possible to obtain mental comfort through vision such as luxury and aesthetic satisfaction. It can be suitably used for mobile phones that are important.

  Further, according to the decorative part for daily necessities of the present invention, when it is made of the ceramic for decorative parts of the present invention, it is possible to obtain mental comfort through vision such as high-class feeling and aesthetic satisfaction.

1 shows an example of a fishing line guide ring and a fishing line guide provided with the fishing line guide ring, which are decorative parts for fishing line guide according to the present invention, FIG. It is a perspective view of the guide for fishing lines provided with the guide ring for fishing lines of a). It is a schematic block diagram of the abrasion-resistance evaluation apparatus used for evaluation of the abrasion resistance of the ceramics for decorative parts of this invention. 1 shows an example of a watch case that is a decorative part for a watch according to the present invention, (a) is a perspective view of the watch case seen from the front side, and (b) is a perspective view of the watch case of (a) seen from the back side. FIG. It is a perspective view which shows another example of the case for timepieces which is the decorative component for timepieces of this invention. It is a schematic diagram which shows an example of a structure of the timepiece band which is the decorative component for timepieces of this invention. It is a perspective view which shows an example of the mobile phone using the decorative component for mobile phones of the present invention. It is a perspective view which shows another example of the mobile phone using the decorative component for mobile phones of the present invention. It is a perspective view which shows an example of the faucet using the decorative component for life goods of this invention. It is a perspective view which shows an example of the shower head using the decorative component for life goods of this invention.

  Examples of embodiments of the ceramic for decorative parts of the present invention will be described below.

  The ceramic for decorative parts of the present invention is a ceramic for decorative parts made of a titanium carbide sintered body, wherein cobalt is 5% by mass to 25% by mass, chromium is 1% by mass to 10% by mass, and niobium 2 The chromium and niobium are contained in a solid solution with cobalt in a content of not less than 10% by mass and not more than 10% by mass.

  In the present invention, the titanium carbide-based sintered body is a sintered body containing titanium carbide (TiC) as a main component, and the main component referred to here is 100% by mass of all components constituting the ceramic for decorative parts. On the other hand, it is a component occupying 50% by mass or more. This main component, titanium carbide, has a feature that it has a good silver color as a decorative product and has high mechanical properties such as strength and hardness, and therefore comprises the titanium carbide sintered body of the present invention. In the ceramic for decorative parts, it is preferable to contain titanium carbide in a content of 70% by mass or more.

  In addition, the content of cobalt is set to 5% by mass or more and 25% by mass or less because cobalt can exist uniformly as a binder among the titanium carbide crystal particles to maintain the strength of the ceramic and maintain the hardness. It is because it can be made hard to be damaged. When cobalt is less than 5% by mass, cobalt is insufficient between the titanium carbide crystal grains, and the structure becomes non-uniform and the strength tends to decrease. On the other hand, when it exceeds 25% by mass, the hardness of the ceramic decreases. This is because it becomes easy to be damaged.

  In particular, cobalt has high corrosion resistance, and in recent years, in countries such as Europe, a material with particularly low nickel elution has been demanded as a countermeasure against metal allergies.

  The chromium content of 1% by mass or more and 10% by mass or less improves the wettability of cobalt and titanium carbide, improves the sinterability, and improves the oxygen content in the air on the surface of the binder phase. This is because the film is bonded to form a chromium oxide film and the corrosion resistance is increased. If the chromium content is less than 1% by mass, the wettability between cobalt and titanium carbide decreases and the sinterability deteriorates, so voids are likely to occur, and it is difficult to form a chromium oxide film on the surface of the binder phase. When the corrosion resistance is reduced and the content exceeds 10% by mass, the binder phase becomes too hard, and the strength is reduced. Chromium is mainly dissolved in cobalt in the binder phase, but a part thereof may exist as a carbide.

  Further, when chromium is in solid solution with cobalt, it is possible to suppress a problem that the surface of the ceramic is corroded or discolored by forming a chromium oxide film on the surface of the binder phase. Further, chromium may partially exist in the form of another compound such as chromium carbide or chromium nitride. The state in which chromium is in solid solution with cobalt is determined by analyzing the sample by X-ray diffraction and confirming that the peak position of cobalt is shifted in the direction of the peak of chromium in the analysis result image or chart. You can check by printing on paper.

Niobium acts as a color tone adjusting agent. In addition to the metal niobium, it also has an effect of increasing wettability, and includes a niobium compound having a composition formula represented by, for example, NbCo ₃ or NbC.

  In addition, the content of niobium is 2% by mass or more and 10% by mass or less because niobium is mainly dissolved in cobalt to improve the action as a color adjusting agent and the wettability between titanium carbide and cobalt. On the other hand, if the content of niobium is large, the liquidus temperature of the binder phase becomes high, so that the sinterability may be lowered.

  The niobium content is more preferably 4% by mass or more and 8% by mass or less. This is because niobium works to suppress grain growth, so the crystal grain boundary increases, and the incident light is strongly influenced by diffuse reflection by the crystal grain boundary in addition to the specular reflection by the crystal forming the decorative surface. In addition, the color tone of the decorative surface increases the glossy color tone, and further, a high-class feeling and aesthetic satisfaction can be obtained. As a result, mental comfort can be obtained through vision.

  Furthermore, since niobium is mainly present in the cobalt of the binder phase, the binder phase is strong against corrosion against sweat and saliva, so the surface of the ceramic is maintained in a stable state and the color tone is also stable. Color unevenness between products can be reduced.

  In addition, niobium can be replaced with tantalum, in which case the amount of tantalum added is 3% by mass or more and 20% by mass or less. Tantalum has the same effect as niobium, and the binder phase is strong against corrosion. However, since the material is expensive, it is preferably used according to the cost.

Furthermore, niobium is preferable that they are precipitated as cobalt niobium, for example NBCO ₃ combines with cobalt by precipitation of NBCO _3, brightness drifting dignity exude. This cobalt niobium such as NbCo ₃ can be detected by an X-ray diffraction method.

  In addition, the decorative surface in the ceramic for decorative parts of the present invention refers to a surface where the decorative value of the decorative component is required, and does not indicate all surfaces. For example, when the ceramics for decorative parts of the present invention is used for a watch case, the outer surface of the watch case is a decorative surface because it is an object of appreciation and requires a decorative value.

  The contents of titanium, cobalt, chromium and niobium can be measured using a fluorescent X-ray analysis (XRF) method. Specifically, at least two kinds of mixed powders having different concentrations of each element of titanium, cobalt, chromium, and niobium are prepared in advance, and are each molded by a pressing method to obtain a standard sample. Next, each of these standard samples is irradiated with X-rays, and a calibration curve is created using the least square method from the relationship between the intensity of the fluorescent X-rays and the known concentration. And the ceramics for decorative parts of this invention are grind | pulverized into a powder, and it shape | molds by the press method, and is set as a measurement sample. This measurement sample is irradiated with X-rays, the intensity of fluorescent X-rays is measured, and the concentration content is obtained from the calibration curve. The contents of titanium, cobalt, chromium, and niobium can also be measured using ICP (Inductively Coupled Plasma) emission spectroscopy. Specifically, the produced ceramics are vaporized and vaporized with discharge plasma and excited, and when the excited atoms return to a low energy level, the type of atoms is identified and the emission intensity is used to identify each type of atom. Quantitative analysis of atoms. Furthermore, carbon can be measured with a carbon analyzer.

  The ceramic for decorative parts of the present invention preferably contains molybdenum in a content of 35% by mass or less with respect to cobalt. When molybdenum is contained in a content of 35% by mass or less with respect to cobalt, the firing temperature can be lowered and the growth of crystal grains is suppressed, so that the graining and chipping are less likely to occur during processing, and the decoration has a beautiful surface. A member can be produced. Molybdenum forms a eutectic alloy with cobalt. However, when the content exceeds 35% by mass with respect to cobalt, a molybdenum-rich phase precipitates in the binder phase, which tends to cause grain separation and chipping when the product is processed. In other words, the surface may be rough and cause variations in color tone.

  In addition, when the ceramic for decorative parts of the present invention contains chromium in a metal element other than titanium at a content of 10% by mass or more and less than 40% by mass, chromium is dissolved in the crystal grain boundary between cobalt and titanium carbide. Thus, the wettability between the binder phase and titanium carbide is improved to improve the sinterability. If the chromium content is less than 10% by mass, the effect of improving the wettability will be reduced and the sinterability will be reduced. It becomes difficult to form the ceramic surface uniformly and beautifully.

  Further, the ceramic for decorative parts of the present invention preferably contains zirconia in a content of 9% by mass to 30% by mass, and the total of zirconia, cobalt, chromium, niobium and molybdenum is less than 50% by mass. Zirconia suppresses the problem that when a fishing line or the like moves while being in contact with the surface of the ceramic, the titanium carbide and the binder phase in the contact portion are oxidized and volume-expanded to cause cracks and wear.

  In the ceramic for decorative parts of the present invention, the content of zirconia is 9% by mass or more and 30% by mass or less because the temperature of the contact surface may increase due to friction when a fishing line or the like moves while contacting the surface of the ceramic. In order to suppress the problem of the presence of moisture, the titanium carbide and the binder phase on the contact surface are gradually oxidized and volume-expanded, causing cracks with the surrounding structure and progressing wear. Even if the fishing line moves while contacting the surface of the ceramic and the titanium carbide or binder phase wears, the zirconia crystal particles remain on the surface as protrusions, which come into contact with the fishing line. Oxidation slows down and wear is suppressed. When the amount of zirconia is less than 9% by mass, the number of zirconia crystal particles present on the surface of the ceramic decreases, and the effect of suppressing oxidation and wear of titanium carbide and the binder phase tends to be reduced. On the other hand, if it exceeds 30% by mass, the ratio of the volume expansion / contraction change due to the phase transformation of zirconia during sintering to the total volume of the ceramic increases, and cracks tend to remain in the sintered ceramic. There is a problem.

  In addition, the total content of zirconia, cobalt, chromium, niobium and molybdenum is less than 50% by mass, the remaining titanium carbide content is 50% by mass or more, high hardness can be maintained, and the surface It is because it is hard to be damaged. When the total content of zirconia, cobalt, chromium, niobium and molybdenum is 50% by mass or more, the content of the remaining titanium carbide decreases, and the surface cannot be maintained, and the surface is easily damaged. is there.

  Moreover, the decorative component for fishing line guide of the present invention is characterized by comprising the ceramic for decorative product of the present invention having the above-described configuration, and specific examples thereof include a guide ring for fishing line and the guide ring for fishing line. There is a guide for fishing lines.

  The ceramics for decorative parts of the present invention, when used for a fishing line guide ring and a fishing line guide provided with the fishing line guide ring, does not impair the aesthetics due to color variations between the guides when assembled as a fishing line guide on a fishing rod. It has a sense of unity in color tone, can provide a high-class feeling as a fishing rod, a satisfactory aesthetic satisfaction, and can provide mental comfort through vision. Furthermore, the decorative component for fishing line guide according to the present invention has high corrosion resistance because the main component of the ceramic binder phase is cobalt, chromium, niobium, molybdenum and zirconia, so the product will be discolored even when used for fishing rods for a long time. As a result, there is no decline in luxury. In particular, when the ceramic for decorative parts of the present invention contains zirconia, zirconia suppresses the problem that titanium carbide and the binder phase are oxidized at the contact portion between the fishing line and the ceramic and volume expansion occurs, and cracks and wear progress. To do.

  FIG. 1 shows an example of a fishing line guide ring that is a decorative part for fishing line guide according to the present invention and a fishing line guide provided with the fishing line guide ring, and (a) is a plan view of the fishing line guide ring. (B) is a perspective view of the fishing line guide provided with the fishing line guide ring of (a).

  The fishing line guide ring 1 of the example shown in FIG. 1 is for guiding a fishing line (not shown) through the inner periphery thereof, and the fishing line guide 6 is a holding portion 2 that holds the fishing line guide ring 1. The fishing line guide ring 1 is provided on a frame 5 integrally formed with a support portion 3 of the holding portion 2 and a fixing portion 4 that is fixed to a fishing rod (not shown). By forming this fishing line guide ring 1 with the ceramics for decorative parts of the present invention, it is possible to give the consumer a sense of quality, aesthetic satisfaction and mental comfort.

  Further, since the fishing line guide ring 1 having a silver color tone and the color tone of the fishing line guide 6 and the fishing rod are in good harmony, the fishing line guide ring 1 can be suitably used for a fishing gear. In particular, since it exhibits a silvery color tone, it can be used as a fishing tackle preferred by those who want a high-class feeling as a luxury item. The surface of the fishing line guide ring 1 may be covered with a transparent film having high wear resistance, for example, a film made of amorphous hard carbon to further improve the wear resistance.

  Further, the wear resistance of the ceramic for decorative parts of the present invention can be evaluated by preparing and using an abrasion resistance evaluation apparatus having the following configuration.

  FIG. 2 is a schematic configuration diagram of an abrasion resistance evaluation apparatus used for evaluating the abrasion resistance of the ceramic for decorative parts of the present invention. The wear resistance evaluation apparatus 10 is connected to a nylon thread 12, a plurality of pulleys 13 that apply tension to the thread 12 at a predetermined position, and a pulley 13a that is one of the pulleys 13, and the thread 12 is indicated by an arrow. It consists of a motor (not shown) that travels in the direction and a water tank 14 that attaches muddy water to the thread 12, and a load corresponding to the mass of the weight 15 is applied. It is structured to slide on the outer peripheral surface of a cylindrical decorative part ceramic 11 fixed with a jig (not shown) or the like, and the number of nylon threads 12 may be, for example, 3 .

  Conditions for evaluating the wear resistance of the ceramic 11 for decorative parts using this wear resistance evaluation apparatus 10 are, for example, that the mass of the weight 15 is 500 g and the thread 12 is a cylindrical ceramic 11 for decorative parts. The speed of sliding on the outer periphery of the thread 12 may be set to 60 m / min, and the traveling distance of the yarn 12 may be set to 3000 m or more. Then, after driving the motor and sliding the thread 12, the deepest part of the scratches caused by the wear of the cylindrical decorative part ceramics 11 was measured with a surface shape measuring microscope (Keyence measuring unit VF-7510 / controller VF). -7500), and the wear resistance can be evaluated by comparing the measured values.

  Moreover, the decorative part for timepieces of the present invention is characterized by comprising the ceramics for decorative parts of the present invention having the above-described configuration, and examples thereof include a timepiece case and a timepiece band piece.

  Since the ceramic for decorative parts of the present invention has little color unevenness between products, when used for a watch case or a watch band piece, it does not impair the aesthetics due to color variations between parts when assembled. It has a sense of unity in color tone, and it can provide a high-class feeling and aesthetic satisfaction as a watch, and can provide mental comfort through vision. Furthermore, the decorative parts for watches of the present invention have high corrosion resistance because the main component of the ceramic binder phase is cobalt, chromium, niobium, molybdenum and zirconia. As a result, there is no decline in luxury.

  3A and 3B show an example of a watch case that is a decorative part for a watch according to the present invention. FIG. 3A is a perspective view of the watch case viewed from the front side, and FIG. 3B is a watch case of FIG. It is the perspective view which looked at from the back side. FIG. 4 is a perspective view showing another example of a watch case which is a decorative part for watch of the present invention. FIG. 5 is a schematic view showing an example of the configuration of a watch band which is a decorative part for watch of the present invention. In addition, when showing the same site | part in these figures, the same code | symbol is attached | subjected.

  A watch case 20A shown in FIG. 3 includes a recess 21 for housing a movement (drive mechanism) (not shown) and a foot 22 for fixing a watch band (not shown) for mounting the watch on an arm. The concave portion 21 includes a thin bottom portion 23 and a thick trunk portion 24. The watch case 20B shown in FIG. 4 has a hole 25 (not shown) for receiving a movement (drive mechanism) and a watch band (not shown) for attaching the watch to the arm formed on the body 24. And a foot part 22 to be provided.

  And the band piece which comprises the timepiece band 50 shown in FIG. 5 is arrange | positioned so that the intermediate piece 30 which has the through-hole 31 in which the pin 40 is inserted, and the intermediate piece 30 may be pinched | interposed, and the pin into which both ends of the pin 40 are inserted The pin 40 is inserted into the through hole 31 of the middle piece 30 and both ends of the inserted pin 40 are inserted into the pin holes 32 of the outer piece 33, The piece 30 and the outer piece 33 are sequentially connected to form a watch band 50.

  Since the watch decorative parts of the present invention used as the band pieces constituting the watch cases 20A and 20B and the watch band 50 are made of the ceramics for decorative parts of the present invention, a high-class feeling as a watch. ， You can get enough aesthetic satisfaction and you can get mental comfort through vision.

  In the ceramic for decorative parts of the present invention, the Vickers hardness (Hv) of the decorative surface is one of the factors affecting long-term reliability, and the Vickers hardness (Hv) is preferably 8 GPa or more. When the Vickers hardness (Hv) is in this range, the decorative surface is difficult to be damaged, so that the decorative surface is not easily damaged even when it comes into contact with a substance having high hardness such as dust made of glass or metal. Because. The Vickers hardness (Hv) of this decorative surface can be measured according to JIS R 1610-2003.

The fracture toughness affects the wear resistance of the decorative surface, and the higher the value, the better. In the ceramic for decorative parts of the present invention, it is preferably 4 MPa · m ^1/2 or more. This fracture toughness can be measured in accordance with the indenter press-in method (IF method) defined in JIS R 1607-1995.

When ceramics for decorative parts are worn and used, the lighter one is preferred, and therefore the apparent density of the ceramics for decorative parts of the present invention is 5 to 6 g / cm ^3. This apparent density is measured according to JIS R 1634-1998. If the ceramic for decorative parts is the middle piece 20 which is a part of the watch band piece, the tensile load is frequently applied to the middle piece 20, so that the ceramic for decorative parts of the present invention has a three-point bending strength of 700 MPa or more. It is preferable that What is necessary is just to measure based on JISR1601-1995 in order to obtain | require this three-point bending strength.

  The decorative part for a mobile phone of the present invention is preferably made of the ceramic for decorative parts of the present invention, and examples thereof include a casing of a mobile phone and operation keys.

  Since the ceramics for decorative parts of the present invention have little color unevenness between products, when used for mobile phone casings and operation keys, the appearance of the parts is not impaired due to color variations between parts when assembled. The color tone has a sense of unity, so that a high-quality feeling and aesthetic satisfaction as a mobile phone can be sufficiently obtained, and mental comfort can be obtained through vision. Furthermore, the decorative parts for mobile phones of the present invention have high corrosion resistance because the main component of the ceramic binder phase is cobalt, chromium, niobium, molybdenum and zirconia. The feeling does not decrease.

FIG. 6 is a perspective view showing an example of a mobile phone using the decorative part for a mobile terminal of the present invention, and FIG. 7 is a perspective view showing a state in which the casing of the mobile phone of the example shown in FIG. 6 is opened. It is.
The decorative part for a portable terminal of the present invention is characterized by comprising the ceramic for decorative parts of the present invention. Specific examples thereof include various operation keys and cases shown in FIGS.

  The mobile phone 60 in the example shown in FIG. 6 includes a mode key 61a for changing the mode of the mobile phone 60 to a radio mode that is a mode for listening to radio, a music mode that is a mode for listening to music, and the like. The first casing 62 is provided with a manner key 61b for detecting a touch of a finger or the like, and a touch sensor 63 for inputting an input by the contact, a camera 64 for imaging a subject, a light 65, and a touch sensor. The second casing 67 is provided with a slide switch 66 for setting validity or invalidity of an input such as 63.

  Next, the cellular phone 60 of the example shown in FIG. 7 shows a state in which the second casing 67 of the cellular phone 60 of the example shown in FIG. The housing 67 is connected via a hinge 68, whereby the second housing 67 can be freely opened and closed. The second casing 67 includes a front case 69a and a rear case 69b, and a liquid crystal display unit 70 is provided in the front case 69a.

  The first housing 62 also has a front case 71a and a rear case 71b, and various operation keys are provided on the front case 71a. The operation keys include a numeric keypad 72a for inputting a telephone number and the like, a cursor movement key 72b for moving a cursor for various function menus, a call key 72c for starting a call by operating upon receiving a call, turning on / off the power and during a call There are a power / end key 72d for ending the call by pushing and operating, and function keys 73L, 73R arranged on the left and right of the center key 72f arranged at the center of the cursor movement key 72b.

  Front cases 69a and 71a, rear cases 69b and 71b, which are the above cases, numeric keys 72a which are operation keys, cursor movement key 72b, call key 72c, power / end key 72d, center key 72f, function keys 73L and R, etc. By forming at least one of the above with the ceramics for decorative parts of the present invention, the user is given a high-quality feeling, aesthetic satisfaction, and mental comfort for a long time, and possesses a mobile phone exhibiting such a color tone. Can make you feel satisfied. Moreover, since the ceramic for decorative parts of the present invention has good compatibility with other color tones, it can be used in combination with members of various color tones, so that it is possible to meet diversification of consumer preferences.

  In addition, although demonstrated using the mobile telephone as an example of a portable terminal, the portable terminal in which the portable terminal of this invention is used is not limited to a mobile telephone, A personal digital assistant (PDA), portable type If the terminal is a portable terminal such as a car navigation system or an audio player and requires decorativeness, various portable terminals are applicable.

  Since the ceramics for decorative parts of the present invention have little color unevenness between products, when used for faucets and faucet handles, which are examples of decorative parts for daily necessities, color variations between parts when assembled. Therefore, it has a sense of unity in color tone, can sufficiently obtain a high-class feeling and aesthetic satisfaction, and can obtain mental comfort through vision. Furthermore, the decorative parts for daily goods of the present invention are high in quality because the main component of the ceramic binder phase is cobalt, chromium, niobium, molybdenum and zirconia, so that the product is discolored even when used for a long time because of its high corrosion resistance. The feeling does not decrease.

  FIG. 8 is a perspective view showing an example of a faucet 90 which is an example of the decorative part for daily use of the present invention, and FIG. 9 shows a shower head 100 which is another example of the decorative part for daily use of the present invention. It is a perspective view.

  A faucet 90 shown in FIG. 8 is branched from a trunk portion 93, a handle 91 attached to the upper end of the trunk portion 93 for opening and closing a faucet inside the trunk portion 93 and adjusting the amount of water, and a side surface of the trunk portion 93. A faucet tube 94 and a discharge port 92 for discharging water flowing through the faucet tube 94 are provided.

  When the member shown in FIG. 8 is formed of the ceramic for decorative parts of the present invention, a beautiful silver faucet can be produced. In particular, even if the decorative part for daily use of the present invention is used in a bathroom in which hot water in which various components are melted, such as a hot spring, it is excellent in corrosion resistance and scratch resistance, so that a high-class feeling can be maintained over a long period of time.

  Even if the body 93, the handle 91, the faucet tube 94, and the discharge port 92 are formed and combined as independent members, the ceramics for decorative parts of the present invention have little color unevenness, so that the sense of uniformity in color tone is not impaired. Absent. Alternatively, the handle 91 and the discharge port 92 are made of white zirconia, and the body 93 and the faucet tube 94 are made of ceramics for decorative parts of the present invention by combining white and silver to create a new decorative pattern, giving a sense of luxury and aesthetic satisfaction. Feeling and mental comfort can be given to the user.

  Next, the shower head 100 shown in FIG. 9 includes a trunk portion 101 and a watering portion 102 that is attached to the upper end of the trunk portion 101 and sprays water that has flowed through the trunk portion 101. It is supplied from a hose 103 attached to the lower end of the body 101.

  When the trunk portion 101 and the water sprinkling portion 102 are formed of the ceramics for decorative parts of the present invention, a beautiful silver shower head 100 can be obtained. In particular, even if the decorative part for daily use of the present invention is used in a bathroom in which hot water in which various components are melted, such as a hot spring, it is excellent in corrosion resistance and scratch resistance, so that a high-class feeling can be maintained over a long period of time.

  Even when the body 101 and the water spray 102 are formed and combined as independent members, the ceramic for decorative parts of the present invention has little color unevenness, so that the sense of unity in color tone is not impaired. Alternatively, the water sprinkling part 102 is made of white zirconia, the body part 101 is made of ceramics for decorative parts of the present invention, and a new decorative pattern is created by using a combination of white and silver, and a sense of luxury, aesthetic satisfaction and mental comfort are used. Can be given to a person.

  Next, the manufacturing method of the ceramics for decorative parts of this invention is demonstrated.

In order to obtain the ceramic for decorative parts of the present invention, first, titanium carbide which is the main component in the sintered body and each powder of cobalt, chromium and niobium are weighed, pulverized and mixed, To do. More specifically, a titanium carbide powder having an average particle diameter of 10 to 30 μm, a cobalt powder having an average particle diameter of 1 to 20 μm, and a chromium powder having an average particle diameter of 3 to 70 μm or a composition formula of Cr ₃ Chromium carbide powder having an average particle diameter of 3 to 60 μm represented as C ₂ and niobium powder having an average particle diameter of 20 to 50 μm are prepared, and the cobalt powder is 5 to 25% by mass, chromium or chromium carbide. The powder may be weighed, pulverized and mixed so that the powder is 1 to 10% by mass, the niobium powder is 2 to 10% by mass, and the balance is titanium carbide.

  The pulverization / mixing time may be 50 hours or longer. At this time, silicon, phosphorus, sulfur, manganese, iron, and the like are listed as inevitable impurities in the blended raw material, but these may have an adverse effect on the color of the decorative surface. Is preferred.

The titanium carbide powder may be TiC having a stoichiometric composition or TiC _1-x N _x (0 ≦ x ≦ 0.2) having a non-stoichiometric composition. From the viewpoint of color tone with high quality and decorative value, the purity of each powder is preferably 99% or more, and titanium carbide powder partially reacts with cobalt powder to produce a small amount of compounds such as Co ₃ Ti It doesn't matter what. In particular, in order to satisfy 0 ≦ x ≦ 0.2 when the composition formula is TiC _1-x N _x for the titanium carbide sintered body forming the ceramic for decorative parts, the titanium carbide powder has a composition formula of TiC _1-x When N _x , 0 ≦ x ≦ 0.3 may be used.

  Next, after adding, for example, isopropanol as an organic solvent to the blended raw material and mixing and pulverizing using a mill, a predetermined amount of paraffin wax is added as a binder, and a desired molding method, for example, a dry pressure molding method, a cold static method, is added. It is formed into a desired shape such as a disk, flat plate, or torus by a hydraulic pressure molding method, extrusion molding method, or the like.

  When dry press is selected as the molding method, the molding pressure affects the open porosity and Vickers hardness (Hv) on the decorative surface, so the molding pressure is preferably 49 to 196 MPa. The molding pressure is set to 49 to 196 MPa because a sintered body having a relative density of 95% or more and an open porosity of 2.5% or less can be obtained, and the Vickers hardness (Hv) can be set to 8 GPa or more. It is. In addition, the life of the mold can be extended.

Then, the obtained molded body is degreased in a non-oxidizing atmosphere such as a vacuum atmosphere or an inert gas atmosphere as necessary, and then fired in an inert gas atmosphere or a vacuum, and the relative density with respect to the theoretical density is 95%. The above sintered body is obtained. In addition, firing in an inert gas atmosphere or in a vacuum is because, when firing in an oxidizing atmosphere, titanium carbide is oxidized and most of the titanium oxide is represented by the composition formula TiO _2. This is because the overall color tone of the ceramic for decorative parts is whitish.

  Moreover, when obtaining the ceramics for decorative parts by baking in a vacuum, it is suitable that the degree of vacuum is 5 Pa or less. The reason why the degree of vacuum is 5 Pa or less is that titanium carbide does not oxidize during firing, and thus a silver-colored ceramic for decorative parts is obtained. Furthermore, the firing temperature is preferably 1200 to 1600 ° C. This is because a sintered body having a relative density of 95% or more and an open porosity of 2.5% or less can be obtained, and the firing cost can be reduced.

  Then, the surface of the sintered body is subjected to grinding using a grinder on the surface where the decorative value of the sintered body is required, and then the surface of the sintered body is a decorative surface having a silver color tone. Thus, the ceramic for decorative parts of the present invention can be obtained. In addition, it is preferable that the pores appearing on such a decorative surface have a maximum diameter of 30 μm or less, and by setting this range, adhesion of germs, foreign matters, contaminants, etc. into the pores is possible. Can be reduced.

  When the shape of the product made of ceramics for decorative parts is complex, close to the block shape or product shape by dry pressure molding method, cold isostatic pressing method, extrusion molding method, injection molding method, etc. After shaping into a shape and sintering, after grinding to give a product shape, barrel polishing may be performed, or product shape may be formed by injection molding from the beginning, and barrel polishing may be performed after firing Good.

  In barrel polishing, a rotating barrel polishing machine is used, and alumina, green carborundum (GC), or the like as a medium is put into the rotating barrel polishing machine together with an appropriate amount of water, and the wet polishing is performed for 24 to 150 hours.

Furthermore, when the ceramic for decorative parts of the present invention contains molybdenum, titanium carbide powder having an average particle diameter of 10 to 30 μm, cobalt powder having an average particle diameter of 1 to 20 μm, and an average particle diameter of 3 to 3 70 μm chromium powder or chromium carbide powder having an average particle size of ₃ to 60 μm represented by a composition formula of Cr ₃ C ₂ , niobium powder having an average particle size of 20 to 50 μm, and an average particle size of 1 μm to 10 μm of molybdenum powder, 5 to 25 mass% of cobalt powder, 1 to 10 mass% of chromium or chromium carbide powder, 2 to 10 mass% of niobium powder, and a ratio of molybdenum to cobalt of 35 %, And the balance may be pulverized and mixed so that the balance is titanium carbide powder. Molding, firing, and processing may be performed in the same manner as described above.

Furthermore, when the ceramic for decorative parts of the present invention contains zirconia, titanium carbide powder having an average particle size of 10 to 30 μm, cobalt powder having an average particle size of 1 to 20 μm, and an average particle size of 3 to 3 70 μm chromium powder or chromium carbide powder having an average particle size of ₃ to 60 μm represented by the composition formula as Cr ₃ C ₂ , niobium powder having an average particle size of 20 to 50 μm, and an average particle size of 1 to A 10 μm molybdenum powder and a zirconia powder having an average particle size of 0.2 to 2 μm are prepared. The cobalt powder is 5 to 25 mass%, the chromium or chromium carbide powder is 1 to 10 mass%, and the niobium powder is 2 to 10% by mass, the ratio of molybdenum to cobalt is 35% or less, the zirconia powder is 9 to 30% by mass, the balance is titanium carbide powder, and the total of cobalt, chromium, niobium, zirconia and molybdenum is 50% by mass Less than Weighed and may be pulverized and mixed so that Yuryou. At this time, molybdenum may not be contained. Molding, firing, and processing may be performed in the same manner as described above.

  The ceramics for decorative parts of the present invention obtained as described above exhibits a silver color that is highly evaluated as a particularly beautiful color tone, has a high-class feeling, and can obtain aesthetic satisfaction, and as a result, mental relaxation through vision. Fishing line guide rings and fishing line guide decoration parts such as fishing line guides, watch case decoration parts such as watch cases, band pieces and buckles, number keys, various input keys, etc. Operation buttons, case, decorative parts for mobile terminals such as frame parts to fix the display, faucets and toiletries in bathrooms or bathrooms, coffee cup sets, spoons, forks, butter knives, fountain pen stationery, toothbrushes and razors Handle, earpick, scissors, seal material, business card, cremation accessory parts, glasses, brooches, neck Accessories such as accessories, earrings, rings, bracelets, anklets, tie pins, tie tacks, medals, buttons, initial logos, fasteners such as bags, operation buttons such as number keys, various input keys, cases, and displays PDA (Personal Digital Assistants: personal information equipment) decoration parts such as fixed frame parts, operation buttons such as number keys and various input keys, cases, and portable music playback devices such as frame parts that fix the display Decorative parts, decorative parts for housing of portable data storage devices, and decorations for building materials such as tiles, handles, garden stones, display boards, road guide markers, tiles that decorate floors, walls and ceilings, and grips for door handles Decoration of parts, sports equipment such as golf clubs, poker chips, shogi pieces, and meteorites, or entertainment equipment , Decorative parts such as musical instrument parts such as musical piece parts, string protection pieces, guitar protection plates, violin bow handles, earphones, speaker boxes, etc., tooth crowns, mouthpieces for musical instruments, It can also be suitably used as ceramics for decorative parts that produce beautiful silver color tones, such as disk brake pads, handles, emblems such as manufacturer names and vehicle types, and decorative parts for automobiles such as corner poles.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

  First, titanium carbide powder (purity 99%, average particle size 22.3μm), cobalt powder (purity 99% or more, average particle size 1.3μm), chromium powder (purity 99%, average particle size 55μm), niobium powder (purity 99.5) %, Average particle size 33 μm) was weighed so that the ratio (content) in the sintered body would be the ratio shown in Table 1, and pulverized and mixed to prepare a blended raw material.

  Next, an isopropanol solution is added to each of the obtained blended raw materials, pulverized and mixed for 72 to 96 hours using a vibration mill, and 3 parts by weight of paraffin wax as a binder is then added to the blended raw materials. Were dried into granules. And the obtained granule was pressure-molded with the pressure of 98 Mpa, and the molded object was produced. Next, this molded body was degreased at 400 ° C. in a vacuum atmosphere and then fired by holding at 1300-1600 ° C. for 2 hours to obtain a cylindrical sintered body having a diameter of 10 mm and a height of 10 mm. It was.

  And the diamond abrasive grain whose average particle diameter is 1 micrometer was supplied to the tin lapping machine, and the end surface of the sintered compact was lapped. Subsequently, using a rotating barrel polisher, water, alumina medium and green carborundum (GC) were added, barrel polishing was performed for 70 hours, and the end surface and outer peripheral surface were finished to a mirror surface. Ceramics for decorative parts comprising 1 to 19 titanium carbide sintered bodies were obtained.

  Thereafter, the contents of titanium, cobalt, chromium and niobium constituting each sample were measured using an ICP emission spectroscopic analyzer. Titanium was converted as carbide.

  For each age group in their 20s to 50s, a questionnaire survey was conducted on a monitor of 40 men and women, each with 5 men and women. ◎ if the number of people is less than one name, ◯ if the number of people who feel uneven color is 4 to 10 people, it can be used and judged as acceptable, and × if the number of people who feel uneven color is 11 or more, it cannot be used It was rejected.

  As for chipping, when lapping of 10 samples is finished, if there are 2 or less chippings with a length of 0.5mm or more on the front and back edges, 2 is a total. When the number was 4 or less, it was judged as “good” as “good” and judged as acceptable, and when the number was 5 or more, “x” as unusable and judged as “bad”.

  In addition, regarding scratch resistance, a watch case shown in FIG. 1 assembled with a watch band shown in FIG. 3 was manufactured, and a total of 40 men and women of each age group in their 20s to 50s. After the monitor has been worn for 300 hours (about 30 days), place the watch case and watch band at a position 30 to 40 cm away from the eyes, and illuminate with a fluorescent light to find a scratch on the monitor of five or less people. ◎ if there are 6 or more and 10 or less monitors visually found scratches, ○ if each is acceptable and judged to be acceptable, and 11 or more monitors find scratches visually As x, it was unusable and rejected. The results are shown in Table 1.

  As shown in Table 1, Sample No. which is outside the scope of the present invention. 1,2,7,8,13,14,19 are also rated as x for uneven color, chipping and scratch resistance, and have a beautiful silver color that gives a sense of luxury, aesthetic satisfaction and mental comfort. A decorative surface could not be formed. In comparison, Sample No. which is a sample within the scope of the present invention. 3 to 6, 9 to 12, 15 to 18 are ○ or ◎ for color unevenness, chipping and scratch resistance, and form a beautiful silver decorative surface that can provide a sense of luxury, aesthetic satisfaction, and mental comfort. I was able to.

  First, about cobalt, sample No. which is outside the scope of the present invention. 1 and 2 have a low cobalt content of less than 5% by mass, and it is difficult to wet the surface of the titanium carbide crystal particles uniformly during sintering. It can be seen that the color unevenness has increased because the mirror surface has become rough due to shedding. In addition, because the crystal grains of titanium carbide are easy to shed, the corners of the sample became brittle and chipping was likely to occur. I understand. Sample No. No. 7 has a cobalt content exceeding 25% by mass, so the proportion of the binder phase on the ceramic surface increased and scratch resistance decreased, resulting in a rough mirror surface and increased color unevenness. I understand.

  On the other hand, sample No. which is an embodiment of the present invention. In No. 3-6, since the content of cobalt is in the range of 5 to 25% by mass, titanium carbide is less likely to be granulated, the strength of the corners of the sample is maintained, and chipping is less likely to occur. It can be seen that there was no degranulation trace and the ceramic had excellent scratch resistance. Therefore, it can be seen that the color unevenness can be prevented from worsening due to mechanical factors such as grain separation and scarring of titanium carbide.

  Next, with respect to chromium, sample No. No. 8 has a chromium content of less than 1% by mass, so that a chromium oxide film cannot be sufficiently formed on the surface of the ceramic, resulting in a decrease in corrosion resistance. For this reason, the surface of the sample reacts with a grinding liquid or a cleaning liquid. It is thought that the color unevenness became large due to the adhesion of scales during drying. Sample No. No. 13 has a chromium content exceeding 10% by mass, so that the binder phase becomes too hard and the titanium carbide crystal particles are easily grained, the mirror surface is rough, and the color unevenness is large. It can be seen that the corners of the sample became brittle and chipping was likely to occur, and the degranulation traces remained streaks even in the flat part of the sample, resulting in a decrease in scratch resistance.

  On the other hand, sample No. which is a sample of the present invention. In Nos. 9 to 12, since the chromium content is in the range of 1 to 10% by mass, it can be seen that a chromium oxide film was formed on the surface of the ceramic and the color tone was stabilized. Moreover, since the binder phase is kept at an appropriate hardness, it can be seen that titanium carbide degranulation is suppressed, and that chipping and scratch resistance are evaluated well.

  Next, with respect to niobium, sample No. No. 14 has a niobium content of less than 2% by mass, and the chemical stability of the surface of the binder phase is lowered, facilitating discoloration, and the color tone of the ceramic varies and the color unevenness increases. Sample No. 19 has a niobium content of more than 10% by mass, which increases the liquidus temperature of the binder phase, lowers the sinterability, and makes it easy for the grains of titanium carbide to fall. It can be seen that the surface becomes rough and uneven color occurs.

  On the other hand, sample No. which is a sample of the present invention. 15 to 18, since the niobium content is in the range of 2 to 10% by mass, the niobium is mainly dissolved in the binder phase cobalt, so that the binder phase is maintained in a stable state on the ceramic surface. The color tone was stable and no color unevenness occurred. Moreover, it is thought that the bonding force between cobalt and titanium carbide is kept high, and it is understood that the titanium carbide is prevented from degranulating and the chipping and scratch resistance are evaluated well.

  A test was conducted to confirm the change in characteristics by changing the ratio of molybdenum to cobalt.

  First, titanium carbide powder (purity 99%, average particle size 22.3μm), cobalt powder (purity 99% or more, average particle size 1.3μm), chromium powder (purity 99%, average particle size 55μm), niobium powder (purity 99.5) %, Average particle size 33 μm) and molybdenum powder (purity 99% or more, average particle size 3.3 μm) are weighed, pulverized and mixed so that the ratio (content) in the sintered body is the ratio shown in Table 2. And used as a blended raw material.

  Next, sample No. 1 was manufactured by the same manufacturing method as in Example 1. Ceramics for decorative parts comprising 20 to 25 titanium carbide sintered bodies were obtained.

  Thereafter, the contents of titanium, cobalt, chromium and molybdenum constituting each sample were measured using an ICP emission spectroscopic analyzer as in Example 1. Titanium was converted as carbide.

  Thereafter, in the same manner as in Example 1, color unevenness, chipping and scratch resistance tests were performed. The results are shown in Table 2.

  As shown in Table 2, among the examples of the present invention, sample No. In 25, since the ratio of molybdenum to cobalt exceeds 35%, a molybdenum-rich phase precipitates in the binder phase, resulting in a partially non-uniform structure, and the ceramic is processed uniformly throughout. It can be seen that threshing and chipping increased. On the other hand, sample No. which is an embodiment of the present invention. In 20-24, since the ratio of the content of molybdenum to cobalt is 35% or less, in addition to small color unevenness, the firing temperature is lowered to suppress the grain growth of the crystal grains. It can be seen that chipping is less likely to occur. From this, if the ratio of molybdenum to cobalt is 35% or less, it is possible to form a beautiful silver-colored decorative surface that can provide a higher-class feeling, aesthetic satisfaction, and mental comfort, and less uneven color. It can be seen that degranulation and chipping during mechanical processing were suppressed and the mechanical strength was maintained.

  A test was conducted to confirm the change in characteristics due to the inclusion of zirconia.

  First, titanium carbide powder (purity 99%, average particle size 22.3μm), zirconia powder (purity 99% or more, average particle size 1.5μm), cobalt powder (purity 99% or more, average particle size 1.3μm), chromium powder ( Purity 99%, average particle size 55μm), niobium powder (purity 99.5%, average particle size 33μm) and molybdenum powder (purity 99% or more, average particle size 3.3μm) ratio (content) in the sintered body 3 was weighed so as to have the ratio shown in FIG.

  Next, sample No. 1 was manufactured by the same manufacturing method as in Example 1. Ceramics for decorative parts comprising 26 to 38 titanium carbide sintered bodies were obtained.

  Thereafter, the contents of titanium, zirconium, cobalt, chromium, niobium and molybdenum constituting each sample were measured using an ICP emission spectroscopic analyzer as in Example 1. Titanium was converted as carbide, and zirconium was converted as zirconia (zirconium oxide).

  Thereafter, in the same manner as in Example 1, color unevenness, chipping, and scratch resistance tests were performed.

Then, the abrasion resistance was newly evaluated. For the evaluation of wear resistance, sample No. 1 was used using the wear resistance evaluation apparatus shown in FIG. A cylindrical ceramics for decorative component of 26 to 38 (in FIG. 2, the position of the ceramics for decorative component 11) place after fixed with jig, half porcelain earth in water 0.001 m ³ (in clay 10 g of clay containing porcelain earth (ceramic stone) was added and mixed to prepare muddy water in the water tank 14. The mass of the weight 15 is set to 500 g, the speed at which the thread 12 slides on the outer peripheral side of the cylindrical ceramic for decorative parts is set to 60 m / min, and the traveling distance of the thread 12 is set to 3000 m. The adhered nylon thread 12 (Toray made silver scale Σ3) was slid on the outer peripheral side of the cylindrical ceramic for decorative parts. Then, using the surface shape measuring microscope (Keyence measuring unit VF-7510 / controller VF-7500), the deepest part of the flaw caused by the wear of the cylindrical ceramics for decorative parts by sliding the thread 12 Was measured, and the average value of 6 samples was calculated as the wear depth. And if the wear depth is less than 10μm, the wear mark is inconspicuous, so it can be used as ◯ and judged as acceptable, and if the wear depth exceeds 10μm, the wear mark is conspicuous and cannot be used as x and rejected. did. The results are shown in Table 3.

  As shown in Table 3, sample No. In 26, 27, and 34, the content of zirconia is as low as less than 9% by mass, so there are not enough zirconia particles on the surface of the ceramic, and oxidation of titanium carbide and binder phase occurs when the fishing line slides. It is thought that the effect of suppressing wear and wear decreased, and the amount of wear increased. Further, among the examples of the present invention, the sample No. In 32, since the content of zirconia exceeds 30% by mass, the ratio of the volume expansion / contraction change due to the phase transformation of zirconia during sintering to the total volume of the ceramic increases, and after sintering It is considered that cracks remained in the ceramics and chipping, scratch resistance, and wear resistance were lowered. Further, among the examples of the present invention, the sample No. In 33 and 38, the content of zirconia exceeds 30% by mass, and the total of zirconia, cobalt, chromium, niobium and molybdenum is 50% by mass or more, so chipping, scratch resistance and wear resistance are further reduced. It can be seen that the uneven color has become noticeable.

  Moreover, although not described in Table 3, when ceramics were produced with the composition not containing zirconia described in Patent Document 4 and the wear resistance was evaluated by the same method, among the examples of the present invention, Sample No. with the least amount of zirconia. The amount of wear increased from 26, and it was found that the product of the present invention was improved in terms of wear resistance.

  On the other hand, sample No. which is an embodiment of the present invention. 28-31 and 35-37 have a zirconia content in the range of 9 to 30% by mass, so even if titanium carbide or the binder phase wears when the fishing line slides, the zirconia crystal particles will remain on the surface. Since this remains in the shape of a protrusion and comes into contact with the fishing line, it can be seen that the oxidation of titanium carbide and the binder phase progresses slowly and wear is suppressed.

  Further, using the ceramics for decorative parts of the present invention, a fishing line guide ring which is a decorative part for fishing line guide, a fishing line guide provided with this fishing line guide ring, a watch case and a watch band piece which are decorative parts for watches , Various operation keys and cases for mobile phones, which are decorative parts for mobile terminals, faucets and shower heads, which are decorative parts for daily necessities, have excellent wear resistance and high hardness. Because it is hard to be scratched and can maintain the silver color for a long time, if these decorative parts are used, it will constitute an attractive product that will continue to give luxury, aesthetic satisfaction and mental comfort for a long time. I found out that

  Using the ceramics for decorative parts of the present invention as described above, decoration parts for fishing lines, decorative parts for watches, decorative parts for mobile phones and decorative parts for wristwatch-type mobile phones, decorative parts for jewelry, and building materials If used as a decorative part or a decorative part for daily life, it has a beautiful silver color and has a high evaluation, giving it a high-class feeling and aesthetic satisfaction. As a result, it can provide mental comfort through vision. It is preferable.

1: Guide ring for fishing line
10: Wear resistance evaluation device
20A, 20B: Watch case
21: Recess
22: Foot
23: Bottom
24: Torso
25: Hole
30: Nakakoma
31: Through hole
32: Pin hole
33: Outer piece
40: Pin
50: Watch band
60: Mobile phone
90: Faucet
100: Shower head

Claims (7)

A ceramic for decorative parts made of a titanium carbide sintered body, containing cobalt in an amount of 5% by mass to 25% by mass, chromium in an amount of 1% by mass to 10% by mass, and niobium in an amount of 2% by mass to 10% by mass. A ceramic for decorative parts, characterized in that chromium and niobium are contained in a solid solution with cobalt. The ceramic for decorative parts according to claim 1, comprising molybdenum in a content of 35% by mass or less based on cobalt. The decorative component according to claim 1 or 2, wherein zirconia is contained in a content of 9% by mass or more and 30% by mass or less, and a total of zirconia, cobalt, chromium, niobium and molybdenum is less than 50% by mass. Ceramics. A decorative part for fishing line guide, comprising the ceramic for decorative parts according to any one of claims 1 to 3. A decorative part for a watch, comprising the ceramic for a decorative part according to any one of claims 1 to 3. A decorative part for a mobile phone, comprising the ceramic for a decorative part according to any one of claims 1 to 3. A decorative part for daily goods, comprising the ceramic for decorative part according to any one of claims 1 to 3.

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