JP5259476B2 - Capstan - Google Patents

Description

The present invention relates to a capstan used for winding an optical fiber or a metal wire, for example.

Ceramics are used as a capstan material used for winding optical fibers and metal wires. This is because ceramics are excellent in wear resistance, so that dust generation from the capstan is small, and contamination to metal wires and optical fibers is reduced. Among ceramics, zirconia, which is particularly excellent in wear resistance, has been proposed as a capstan material (see Patent Document 1).

Patent Document 1 discloses a capstan roller having a zirconia slidable contact surface that is HIP-treated. According to this, the surface of the ceramic becomes very smooth as the crystal grains become denser by the HIP treatment.

JP 2005-297037 A

However, with this processing method, it is easy to produce a locally different color tone, and in some cases, this color tone difference may appear as a difference in wear. If there is a local low-abrasion part, there is a problem because the wear selectively proceeds in that part.

The present invention has been made in view of these problems, and provides a capstan that has excellent tissue homogeneity and is less susceptible to local wear.

In order to solve these problems, the present invention provides the following (1) to (5).
(1) One or more elements selected from V, Cr, Mn, Fe, Co, Ni, Cu, Mo, and W are contained in an amount of 0.5% by volume or more and 8% by volume or less in terms of oxide, and brightness L * Is a ceramic sintered body having a brightness difference ΔL * of 10 or less, a porosity of 1% or less, and a crystal grain size of 2 μm or less.
(2) The capstan according to (1), wherein the ceramic sintered body contains zirconia as a main component.
(3) The capstan according to (2), wherein the ceramic sintered body contains 0.5% by volume or more of alumina.
(4) The capstan according to (2) or (3), wherein the ceramic sintered body contains 0.1 to 2% by volume of a non-oxide ceramic.
(5) The capstan according to (4), wherein the non-oxide ceramic is silicon carbide.

Capstan with excellent tissue homogeneity and less local wear can be provided.

The capstan of the present invention contains one or more elements selected from V, Cr, Mn, Fe, Co, Ni, Cu, Mo, and W in an amount of 0.5% by volume to 8% by volume in terms of oxide. It is characterized by comprising a ceramic sintered body having a lightness L * of 45 or less.

Conventionally, a ceramic sintered body that does not contain the elements as described above and has been used for a capstan as in the invention of Patent Document 1, for example, is generally used in such a ceramic sintered body. Although it is densified, a difference in the particle size of the sintered body tends to occur, and the wearability tends to become non-uniform accordingly.

In the present invention, by including one or more elements selected from V, Cr, Mn, Fe, Co, Ni, Cu, Mo, and W, conventional wear nonuniformity is prevented.

Moreover, the color tone of a sintered compact becomes uniform by containing said element. Moreover, the lightness L * in the L * a * b * color system (JISZ8729) can be 45 or less. The lightness L * indicates that the closer to 0, the closer to black. Therefore, the capstan of the present invention has a color tone close to black. The fact that the lightness L * is small and close to black means that when winding an optical fiber or metal wire, it is easier to distinguish the optical fiber or metal wire than when the lightness L * is large and close to white, and inspection is easy. There is an effect of becoming. In addition, the conventional HIP-processed ceramic sintered body has a non-uniform color due to a non-uniform structure that causes a difference in wearability. There was a problem that it was difficult to distinguish. Since the capstan of the present invention has a uniform color tone of the ceramic sintered body, such a problem can be solved.

The capstan of the present invention has a brightness difference ΔL * of 10 or less. As described above, color tone nonuniformity due to the HIP process does not occur. Therefore, the lightness difference ΔL * can be controlled to 10 or less, and further to 6 or less. The small brightness difference ΔL * indicates that the tissue is extremely homogeneous. Therefore, the problem of being partially inferior in wear resistance and being selectively worn out from that portion can be solved.

The ceramic sintered body constituting the capstan of the present invention preferably has a porosity of 1% or less, more preferably 0.5% or less. A high porosity is not preferred because it tends to wear out. The crystal grain size of the ceramic sintered body is preferably 2 μm or less, more preferably 1.5 μm or less, and further preferably 0.1 to 1.0 μm. By suppressing the grain growth, the color tone of the ceramic sintered body can be made uniform, and can be made suitable as a capstan.

Various oxide ceramics such as alumina, zirconia, titania, and spinel can be applied to the ceramic sintered body, but alumina or zirconia is preferable. Of these, zirconia is most preferred. Zirconia has excellent wear resistance, and by containing one or more elements selected from V, Cr, Mn, Fe, Co, Ni, Cu, Mo, and W as described above, the brightness L * is 45 or less. Can be close to black.

One or more elements selected from V, Cr, Mn, Fe, Co, Ni, Cu, Mo, and W are present at the grain boundaries of zirconia as oxides in the ceramic sintered body. Further, when alumina is contained in zirconia, it exists at the grain boundary as a composite oxide of these metals and aluminum. Furthermore, some may be dissolved in zirconia or alumina.

Since these additives become a sintering inhibitor of ceramics, especially zirconia, the abnormal grain growth of zirconia is suppressed, and the sintered grain size is easily made uniform. For this reason, it becomes difficult to produce the change of local abrasion property. When these contents increase, the wear resistance deteriorates. This is because the presence of many of these at the grain boundaries of zirconia facilitates degranulation. Therefore, the content is preferably 8% by volume or less, and more preferably 6% by volume or less.

In addition, the color tone is affected by a difference in translucency caused by a difference in the structure of the ceramic sintered body due to the color of the additive itself and the grain size of the ceramic sintered body. Additives are dispersed and added, and the presence state of the additives at the grain boundary is uniform, the formation of the compound with the ceramic, the solid solution in the ceramic occurs uniformly, and the crystal grains grow uniformly. It can be made uniform.

Zirconia may contain yttria. This is to prevent zirconia alone from cracking due to a volume change due to a crystal phase transition from monoclinic to tetragonal at around 1000 ° C. during the sintering process. The yttria content is preferably 3 to 8 mol%.

In the case of zirconia, the reason is unknown, but dispersibility is further improved by containing 0.5% by volume or more of alumina. The content of alumina is more preferably 0.5 to 10% by volume, and further preferably 0.5 to 5% by volume. If it is in the said range, the uniformity of a color tone can be improved, without promoting grain growth.

Furthermore, the capstan of the present invention can be an oxide ceramic containing 0.1 to 2% by volume of a non-oxide ceramic. Examples of non-oxide ceramics include silicon carbide and silicon nitride, among which silicon carbide is preferable. If it is in the said range, it can densify, suppressing grain growth.

By including silicon carbide in oxide ceramics, particularly zirconia, abnormal grain growth and grain growth of the zirconia sintered body can be further reduced, and the crystal grain size can be made uniform.

Moreover, the empty slip at the time of winding up an optical fiber, a metal wire, etc. is reduced by containing silicon carbide. Since the wear can be suppressed by reducing the skid, a synergistic effect can be expected. It is not certain how silicon carbide acts against such an effect, but it is thought that by containing silicon carbide and suppressing grain growth, the number of particles that come into contact with a metal wire or the like increases.

Hereinafter, the manufacturing method of the capstan of this invention is demonstrated.

As the raw material ceramic powder, one having a high purity and a small average particle diameter is preferable. As the zirconia powder, those containing a predetermined amount of yttria and other impurities in an amount of 1% by mass or less are preferable. Other impurities having an amount of 0.1% by mass or less can be used more suitably. The average particle diameter of the zirconia powder is preferably 1 μm or less, more preferably 0.5 μm or less, and further preferably 0.1 μm or less. In this specification, the median diameter D50 obtained by laser diffraction particle size distribution measurement is used as the average particle diameter.

It is preferable to use a high-purity alumina powder. Specifically, the purity is preferably 99% or more, and more preferably 99.9% or more. The average particle size of the alumina powder is preferably 1 μm or less, and more preferably 0.3 μm or less.

One or more elements selected from V, Cr, Mn, Fe, Co, Ni, Cu, Mo, W are added in the form of various compounds such as oxides, carbides, nitrides, carbonates, nitrates, etc. May be good. The amount added is calculated in terms of the oxide produced when sintered. These are preferably high-purity ones. Specifically, the purity is preferably 95% or more, and more preferably 98% or more. In addition, the average particle diameter when added as a powder is preferably 1 μm or less, and more preferably 0.5 μm or less.

As the silicon carbide powder, it is preferable to use a high-purity one. Specifically, the purity is preferably 95% or more, and more preferably 97% or more. The average particle size of the silicon carbide powder is preferably 1 μm or less, and more preferably 0.5 μm or less.

In order to uniformly disperse additives such as alumina powder, silicon carbide, and metal oxides such as V, Cr, and Mn, it is desirable that the particle size distribution of the additive raw material powder is sharp. Specifically, the ratio D90 / D10 of D10 and D90 by laser diffraction particle size distribution measurement is preferably 10 or less, more preferably 8 or less, and even more preferably 4 or less.

These raw material powders are mixed by a known method such as a ball mill, and then molded by a known method such as CIP molding or casting. In the case of CIP molding, a solvent, organic binder, etc. are added to the raw material powder to form a slurry, which is granulated by spray drying, and then a CIP molding is applied to the molded product obtained by press molding using a mold or the like. can do.

In the case of a molded body to which an organic substance such as a binder is added, degreasing is performed before firing. Degreasing is preferably performed at 500 to 800 ° C.

Firing can be performed in an oxidizing atmosphere such as the air. In the vicinity of the surface of the molded body, the volatilization of the additive occurs during firing. Therefore, it is desirable to place zirconia containing the additive powder in the firing atmosphere. The firing temperature can be 1350-1500 ° C.

The sintered body obtained by firing is processed into a desired shape to obtain a capstan. The processing can be performed by a known method such as surface grinding, lathe processing, machining center or the like.

Hereinafter, the present invention will be specifically described using test examples.

A zirconia powder having an average particle diameter of 0.05 μm and 3 mol% of yttria was used, and additives and the like were mixed in a composition as shown in Table 1. An acrylic resin as a molding binder and ion-exchanged water as a solvent were added to the obtained mixed powder. After spray drying, molding granules were obtained through a sieve. In addition, the oxide of Table 1 was added about V, Cr, Mn, Fe, and Co, and the metal powder was added about Ni, Cu, Mo, and W.

The obtained granules for molding were uniaxial press-molded by a mold and then CIP molded to obtain a molded body of 120 × 120 × 10 mm. After degreasing, the sintered body obtained by firing was processed into a 100 × 100 mm × 5 mm sintered body.

For comparison, zirconia by conventional HIP treatment (argon atmosphere, 1300 ° C., 150 MPa) was also produced (Test No. 25).

The lightness L * and the lightness difference ΔL * were measured using a spectrocolorimeter after mirror-finishing the test piece. The measurement was carried out at five arbitrary locations, the average being the lightness L *, and the difference between the maximum value and the minimum value being the lightness difference ΔL *. The porosity of the sintered body was calculated by the Archimedes method. Further, the average crystal grain size of the sintered body was determined by a line intercept method after mirror-polishing the surface of the sintered body and then performing SEM observation after thermally polishing the polished surface. The results are shown in Table 1. In addition, the content rate of an additive, an alumina, and silicon carbide is computed based on the theoretical density and raw material composition of a compound containing zirconia and yttria. The oxides shown in Table 1 were used for the oxide conversion of the additive. Moreover, each content rate is the volume% which occupies for a ceramic sintered compact.

Test No. containing no alumina or silicon carbide. 1-11, test no. In 1 to 9, the brightness L * was 45 or less, the brightness difference ΔL * was 10 or less, the porosity was 1% or less, and the crystal grain size was 2 μm or less. Test No. with low additive content. At 10, the lightness L * was large and the crystal grain size was also large. Test No. with a high content of additives. 11, the brightness difference ΔL * was large, and the densification was insufficient.

Test No. containing alumina. In 12-16, the tendency for lightness L * and lightness difference (DELTA) L * to become small was seen. By combining with the additive, the lightness L * could be 18 or less. It was also found that the brightness difference ΔL * can be made 4 or less by appropriately controlling the alumina content. Test No. containing a lot of alumina In No. 16, the crystal grain size increased.

Test No. containing silicon carbide. In 17-21, the tendency for lightness difference (DELTA) L * to become small was seen especially. However, test no. In No. 21, densification was insufficient.

Test No. containing alumina and silicon carbide. In 22 to 24, the lightness L * and the lightness difference ΔL * could be 20 or less and 3 or less, respectively.

Test No. produced by conventional HIP treatment. At 25, the lightness L * was 23, but the lightness difference ΔL * was as large as 15.

The capstan to which the ceramic sintered body of the present invention shown by the above results is applied is excellent in the homogeneity of the structure, so that local wear hardly occurs. Also, since the color tone is uniform, it is easy to distinguish between optical fibers and metal wires, and it is possible to easily inspect wear debris, dust, and the like.

Claims (5)

One or more elements selected from V, Cr, Mn, Fe, Co, Ni, Cu, Mo, and W, including 0.5% by volume or more and 8% by volume or less in terms of oxide,
The lightness L * is 45 or less, the lightness difference ΔL * is 10 or less,
A capstan comprising a ceramic sintered body having a porosity of 1% or less and a crystal grain size of 2 μm or less. The capstan according to claim 1, wherein the ceramic sintered body contains zirconia as a main component. The capstan according to claim 2, wherein the ceramic sintered body contains 0.5% by volume or more of alumina. The capstan according to claim 2 or 3, wherein the ceramic sintered body contains 0.1 to 2% by volume of a non-oxide ceramic. The capstan according to claim 4, wherein the non-oxide ceramic is silicon carbide.