JPH0520379B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a ceramic material composition for producing a high-density and tough alumina-based ceramic material, particularly tools reinforced with SiC whiskers. (Prior Art) Alumina is a typical ceramic material and has excellent heat resistance and corrosion resistance, and is expected to be applied to tools and the like by increasing its strength. Recently, fiber reinforced ceramics (FRC) has been seen as a promising means of reinforcing ceramics.
It is said to be an extremely effective means to prevent toughness deterioration at high temperatures, and is expected to be applied to tool materials. By the way, fiber-reinforced alumina was created by using Al ₂ O ₃ , which is suitable for tools, as a matrix, using SiC whiskers as dispersed fibers, and adding a conventionally used Al ₂ O ₃ sintering agent. Although it has been recognized that the toughness is considerably improved compared to a simple sintered body of Al ₂ O ₃ , it has not yet been able to fully satisfy market demands. After various studies on the cause, we found that Al ₂ O ₃ and
It was thought that this was because the dispersion-enhancing effect of the whiskers was not utilized due to poor affinity with the SiC whiskers. That is, SiC itself originally has poor affinity with Al ₂ O ₃ , and since whiskers have extremely few lattice defects that act as a driving force for sintering, the affinity between the two is further deteriorated. Therefore, in the past, when whiskers were added to a normal Al ₂ O ₃ sintered body, it was necessary to increase the amount of sintering aid, raise the sintering temperature, or even use a pressure sintering method. The current situation is that the matrix is oversintered. (Problems to be Solved by the Invention) When the above conventional method is used, the strength of the Al ₂ O ₃ matrix itself is reduced, and furthermore, the Al ₂ O ₃ matrix and the SiC whiskers are not in close contact with each other, so that the final baking is difficult. The compact could not obtain sufficient toughness and strength. (Means for solving the problems) As a result of various studies on the above problems, the present invention is based on Al ₂
This was done based on the idea that the toughness of ceramic could be improved by improving the affinity between the O ₃ matrix and SiC whiskers.
By modifying the whisker surface, Al ₂ O ₃
This is based on the knowledge that adhesion to the matrix can be improved. That is, the present invention includes 10 to 60% by weight of SiC whiskers, 0.1 to 0.1 to 10% of one or more selected from oxides of CaO, MgO, SiO ₂ , ZrO ₂ , NiO, Y ₂ O ₃ , and lanthanoids.
7% by weight, B, C, AlN, BaC and “Si, Al,
The ceramic material has a composition of 0.05 to 7% by weight of at least one selected from borides _of Y, lanoids, transition metals of group a, a, group a, and the balance _Al2O3 . (Function) In the above, if the amount of SiC whiskers is less than 10% by weight, the reinforcing effect will be too small, and if it exceeds 60% by weight, the sinterability will deteriorate, which is not preferable. Oxides of Cao, MgO, SiO ₂ , ZrO ₂ , NiO ₂ , Y ₂ O ₃ lanthanoids are sintering aids, which are used to sinter the alumina matrix, but their effectiveness is reduced below 0.1% by weight. If it is too small, and conversely exceeds 7% by weight, the toughness will drop significantly. Furthermore, B, C, AlN, BaC and “Si, Al, Y,
lanthanoids, transition metals of group a, a, a
of boride was added to the Al ₂ O ₃ matrix
This improves the affinity of SiC whiskers, especially
If it is less than 0.05% by weight, sufficient effects cannot be obtained;
If it exceeds 7% by weight, compounds with Si tend to form, reducing the strength of the matrix-whisker interface, making it impossible to obtain good results. In addition, to be sure, the transition metals of group a, a, and a are listed as group a: Ti, Zr, group a, Nb,
They are group a Cr and Mo. (Example) Al ₂ O ₃ powder with an average particle size of 0.7 μm as raw material powder,
SiC whisker (diameter 0.1~1.0μm main diameter 0.2~
0.5μm, length 50~200μm, aspect ratio 50~300,
density 3.19 g/cm ³ ) and sintering aids (Cao, MgO, SiO ₂ , ZrO ₂ , NiO, Y ₂ O ₃ ,
lanthanoid oxide) and average particle size 0.5-5μm
B, AlN, B ₄ C and borides (additives) of "Si, Y, lanthanides, transition metals of group a, After mixing for a while, drying to prepare a base powder, this base powder was sintered in a graphite mold using the pressure sintering method at the sintering temperature shown in Table 1 at a pressure of 200Kg/cm ² and a pressurization time of 15 minutes. Sintered. The thus obtained sintered body was ground to SNGN432TN using a diamond grindstone to a surface of 3S or less (according to JIS), and the hardness was measured and a cutting test was conducted under the conditions shown below. The results are shown in Table 1. Cutting test conditions 1 Material to be cut: FC23 Cutting conditions: Cutting speed (V) = 150 m/min Feed rate (f) = 0.6 mm/rev Depth of cut (t) = 2 mm Life judgment: Width of 1 thread of 120 mmφ wire 10 mm Measure the number of cutting ridges until breakage when cutting with a pitch of 5 mm between ridges.

【table】

[Table] (Effects of the invention) According to the present invention, Al ₂ O ₃ and SiC whiskers are
The affinity can be improved by boride of C, AlN, B ₄ C and "Si, Al, Y, lanthanoids, transition metals of group a, a, a", and the specified ratio of each component can be improved. This makes it possible to manufacture products that not only have excellent heat resistance and corrosion resistance, but also have increased strength, making it possible to provide ceramic tools with excellent properties.

Claims (1)

[Claims] 1 SiC whiskers 10-60% by weight, CaO, MgO,
0.1 to 7% by weight of one or more selected from SiO ₂ , ZrO ₂ , NiO, Y ₂ O ₃ , lanthanoid oxides, B, C,
AlN, B ₄ C and “Si, Al, Y, lanthanoids,
0.05 to 7% by weight of one or more borides of transition metals of groups a, a, a of the periodic table, Al ₂ O ₃
A whisker-reinforced ceramic material for tools consisting of the remainder.