WO2021225190A1 - Low-k, high-strength ceramic composition, and rear cover using same for mobile device - Google Patents

Abstract

The present invention relates to a low-k, high-strength ceramic composition, and a rear cover using same. A low-k, high-strength ceramic composition according to an embodiment of the present invention comprises stabilized zirconia and zirconium silicate, wherein the stabilized zirconia may be contained in an amount of 20 to 60% by weight, and the zirconium silicate may be contained in an amount of 40 to 80% by weight. Accordingly, the composition can have high strength properties and low dielectric properties.

Description

Low dielectric high strength ceramic composition and rear cover for mobile using same

The present invention relates to a low-k, high-strength ceramic composition and a rear cover for mobile using the same, and more particularly, to zirconia (ZrO ₂ ) by adding zirconium silicate (ZrSiO ₄ ) to high strength characteristics and low dielectric It relates to a ceramic composition having characteristics and a rear cover for mobile using the same.

As communication technology advances from the 4th generation to the next generation (5th and 6th generation), a high frequency or very high frequency is used to transmit and receive a large amount of data. The frequency currently used is gradually changing from sub6 (4.5 GHz) to 28, 40 GHz, and it is expected that ultra-high frequencies above 100 GHz will be used in the future.

Meanwhile, ion-strengthened glass is currently used as a rear cover of a mobile terminal, and ceramics are being considered as a material having higher strength than this. However, the ceramic material has a very good strength compared to ion-strengthened glass, but has a problem in that a received signal may be lost or distorted because of a high dielectric constant.

The standard characteristics required to be usable as a rear cover of a mobile terminal can be defined as three-point flexural strength of 700 MPa to 800 MPa or more, dielectric constant 15, and signal loss of -4 dB or less.

The currently used zirconia (ZrO ₂ ) ceramic material has excellent flexural strength of 1000 MPa or more, but has a dielectric constant of 28 to 32, and a signal loss of about -9 to 10 dB. Therefore, since the conventional zirconia (ZrO ₂ ) ceramic material has a high dielectric constant and thus a signal loss is large, when used as a material for a rear cover of a mobile terminal or a component material for an electronic device exterior, a received signal may be lost or severely distorted. Therefore, there is a problem in that it is difficult to be used as a material for a rear cover for a mobile device or a component material for the exterior of an electronic device.

On the other hand, zirconia (ZrO ₂₎ in order to reduce the high dielectric constant of the ceramic material, zirconia (ZrO ₂₎ a mixture of silica (silica, SiO ₂₎ in the ceramic material should also take advantage of the sintered composition. Silica has a dielectric constant of about 3.9.

Table 1 below is zirconia (ZrO ₂ ) and silica (SiO ₂ ) Flexural strength, dielectric constant (permittivity) and signal loss according to the composition ratio (weight percent, wt%) of a mixture of silica (SiO 2 ) shows the measurement results.

division	ZrO 2 (wt%)	SiO 2 (wt%)	Flexural strength (MPa)	permittivity	Signal loss (dB)
mixture	92	8	620	18.4245	-4.7241
	84	16	535	14.8083	-3.5938
	76	24	477	12.3654	-3.59
	36	64	150	-4.64	-One
	20	80	Impossible to measure due to microplasticity	-4.36	-One

Referring to Table 1, as _{the mixing ratio of silica (SiO 2} ) increases, the dielectric constant decreases, so that the dielectric properties are improved, and thus the magnitude of the signal loss is reduced. However, the flexural strength decreases accordingly. When the mixing ratio of silica is 16% or more, the flexural strength decreases to 550 MPa or less. That is, since the flexural strength is too low, there is a problem in that it is difficult to be used as a material for a rear cover of a mobile terminal or a component material for an exterior of an electronic device.

1 is a SEM image of a mixed composition containing zirconia (ZrO ₂ ) and silica (SiO _{2 ).}

Referring to FIG. 1 , when _{the mixing ratio of zirconia (ZrO 2} ) and silica (SiO ₂ ) is 76:24 based on weight percent, it can be seen that many pores (C) are formed in the ceramic. Therefore, it can be confirmed that the flexural strength of the ceramic composition is greatly reduced due to the low strength silica (SiO _{2 ) and a large number of pores.}

An object of the present invention is to provide a ceramic composition having high strength characteristics and low dielectric properties by adding zirconium silicate (ZrSiO _{4 ) to zirconia (ZrO 2} ) and a rear cover using the same in order to solve the above problems.

The problems of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those of ordinary skill in the art to which this invention belongs from the following description.

The low dielectric high strength ceramic composition according to an embodiment of the present invention for achieving the above object includes stabilized zirconia and zirconium silicate (ZrSiO ₄ ), and the stabilized zirconia is included in 20 to 60 weight percent (weight %), Zirconium silicate (ZrSiO ₄ ) may be included in 40 to 80 weight percent (weight %).

Meanwhile, in the low dielectric high strength ceramic composition according to an embodiment of the present invention for achieving the above object, flexural strength may be 700 MPa to 1000 MPa.

Meanwhile, in the low-k, high-strength ceramic composition according to an embodiment of the present invention for achieving the above object, the dielectric constant may be 10 to 15.

Meanwhile, in the low-k, high-strength ceramic composition according to an embodiment of the present invention for achieving the above object, the stabilized zirconia may contain 2 to 5 mole percent (mol%) of a stabilizer.

On the other hand, in the low-k, high-strength ceramic composition according to an embodiment of the present invention for achieving the above object, the stabilizer may be yttria (Yttria, Y ₂ O ₃ ).

On the other hand, in the low dielectric high strength ceramic composition according to an embodiment of the present invention for achieving the above object, 0.5 to 2.5 weight percent (weight %) of aluminum oxide (Al ₂ O ₃ ) based on the total weight of the ceramic composition. can

On the other hand, in the low dielectric high strength ceramic composition according to an embodiment of the present invention for achieving the above object, zirconium silicate (ZrSiO ₄ ) is zirconia (ZrO ₂ ) and silica (SiO ₂ ) Co-precipitation or It can be synthesized using a solid-reaction method.

Meanwhile, in the low dielectric high strength ceramic composition according to an embodiment of the present invention for achieving the above object, zirconium silicate (ZrSiO ₄ ) may have an average particle size of 0.5 μm to 1 μm.

Meanwhile, the rear cover for mobile according to an embodiment of the present invention for achieving the above object may be formed by processing the ceramic composition.

The details of other embodiments are included in the detailed description and drawings.

According to the present invention, there are the following effects.

The low-k, high-strength ceramic composition and the rear cover using the same according to an embodiment of the present invention have the effect of increasing strength and reducing signal loss by adding zirconium silicate (ZrSiO _{4 ) to zirconia (ZrO 2 ).}

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those of ordinary skill in the art to which this invention belongs from the description of the claims.

1 is a SEM image of a mixture containing zirconia (ZrO ₂ ) and silica (SiO _{2 ).}

2a to 2e are SEM images according to the mixing ratio of _{zirconia (ZrO 2} ) and zirconium silicate (ZrSiO ₄ ) in the ceramic composition according to an embodiment of the present invention.

FIG. 3 is an XRD data plot according to the mixing ratio of zirconium silicate (ZrSiO _{4 ) of FIGS. 2b to 2e.}

4 is a graph showing the flexural strength according to the mixing ratio _{of zirconium silicate (ZrSiO 4} ) of FIGS. 2a to 2e.

5 is a graph showing the dielectric constant and signal loss according to the zirconium silicate (ZrSiO _{4 ) mixing ratio of FIGS. 2A to 2E .}

Hereinafter, the present invention will be described in more detail with reference to the drawings.

Regardless of the reference numerals, the same or similar components are assigned the same reference numerals, and overlapping descriptions thereof will be omitted. The suffixes "module" and "part" for the components used in the following description are given or mixed in consideration of only the ease of writing the specification, and do not have a meaning or role distinct from each other by themselves. Accordingly, the terms “module” and “unit” may be used interchangeably.

In addition, in describing the embodiments disclosed in the present specification, if it is determined that detailed descriptions of related known technologies may obscure the gist of the embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are only for easy understanding of the embodiments disclosed in the present specification, and the technical spirit disclosed herein is not limited by the accompanying drawings, and all changes included in the spirit and scope of the present invention , should be understood to include equivalents or substitutes.

Terms including an ordinal number, such as first, second, etc., may be used to describe various elements, but the elements are not limited by the terms. The above terms are used only for the purpose of distinguishing one component from another.

When a component is referred to as being “connected” or “connected” to another component, it is understood that the other component may be directly connected or connected to the other component, but other components may exist in between. it should be On the other hand, when it is said that a certain element is "directly connected" or "directly connected" to another element, it should be understood that no other element is present in the middle.

The singular expression includes the plural expression unless the context clearly dictates otherwise.

In the present application, terms such as "comprises" or "have" are intended to designate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, but one or more other features It should be understood that this does not preclude the existence or addition of numbers, steps, operations, components, parts, or combinations thereof.

The ceramic composition according to an embodiment of the present invention may include a single low-k compound in stabilized zirconia. Specifically, it may include a low-k single compound, zirconium silicate (ZrSiO _{4 ).}

Stabilized zirconia is prepared by adding a stabilizer to zirconia (ZrO _{2 ).} Pure zirconia (ZrO ₂ ) changes its crystal form from a tetragonal phase to a monoclinic phase at around 1100℃, and a rapid volume change causes cracks in the ceramics and self-destruction. none. Therefore, stabilized zirconia prepared by adding a stabilizer to prevent such a volume change may be used.

Since stabilized zirconia exhibits almost linear thermal expansion without a change in crystal form from room temperature to high temperature, a dense sintered body can be manufactured. In addition, stabilized zirconia has very high flexural strength.

Zirconium silicate (ZrSiO4) is a material with excellent thermal, mechanical, and chemical properties, and its sintered body is used in refractory materials, electromagnetic materials, and various chemical devices. Zirconium silicate has a dielectric constant of 8.8 at a frequency of 1 MHz and a flexural strength of about 450 MPa.

Specifically, in the ceramic composition according to an embodiment of the present invention, stabilized zirconia is included in 20 to 60 weight percent (weight %), and zirconium silicate (ZrSiO ₄ ) is included in 40 to 80 weight percent (weight %). have.

Preferably, in the ceramic composition of the present invention, stabilized zirconia is included in 40 to 60 weight percent (weight %), and zirconium silicate (ZrSiO ₄ ) may be included in 40 to 60 weight percent (weight %).

If the content of the stabilized zirconia is less than 20 weight percent, the flexural strength of the ceramic composition of the present invention is too low, and there is a risk of easily breaking when used as a mobile rear cover.

Conversely, when the content of the stabilized zirconia exceeds 60 weight percent, the signal loss due to the ceramic composition increases, so that the radio wave reception ability of the mobile device is deteriorated when used as a mobile rear cover.

Similarly, when the content of zirconium silicate (ZrSiO ₄ ) is less than 40 weight percent, the signal loss due to the ceramic composition increases, _{and when the content of zirconium silicate (ZrSiO 4} ) is 80 weight percent or more, the flexural strength of the ceramic composition is too low.

Meanwhile, in the ceramic composition according to an embodiment of the present invention, the dielectric constant of the ceramic composition may be 10 to 15.

When the permittivity is 15 or more, the signal loss is excessively large, so that the radio wave reception ability of the mobile device is deteriorated when used as a rear cover for a mobile device.

Meanwhile, in the ceramic composition according to an embodiment of the present invention, the flexural strength of the ceramic composition may be 700 MPa to 1000 MPa. Preferably, in the ceramic composition of the present invention, the flexural strength of the ceramic composition may be 800 MPa to 1000 MPa.

The ceramic composition of the present invention is obtained _{by mixing zirconia (ZrO 2} ) and zirconium silicate (ZrSiO ₄ ) in the same ratio as above and sintering, so that a low-k single compound such as _{zirconium silicate (ZrSiO 4 ) is zirconia (ZrO 2} ) It should be located in the grain interior and grain boundary of Accordingly, it is possible to implement a ceramic composition having low dielectric properties and high strength properties.

Meanwhile, in the ceramic composition according to an embodiment of the present invention, the stabilized zirconia may include yttria (Yttria, Y ₂ O ₃ ) as a stabilizer. However, the stabilizer may be calcium oxide (CaO), magnesium oxide (MgO), or a rare earth oxide, but is not limited thereto.

The stabilized zirconia may contain from 2 to 5 mole percent (mol %) of a stabilizer. Preferably, the stabilized zirconia may contain 3 mole percent of a stabilizer.

If the content of yttria (Y ₂ O ₃ ) is less than 2 mole percent, zirconia (ZrO ₂ ) has a monoclinic crystalline phase, thereby reducing flexural strength.

Conversely, when the content of yttria (Y ₂ O ₃ ) exceeds 5 mol percent, densification during sintering is difficult due to the difficult-to-sinter property of _{yttria (Y 2} O _{3 ), thereby reducing the fracture toughness of the ceramic composition.} Reduce.

When yttria (Y ₂ O ₃ ) is added to zirconia (ZrO ₂ ), a stabilized zirconia crystal in which all particles are tetragonal can be obtained by sintering under a stable tetragonal phase. Such stabilized zirconia may have high strength properties of 1000 MPa or more.

When the zirconia (ZrO ₂ ) contains 3 mole percent of the stabilizer _{, the calcination temperature of the zirconia (ZrO 2} ) may be 1450° C. or less. The more a lot of stabilizers added to zirconia (ZrO ₂₎ is the sintering temperature of the zirconia (ZrO ₂₎ can be raised.

Meanwhile, the ceramic composition according to an embodiment of the present invention may further include _{aluminum oxide (Al 2} O ₃ ) in an amount of 0.5 to 2.5 weight percent based on the total weight of the ceramic composition.

Aluminum oxide has a dielectric constant of about 9.4. Therefore, when the aluminum oxide is in the range of 0.5 to 2.5 weight percent, the dielectric constant of the ceramic composition may be reduced. In addition, due to the addition of aluminum oxide, it is possible to further improve the strength of the ceramic composition.

Yttria-stabilized zirconia (YSZ) undergoes a phase transition from a tetragonal phase to a monoclinic phase when exposed for a long time in a temperature range of room temperature (25° C.) to 400° C. As a result, cracks occur, resulting in a low-temperature deterioration phenomenon in which properties such as strength and thermal shock resistance are deteriorated. When aluminum oxide is included in zirconia (ZrO ₂ ), such a low-temperature deterioration phenomenon and a decrease in strength can be prevented.

When the aluminum oxide is added to zirconia (ZrO _2), aluminum oxide and minimizes the defect size (flaw size), suppresses grain growth of zirconia (ZrO _2), zirconia-alumina composite is much higher strength than zirconia (ZrO ₂₎ can have

Strength of zirconia (ZrO ₂₎ is that it is inversely proportional to particle size, and the aluminum oxide added to zirconia (ZrO ₂₎ inhibit the sintering when zirconia (ZrO ₂₎ grain growth, increase the strength of the tetragonal zirconia (ZrO ₂₎ It works.

In addition, when aluminum oxide is added, there is an effect of improving the toughness of zirconia.

Meanwhile, in the ceramic composition according to an embodiment of the present invention, the zirconium silicate (ZrSiO ₄ ) may have an average particle size of 0.5 μm to 1 μm.

Zirconium silicate (ZrSiO ₄ ) may improve the mechanical properties of the ceramic composition by increasing the crack propagation path as the average particle size is small.

However, when the average particle size of zirconium silicate (ZrSiO ₄ ) is less than 0.5 μm, there is a problem in that a suitable composition cannot be obtained due to reduced sinterability during sintering.

Conversely, when the average particle size of zirconium silicate (ZrSiO ₄ ) exceeds 1 μm, there is a risk that the sintered body may be cracked due to volume expansion during sintering, and there is a problem in that the flexural strength of the composition is reduced.

On the other hand, in the ceramic composition according to an embodiment of the present invention, zirconium silicate (ZrSiO ₄ ) zirconia (ZrO ₂ ) and silica (SiO ₂ ) co-precipitation (Co-precipitation) or solid-phase reaction method (Solid-reaction) It can be obtained by synthesis.

In the case of using the solid-state reaction method, zirconia (ZrO _{2 ) powder, which is an oxide containing a zirconium (Zr) component, and silica (SiO 2} ) powder, which is an oxide containing a silicon (Si) component, are prepared as raw materials according to a molar ratio. The prepared raw material is put into a milling machine together with a ball and a solvent and mechanically mixed and pulverized to cause a solid-state reaction between the oxides. Thereafter, the pulverized product may be calcined _{to prepare a zirconium silicate (ZrSiO 4} ) powder.

_{A method of synthesizing zirconium silicate (ZrSiO 4} ) using a co-precipitation method is widely used in the related art, and a detailed description thereof will be omitted.

However, zirconium silicate (ZrSiO ₄ ) may also be obtained by a sol-gel method, a thermal spray method, or a spray pyrolysis method, but is not limited thereto.

_{2a to 2e are SEM images according to the mixing ratio of zirconia (ZrO 2} ) and zirconium silicate (ZrSiO ₄ ) in the ceramic composition according to an embodiment of the present invention, and FIG. 3 is the zirconium of FIGS. 2b to 2e. The XRD data plot according to the mixing ratio of silicate (ZrSiO _{4 ) is shown.}

Referring to the SEM images of FIGS. 2A to 2E , the ceramic composition of the present invention includes zirconia (A) and zirconium silicate (B). It can be seen that the zirconium silicate (B) is evenly distributed in the grain boundaries and in the grains of the zirconia (A).

Zirconium silicate (ZrSiO ₄ ) The melting point is about 2550 ℃. Since the heat treatment temperature for forming the ceramic composition in the present invention _{is a temperature lower than the melting point of zirconium silicate (ZrSiO 4} ) by a certain temperature or more, zirconium silicate (ZrSiO ₄ ) is zirconia (ZrO ₂ ) and silica (SiO ₂ ). Rather, it is mostly sintered by itself.

Therefore, as in the SEM image of FIGS. 2a to 2e, in the ceramic composition of the present invention, silica (SiO ₂ ) is hardly present, and only zirconia (ZrO ₂ ) and zirconium silicate (ZrSiO ₄ ) It can be confirmed that have.

The following Tables 2 to 5 show XRD data according to the mixing ratio _{of zirconium silicate (ZrSiO 4 ) of FIGS. 2b to 2e.} In the table, the unit of content ratio is weight percent.

- content ratio (ZrSiO ₄ : ZrO ₂ = 4 : 6)

Prize	structure	space group	Phase fraction (%)
ZrSiO 4	Tetragonal	I 41/a m d	41.4
ZrO 1.99	Tetragonal	P 42/n m c	56.9
SiO 2	Hexagonal	P 31 2 1	1.7

- content ratio (ZrSiO ₄ : ZrO ₂ = 6: 4)

Prize	structure	space group	Phase fraction (%)
ZrSiO 4	Tetragonal	I 41/a m d	65.9
ZrO 1.99	Tetragonal	P 42/n m c	34.1

- content ratio (ZrSiO ₄ : ZrO ₂ = 8: 2)

Prize	structure	space group	Phase fraction (%)
ZrSiO 4	Tetragonal	I 41/a m d	76.7
ZrO 2	Tetragonal	P 42/n m c	21.8
ZrO 2	monoclinic		P 1 21/c 1	1.5

- content ratio (ZrSiO ₄ : ZrO ₂ = 9: 1)

Prize	structure	space group	Phase fraction (%)
ZrSiO 4	Tetragonal	I 41/a m d	89.7
ZrO 2	Tetragonal	P 42/n m c	7.7
ZrO 2	monoclinic		P 1 21/c 1	2.5

Referring to Tables 2 to 5 together with FIG. 3 , in _{the ceramic composition including zirconia (ZrO 2} ) and zirconium silicate (ZrSiO ₄ ), zirconium silicate (ZrSiO ₄ ) All exist in a tetragonal phase.

On the other hand, zirconia (ZrO ₂ ) is present in a tetragonal phase when the content ratio of zirconium silicate (ZrSiO _{4 ) is less than 80 weight percent.} However, when the content ratio of zirconium silicate (ZrSiO ₄ ) is 80 weight percent or more, it can be confirmed that some are present in a monoclinic phase.

Table 6 below shows the results of measuring flexural strength, dielectric constant, and signal loss according to the composition ratio (weight percent, wt%) of the composition in which the stabilized zirconia is mixed with zirconium silicate (ZrSiO _{4 ).}

As the stabilized zirconia in Table 6, yttria-stabilized zirconia (3YSZ) containing _{3 mole percent of yttria (Y 2} O _{3 ) was used.}

division	ZrSiO 4	3YSZ	flexural strength	Signal loss (Db)	permittivity
Ref.	0	100	1280	-9.000	28.380
Low dielectric high strength ceramic	40	60	1000.8	-4.360	15.405
	60	40	802.8	-3.038	13.095
	80	20	703.6	-2.234	10.704
	90	10	650.9	-1.938	9.848

Referring to Table 6, in a ceramic composition comprising _{zirconia (ZrO 2} ) and zirconium silicate (ZrSiO _{4 ), the content ratio of zirconia (ZrO 2} ) is lowered and the content ratio of zirconium silicate (ZrSiO ₄ ) is increased, the bending The magnitude of the intensity decreases, the dielectric constant decreases, and the magnitude of the signal loss decreases.

In the table, when _{the content of zirconium silicate (ZrSiO 4} ) is 0 weight percent, the flexural strength of yttria-stabilized zirconia (3YSZ) is very good at 1280 MPa, but the dielectric constant is 28 or more, and the signal loss reaches -9 dB. Therefore, due to such a high dielectric characteristic, it cannot be used as a material for a rear cover for a mobile device or a component material for an exterior of an electronic device.

On the other hand, when _{the content of zirconium silicate (ZrSiO 4} ) is 90 weight percent, the dielectric constant is about 9.8 and the signal loss is about -1.9, so it has excellent properties. However, the flexural strength is about 650 MPa, and the strength characteristics are not suitable, so it cannot be used as a rear cover for mobile.

4 is a graph showing the flexural strength according to the mixing ratio _{of zirconium silicate (ZrSiO 4} ) of FIGS. 2a to 2e.

As shown in Table 2, with increasing the content ratio of zirconium silicate (ZrSiO _4), the flexural strength is reduced, When the content ratio of zirconium silicate (ZrSiO ₄₎ 80 percent by weight of the flexural strength is therefore fall below 700MPa , it is no longer possible to utilize the rear cover for mobile devices or parts and materials for the exterior of electronic devices.

5 is a graph showing the dielectric constant and signal loss according to the zirconium silicate (ZrSiO _{4 ) mixing ratio of FIGS. 2A to 2E .}

As shown in Table 2, with increasing the content ratio of zirconium silicate (ZrSiO _4), it reduced dielectric constant, and also, the smaller the signal loss, the dielectric constant When the content ratio is less than 40 percent by weight of zirconium silicate (ZrSiO ₄₎ 15 or more and the magnitude of the signal loss is greater than 4 dB, so it cannot be used as a material for a rear cover for a mobile device or a component material for an electronic device exterior.

Meanwhile, the ceramic composition according to an embodiment of the present invention may be processed to form a mobile rear cover, a side cover, or an exterior part. These mobile rear covers, side covers, or exterior parts have sufficient flexural strength and can minimize signal loss in high-frequency or ultra-high-frequency environments.

On the other hand, since the ceramic composition according to an embodiment of the present invention has excellent signal loss characteristics and thermal characteristics, it can be used in application fields such as ADAS substrate materials and various LTCC (Low Temperature Co-firing Ceramics) substrate materials. .

In the above, preferred embodiments of the present invention have been illustrated and described, but the present invention is not limited to the specific embodiments described above, and it is common in the technical field to which the present invention pertains without departing from the gist of the present invention as claimed in the claims. Various modifications may be made by those having the knowledge of, of course, and these modifications should not be individually understood from the technical spirit or perspective of the present invention.

Claims (9)

1. Stabilized Zirconia and

   Contains zirconium silicate (ZrSiO ₄ ),

   The stabilized zirconia is included in 20 to 60 weight percent (weight %),

   The low dielectric high strength ceramic composition, characterized in that the zirconium silicate is included in 40 to 80 weight percent (weight %).
2. According to claim 1,

   The low dielectric high strength ceramic composition, characterized in that the flexural strength of the low dielectric high strength ceramic composition is 700 MPa to 1000 MPa.
3. According to claim 1,

   The low dielectric high strength ceramic composition, characterized in that the dielectric constant of the low dielectric high strength ceramic composition is 10 to 15.
4. According to claim 1,

   The stabilized zirconia is

   A low dielectric high strength ceramic composition comprising 2 to 5 mole percent (mol %) of a stabilizer.
5. 5. The method of claim 4,

   The stabilizer is yttria (Yttria, Y ₂ O ₃ ) Low dielectric high strength ceramic composition, characterized in that
6. According to claim 1,

   Low dielectric high strength ceramic composition, characterized in that it further comprises 0.5 to 2.5 weight percent (weight %) of aluminum oxide (Al ₂ O _{3 ) relative to the total weight of the ceramic composition.}
7. According to claim 1,

   The zirconium silicate is

   A low dielectric high strength ceramic composition characterized in that zirconia and silica (SiO ₂ ) are synthesized by co-precipitation or solid-reaction.
8. According to claim 1,

   The zirconium silicate is

   A low-k, high-strength ceramic composition having an average particle size of 0.5 μm to 1 μm.
9. The rear cover for mobile formed by processing the ceramic composition of any one of claims 1 to 8.

Images