Application of Zirconia in Fingerprint Identification

Fingerprint recognition module is widely used in intelligent portable devices because of its fast, safe, convenient and other advantages. However, due to the small area of the fingerprint module and complex application environment, it requires high identification sensitivity and speed, which also puts forward very high requirements for fingerprint identification chips and surface protection materials.

At present, there are two commonly used fingerprint identification schemes: pressing on the front of sapphire cover and coating on the back.

iphone-6s-touch-id
iPhone-6S-Touch-ID

Cost and Performance

In terms of cost and performance, sapphire has high hardness and corrosion resistance, but it has some weaknesses such as high cost and weak anti-falling ability, while the coated back fingerprint recognition scheme has the disadvantages of easy wear and sweat corrosion due to the low hardness of the coating.

Operation

In terms of operation, the two schemes have their own merits. The back fingerprint identification is convenient only for holding the index finger of the hand, while other fingers are inconvenient, and it can’t be used on a plane, it has to be picked up, too, which is not convenient in some special application scenarios (such as driving). Meanwhile, the positive fingerprint is much smoother for the current hot fingerprint payment.

fingerprint-scanner

Appearance

In terms of appearance, the texture of backside fingerprint recognition is slightly poor, and it is easy to destroy the overall aesthetics of the backside while putting fingerprints on the front not only makes the back of the phone more beautiful but also more in line with users’ habits and aesthetics.

Overall, a positive fingerprint is more popular with users, but it costs more. Many years of research have proved that zirconia ceramic cover products can be used for positive pressure fingerprint identification scheme.

The ceramic cover is zirconia ceramic (ZrO2), also known as zirconium gem. It has superior hardness, toughness, insulation, heat conduction, and other advantages, showing abrasion resistance, fall resistance, corrosion resistance, high-temperature resistance and other excellent characteristics, which is very suitable for pressing fingerprint identification module cover.

Zirconia ceramic is a cost-effective alternative to sapphire, and the zirconia product has been used in many well-known brands of mobile phones, which has the following advantages.

Zirconia

High hardness

The hardness of zirconia ceramics is 8.5 and that of single crystal alumina (sapphire) is 9, so they are quite similar in wear and scratch resistance.

High permittivity

The permittivity of zirconia is 32-35, which is three times that of sapphire, while all other materials are within 10. This characteristic is beneficial to improve the capacitance difference between the high and low levels of fingerprint identification module, so that fingerprint identification is more sensitive, the success rate is higher, and the speed is faster.

Thin in thickness

At present, the thinnest mass production thickness is as low as 0.1mm under the protection of falling strength of zirconia protective layer, which is easier to identify than the thinnest sapphire cover with a thickness of 0.3mm. If the thickness is the same as that of sapphire, the strength and fall resistance of zirconia protective coating will be significantly better than that of sapphire.

Good processability

Zirconia ceramics are directly prepared by casting, polishing and other ceramic processes. Its process is simple and its shape is easy to process, so it costs less than sapphire.

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10 Applications of Zirconium You Should Know

Zirconium, chemical symbol Zr, atomic number 40, melting point 1852°C, is one of the high melting point metals. Zirconium with special excellent properties, such as the resistance from high temperature, oxidation, corrosion, and abrasion, all of which made it a wide range of application as the structured and functional ceramic material in many industrial sectors, especially in the high-tech industry.

Zirconium products and their applications

  1. Zirconium silicate

Zirconium silicate is an important kind of traditional zirconium products. Products can be prepared with zircon sand as raw material, after grinding, calcination, powder, is a kind of high quality and inexpensive ceramic glaze opacifying agent, mainly used in ceramics and porcelain, building ceramics color glaze production, has been widely used in high-grade refractory materials, precision casting, emulsified glass and other industries.

zirconium-silicate-powder

  1. Zirconium carbonate

Zirconium carbonate mainly used as cosmetic additives and waterproof agent, flame retardant, sunscreen, fiber and paper surface additives, and can be used for preparing zirconium cerium catalytic composite material, is an important raw material for textile, papermaking, paint, cosmetics industry, the amount of growth in recent years.

  1. Zirconium oxychloride

It can be used other zirconium products such as two – zirconium oxide, zirconium carbonate, zirconium sulfate, zirconium and hafnium compound preparation and separation of zirconium and hafnium metal material, can also be used for textile, leather, rubber additives, metal surface treatment agent, coating driers, refractories, ceramics, catalyst, fire retardant, and other products.

  1. Fused zirconia

Fused zirconia, mainly used in the production of glazes and refractories. Due to the high content of impurities in the fused zirconia, the use is limited.

  1. Zirconium sulfate

It is the important raw material in the production of leather tanning agent, wool processing agent and paint surface oxidation agent, can be used as a catalyst carrier, amino acid, and protein, precipitant, and deodorant, intermediate raw materials are for zirconium chemicals and metal zirconium and hafnium.

  1. Zirconium oxide

The white solid, non-toxic, tasteless, has enough stability of alkali solution and many acidic solutions, suitable for precision ceramics, electronic ceramics, optical lenses, glass additives, dissolving zirconia brick, ceramic pigment, glaze, artificial stone, refractory materials, grinding and polishing industry and products.

It is also known as semi-stable, stable zirconia is white powder non-toxic, tasteless, stable chemical properties, the specific surface area is controllable, manufacturing all kinds of special ceramics, advanced refractories, new energy materials, optical communication devices, based on raw materials.

  1. Zirconia structural ceramics

Using the composite zirconium oxide as the raw material, including two kinds of products such as zirconia grinding and zirconia structure, the structure of zirconia mainly includes the zirconia special ceramic valves, fiber optic connectors, ceramic knives, watches accessories, ceramic scissors, textile porcelain, etc.

Since Zirconium has very good chemical corrosion resistance, zirconium shapes, such as zirconium tubes and zirconium rods are used to make equipment for the chemical industry.

zirconium-tube

  1. Nuclear grade zirconium

It is an important strategic metal used primarily for nuclear-powered aircraft carriers, nuclear submarines, and civilian power reactors, as well as the cladding of uranium fuel elements.

  1. Industrial grade zirconium

It is mainly used for the production of industrial grade zirconium – chemical corrosion resistance equipment, military industry, electronic industry, pipeline valve materials, special high strength and high-temperature alloy materials, electric vacuum and lighting industry getter.

  1. Firearm zirconium

It is also used in the combustion of the flame zirconium sponge, and also can be used in alloy additives and metallurgical deoxidizer, chemical industry, civil flash fireworks and so on.

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