671 results about "Transparent ceramics" patented technology

A ceramic composite and method of making are provided. The ceramic composite may be transparent and may serve as transparent armor. The ceramic portion of the composite may be single crystal sapphire. The composite may provide adequate protection from projectiles while exhibiting large surface areas and relatively low areal densities.

A fully reflective and highly thermoconductive electronic module includes a metal bottom layer, a transparent ceramic layer and a patterned metal wiring layer. The metal bottom layer has a lower reflective surface. The transparent ceramic layer has an upper surface and a lower surface. The lower surface of the transparent ceramic layer is bonded to the lower reflective surface of the metal bottom layer. The metal wiring layer is bonded to the upper surface of the transparent ceramic layer. The lower reflective surface reflects a first light ray, transmitting through the transparent ceramic layer, to the upper surface of the transparent ceramic layer. A method of manufacturing the fully reflective and highly thermoconductive electronic module is also disclosed.

A reflector with high total reflection which is resistant to mechanical stresses. The reflector includes a reflector body and superimposed thereon (a) a functional coating such as a varnish, (b) a reflecting layer structure composed of a reflecting metallic layer and optionally arranged thereon one or several transparent ceramic layers, for example, layers having an optical depth of lambda/2. The reflecting layer structure contains, as its surface layer, a protective layer. The protective layer is a silicon oxide of general formula SiOx, wherein x is a number from 1.1 to 2.0, or it is aluminum oxide of formula Al2O3, in a thickness of 3 nm or more. The protective layer protects the underlying layers from mechanical damages. In the DIN 58196 abrasion test the protected surface does not show any damages after 50 test cycles with 100 abrasion strokes.

The invention provides a transparent fluorescent body, and particularly relates to a transparent ceramic fluorescent body, a transparent glass fluorescent body and a transparent composite fluorescent body, and a white-light LED (light-emitting diode) applying the three transparent fluorescent bodies. According to the technical scheme provided by the invention, fluorescent powder in the traditional white-light LED light source is replaced by the transparent fluorescent materials, so as to realize white-light LED; and because the transparent fluorescent bodies have the advantages of being high in thermal conductance, high in stability and high in crystallinity, avoiding the colour temperature drift of the white-light LED light source caused by a high temperature, improving the stability of the white-light LED light source and improving the lighting effect of the white-light LED light source.

The invention relates to a method for preparing Re:YAG polycrystalline transparent ceramic by using different molding modes, which adopts commercial high-purity Y2O3, Al2O3 and Re2O3 as raw materials, adopts MgO, CaO or TEOS (tetraethyl orthosilicate) as sintering additive, and prepares a raw blank by a cold isostatic pressing, slip casting or tape casting process to react and sinter the transparent polycrystalline Re:YAG ceramic. The method comprises the following steps: mixing and adding the oxides into a liquid medium; adding a certain amount of dispersant, adhesive, plasticizer, pressing agent and defoaming agent, carrying out ball milling, and mixing; treating the slurry under different conditions in different molding modes to obtain the raw blank; and sintering the degreased raw blank in a vacuum furnace. For the Re:YAG ceramic sintering body with thickness of 1.5mm, the transmission rate of straight light in the wavelength of 1064nm is not lower than 80% after the Re:YAG ceramic sintering body is subjected to double-sided polishing. For the raw blank which is prepared by different molding modes and is sintered for 10 hours at 1750 DEG C, sizes of ceramic grains are different, wherein regarding the raw blank prepared by cold isostatic pressing, the average grain of the ceramic is 13.5mu m; regarding the raw blank prepared by slip casting, the average grain of the ceramic is 3.5mu m; and regarding the raw blank prepared by tape casting, the average grain of the ceramic is 1.5mu m.

The transparent window is suitable for use in applications that require a host of very demanding performance criteria. In the window, a transparent polymer is chemically bonded to an adhesive at an interface between the two, which enables the window to resist delamination. The window also has a polymer or plastic strike face with a coating that enables it to endure rigorous field conditions and still pass critical rock strike tests. The window also has a bulk layer with at least one layer of a glass, glass-ceramic, or transparent ceramic material.

The invention discloses a preparation method of yttrium aluminium garnet doped transparent laser ceramics. The method includes using an alcohol-aqueous system stepping chemical co-precipitation method to firstly prepare high-dispersity and high-activity nanometer Y2O3 oxide powders, Al2O3 oxide powders and rare earth (Re) oxide powders, weighing raw materials of the powders according to a stoichiometric ratio of Y<3-x>RexAl5O12 when the powders are prepared, placing the powders, sintering aids, dispersing agents and absolute ethyl alcohol into a ball-milling tank for ball milling, drying ball-milling mixing slurries into powders, forming the powders into green bodies with certain shapes by dry pressing, and then subjecting the green bodies to isostatic cool pressing to obtain ceramic biscuits. The ceramic biscuits are subjected to binder removing, vacuum sintering, powder-burying hot-pressing post-processing, annealing and optical polishing to obtain Re:YAG transparent ceramics. The preparation method has the advantages of being controllable, high in repeatability, low in cost and high in transmittance.

A composite transparent ceramic used for white-light LED fluorescence conversion and a preparation method thereof are provided. The composite transparent ceramic is composed of an upper and a lower layer of transparent ceramic bonded; chemical composition of the upper layer of transparent ceramic is (PrxY1-x)3Al5O12, wherein 0.0003<=x<=0.06; and chemical composition of the lower layer of transparent ceramic is (CeyY1-y)3Al5O12, wherein 0.0003<=y<=0.06. When a blue-light LED excites the composite transparent ceramic, yellow light generated by the lower layer of transparent ceramic mixes with red light generated by the upper layer of transparent ceramic and blue light transmitted through the upper layer of transparent ceramic to form high-quality white light, to thereby obtain the characteristics of high color rendering index and mild color temperature. In addition, the inventive composite transparent ceramic has the advantages of high shine quenches temperature, stable physicochemical properties, low cost, etc.

The invention belongs to the field of ceramic material preparation, in particular relates to a sintering method of yttrium oxide base transparent ceramic. The method of the invention includes the following steps: mixed powder after cold isostatic pressing moulding is heated to 1200-1600 DEG C and then instantly cooled to 350-800 DEG C, heat preservation is carried out, and finally the mixed powder after heat preservation is sintered under vacuum for 2-10 hours. The sintering method of the invention utilizes special sintering performance of nano powder, firstly treatment at low temperature (about 40% of melting-point) is carried out, so that sample is densified (reaching about 90% of theoretical density) while grain growth is effectively controlled, and warming sintering is further carried out under vacuum to obtain micro crystal transparent ceramic. The sintering method of the invention can effectively control grain growth in sintering process and is benefit for air hole exhaust, and sintering sample has favourable transmission without annealing treatment. The sintering method of the invention also has the characteristics of lower cost and easy operation.

The invention relates to a method for preparing pure-phase gamma-AlON transparent ceramic powder by carbothermal reduction of gamma-Al2O3, and belongs to the field of preparation of transparent ceramic materials. According to the preparation method, nano-alpha-Al2O3 and activated carbon are taken as raw materials; powder is filled in a graphite crucible loosely, wherein an aluminum oxide plate is paved at the bottom of the graphite crucible; an air hole which penetrates through the powder is preformed at the aluminum oxide plate; a graphite cover provided with fine and dense air holes is used for covering the hole; the pure-phase gamma-AlON transparent ceramic powder is prepared by adopting a two-step heating process in a flowing nitrogen environment with a micro positive pressure. By the adoption of the preparation method, the vacuumizing difficulty can be effectively reduced, powder is prevented from scattering in a vacuumizing stage, the time required for discharging adsorbed gas can be greatly shortened, the vacuumizing speed is high, and the preparation efficiency of the gamma-AlON powder is greatly improved; the obtained gamma-AlON powder phase has stable and reliable compositions and can be used for pressure-less sintering preparation of AlON transparent ceramics with high transmittance; the process is simple and is easy to operate, and is suitable for industrial production.

A thin-film thermocouple (12) is disclosed for use with a gas turbine component. The thermocouple may be formed on a non-planar substrate (22) having formed thereon an electrically insulating layer (34) capable of maintaining its insulating properties at gas turbine operating temperatures. A first thermocouple leg (26) made of pure platinum is then deposited on the dielectric layer (34). A second thermocouple leg (28) made of another pure metal or a transparent ceramic oxide is also formed on the dielectric layer (34) wherein the first and second thermocouple legs make ohmic contact at a first end of each leg to form a hot junction (30) for conversion of heat into an electrical signal. The thermocouple may be deposited on a surface of a thermal barrier coating or between a thermal barrier coating and an underlying metal substrate.

The invention relates to a preparation method of transparent yttria ceramics with high optical quality, which belongs to the field of preparation of transparent ceramics. The preparation method comprises the following steps: adding anhydrous ethanol to the mixture of commercial high-purity Y2O3 powder serving as a raw material, ZrO2 serving as a sintering additive and zirconia balls serving as a grinding medium, and carrying out mixing and ball milling for 3-30 hours; adding a crylic acid salt dispersant in the powder to prepare water-based slurry of Y2O3, and adopting a porous resin mold or porous alumina ceramic mold to achieve slip casting; and finally, carrying out pressureless sintering in a vacuum or hydrogen atmosphere furnace to obtain the transparent yttria ceramics with high optical quality. The transmission rate of the Y2O3 transparent ceramics with thickness of 2mm is up to 81.3% at the wavelength of 1100nm. The invention has the advantages of simple process, low cost and no pollution, and is easy to control, and the transparent yttria ceramics with high optical quality can be prepared at lower sintering temperature in shorter holding time.

The invention discloses a method for preparing a white-light LED by YAG transparent ceramics. Firstly, a bare blue-light or ultraviolet-light LED chip is fixed in a support reflector by insulating glue; a YAG transparent ceramic layer is coated or enclosed on the light emitting path of the blue-light or ultraviolet-light chip after the electrode lead is welded by an ultrasonic ball-bonding machine; the wavelength of the blue-light LED chip drops within 450nm-480nm, and the wavelength of the ultraviolet LED drops within 250nm-540nm; the ceramic granules used by the YAG transparent ceramic layer drops within 1nm-300nm. The color coordinate of the emitted light can be changed by adjusting the thickness and the granule density of the ceramic layer. The invention can efficiently settle the problem of the attenuation of wavelength conversion material under high temperature; in addition, the invention can also effectively settle the problems of inconsistency of yellow diaphragm, blue-light diaphragm and white-light diaphragm, etc in the existing methods of white-light LED fabrication; the operation process is relatively simple, the reliability is high and the cost is low.