CO2 laser for dental alumina ceramic framework welding

Objective: Despite the increase of all-ceramic prosthesis in dental practice there is no evidence of the possibility of welding these structures if necessary. The objective of this study was to use CO2 laser (?=10.6µm) as a welding agent to fuse dental polycrystalline alumina ceramic. Methods: Ceramic blocks of pre-sintered alumina were sectioned into 20 bars (10.0 x 1.5 x 1.5mm) and sintered to the final cross?section dimension of 1.2 x 1.2mm. The bars were adapted to an LHPG (Laser Heated Pedestal Growth) system device where the bars could be fixed in pairs and have their ends irradiated with CO2 laser to fusion. The ring-shaped laser beam (300 µm thickness) was directed with the aid of mirrors to reach samples’ ends. The laser was continuously applied (40W nominal power, 5 seconds). After welding, the samples were analyzed in stereomicroscope and SEM. A diffraction analysis was carried out with one sample. Results: The ceramic bars were successfully fused, but some of them showed some shape distortion in the fusion zone. The aspect of the fused alumina differed in color and translucency from the original sintered material. SEM evidenced the presence of porosity and voids in the center of the fusion zone. X-ray diffraction pointed to a reduction in crystallite size by two to four times in the welded region of samples. Conclusions: This study points to CO2 laser as a possible welding agent to polycrystalline alumina dental ceramic. Porosity observed in the molten zone gives cause for concern regarding weld resistance.

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Zirconia Blocks Properties Used for CAD/CAM Dentistry Restorations

Materials Science Forum ◽

10.4028/www.scientific.net/msf.727-728.804 ◽

2012 ◽

Vol 727-728 ◽

pp. 804-808 ◽

Cited By ~ 1

Author(s):

C. Santos ◽

Carlos Nelson Elias ◽

Andréa Matos Melo ◽

Sérgio Neves Monteiro

Keyword(s):

Mechanical Properties ◽

Fracture Resistance ◽

X Ray Diffraction ◽

X Ray ◽

M 10 ◽

All Ceramic ◽

Cad Cam ◽

Ceramic Blocks ◽

Bending Fracture ◽

Cam Systems

Several CAD/CAM systems are available to dental prosthesis laboratories that can be used to make all-ceramic copings and frameworks. In Brazil, the use of these systems presents low demand, due principally the high blocks ceramics cost used for theses systems. The ceramic blocks are imported. To increase the dental ceramic CAD/CAM applications is necessary develop and produce the ceramics blocks in Brazil. The purpose of the present work is to compare the mechanical properties of blocks of zirconium developed in the Brazil (ProtMat® Co) and imported (VITA). It was determined the mechanical and physics properties of the two types of blocks of zirconium stabilized with ytria. The blocks have been sinterized at 1530 °C and their mechanical and physics properties were measured. The x-ray diffraction analysis showed only tetragonal phase, which improve the blocks toughness. The Vickers hardness and fracture toughness were 1300HV and 9 MPam1/2, respectively. High bending fracture resistance was obtained for both materials with average values of 910MPa. The Weibull modulus was m=10 for Brazilian and imported blocks. It was not observed an important difference among the microstructures and mechanical properties of the analyzed zirconium blocks.

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Fabrication and study the effect of the laser on the properties of the compound Tl2-xHgxBa2-ySryCa2Cu3O10+δ superconductor

Ibn AL- Haitham Journal For Pure and Applied Science ◽

10.30526/2017.ihsciconf.1789 ◽

2018 ◽

pp. 168

Author(s):

A. Kareem Dahash Ali ◽

Nihad Ali Shafeek

Keyword(s):

Transition Temperature ◽

Solid State ◽

Hydrostatic Pressure ◽

Electrical Properties ◽

Co2 Laser ◽

Temperature Shift ◽

Unit Cell ◽

X Ray Diffraction ◽

X Ray ◽

Structural And Electrical Properties

This study included the fabrication of compound (Tl2-xHgxBa2-ySryCa2Cu3O10+δ) in a manner solid state and under hydrostatic pressure ( 8 ton/cm2) and temperature annealing(850°C), and determine the effect of the laser on the structural and electrical properties elements in the compound, and various concentrations of x where (x= 0.1,0.2,0.3 ). Observed by testing the XRD The best ratio of compensation for x is 0.2 as the value of a = b = 5.3899 (A °), c = 36.21 (A °) show that the installation of four-wheel-based type and that the best temperature shift is TC= 142 K .When you shine a CO2 laser on the models in order to recognize the effect of the laser on these models showed the study of X-ray diffraction of these samples when preparing models with different concentrations of the values of x, the best ratio of compensation is 0.2 which showed an increase in the values of the dimensions of the unit cell a=b = 5.3929 (A °), c = 36.238 (A°). And the best transition temperature after shedding laser is TC=144 K.

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In situ synchrotron X-ray diffraction with laser-heated diamond anvil cells study of Pt up to 95 GPa and 3150 K

RSC Advances ◽

10.1039/c4ra12769b ◽

2015 ◽

Vol 5 (19) ◽

pp. 14603-14609 ◽

Cited By ~ 2

Author(s):

Xiaoli Huang ◽

Fangfei Li ◽

Qiang Zhou ◽

Gang Wu ◽

Yanping Huang ◽

...

Keyword(s):

X Ray Diffraction ◽

Diamond Anvil Cells ◽

X Ray ◽

Diamond Anvil ◽

Laser Heated

In situ synchrotron X-ray diffraction with laser-heated diamond anvil cells study the EOS of Pt.

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Effect of La doping on microwave dielectric properties of translucent polycrystalline alumina ceramic

Ceramics International ◽

10.1016/j.ceramint.2012.11.084 ◽

2013 ◽

Vol 39 (5) ◽

pp. 4907-4911 ◽

Cited By ~ 11

Author(s):

Huijun Wang ◽

Huixing Lin ◽

Wei Li ◽

Jianlin Shi

Keyword(s):

Dielectric Properties ◽

Microwave Dielectric Properties ◽

Alumina Ceramic ◽

Polycrystalline Alumina ◽

La Doping ◽

Microwave Dielectric

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A Ceramic Diffusion Bonding Method for Passive LC High-Temperature Pressure Sensor

Sensors ◽

10.3390/s18082676 ◽

2018 ◽

Vol 18 (8) ◽

pp. 2676

Author(s):

Chen Li ◽

Boshan Sun ◽

Yanan Xue ◽

Jijun Xiong

Keyword(s):

High Temperature ◽

Pressure Sensor ◽

Pressure Sensors ◽

Alumina Ceramic ◽

Harsh Environments ◽

Ceramic Substrates ◽

Integrated Technology ◽

All Ceramic ◽

Test Platform ◽

Bonding Method

Alumina ceramic is a highly promising material for fabricating high-temperature pressure sensors. In this paper, a direct bonding method for fabricating a sensitive cavity with alumina ceramic is presented. Alumina ceramic substrates were bonded together to form a sensitive cavity for high-temperature pressure environments. The device can sense pressure parameters at high temperatures. To verify the sensitivity performance of the fabrication method in high-temperature environments, an inductor and capacitor were integrated on the ceramic substrate with the fabricated sensitive cavity to form a wireless passive LC pressure sensor with thick-film integrated technology. Finally, the fabricated sensor was tested using a system test platform. The experimental results show that the sensor can realize pressure measurements above 900 °C, confirming that the fabricated sensitive cavity has excellent sealing properties. Therefore, the direct bonding method can potentially be used for developing all-ceramic high-temperature pressure sensors for application in harsh environments.

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Construction of laser-heated diamond anvil cell system for in situ x-ray diffraction study at SPring-8

Review of Scientific Instruments ◽

10.1063/1.1343869 ◽

2001 ◽

Vol 72 (2) ◽

pp. 1289 ◽

Cited By ~ 68

Author(s):

Tetsu Watanuki ◽

Osamu Shimomura ◽

Takehiko Yagi ◽

Tadashi Kondo ◽

Maiko Isshiki

Keyword(s):

Diffraction Study ◽

Diamond Anvil Cell ◽

Cell System ◽

X Ray Diffraction ◽

X Ray ◽

Diamond Anvil ◽

Laser Heated

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Performance of Precursor Materials and Fired Ceramics for Structural Blocks

Materials Science Forum ◽

10.4028/www.scientific.net/msf.820.13 ◽

2015 ◽

Vol 820 ◽

pp. 13-17

Author(s):

Neila Gondim Azeredo ◽

Euzébio Barnabé Zanelato ◽

Jonas Alexandre ◽

Afonso Rangel Garcez de Azevedo ◽

Gustavo de Castro Xavier ◽

...

Keyword(s):

Building Construction ◽

Structural Ceramic ◽

X Ray Diffraction ◽

Mineralogical Characterization ◽

X Ray ◽

Physical Chemical ◽

Ceramic Blocks ◽

Clay Body ◽

Structural Blocks

The physical, chemical and mineralogical characterization of a precursor clay body before firing is of relevance for understanding the technological performance of the fired clay ceramic. In particular, structural clay ceramic blocks used in building construction need to attend standard properties specified by the norms. In the present work the precursor clay body, typically used to fabricate structural blocks in Campos dos Goytacazes, state of Rio de Janeiro, Brazil, was characterized in terms of particle size distribution, X-ray diffraction, chemical composition and Atterberg limits. In addition, the performance of structural ceramic blocks, fabricated from the extruded clay body and fired at 850oC, was evaluated. The results indicated that the ceramic mechanical strength complies with the Brazilian norm but the water absorption is higher than the maximum specified by the norm. The characteristic of the clay body contribute to justify the structural blocks performance.

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